[client] Unify peer and route ACL filtering with multi-source rules (#6322)

* Unify peer and route ACL filtering with multi-source peer rules

* Remove partial userspace firewall mode and open foreign chains via a table-less allower

* Snapshot iptables rule maps before persisting state

* Scope userspace firewall wildcard source rules per address family

* Install nftables peer filter and mangle rules in a single transaction

* Share the iptables jump rule spec between install and cleanup

* Fix legacy ACL source wildcard and keep rollback tracking on delete failure

* Fix CI: recognize multi-value port set lookups in tests and correct PeerIP lint suppression

* Fall back to per-prefix filter rules when ipset is unavailable

* Annotate legacy PeerIP usages in ACL tests and fix import formatting

* Keep firewall rule bookkeeping in step with the kernel on replace and teardown

* Release the routing reference when the route manager shuts down

* Keep set references and rule tracking consistent when a routing rule fails

client/firewall/allower_other.go

@@ -0,0 +1,11 @@
+//go:build android || (!linux && !windows)
+
+package firewall
+
+import "github.com/netbirdio/netbird/client/firewall/uspfilter"
+
+// interfaceAllower returns no allower: these platforms have no host firewall to
+// open for the interface.
+func interfaceAllower(IFaceMapper, uint16) uspfilter.InterfaceAllower {
+	return nil
+}

client/firewall/allower_windows.go

@@ -0,0 +1,10 @@
+//go:build windows
+
+package firewall
+
+import "github.com/netbirdio/netbird/client/firewall/uspfilter"
+
+// interfaceAllower returns the Windows netsh-based interface allower.
+func interfaceAllower(iface IFaceMapper, _ uint16) uspfilter.InterfaceAllower {
+	return uspfilter.NewWindowsInterfaceAllower(iface)
+}

client/firewall/create.go

@@ -6,8 +6,6 @@ import (
 	"fmt"
 	"runtime"
 
-	log "github.com/sirupsen/logrus"
-
 	firewall "github.com/netbirdio/netbird/client/firewall/manager"
 	"github.com/netbirdio/netbird/client/firewall/uspfilter"
 	nftypes "github.com/netbirdio/netbird/client/internal/netflow/types"
@@ -21,13 +19,11 @@ func NewFirewall(iface IFaceMapper, _ *statemanager.Manager, flowLogger nftypes.
 	}
 
 	// use userspace packet filtering firewall
-	fm, err := uspfilter.Create(iface, disableServerRoutes, flowLogger, mtu)
+	return uspfilter.Create(uspfilter.Config{
-	if err != nil {
+		IFace:               iface,
-		return nil, err
+		DisableServerRoutes: disableServerRoutes,
-	}
+		FlowLogger:          flowLogger,
-	err = fm.AllowNetbird()
+		MTU:                 mtu,
-	if err != nil {
+		InterfaceAllower:    interfaceAllower(iface, mtu),
-		log.Warnf("failed to allow netbird interface traffic: %v", err)
+	})
-	}
-	return fm, nil
 }

client/firewall/create_linux.go

@@ -16,6 +16,7 @@ import (
 	firewall "github.com/netbirdio/netbird/client/firewall/manager"
 	nbnftables "github.com/netbirdio/netbird/client/firewall/nftables"
 	"github.com/netbirdio/netbird/client/firewall/uspfilter"
+	"github.com/netbirdio/netbird/client/iface/netstack"
 	nftypes "github.com/netbirdio/netbird/client/internal/netflow/types"
 	"github.com/netbirdio/netbird/client/internal/statemanager"
 )
@@ -29,47 +30,107 @@ const (
 	NFTABLES
 )
 
-// SKIP_NFTABLES_ENV is the environment variable to skip nftables check
+// SkipNftablesEnv is the environment variable to skip nftables check
-const SKIP_NFTABLES_ENV = "NB_SKIP_NFTABLES_CHECK"
+const SkipNftablesEnv = "NB_SKIP_NFTABLES_CHECK"
+
+// errNoFirewallManager indicates no kernel firewall backend is present,
+// as opposed to a backend that exists but failed to create or initialize.
+var errNoFirewallManager = errors.New("no firewall manager found")
 
 // FWType is the type for the firewall type
 type FWType int
 
 func NewFirewall(iface IFaceMapper, stateManager *statemanager.Manager, flowLogger nftypes.FlowLogger, disableServerRoutes bool, mtu uint16) (firewall.Manager, error) {
-	// We run in userspace mode and force userspace firewall was requested. We don't attempt native firewall.
+	// Userspace firewall without a native counterpart: routing is handled
-	if iface.IsUserspaceBind() && forceUserspaceFirewall() {
+	// entirely in userspace. The interface is opened in the kernel's foreign
-		log.Info("forcing userspace firewall")
+	// filter chains via a table-less allower, except in netstack mode where no
-		return createUserspaceFirewall(iface, nil, disableServerRoutes, flowLogger, mtu)
+	// kernel interface exists.
+	if netstack.IsEnabled() || (iface.IsUserspaceBind() && forceUserspaceFirewall()) {
+		if netstack.IsEnabled() {
+			log.Info("netstack mode, using userspace firewall")
+		} else {
+			log.Info("forcing userspace firewall")
+		}
+		cfg := uspfilter.Config{
+			IFace:               iface,
+			DisableServerRoutes: disableServerRoutes,
+			FlowLogger:          flowLogger,
+			MTU:                 mtu,
+			InterfaceAllower:    interfaceAllower(iface, mtu),
+		}
+
+		return uspfilter.Create(cfg)
 	}
 
 	// Use native firewall for either kernel or userspace, the interface appears identical to netfilter
-	fm, err := createNativeFirewall(iface, stateManager, disableServerRoutes, mtu)
+	fm, err := createNativeFirewall(iface, stateManager, mtu)
-
+	switch {
-	// Kernel cannot fall back to anything else, need to return error
+	case err == nil && !iface.IsUserspaceBind():
-	if !iface.IsUserspaceBind() {
+		// Nothing to do, fall through
-		return fm, err
+	case err == nil && iface.IsUserspaceBind():
-	}
+		// Native firewall handles packet filtering, but the userspace WireGuard bind
-
+		// needs a device filter for DNS interception hooks. Install a minimal
-	// Fall back to the userspace packet filter if native is unavailable
+		// hooks-only filter that passes all traffic through to the kernel firewall.
-	if err != nil {
+		if err := iface.SetFilter(&uspfilter.HooksFilter{}); err != nil {
-		log.Warnf("failed to create native firewall: %v. Proceeding with userspace", err)
+			log.Warnf("failed to set hooks filter, DNS via memory hooks will not work: %v", err)
-		return createUserspaceFirewall(iface, nil, disableServerRoutes, flowLogger, mtu)
+		}
-	}
+	case err != nil && !iface.IsUserspaceBind():
-
+		// Kernel cannot fall back to anything else, need to return error
-	// Native firewall handles packet filtering, but the userspace WireGuard bind
+		return nil, err
-	// needs a device filter for DNS interception hooks. Install a minimal
+	case err != nil && iface.IsUserspaceBind():
-	// hooks-only filter that passes all traffic through to the kernel firewall.
+		// Fall back to the userspace packet filter if native is unavailable
-	if err := iface.SetFilter(&uspfilter.HooksFilter{}); err != nil {
+		logNativeFirewallUnavailable(err)
-		log.Warnf("failed to set hooks filter, DNS via memory hooks will not work: %v", err)
+		return uspfilter.Create(uspfilter.Config{
+			IFace:               iface,
+			DisableServerRoutes: disableServerRoutes,
+			FlowLogger:          flowLogger,
+			MTU:                 mtu,
+			InterfaceAllower:    interfaceAllower(iface, mtu),
+		})
 	}
 
 	return fm, nil
 }
 
-func createNativeFirewall(iface IFaceMapper, stateManager *statemanager.Manager, routes bool, mtu uint16) (firewall.Manager, error) {
+// interfaceAllower selects how the userspace firewall opens the interface in
+// foreign kernel chains: nftables when available (which also opens foreign nft
+// tables), else iptables (the legacy fallback, filter INPUT only), else nil.
+// firewalld trust is applied separately by the manager. Netstack has no kernel
+// interface to open.
+func interfaceAllower(iface IFaceMapper, mtu uint16) uspfilter.InterfaceAllower {
+	if netstack.IsEnabled() {
+		return nil
+	}
+
+	nftAllower, err := nbnftables.NewInterfaceAllower(iface, mtu)
+	if err == nil {
+		return nftAllower
+	}
+	log.Infof("no nftables interface allower: %v", err)
+
+	iptAllower, err := nbiptables.NewInterfaceAllower(iface)
+	if err == nil {
+		return iptAllower
+	}
+	log.Infof("no iptables interface allower: %v", err)
+
+	return nil
+}
+
+// logNativeFirewallUnavailable logs the fallback to userspace at info level
+// when no kernel firewall backend exists, and at warn level otherwise.
+func logNativeFirewallUnavailable(err error) {
+	if errors.Is(err, errNoFirewallManager) {
+		log.Infof("no native firewall backend available: %v. Proceeding with userspace", err)
+	} else {
+		log.Warnf("failed to create native firewall: %v. Proceeding with userspace", err)
+	}
+}
+
+func createNativeFirewall(iface IFaceMapper, stateManager *statemanager.Manager, mtu uint16) (firewall.Manager, error) {
 	fm, err := createFW(iface, mtu)
 	if err != nil {
-		return nil, fmt.Errorf("create firewall: %s", err)
+		return nil, fmt.Errorf("create firewall: %w", err)
 	}
 
 	if err = fm.Init(stateManager); err != nil {
@@ -88,29 +149,10 @@ func createFW(iface IFaceMapper, mtu uint16) (firewall.Manager, error) {
 		log.Info("creating an nftables firewall manager")
 		return nbnftables.Create(iface, mtu)
 	default:
-		log.Info("no firewall manager found, trying to use userspace packet filtering firewall")
+		return nil, errNoFirewallManager
-		return nil, errors.New("no firewall manager found")
 	}
 }
 
-func createUserspaceFirewall(iface IFaceMapper, fm firewall.Manager, disableServerRoutes bool, flowLogger nftypes.FlowLogger, mtu uint16) (firewall.Manager, error) {
-	var errUsp error
-	if fm != nil {
-		fm, errUsp = uspfilter.CreateWithNativeFirewall(iface, fm, disableServerRoutes, flowLogger, mtu)
-	} else {
-		fm, errUsp = uspfilter.Create(iface, disableServerRoutes, flowLogger, mtu)
-	}
-
-	if errUsp != nil {
-		return nil, fmt.Errorf("create userspace firewall: %s", errUsp)
-	}
-
-	if err := fm.AllowNetbird(); err != nil {
-		log.Errorf("failed to allow netbird interface traffic: %v", err)
-	}
-	return fm, nil
-}
-
 // check returns the firewall type based on common lib checks. It returns UNKNOWN if no firewall is found.
 func check() FWType {
 	useIPTABLES := false
@@ -132,35 +174,38 @@ func check() FWType {
 		}
 	}
 
-	nf := nftables.Conn{}
+	// Honor the skip env before probing nftables at all.
-	if chains, err := nf.ListChains(); err == nil && os.Getenv(SKIP_NFTABLES_ENV) != "true" {
+	if os.Getenv(SkipNftablesEnv) != "true" {
-		if !useIPTABLES {
+		nf := nftables.Conn{}
-			return NFTABLES
+		if chains, err := nf.ListChains(); err == nil {
-		}
+			if !useIPTABLES {
-
-		// search for chains where table is filter
-		// if we find one, we assume that nftables manager can be used with iptables
-		for _, chain := range chains {
-			if chain.Table.Name == "filter" {
 				return NFTABLES
 			}
-		}
 
-		// check tables for the following constraints:
+			// search for chains where table is filter
-		// 1. there is no chain in nftables for the filter table and there is at least one chain in iptables, we assume that nftables manager can not be used
+			// if we find one, we assume that nftables manager can be used with iptables
-		// 2. there is no tables or more than one table, we assume that nftables manager can be used
+			for _, chain := range chains {
-		// 3. there is only one table and its name is filter, we assume that nftables manager can not be used, since there was no chain in it
+				if chain.Table.Name == "filter" {
-		// 4. if we find an error we log and continue with iptables check
+					return NFTABLES
-		nbTablesList, err := nf.ListTables()
+				}
-		switch {
+			}
-		case err == nil && len(iptablesChains) > 0:
+
-			return IPTABLES
+			// check tables for the following constraints:
-		case err == nil && len(nbTablesList) != 1:
+			// 1. there is no chain in nftables for the filter table and there is at least one chain in iptables, we assume that nftables manager can not be used
-			return NFTABLES
+			// 2. there is no tables or more than one table, we assume that nftables manager can be used
-		case err == nil && len(nbTablesList) == 1 && nbTablesList[0].Name == "filter":
+			// 3. there is only one table and its name is filter, we assume that nftables manager can not be used, since there was no chain in it
-			return IPTABLES
+			// 4. if we find an error we log and continue with iptables check
-		case err != nil:
+			nbTablesList, err := nf.ListTables()
-			log.Errorf("failed to list nftables tables on fw manager discovery: %s", err)
+			switch {
+			case err == nil && len(iptablesChains) > 0:
+				return IPTABLES
+			case err == nil && len(nbTablesList) != 1:
+				return NFTABLES
+			case err == nil && len(nbTablesList) == 1 && nbTablesList[0].Name == "filter":
+				return IPTABLES
+			case err != nil:
+				log.Errorf("failed to list nftables tables on fw manager discovery: %s", err)
+			}
 		}
 	}
 
@@ -176,15 +221,21 @@ func isIptablesClientAvailable(client *iptables.IPTables) bool {
 	return err == nil
 }
 
+// forceUserspaceFirewall reports whether the userspace firewall is forced.
+// NB_FORCE_USERSPACE_ROUTER is an alias: forcing userspace routing implies the
+// userspace firewall, since the two are no longer separable.
 func forceUserspaceFirewall() bool {
-	val := os.Getenv(EnvForceUserspaceFirewall)
+	return envForceBool(EnvForceUserspaceFirewall) || envForceBool(uspfilter.EnvForceUserspaceRouter)
+}
+
+func envForceBool(name string) bool {
+	val := os.Getenv(name)
 	if val == "" {
 		return false
 	}
-
 	force, err := strconv.ParseBool(val)
 	if err != nil {
-		log.Warnf("failed to parse %s: %v", EnvForceUserspaceFirewall, err)
+		log.Warnf("failed to parse %s: %v", name, err)
 		return false
 	}
 	return force

client/firewall/iptables/acl_linux.go

@@ -1,603 +0,0 @@
-package iptables
-
-import (
-	"errors"
-	"fmt"
-	"maps"
-	"net"
-	"slices"
-
-	"github.com/coreos/go-iptables/iptables"
-	"github.com/google/uuid"
-	ipset "github.com/lrh3321/ipset-go"
-	log "github.com/sirupsen/logrus"
-
-	firewall "github.com/netbirdio/netbird/client/firewall/manager"
-	"github.com/netbirdio/netbird/client/internal/statemanager"
-	nbnet "github.com/netbirdio/netbird/client/net"
-)
-
-const (
-	tableName = "filter"
-
-	// rules chains contains the effective ACL rules
-	chainNameInputRules = "NETBIRD-ACL-INPUT"
-
-	// mangleFwdKey is the entries map key for mangle FORWARD guard rules that prevent
-	// external DNAT from bypassing ACL rules.
-	mangleFwdKey = "MANGLE-FORWARD"
-)
-
-type aclEntries map[string][][]string
-
-type entry struct {
-	spec     []string
-	position int
-}
-
-type aclManager struct {
-	iptablesClient  *iptables.IPTables
-	wgIface         iFaceMapper
-	entries         aclEntries
-	optionalEntries map[string][]entry
-	ipsetStore      *ipsetStore
-	v6              bool
-	ipsetSupported  bool
-
-	stateManager *statemanager.Manager
-}
-
-func newAclManager(iptablesClient *iptables.IPTables, wgIface iFaceMapper) (*aclManager, error) {
-	return &aclManager{
-		iptablesClient:  iptablesClient,
-		wgIface:         wgIface,
-		entries:         make(map[string][][]string),
-		optionalEntries: make(map[string][]entry),
-		ipsetStore:      newIpsetStore(),
-		v6:              iptablesClient.Proto() == iptables.ProtocolIPv6,
-	}, nil
-}
-
-func (m *aclManager) init(stateManager *statemanager.Manager) error {
-	m.stateManager = stateManager
-
-	m.ipsetSupported = m.probeIPSetSupport()
-
-	m.seedInitialEntries()
-	m.seedInitialOptionalEntries()
-
-	if err := m.cleanChains(); err != nil {
-		return fmt.Errorf("clean chains: %w", err)
-	}
-
-	if err := m.createDefaultChains(); err != nil {
-		return fmt.Errorf("create default chains: %w", err)
-	}
-
-	m.updateState()
-
-	return nil
-}
-
-func (m *aclManager) AddPeerFiltering(
-	id []byte,
-	ip net.IP,
-	protocol firewall.Protocol,
-	sPort *firewall.Port,
-	dPort *firewall.Port,
-	action firewall.Action,
-	ipsetName string,
-) ([]firewall.Rule, error) {
-	chain := chainNameInputRules
-
-	ipsetName = transformIPsetName(ipsetName, sPort, dPort, action)
-	if m.v6 && ipsetName != "" {
-		ipsetName += "-v6"
-	}
-	// When the kernel lacks the required ipset hash module, fall back to
-	// per-IP iptables rules (pre-0.68 behavior) so ACLs keep working instead
-	// of silently leaving the chain empty.
-	if ipsetName != "" && !m.ipsetSupported {
-		ipsetName = ""
-	}
-	proto := protoForFamily(protocol, m.v6)
-	specs := filterRuleSpecs(ip, proto, sPort, dPort, action, ipsetName)
-
-	mangleSpecs := slices.Clone(specs)
-	mangleSpecs = append(mangleSpecs,
-		"-i", m.wgIface.Name(),
-		"-m", "addrtype", "--dst-type", "LOCAL",
-		"-j", "MARK", "--set-xmark", fmt.Sprintf("%#x", nbnet.PreroutingFwmarkRedirected),
-	)
-
-	specs = append(specs, "-j", actionToStr(action))
-	if ipsetName != "" {
-		if ipList, ipsetExists := m.ipsetStore.ipset(ipsetName); ipsetExists {
-			if err := m.addToIPSet(ipsetName, ip); err != nil {
-				return nil, fmt.Errorf("add IP to ipset: %w", err)
-			}
-			// if ruleset already exists it means we already have the firewall rule
-			// so we need to update IPs in the ruleset and return new fw.Rule object for ACL manager.
-			ipList.addIP(ip.String())
-			return []firewall.Rule{&Rule{
-				ruleID:    uuid.New().String(),
-				ipsetName: ipsetName,
-				ip:        ip.String(),
-				chain:     chain,
-				specs:     specs,
-				v6:        m.v6,
-			}}, nil
-		}
-
-		if err := m.flushIPSet(ipsetName); err != nil {
-			if errors.Is(err, ipset.ErrSetNotExist) {
-				log.Debugf("flush ipset %s before use: %v", ipsetName, err)
-			} else {
-				log.Errorf("flush ipset %s before use: %v", ipsetName, err)
-			}
-		}
-		if err := m.createIPSet(ipsetName); err != nil {
-			return nil, fmt.Errorf("create ipset: %w", err)
-		}
-		if err := m.addToIPSet(ipsetName, ip); err != nil {
-			return nil, fmt.Errorf("add IP to ipset: %w", err)
-		}
-
-		ipList := newIpList(ip.String())
-		m.ipsetStore.addIpList(ipsetName, ipList)
-	}
-
-	ok, err := m.iptablesClient.Exists(tableFilter, chain, specs...)
-	if err != nil {
-		return nil, fmt.Errorf("failed to check rule: %w", err)
-	}
-	if ok {
-		return nil, fmt.Errorf("rule already exists")
-	}
-
-	// Insert DROP rules at the beginning, append ACCEPT rules at the end
-	if action == firewall.ActionDrop {
-		// Insert at the beginning of the chain (position 1)
-		err = m.iptablesClient.Insert(tableFilter, chain, 1, specs...)
-	} else {
-		err = m.iptablesClient.Append(tableFilter, chain, specs...)
-	}
-	if err != nil {
-		return nil, err
-	}
-
-	if err := m.iptablesClient.Append(tableMangle, chainRTPRE, mangleSpecs...); err != nil {
-		log.Errorf("failed to add mangle rule: %v", err)
-		mangleSpecs = nil
-	}
-
-	rule := &Rule{
-		ruleID:      uuid.New().String(),
-		specs:       specs,
-		mangleSpecs: mangleSpecs,
-		ipsetName:   ipsetName,
-		ip:          ip.String(),
-		chain:       chain,
-		v6:          m.v6,
-	}
-
-	m.updateState()
-
-	return []firewall.Rule{rule}, nil
-}
-
-// DeletePeerRule from the firewall by rule definition
-func (m *aclManager) DeletePeerRule(rule firewall.Rule) error {
-	r, ok := rule.(*Rule)
-	if !ok {
-		return fmt.Errorf("invalid rule type")
-	}
-
-	shouldDestroyIpset := false
-	if ipsetList, ok := m.ipsetStore.ipset(r.ipsetName); ok {
-		// delete IP from ruleset IPs list and ipset
-		if _, ok := ipsetList.ips[r.ip]; ok {
-			ip := net.ParseIP(r.ip)
-			if ip == nil {
-				return fmt.Errorf("parse IP %s", r.ip)
-			}
-			if err := m.delFromIPSet(r.ipsetName, ip); err != nil {
-				return fmt.Errorf("delete ip from ipset: %w", err)
-			}
-			delete(ipsetList.ips, r.ip)
-		}
-
-		// if after delete, set still contains other IPs,
-		// no need to delete firewall rule and we should exit here
-		if len(ipsetList.ips) != 0 {
-			return nil
-		}
-
-		// we delete last IP from the set, that means we need to delete
-		// set itself and associated firewall rule too
-		m.ipsetStore.deleteIpset(r.ipsetName)
-		shouldDestroyIpset = true
-	}
-
-	if err := m.iptablesClient.Delete(tableName, r.chain, r.specs...); err != nil {
-		return fmt.Errorf("failed to delete rule: %s, %v: %w", r.chain, r.specs, err)
-	}
-
-	if r.mangleSpecs != nil {
-		if err := m.iptablesClient.Delete(tableMangle, chainRTPRE, r.mangleSpecs...); err != nil {
-			log.Errorf("failed to delete mangle rule: %v", err)
-		}
-	}
-
-	if shouldDestroyIpset {
-		if err := m.destroyIPSet(r.ipsetName); err != nil {
-			if errors.Is(err, ipset.ErrBusy) || errors.Is(err, ipset.ErrSetNotExist) {
-				log.Debugf("destroy empty ipset: %v", err)
-			} else {
-				log.Errorf("destroy empty ipset: %v", err)
-			}
-		}
-	}
-
-	m.updateState()
-
-	return nil
-}
-
-func (m *aclManager) Reset() error {
-	if err := m.cleanChains(); err != nil {
-		return fmt.Errorf("clean chains: %w", err)
-	}
-
-	m.updateState()
-
-	return nil
-}
-
-// todo write less destructive cleanup mechanism
-func (m *aclManager) cleanChains() error {
-	ok, err := m.iptablesClient.ChainExists(tableName, chainNameInputRules)
-	if err != nil {
-		log.Debugf("failed to list chains: %s", err)
-		return err
-	}
-	if ok {
-		for _, rule := range m.entries["INPUT"] {
-			err := m.iptablesClient.DeleteIfExists(tableName, "INPUT", rule...)
-			if err != nil {
-				log.Errorf("failed to delete rule: %v, %s", rule, err)
-			}
-		}
-
-		for _, rule := range m.entries["FORWARD"] {
-			err := m.iptablesClient.DeleteIfExists(tableName, "FORWARD", rule...)
-			if err != nil {
-				log.Errorf("failed to delete rule: %v, %s", rule, err)
-			}
-		}
-
-		err = m.iptablesClient.ClearAndDeleteChain(tableName, chainNameInputRules)
-		if err != nil {
-			log.Debugf("failed to clear and delete %s chain: %s", chainNameInputRules, err)
-			return err
-		}
-	}
-
-	ok, err = m.iptablesClient.ChainExists("mangle", "PREROUTING")
-	if err != nil {
-		return fmt.Errorf("list chains: %w", err)
-	}
-	if ok {
-		for _, rule := range m.entries["PREROUTING"] {
-			err := m.iptablesClient.DeleteIfExists("mangle", "PREROUTING", rule...)
-			if err != nil {
-				log.Errorf("failed to delete rule: %v, %s", rule, err)
-			}
-		}
-	}
-
-	for _, rule := range m.entries[mangleFwdKey] {
-		if err := m.iptablesClient.DeleteIfExists(tableMangle, chainFORWARD, rule...); err != nil {
-			log.Errorf("failed to delete mangle FORWARD guard rule: %v, %s", rule, err)
-		}
-	}
-
-	for _, ipsetName := range m.ipsetStore.ipsetNames() {
-		if err := m.flushIPSet(ipsetName); err != nil {
-			if errors.Is(err, ipset.ErrSetNotExist) {
-				log.Debugf("flush ipset %q during reset: %v", ipsetName, err)
-			} else {
-				log.Errorf("flush ipset %q during reset: %v", ipsetName, err)
-			}
-		}
-		if err := m.destroyIPSet(ipsetName); err != nil {
-			if errors.Is(err, ipset.ErrBusy) || errors.Is(err, ipset.ErrSetNotExist) {
-				log.Debugf("destroy ipset %q during reset: %v", ipsetName, err)
-			} else {
-				log.Errorf("destroy ipset %q during reset: %v", ipsetName, err)
-			}
-		}
-		m.ipsetStore.deleteIpset(ipsetName)
-	}
-
-	return nil
-}
-
-func (m *aclManager) createDefaultChains() error {
-	// chain netbird-acl-input-rules
-	if err := m.iptablesClient.NewChain(tableName, chainNameInputRules); err != nil {
-		log.Debugf("failed to create '%s' chain: %s", chainNameInputRules, err)
-		return err
-	}
-
-	for chainName, rules := range m.entries {
-		// mangle FORWARD guard rules are handled separately below
-		if chainName == mangleFwdKey {
-			continue
-		}
-		for _, rule := range rules {
-			if err := m.iptablesClient.InsertUnique(tableName, chainName, 1, rule...); err != nil {
-				log.Debugf("failed to create input chain jump rule: %s", err)
-				return err
-			}
-		}
-	}
-
-	for chainName, entries := range m.optionalEntries {
-		for _, entry := range entries {
-			if err := m.iptablesClient.InsertUnique(tableName, chainName, entry.position, entry.spec...); err != nil {
-				log.Errorf("failed to insert optional entry %v: %v", entry.spec, err)
-				continue
-			}
-			m.entries[chainName] = append(m.entries[chainName], entry.spec)
-		}
-	}
-	clear(m.optionalEntries)
-
-	// Insert mangle FORWARD guard rules to prevent external DNAT bypass.
-	for _, rule := range m.entries[mangleFwdKey] {
-		if err := m.iptablesClient.AppendUnique(tableMangle, chainFORWARD, rule...); err != nil {
-			log.Errorf("failed to add mangle FORWARD guard rule: %v", err)
-		}
-	}
-
-	return nil
-}
-
-// seedInitialEntries adds default rules to the entries map, rules are inserted on pos 1, hence the order is reversed.
-// We want to make sure our traffic is not dropped by existing rules.
-
-// The existing FORWARD rules/policies decide outbound traffic towards our interface.
-// In case the FORWARD policy is set to "drop", we add an established/related rule to allow return traffic for the inbound rule.
-func (m *aclManager) seedInitialEntries() {
-	established := getConntrackEstablished()
-
-	m.appendToEntries("INPUT", []string{"-i", m.wgIface.Name(), "-j", "DROP"})
-	m.appendToEntries("INPUT", []string{"-i", m.wgIface.Name(), "-j", chainNameInputRules})
-	m.appendToEntries("INPUT", append([]string{"-i", m.wgIface.Name()}, established...))
-
-	// Inbound is handled by our ACLs, the rest is dropped.
-	// For outbound we respect the FORWARD policy. However, we need to allow established/related traffic for inbound rules.
-	m.appendToEntries("FORWARD", []string{"-i", m.wgIface.Name(), "-j", "DROP"})
-
-	m.appendToEntries("FORWARD", []string{"-o", m.wgIface.Name(), "-j", chainRTFWDOUT})
-	m.appendToEntries("FORWARD", []string{"-i", m.wgIface.Name(), "-j", chainRTFWDIN})
-
-	// Mangle FORWARD guard: when external DNAT redirects traffic from the wg interface, it
-	// traverses FORWARD instead of INPUT, bypassing ACL rules. ACCEPT rules in filter FORWARD
-	// can be inserted above ours. Mangle runs before filter, so these guard rules enforce the
-	// ACL mark check where it cannot be overridden.
-	m.appendToEntries(mangleFwdKey, []string{
-		"-i", m.wgIface.Name(),
-		"-m", "conntrack", "--ctstate", "RELATED,ESTABLISHED",
-		"-j", "ACCEPT",
-	})
-	m.appendToEntries(mangleFwdKey, []string{
-		"-i", m.wgIface.Name(),
-		"-m", "conntrack", "--ctstate", "DNAT",
-		"-m", "mark", "!", "--mark", fmt.Sprintf("%#x", nbnet.PreroutingFwmarkRedirected),
-		"-j", "DROP",
-	})
-}
-
-func (m *aclManager) seedInitialOptionalEntries() {
-	m.optionalEntries["FORWARD"] = []entry{
-		{
-			spec:     []string{"-m", "mark", "--mark", fmt.Sprintf("%#x", nbnet.PreroutingFwmarkRedirected), "-j", "ACCEPT"},
-			position: 2,
-		},
-	}
-}
-
-func (m *aclManager) appendToEntries(chainName string, spec []string) {
-	m.entries[chainName] = append(m.entries[chainName], spec)
-}
-
-func (m *aclManager) updateState() {
-	if m.stateManager == nil {
-		return
-	}
-
-	var currentState *ShutdownState
-	if existing := m.stateManager.GetState(currentState); existing != nil {
-		if existingState, ok := existing.(*ShutdownState); ok {
-			currentState = existingState
-		}
-	}
-	if currentState == nil {
-		currentState = &ShutdownState{}
-	}
-
-	currentState.Lock()
-	defer currentState.Unlock()
-
-	// Clone the maps so the persisted state holds a private snapshot. The
-	// live maps keep being mutated by subsequent rule operations while the
-	// state manager marshals the state from its periodic-save goroutine.
-	// Sharing them by reference races the two and aborts the process with a
-	// concurrent map iteration and write.
-	if m.v6 {
-		currentState.ACLEntries6 = maps.Clone(m.entries)
-		currentState.ACLIPsetStore6 = m.ipsetStore.clone()
-	} else {
-		currentState.ACLEntries = maps.Clone(m.entries)
-		currentState.ACLIPsetStore = m.ipsetStore.clone()
-	}
-
-	if err := m.stateManager.UpdateState(currentState); err != nil {
-		log.Errorf("failed to update state: %v", err)
-	}
-}
-
-// filterRuleSpecs returns the specs of a filtering rule
-// protoForFamily translates ICMP to ICMPv6 for ip6tables.
-// ip6tables requires "ipv6-icmp" (or "icmpv6") instead of "icmp".
-func protoForFamily(protocol firewall.Protocol, v6 bool) string {
-	if v6 && protocol == firewall.ProtocolICMP {
-		return "ipv6-icmp"
-	}
-	return string(protocol)
-}
-
-func filterRuleSpecs(ip net.IP, protocol string, sPort, dPort *firewall.Port, action firewall.Action, ipsetName string) (specs []string) {
-	// don't use IP matching if IP is 0.0.0.0
-	matchByIP := !ip.IsUnspecified()
-
-	if matchByIP {
-		if ipsetName != "" {
-			specs = append(specs, "-m", "set", "--match-set", ipsetName, "src")
-		} else {
-			specs = append(specs, "-s", ip.String())
-		}
-	}
-	if protocol != "all" {
-		specs = append(specs, "-p", protocol)
-	}
-	specs = append(specs, applyPort("--sport", sPort)...)
-	specs = append(specs, applyPort("--dport", dPort)...)
-	return specs
-}
-
-func actionToStr(action firewall.Action) string {
-	if action == firewall.ActionAccept {
-		return "ACCEPT"
-	}
-	return "DROP"
-}
-
-func transformIPsetName(ipsetName string, sPort, dPort *firewall.Port, action firewall.Action) string {
-	if ipsetName == "" {
-		return ""
-	}
-
-	actionSuffix := ""
-	if action == firewall.ActionDrop {
-		actionSuffix = "-drop"
-	}
-
-	switch {
-	case sPort != nil && dPort != nil:
-		return ipsetName + "-sport-dport" + actionSuffix
-	case sPort != nil:
-		return ipsetName + "-sport" + actionSuffix
-	case dPort != nil:
-		return ipsetName + "-dport" + actionSuffix
-	default:
-		return ipsetName + actionSuffix
-	}
-}
-
-// probeIPSetSupport checks whether the kernel can create the ipset type used for
-// ACL rules. On kernels lacking the required ipset hash module, ipset creation
-// fails (e.g. "invalid argument"), which would otherwise leave the ACL chain
-// empty and silently drop all policy-permitted inbound traffic. When unsupported,
-// the manager falls back to per-IP iptables rules.
-func (m *aclManager) probeIPSetSupport() bool {
-	// Use a unique name so concurrent processes don't collide and we only ever
-	// destroy the set we created ourselves. ipset names are limited to 31 chars,
-	// so use a short random suffix.
-	probeName := "nb-probe-" + uuid.New().String()[:8]
-
-	opts := ipset.CreateOptions{
-		Replace: true,
-	}
-	if m.v6 {
-		opts.Family = ipset.FamilyIPV6
-	}
-
-	if err := ipset.Create(probeName, ipset.TypeHashNet, opts); err != nil {
-		log.Warnf("ipset is not available (failed to create probe set: %v); "+
-			"falling back to per-IP iptables ACL rules. Ensure the kernel provides "+
-			"the ipset hash:net module (ip_set_hash_net) for better performance with large rule sets", err)
-		return false
-	}
-
-	defer func() {
-		if err := ipset.Destroy(probeName); err != nil {
-			log.Debugf("destroy ipset probe set %q: %v", probeName, err)
-		}
-	}()
-
-	return true
-}
-
-func (m *aclManager) createIPSet(name string) error {
-	opts := ipset.CreateOptions{
-		Replace: true,
-	}
-	if m.v6 {
-		opts.Family = ipset.FamilyIPV6
-	}
-
-	if err := ipset.Create(name, ipset.TypeHashNet, opts); err != nil {
-		return fmt.Errorf("create ipset %s: %w", name, err)
-	}
-
-	log.Debugf("created ipset %s with type hash:net", name)
-	return nil
-}
-
-func (m *aclManager) addToIPSet(name string, ip net.IP) error {
-	cidr := uint8(32)
-	if ip.To4() == nil {
-		cidr = 128
-	}
-
-	entry := &ipset.Entry{
-		IP:      ip,
-		CIDR:    cidr,
-		Replace: true,
-	}
-
-	if err := ipset.Add(name, entry); err != nil {
-		return fmt.Errorf("add IP to ipset %s: %w", name, err)
-	}
-
-	return nil
-}
-
-func (m *aclManager) delFromIPSet(name string, ip net.IP) error {
-	cidr := uint8(32)
-	if ip.To4() == nil {
-		cidr = 128
-	}
-
-	entry := &ipset.Entry{
-		IP:   ip,
-		CIDR: cidr,
-	}
-
-	if err := ipset.Del(name, entry); err != nil {
-		return fmt.Errorf("delete IP from ipset %s: %w", name, err)
-	}
-
-	return nil
-}
-
-func (m *aclManager) flushIPSet(name string) error {
-	return ipset.Flush(name)
-}
-
-func (m *aclManager) destroyIPSet(name string) error {
-	return ipset.Destroy(name)
-}

client/firewall/iptables/chains_linux.go

@@ -0,0 +1,346 @@
+//go:build !android
+
+package iptables
+
+import (
+	"fmt"
+
+	"github.com/hashicorp/go-multierror"
+	log "github.com/sirupsen/logrus"
+
+	nberrors "github.com/netbirdio/netbird/client/errors"
+	firewall "github.com/netbirdio/netbird/client/firewall/manager"
+	nbnet "github.com/netbirdio/netbird/client/net"
+)
+
+func (r *family) createContainers() error {
+	for _, chainInfo := range []struct {
+		chain string
+		table string
+	}{
+		{chainRTFwdIn, tableFilter},
+		{chainRTFwdOut, tableFilter},
+		{chainRTPre, tableMangle},
+		{chainRTNAT, tableNat},
+		{chainRTRdr, tableNat},
+		{chainRTMSSClamp, tableMangle},
+	} {
+		// Fallback: clear chains that survived an unclean shutdown.
+		if ok, _ := r.iptablesClient.ChainExists(chainInfo.table, chainInfo.chain); ok {
+			if err := r.iptablesClient.ClearAndDeleteChain(chainInfo.table, chainInfo.chain); err != nil {
+				log.Warnf("clear stale chain %s in %s: %v", chainInfo.chain, chainInfo.table, err)
+			}
+		}
+		if err := r.iptablesClient.NewChain(chainInfo.table, chainInfo.chain); err != nil {
+			return fmt.Errorf("create chain %s in table %s: %w", chainInfo.chain, chainInfo.table, err)
+		}
+	}
+
+	if err := r.insertEstablishedRule(chainRTFwdIn); err != nil {
+		return fmt.Errorf("insert established rule: %w", err)
+	}
+
+	if err := r.insertEstablishedRule(chainRTFwdOut); err != nil {
+		return fmt.Errorf("insert established rule: %w", err)
+	}
+
+	if err := r.addPostroutingRules(); err != nil {
+		return fmt.Errorf("add static nat rules: %w", err)
+	}
+
+	if err := r.addJumpRules(); err != nil {
+		return fmt.Errorf("add jump rules: %w", err)
+	}
+
+	if err := r.addMSSClampingRules(); err != nil {
+		log.Errorf("failed to add MSS clamping rules: %s", err)
+	}
+
+	return nil
+}
+
+func (r *family) addJumpRules() error {
+	// Jump to nat chain
+	natRule := jumpRuleSpec(chainRTNAT)
+	if err := r.iptablesClient.Insert(tableNat, chainPostrouting, 1, natRule...); err != nil {
+		return fmt.Errorf("add nat postrouting jump rule: %w", err)
+	}
+	r.rules[jumpNATPost] = natRule
+
+	// Jump to mangle prerouting chain
+	preRule := jumpRuleSpec(chainRTPre)
+	if err := r.iptablesClient.Insert(tableMangle, chainPrerouting, 1, preRule...); err != nil {
+		return fmt.Errorf("add mangle prerouting jump rule: %w", err)
+	}
+	r.rules[jumpManglePre] = preRule
+
+	// Jump to nat prerouting chain
+	rdrRule := jumpRuleSpec(chainRTRdr)
+	if err := r.iptablesClient.Insert(tableNat, chainPrerouting, 1, rdrRule...); err != nil {
+		return fmt.Errorf("add nat prerouting jump rule: %w", err)
+	}
+	r.rules[jumpNATPre] = rdrRule
+
+	return nil
+}
+
+func (r *family) setupDataPlaneMark() error {
+	var merr *multierror.Error
+	preRule := []string{
+		"-i", r.wgIface.Name(),
+		"-m", "conntrack", "--ctstate", "NEW",
+		"-j", "CONNMARK", "--set-mark", fmt.Sprintf("%#x", nbnet.DataPlaneMarkIn),
+	}
+
+	if err := r.iptablesClient.AppendUnique(tableMangle, chainPrerouting, preRule...); err != nil {
+		merr = multierror.Append(merr, fmt.Errorf("add mangle prerouting rule: %w", err))
+	} else {
+		r.rules[markManglePre] = preRule
+	}
+
+	postRule := []string{
+		"-o", r.wgIface.Name(),
+		"-m", "conntrack", "--ctstate", "NEW",
+		"-j", "CONNMARK", "--set-mark", fmt.Sprintf("%#x", nbnet.DataPlaneMarkOut),
+	}
+
+	if err := r.iptablesClient.AppendUnique(tableMangle, chainPostrouting, postRule...); err != nil {
+		merr = multierror.Append(merr, fmt.Errorf("add mangle postrouting rule: %w", err))
+	} else {
+		r.rules[markManglePost] = postRule
+	}
+
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+// seedInitialEntries adds default rules to the entries map. Rules are
+// inserted at position 1, so the order here is reversed.
+//
+// Existing FORWARD policy decides outbound traffic towards our
+// interface. If FORWARD policy is "drop", we add an
+// established/related rule to allow return traffic for inbound rules.
+func (r *family) seedInitialEntries() {
+	established := getConntrackEstablished()
+
+	r.appendToEntries(chainInput, []string{"-i", r.wgIface.Name(), "-j", "DROP"})
+	r.appendToEntries(chainInput, []string{"-i", r.wgIface.Name(), "-j", chainACLInput})
+	r.appendToEntries(chainInput, append([]string{"-i", r.wgIface.Name()}, established...))
+
+	r.appendToEntries(chainForward, []string{"-i", r.wgIface.Name(), "-j", "DROP"})
+	r.appendToEntries(chainForward, []string{"-o", r.wgIface.Name(), "-j", chainRTFwdOut})
+	r.appendToEntries(chainForward, []string{"-i", r.wgIface.Name(), "-j", chainRTFwdIn})
+
+	// Mangle FORWARD guard: when external DNAT redirects traffic from
+	// the wg interface, it traverses FORWARD instead of INPUT,
+	// bypassing ACL rules. ACCEPT rules in filter FORWARD can be
+	// inserted above ours. Mangle runs before filter, so these guard
+	// rules enforce the ACL mark check where it cannot be overridden.
+	r.appendToEntries(mangleForwardKey, []string{
+		"-i", r.wgIface.Name(),
+		"-m", "conntrack", "--ctstate", "RELATED,ESTABLISHED",
+		"-j", "ACCEPT",
+	})
+	r.appendToEntries(mangleForwardKey, []string{
+		"-i", r.wgIface.Name(),
+		"-m", "conntrack", "--ctstate", "DNAT",
+		"-m", "mark", "!", "--mark", fmt.Sprintf("%#x", nbnet.PreroutingFwmarkRedirected),
+		"-j", "DROP",
+	})
+}
+
+func (r *family) seedInitialOptionalEntries() {
+	r.optionalEntries[chainForward] = []entry{
+		{
+			spec:     []string{"-m", "mark", "--mark", fmt.Sprintf("%#x", nbnet.PreroutingFwmarkRedirected), "-j", "ACCEPT"},
+			position: 2,
+		},
+	}
+}
+
+func (r *family) appendToEntries(chain chainKey, spec ruleSpec) {
+	r.entries[chain] = append(r.entries[chain], spec)
+}
+
+func (r *family) createDefaultChains() error {
+	if err := r.iptablesClient.NewChain(tableFilter, chainACLInput); err != nil {
+		return fmt.Errorf("create %s chain: %w", chainACLInput, err)
+	}
+
+	for chain, rules := range r.entries {
+		// mangle FORWARD guard rules are handled separately below
+		if chain == mangleForwardKey {
+			continue
+		}
+		for _, rule := range rules {
+			if err := r.iptablesClient.InsertUnique(tableFilter, string(chain), 1, rule...); err != nil {
+				return fmt.Errorf("insert jump rule into %s: %w", chain, err)
+			}
+		}
+	}
+
+	for chain, entries := range r.optionalEntries {
+		for _, entry := range entries {
+			if err := r.iptablesClient.InsertUnique(tableFilter, string(chain), entry.position, entry.spec...); err != nil {
+				log.Errorf("failed to insert optional entry %v: %v", entry.spec, err)
+				continue
+			}
+			r.entries[chain] = append(r.entries[chain], entry.spec)
+		}
+	}
+	clear(r.optionalEntries)
+
+	// Insert mangle FORWARD guard rules to prevent external DNAT bypass.
+	for _, rule := range r.entries[mangleForwardKey] {
+		if err := r.iptablesClient.AppendUnique(tableMangle, chainForward, rule...); err != nil {
+			log.Errorf("failed to add mangle FORWARD guard rule: %v", err)
+		}
+	}
+
+	return nil
+}
+
+func (r *family) cleanUpDefaultForwardRules() error {
+	var merr *multierror.Error
+
+	// cleanJumpRules removes the OUTPUT jump to NETBIRD-NAT-OUTPUT among
+	// the others, so the chain below deletes cleanly instead of failing
+	// with "device or resource busy".
+	if err := r.cleanJumpRules(); err != nil {
+		merr = multierror.Append(merr, fmt.Errorf("clean jump rules: %w", err))
+	}
+
+	for _, chainInfo := range []struct {
+		chain string
+		table string
+	}{
+		{chainRTFwdIn, tableFilter},
+		{chainRTFwdOut, tableFilter},
+		{chainRTPre, tableMangle},
+		{chainRTNAT, tableNat},
+		{chainRTRdr, tableNat},
+		{chainNATOutput, tableNat},
+		{chainRTMSSClamp, tableMangle},
+	} {
+		ok, err := r.iptablesClient.ChainExists(chainInfo.table, chainInfo.chain)
+		if err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("check chain %s in table %s: %w", chainInfo.chain, chainInfo.table, err))
+			continue
+		}
+		if ok {
+			if err := r.iptablesClient.ClearAndDeleteChain(chainInfo.table, chainInfo.chain); err != nil {
+				merr = multierror.Append(merr, fmt.Errorf("clear and delete chain %s in table %s: %w", chainInfo.chain, chainInfo.table, err))
+			}
+		}
+	}
+
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+func (r *family) cleanJumpRules() error {
+	// locations maps each jump rule to the built-in table and chain it
+	// was inserted into, plus the netbird chain it targets.
+	locations := map[firewall.RuleID]struct{ table, chain, target string }{
+		jumpNATPost:   {tableNat, chainPostrouting, chainRTNAT},
+		jumpManglePre: {tableMangle, chainPrerouting, chainRTPre},
+		jumpNATPre:    {tableNat, chainPrerouting, chainRTRdr},
+		jumpMSSClamp:  {tableMangle, chainForward, chainRTMSSClamp},
+		jumpNATOutput: {tableNat, chainOutput, chainNATOutput},
+	}
+
+	var merr *multierror.Error
+	for ruleID, loc := range locations {
+		rule, exists := r.rules[ruleID]
+		if !exists {
+			// Untracked (e.g. fresh start after an unclean shutdown with no
+			// restored state): if the target chain survived, remove the stale
+			// jump to it so the chain can be deleted.
+			ok, err := r.iptablesClient.ChainExists(loc.table, loc.target)
+			if err != nil {
+				merr = multierror.Append(merr, fmt.Errorf("check chain %s in table %s: %w", loc.target, loc.table, err))
+				continue
+			}
+			if !ok {
+				continue
+			}
+			rule = jumpRuleSpec(loc.target)
+		}
+		if err := r.iptablesClient.DeleteIfExists(loc.table, loc.chain, rule...); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("delete rule from chain %s in table %s: %w", loc.chain, loc.table, err))
+			continue
+		}
+		delete(r.rules, ruleID)
+	}
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+// jumpRuleSpec builds the iptables rule spec that jumps to target. Create
+// and cleanup sites share it so the installed and deleted specs cannot drift.
+func jumpRuleSpec(target string) []string {
+	return []string{"-j", target}
+}
+
+func (r *family) cleanAclChains() error {
+	var merr *multierror.Error
+
+	if err := r.cleanInputAclChain(); err != nil {
+		merr = multierror.Append(merr, err)
+	}
+
+	for _, rule := range r.entries[mangleForwardKey] {
+		if err := r.iptablesClient.DeleteIfExists(tableMangle, chainForward, rule...); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("delete mangle %s guard rule %v: %w", chainForward, rule, err))
+		}
+	}
+
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+func (r *family) cleanInputAclChain() error {
+	ok, err := r.iptablesClient.ChainExists(tableFilter, chainACLInput)
+	if err != nil {
+		return fmt.Errorf("check chain %s: %w", chainACLInput, err)
+	}
+	if !ok {
+		return nil
+	}
+
+	var merr *multierror.Error
+	for _, rule := range r.entries[chainInput] {
+		if err := r.iptablesClient.DeleteIfExists(tableFilter, chainInput, rule...); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("delete %s rule %v: %w", chainInput, rule, err))
+		}
+	}
+
+	for _, rule := range r.entries[chainForward] {
+		if err := r.iptablesClient.DeleteIfExists(tableFilter, chainForward, rule...); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("delete %s rule %v: %w", chainForward, rule, err))
+		}
+	}
+
+	if err := r.iptablesClient.ClearAndDeleteChain(tableFilter, chainACLInput); err != nil {
+		merr = multierror.Append(merr, fmt.Errorf("clear and delete %s chain: %w", chainACLInput, err))
+	}
+
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+func (r *family) cleanupDataPlaneMark() error {
+	var merr *multierror.Error
+	if preRule, exists := r.rules[markManglePre]; exists {
+		if err := r.iptablesClient.DeleteIfExists(tableMangle, chainPrerouting, preRule...); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("remove mangle prerouting rule: %w", err))
+		} else {
+			delete(r.rules, markManglePre)
+		}
+	}
+
+	if postRule, exists := r.rules[markManglePost]; exists {
+		if err := r.iptablesClient.DeleteIfExists(tableMangle, chainPostrouting, postRule...); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("remove mangle postrouting rule: %w", err))
+		} else {
+			delete(r.rules, markManglePost)
+		}
+	}
+
+	return nberrors.FormatErrorOrNil(merr)
+}

client/firewall/iptables/dnat_linux.go

@@ -0,0 +1,302 @@
+//go:build !android
+
+package iptables
+
+import (
+	"fmt"
+	"net/netip"
+	"strconv"
+	"strings"
+
+	"github.com/hashicorp/go-multierror"
+	log "github.com/sirupsen/logrus"
+
+	nberrors "github.com/netbirdio/netbird/client/errors"
+	firewall "github.com/netbirdio/netbird/client/firewall/manager"
+)
+
+func (r *family) AddDNATRule(rule firewall.ForwardRule) (firewall.Rule, error) {
+	ruleID := rule.ID()
+	if _, exists := r.rules[ruleID+dnatSuffix]; exists {
+		return rule, nil
+	}
+
+	toDestination := rule.TranslatedAddress.String()
+	switch {
+	case len(rule.TranslatedPort.Values) == 0:
+		// no translated port, use original port
+	case len(rule.TranslatedPort.Values) == 1:
+		toDestination += fmt.Sprintf(":%d", rule.TranslatedPort.Values[0])
+	case rule.TranslatedPort.IsRange && len(rule.TranslatedPort.Values) == 2:
+		// need the "/originalport" suffix to avoid dnat port randomization
+		toDestination += fmt.Sprintf(":%d-%d/%d", rule.TranslatedPort.Values[0], rule.TranslatedPort.Values[1], rule.DestinationPort.Values[0])
+	default:
+		return nil, fmt.Errorf("invalid translated port: %v", rule.TranslatedPort)
+	}
+
+	proto := strings.ToLower(string(rule.Protocol))
+
+	rules := make(map[firewall.RuleID]ruleInfo, 3)
+
+	// DNAT rule
+	dnatRule := []string{
+		"!", "-i", r.wgIface.Name(),
+		"-p", proto,
+		"-j", "DNAT",
+		"--to-destination", toDestination,
+	}
+	dnatRule = append(dnatRule, applyPort("--dport", &rule.DestinationPort)...)
+	rules[ruleID+dnatSuffix] = ruleInfo{
+		table: tableNat,
+		chain: chainRTRdr,
+		rule:  dnatRule,
+	}
+
+	// SNAT rule
+	snatRule := []string{
+		"-o", r.wgIface.Name(),
+		"-p", proto,
+		"-d", rule.TranslatedAddress.String(),
+		"-j", "MASQUERADE",
+	}
+	snatRule = append(snatRule, applyPort("--dport", &rule.TranslatedPort)...)
+	rules[ruleID+snatSuffix] = ruleInfo{
+		table: tableNat,
+		chain: chainRTNAT,
+		rule:  snatRule,
+	}
+
+	// Forward filtering rule, if fwd policy is DROP
+	forwardRule := []string{
+		"-o", r.wgIface.Name(),
+		"-p", proto,
+		"-d", rule.TranslatedAddress.String(),
+		"-j", "ACCEPT",
+	}
+	forwardRule = append(forwardRule, applyPort("--dport", &rule.TranslatedPort)...)
+	rules[ruleID+fwdSuffix] = ruleInfo{
+		table: tableFilter,
+		chain: chainRTFwdOut,
+		rule:  forwardRule,
+	}
+
+	for key, ruleInfo := range rules {
+		if err := r.iptablesClient.Append(ruleInfo.table, ruleInfo.chain, ruleInfo.rule...); err != nil {
+			r.cleanupFailedDNATAdd(rules)
+			return nil, fmt.Errorf("add rule %s: %w", key, err)
+		}
+		r.rules[key] = ruleInfo.rule
+	}
+
+	if err := r.ipFwdState.RequestForwarding(r.v6); err != nil {
+		r.cleanupFailedDNATAdd(rules)
+		return nil, fmt.Errorf("enable forwarding: %w", err)
+	}
+
+	r.updateState()
+	return rule, nil
+}
+
+// cleanupFailedDNATAdd removes the bookkeeping written by a partially applied
+// AddDNATRule before rolling back the kernel rules, so no entries remain that
+// never got a forwarding refcount. rollbackRules re-adds entries it failed to
+// remove from the kernel.
+func (r *family) cleanupFailedDNATAdd(rules map[firewall.RuleID]ruleInfo) {
+	for key := range rules {
+		delete(r.rules, key)
+	}
+	if err := r.rollbackRules(rules); err != nil {
+		log.Errorf("rollback failed: %v", err)
+	}
+}
+
+func (r *family) rollbackRules(rules map[firewall.RuleID]ruleInfo) error {
+	var merr *multierror.Error
+	for key, ruleInfo := range rules {
+		if err := r.iptablesClient.DeleteIfExists(ruleInfo.table, ruleInfo.chain, ruleInfo.rule...); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("rollback rule %s: %w", key, err))
+			// On rollback error, add to rules map for next cleanup
+			r.rules[key] = ruleInfo.rule
+		}
+	}
+	if merr != nil {
+		r.updateState()
+	}
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+func (r *family) DeleteDNATRule(rule firewall.Rule) error {
+	ruleID := rule.ID()
+
+	_, hadDNAT := r.rules[ruleID+dnatSuffix]
+	_, hadSNAT := r.rules[ruleID+snatSuffix]
+	_, hadFWD := r.rules[ruleID+fwdSuffix]
+	if !hadDNAT && !hadSNAT && !hadFWD {
+		return nil
+	}
+
+	var merr *multierror.Error
+	if dnatRule, exists := r.rules[ruleID+dnatSuffix]; exists {
+		if err := r.iptablesClient.Delete(tableNat, chainRTRdr, dnatRule...); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("delete DNAT rule: %w", err))
+		} else {
+			delete(r.rules, ruleID+dnatSuffix)
+		}
+	}
+
+	if snatRule, exists := r.rules[ruleID+snatSuffix]; exists {
+		if err := r.iptablesClient.Delete(tableNat, chainRTNAT, snatRule...); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("delete SNAT rule: %w", err))
+		} else {
+			delete(r.rules, ruleID+snatSuffix)
+		}
+	}
+
+	if fwdRule, exists := r.rules[ruleID+fwdSuffix]; exists {
+		if err := r.iptablesClient.Delete(tableFilter, chainRTFwdOut, fwdRule...); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("delete forward rule: %w", err))
+		} else {
+			delete(r.rules, ruleID+fwdSuffix)
+		}
+	}
+
+	// Release the refcount only once all rules are gone from the kernel. On
+	// partial failure the failed entries stay in r.rules so a retry can remove
+	// them and release then.
+	if merr == nil {
+		r.releaseForwarding()
+	}
+
+	r.updateState()
+
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+// releaseForwarding drops one IP forwarding reference, logging any error.
+func (r *family) releaseForwarding() {
+	if err := r.ipFwdState.ReleaseForwarding(r.v6); err != nil {
+		log.Errorf("release IP forwarding: %v", err)
+	}
+}
+
+func (r *family) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+	ruleID := firewall.RuleID(fmt.Sprintf("inbound-dnat-%s-%s-%d-%d", localAddr.String(), protocol, originalPort, translatedPort))
+
+	if _, exists := r.rules[ruleID]; exists {
+		return nil
+	}
+
+	dnatRule := []string{
+		"-i", r.wgIface.Name(),
+		"-p", strings.ToLower(protoForFamily(protocol, r.v6)),
+		"--dport", strconv.Itoa(int(originalPort)),
+		"-d", localAddr.String(),
+		"-m", "addrtype", "--dst-type", "LOCAL",
+		"-j", "DNAT",
+		"--to-destination", ":" + strconv.Itoa(int(translatedPort)),
+	}
+
+	info := ruleInfo{
+		table: tableNat,
+		chain: chainRTRdr,
+		rule:  dnatRule,
+	}
+
+	if err := r.iptablesClient.Append(info.table, info.chain, info.rule...); err != nil {
+		return fmt.Errorf("add inbound DNAT rule: %w", err)
+	}
+	r.rules[ruleID] = info.rule
+
+	r.updateState()
+	return nil
+}
+
+// RemoveInboundDNAT removes an inbound DNAT rule.
+func (r *family) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+	ruleID := firewall.RuleID(fmt.Sprintf("inbound-dnat-%s-%s-%d-%d", localAddr.String(), protocol, originalPort, translatedPort))
+
+	if dnatRule, exists := r.rules[ruleID]; exists {
+		if err := r.iptablesClient.Delete(tableNat, chainRTRdr, dnatRule...); err != nil {
+			return fmt.Errorf("delete inbound DNAT rule: %w", err)
+		}
+		delete(r.rules, ruleID)
+	}
+
+	r.updateState()
+	return nil
+}
+
+// ensureNATOutputChain lazily creates the OUTPUT NAT chain and jump rule on first use.
+func (r *family) ensureNATOutputChain() error {
+	if _, exists := r.rules[jumpNATOutput]; exists {
+		return nil
+	}
+
+	chainExists, err := r.iptablesClient.ChainExists(tableNat, chainNATOutput)
+	if err != nil {
+		return fmt.Errorf("check chain %s: %w", chainNATOutput, err)
+	}
+	if !chainExists {
+		if err := r.iptablesClient.NewChain(tableNat, chainNATOutput); err != nil {
+			return fmt.Errorf("create chain %s: %w", chainNATOutput, err)
+		}
+	}
+
+	jumpRule := jumpRuleSpec(chainNATOutput)
+	if err := r.iptablesClient.Insert(tableNat, chainOutput, 1, jumpRule...); err != nil {
+		if !chainExists {
+			if delErr := r.iptablesClient.ClearAndDeleteChain(tableNat, chainNATOutput); delErr != nil {
+				log.Warnf("failed to rollback chain %s: %v", chainNATOutput, delErr)
+			}
+		}
+		return fmt.Errorf("add OUTPUT jump rule: %w", err)
+	}
+	r.rules[jumpNATOutput] = jumpRule
+
+	r.updateState()
+	return nil
+}
+
+// AddOutputDNAT adds an OUTPUT chain DNAT rule for locally-generated traffic.
+func (r *family) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+	ruleID := firewall.RuleID(fmt.Sprintf("output-dnat-%s-%s-%d-%d", localAddr.String(), protocol, originalPort, translatedPort))
+
+	if _, exists := r.rules[ruleID]; exists {
+		return nil
+	}
+
+	if err := r.ensureNATOutputChain(); err != nil {
+		return err
+	}
+
+	dnatRule := []string{
+		"-p", strings.ToLower(protoForFamily(protocol, localAddr.Is6())),
+		"--dport", strconv.Itoa(int(originalPort)),
+		"-d", localAddr.String(),
+		"-j", "DNAT",
+		"--to-destination", ":" + strconv.Itoa(int(translatedPort)),
+	}
+
+	if err := r.iptablesClient.Append(tableNat, chainNATOutput, dnatRule...); err != nil {
+		return fmt.Errorf("add output DNAT rule: %w", err)
+	}
+	r.rules[ruleID] = dnatRule
+
+	r.updateState()
+	return nil
+}
+
+// RemoveOutputDNAT removes an OUTPUT chain DNAT rule.
+func (r *family) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+	ruleID := firewall.RuleID(fmt.Sprintf("output-dnat-%s-%s-%d-%d", localAddr.String(), protocol, originalPort, translatedPort))
+
+	if dnatRule, exists := r.rules[ruleID]; exists {
+		if err := r.iptablesClient.Delete(tableNat, chainNATOutput, dnatRule...); err != nil {
+			return fmt.Errorf("delete output DNAT rule: %w", err)
+		}
+		delete(r.rules, ruleID)
+	}
+
+	r.updateState()
+	return nil
+}

client/firewall/iptables/dnat_refcount_linux_test.go

@@ -80,7 +80,7 @@ func iptDnatV6(port uint16) fw.ForwardRule {
 // and a single DisableRouting drops both back to zero.
 func TestIptablesRouting_RepeatedEnableSingleReference(t *testing.T) {
 	m := newIptRefcountManager(t, true)
-	state := m.router.ipFwdState
+	state := m.family4.ipFwdState
 
 	require.NoError(t, m.EnableRouting(), "first enable")
 	require.NoError(t, m.EnableRouting(), "second enable")
@@ -99,7 +99,7 @@ func TestIptablesRouting_RepeatedEnableSingleReference(t *testing.T) {
 // DisableRouting does not release references held by active DNAT rules.
 func TestIptablesRouting_DisableKeepsDNATReference(t *testing.T) {
 	m := newIptRefcountManager(t, true)
-	state := m.router.ipFwdState
+	state := m.family4.ipFwdState
 
 	r1, err := m.AddDNATRule(iptDnatV6(9095))
 	require.NoError(t, err, "add v6 dnat")
@@ -116,7 +116,7 @@ func TestIptablesRouting_DisableKeepsDNATReference(t *testing.T) {
 // TestIptablesDNAT_RefcountBalancedV4 covers a Balanced Add/Delete pair on v4.
 func TestIptablesDNAT_RefcountBalancedV4(t *testing.T) {
 	m := newIptRefcountManager(t, false)
-	state := m.router.ipFwdState
+	state := m.family4.ipFwdState
 
 	r1, err := m.AddDNATRule(iptDnatV4(7081))
 	require.NoError(t, err, "add v4 dnat 1")
@@ -145,9 +145,9 @@ func TestIptablesDNAT_RefcountBalancedV4(t *testing.T) {
 // decrements back to zero.
 func TestIptablesDNAT_RefcountBalancedV6(t *testing.T) {
 	m := newIptRefcountManager(t, true)
-	require.NotNil(t, m.router6, "v6 router")
+	require.NotNil(t, m.family6, "v6 family")
-	require.Same(t, m.router.ipFwdState, m.router6.ipFwdState, "shared state")
+	require.Same(t, m.family4.ipFwdState, m.family6.ipFwdState, "shared state")
-	state := m.router.ipFwdState
+	state := m.family4.ipFwdState
 
 	r1, err := m.AddDNATRule(iptDnatV6(9081))
 	require.NoError(t, err, "add v6 dnat 1")
@@ -176,7 +176,7 @@ func TestIptablesDNAT_RefcountBalancedV6(t *testing.T) {
 // without bumping the refcount.
 func TestIptablesDNAT_DuplicateAddNoLeak(t *testing.T) {
 	m := newIptRefcountManager(t, true)
-	state := m.router.ipFwdState
+	state := m.family4.ipFwdState
 
 	rule := iptDnatV4(7083)
 	r1, err := m.AddDNATRule(rule)
@@ -198,7 +198,7 @@ func TestIptablesDNAT_DuplicateAddNoLeak(t *testing.T) {
 // neither errors nor releases the refcount.
 func TestIptablesDNAT_DeleteMissingNoUnderflow(t *testing.T) {
 	m := newIptRefcountManager(t, true)
-	state := m.router.ipFwdState
+	state := m.family4.ipFwdState
 
 	phantom := iptDnatV4(7099)
 	require.NoError(t, m.DeleteDNATRule(&phantom), "delete missing v4")
@@ -223,7 +223,7 @@ func TestIptablesDNAT_DeleteMissingNoUnderflow(t *testing.T) {
 // rule is a no-op.
 func TestIptablesDNAT_DoubleDeleteNoUnderflow(t *testing.T) {
 	m := newIptRefcountManager(t, true)
-	state := m.router.ipFwdState
+	state := m.family4.ipFwdState
 
 	r1, err := m.AddDNATRule(iptDnatV6(9083))
 	require.NoError(t, err)

client/firewall/iptables/family_linux.go

@@ -0,0 +1,258 @@
+//go:build !android
+
+package iptables
+
+import (
+	"fmt"
+	"maps"
+	"net/netip"
+
+	"github.com/coreos/go-iptables/iptables"
+	"github.com/hashicorp/go-multierror"
+	log "github.com/sirupsen/logrus"
+
+	nberrors "github.com/netbirdio/netbird/client/errors"
+	firewall "github.com/netbirdio/netbird/client/firewall/manager"
+	nbid "github.com/netbirdio/netbird/client/internal/acl/id"
+	"github.com/netbirdio/netbird/client/internal/routemanager/ipfwdstate"
+	"github.com/netbirdio/netbird/client/internal/routemanager/refcounter"
+	"github.com/netbirdio/netbird/client/internal/statemanager"
+)
+
+// constants needed to manage and create iptable rules
+const (
+	tableFilter = "filter"
+	tableNat    = "nat"
+	tableMangle = "mangle"
+
+	// chainACLInput is the peer ACL chain that holds installed
+	// peer-filtering rules.
+	chainACLInput = "NETBIRD-ACL-INPUT"
+
+	// mangleForwardKey is the entries map key for mangle FORWARD guard
+	// rules that prevent external DNAT from bypassing ACL rules.
+	mangleForwardKey chainKey = "MANGLE-FORWARD"
+
+	chainInput       = "INPUT"
+	chainPostrouting = "POSTROUTING"
+	chainPrerouting  = "PREROUTING"
+	chainForward     = "FORWARD"
+	chainRTNAT       = "NETBIRD-RT-NAT"
+	chainRTFwdIn     = "NETBIRD-RT-FWD-IN"
+	chainRTFwdOut    = "NETBIRD-RT-FWD-OUT"
+	chainRTPre       = "NETBIRD-RT-PRE"
+	chainRTRdr       = "NETBIRD-RT-RDR"
+	chainNATOutput   = "NETBIRD-NAT-OUTPUT"
+	chainRTMSSClamp  = "NETBIRD-RT-MSSCLAMP"
+
+	jumpManglePre  = "jump-mangle-pre"
+	jumpNATPre     = "jump-nat-pre"
+	jumpNATPost    = "jump-nat-post"
+	jumpNATOutput  = "jump-nat-output"
+	jumpMSSClamp   = "jump-mss-clamp"
+	markManglePre  = "mark-mangle-pre"
+	markManglePost = "mark-mangle-post"
+	matchSet       = "--match-set"
+
+	dnatSuffix firewall.RuleID = "_dnat"
+	snatSuffix firewall.RuleID = "_snat"
+	fwdSuffix  firewall.RuleID = "_fwd"
+
+	// ipv4TCPHeaderSize is the minimum IPv4 (20) + TCP (20) header size for MSS calculation.
+	ipv4TCPHeaderSize = 40
+	// ipv6TCPHeaderSize is the minimum IPv6 (40) + TCP (20) header size for MSS calculation.
+	ipv6TCPHeaderSize = 60
+)
+
+type ruleInfo struct {
+	chain string
+	table string
+	rule  []string
+}
+
+type routeRules map[firewall.RuleID][]string
+
+// ruleSpec is a single iptables rule expressed as its argument list
+// (e.g. {"-i", "wg0", "-j", "DROP"}).
+type ruleSpec []string
+
+// chainKey identifies the chain a seeded entry belongs to. It holds
+// built-in chain names ("INPUT", "FORWARD", "PREROUTING") plus the
+// synthetic mangleForwardKey bucket for the mangle FORWARD guard rules.
+type chainKey string
+
+// aclEntries maps a chain to the rules seeded into it to jump into or
+// guard the netbird ACL chains.
+type aclEntries map[chainKey][]ruleSpec
+
+type entry struct {
+	spec     ruleSpec
+	position int
+}
+
+// ipsetCounter is the shared hash:net refcounter used by peer and
+// route ACLs alike. The ipset library does not support comments, so
+// the key is just the set name (string).
+type ipsetCounter = refcounter.Counter[string, []netip.Prefix, struct{}]
+
+// family holds the per-address-family iptables state. One instance
+// handles route ACLs, peer ACLs, NAT, DNAT, and MSS clamping for a
+// single family; the top-level Manager owns one for v4 and another
+// for v6.
+type family struct {
+	iptablesClient *iptables.IPTables
+	wgIface        iFaceMapper
+	v6             bool
+
+	// Peer ACL chain bookkeeping.
+	entries         aclEntries
+	optionalEntries map[chainKey][]entry
+
+	// filters holds peer + route filter rules keyed by content hash.
+	// AddFilterRule writes here; DeleteFilterRule looks up by id.
+	filters      map[nbid.RuleID]*Rule
+	ipsetCounter *ipsetCounter
+	// ipsetSupported records whether the kernel can create the hash:net
+	// sets the source matches rely on; probed once at init. When false,
+	// multi-source rules expand to one rule per source prefix.
+	ipsetSupported bool
+
+	// rules holds NAT, jump, and MSS-clamping rules (auxiliary
+	// plumbing that isn't a filter rule).
+	rules routeRules
+
+	// Routing / NAT.
+	legacyManagement bool
+	mtu              uint16
+	ipFwdState       *ipfwdstate.IPForwardingState
+
+	stateManager *statemanager.Manager
+}
+
+func newFamily(iptablesClient *iptables.IPTables, wgIface iFaceMapper, mtu uint16) (*family, error) {
+	r := &family{
+		iptablesClient:  iptablesClient,
+		wgIface:         wgIface,
+		v6:              iptablesClient.Proto() == iptables.ProtocolIPv6,
+		entries:         make(aclEntries),
+		optionalEntries: make(map[chainKey][]entry),
+		filters:         make(map[nbid.RuleID]*Rule),
+		rules:           make(routeRules),
+		mtu:             mtu,
+		ipFwdState:      ipfwdstate.NewIPForwardingState(wgIface.Name()),
+	}
+
+	r.ipsetCounter = refcounter.New(
+		func(name string, sources []netip.Prefix) (struct{}, error) {
+			return struct{}{}, r.createIpSet(name, sources)
+		},
+		func(name string, _ struct{}) error {
+			return r.deleteIpSet(name)
+		},
+	)
+
+	return r, nil
+}
+
+// init wires the family to the state manager and installs both the
+// route ACL containers and the peer ACL chain skeleton.
+func (r *family) init(stateManager *statemanager.Manager) error {
+	r.stateManager = stateManager
+
+	r.ipsetSupported = r.probeIPSetSupport()
+
+	if err := r.cleanUpDefaultForwardRules(); err != nil {
+		log.Errorf("failed to clean up rules from FORWARD chain: %s", err)
+	}
+
+	if err := r.createContainers(); err != nil {
+		return fmt.Errorf("create containers: %w", err)
+	}
+
+	if err := r.setupDataPlaneMark(); err != nil {
+		log.Errorf("failed to set up data plane mark: %v", err)
+	}
+
+	r.seedInitialEntries()
+	r.seedInitialOptionalEntries()
+
+	if err := r.cleanAclChains(); err != nil {
+		return fmt.Errorf("clean acl chains: %w", err)
+	}
+	if err := r.createDefaultChains(); err != nil {
+		return fmt.Errorf("create default chains: %w", err)
+	}
+
+	r.updateState()
+
+	return nil
+}
+
+// Reset tears down all firewall state owned by this family. ACL
+// chain cleanup runs before route-chain cleanup because the route
+// chains are still referenced by FORWARD jumps installed during
+// seedInitialEntries; deleting them first would trip EBUSY.
+func (r *family) Reset() error {
+	var merr *multierror.Error
+
+	if err := r.cleanAclChains(); err != nil {
+		merr = multierror.Append(merr, err)
+	}
+
+	if err := r.cleanUpDefaultForwardRules(); err != nil {
+		merr = multierror.Append(merr, err)
+	}
+
+	if err := r.ipsetCounter.Flush(); err != nil {
+		merr = multierror.Append(merr, err)
+	}
+
+	if err := r.cleanupDataPlaneMark(); err != nil {
+		merr = multierror.Append(merr, err)
+	}
+
+	clear(r.rules)
+	clear(r.filters)
+	r.updateState()
+
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+func (r *family) updateState() {
+	if r.stateManager == nil {
+		return
+	}
+
+	var currentState *ShutdownState
+	if existing := r.stateManager.GetState(currentState); existing != nil {
+		if existingState, ok := existing.(*ShutdownState); ok {
+			currentState = existingState
+		}
+	}
+	if currentState == nil {
+		currentState = &ShutdownState{}
+	}
+
+	currentState.Lock()
+	defer currentState.Unlock()
+
+	// Clone the rule maps so the persisted state holds a private snapshot.
+	// The live maps keep being mutated by subsequent rule operations while
+	// the state manager marshals the state from its periodic-save goroutine.
+	// Sharing the maps by reference races the two and aborts the process with
+	// a concurrent map iteration and write. The ipset counter guards itself
+	// during marshaling, so it can be shared directly.
+	if r.v6 {
+		currentState.RouteRules6 = maps.Clone(r.rules)
+		currentState.RouteIPsetCounter6 = r.ipsetCounter
+		currentState.ACLEntries6 = maps.Clone(r.entries)
+	} else {
+		currentState.RouteRules = maps.Clone(r.rules)
+		currentState.RouteIPsetCounter = r.ipsetCounter
+		currentState.ACLEntries = maps.Clone(r.entries)
+	}
+
+	if err := r.stateManager.UpdateState(currentState); err != nil {
+		log.Errorf("failed to update state: %v", err)
+	}
+}

client/firewall/iptables/filter_linux.go

@@ -0,0 +1,430 @@
+//go:build !android
+
+package iptables
+
+import (
+	"fmt"
+	"net/netip"
+	"slices"
+	"strconv"
+	"strings"
+
+	"github.com/hashicorp/go-multierror"
+	log "github.com/sirupsen/logrus"
+
+	nberrors "github.com/netbirdio/netbird/client/errors"
+	firewall "github.com/netbirdio/netbird/client/firewall/manager"
+	nbid "github.com/netbirdio/netbird/client/internal/acl/id"
+	nbnet "github.com/netbirdio/netbird/client/net"
+)
+
+// AddFilterRule installs a packet-filtering rule. With destination
+// empty, the rule goes to the peer ACL input chain plus a paired
+// mangle PREROUTING rule for the redirect mark. With destination set
+// (prefix or named set), it goes to the route ACL forward chain.
+// Multi-source rules collapse to one iptables rule via the shared
+// hash:net ipset.
+func (r *family) AddFilterRule(
+	id []byte,
+	sources []netip.Prefix,
+	destination firewall.Network,
+	proto firewall.Protocol,
+	sPort *firewall.Port,
+	dPort *firewall.Port,
+	action firewall.Action,
+) (firewall.Rule, error) {
+	ruleID := nbid.GenerateRuleID(sources, destination, proto, sPort, dPort, action)
+	if existing, ok := r.filters[ruleID]; ok {
+		return existing, nil
+	}
+
+	rule, err := r.installFilterRules(ruleID, sources, destination, proto, sPort, dPort, action, r.ipsetSupported)
+	if err != nil {
+		return nil, err
+	}
+
+	r.filters[ruleID] = rule
+	r.updateState()
+	return rule, nil
+}
+
+// installFilterRules resolves the source matches and installs one
+// iptables rule per match. It is more than one rule only when useIPSet
+// is false and a multi-source rule has to be expanded per prefix.
+func (r *family) installFilterRules(
+	ruleID nbid.RuleID,
+	sources []netip.Prefix,
+	destination firewall.Network,
+	proto firewall.Protocol,
+	sPort *firewall.Port,
+	dPort *firewall.Port,
+	action firewall.Action,
+	useIPSet bool,
+) (*Rule, error) {
+	srcMatches, err := r.applySourceMatches(sources, useIPSet)
+	if err != nil {
+		return nil, fmt.Errorf("apply source match: %w", err)
+	}
+
+	rule, err := r.installFilterRule(ruleID, srcMatches, destination, proto, sPort, dPort, action)
+	if err != nil {
+		for _, srcMatch := range srcMatches {
+			r.dropSourceMatch(srcMatch)
+		}
+		return nil, err
+	}
+	return rule, nil
+}
+
+func (r *family) hasRule(id nbid.RuleID) bool {
+	_, ok := r.filters[id]
+	return ok
+}
+
+// hasDNATRule reports whether this family owns the DNAT rule set for
+// the given user id. DNAT rules live in r.rules under the well-known
+// "<id>_dnat" key; the lookup here is used by Manager.DeleteDNATRule
+// to pick the right family.
+func (r *family) hasDNATRule(id firewall.RuleID) bool {
+	_, ok := r.rules[id+dnatSuffix]
+	return ok
+}
+
+// DeleteFilterRule removes a previously installed filter rule. The
+// rule's stored chain/table identify where to delete from; source set
+// references are recovered from the spec via findSets and dropped
+// from the shared ipset counter.
+func (r *family) DeleteFilterRule(rule firewall.Rule) error {
+	ruleID := rule.ID()
+	pr, ok := r.filters[ruleID]
+	if !ok {
+		log.Debugf("filter rule %s not found", ruleID)
+		return nil
+	}
+
+	// DeleteIfExists keeps the deletes idempotent so a retry after a
+	// partial failure does not error on the parts already removed.
+	var merr *multierror.Error
+	for _, fs := range pr.allSpecs() {
+		if err := r.iptablesClient.DeleteIfExists(tableFilter, pr.chain, fs.specs...); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("delete rule from %s: %w", pr.chain, err))
+		}
+		if fs.mangleSpecs != nil {
+			if err := r.iptablesClient.DeleteIfExists(tableMangle, chainRTPre, fs.mangleSpecs...); err != nil {
+				merr = multierror.Append(merr, fmt.Errorf("delete mangle rule: %w", err))
+			}
+		}
+	}
+	if merr != nil {
+		// Leave the rule tracked so the caller retries the remaining part.
+		return nberrors.FormatErrorOrNil(merr)
+	}
+
+	// The rule is gone from iptables, so untrack it regardless of how the
+	// refcount decrement goes, but surface decrement failures so callers
+	// see the ipset desync. Only the primary spec can reference sets: the
+	// per-prefix expansion never uses them.
+	delete(r.filters, ruleID)
+	r.updateState()
+	if err := r.decrementSetCounter(pr.specs); err != nil {
+		return fmt.Errorf("drop source set references: %w", err)
+	}
+	return nil
+}
+
+// findSets scans an iptables rule spec for "-m set --match-set <name>
+// <dir>" fragments and returns the named sets in occurrence order.
+// Used at delete time to drop ipsetCounter references.
+func findSets(rule []string) []string {
+	var sets []string
+	for i, arg := range rule {
+		if arg == "-m" && i+3 < len(rule) && rule[i+1] == "set" && rule[i+2] == matchSet {
+			sets = append(sets, rule[i+3])
+		}
+	}
+	return sets
+}
+
+// sourceNetwork classifies a source-prefix list into the firewall.Network
+// shape the rest of the spec-builder consumes: empty for match-any, a
+// single prefix inline, or an ipset for multiple sources.
+func sourceNetwork(sources []netip.Prefix) firewall.Network {
+	switch {
+	case len(sources) == 0:
+		return firewall.Network{}
+	case len(sources) == 1 && sources[0].Bits() == 0:
+		return firewall.Network{}
+	case len(sources) == 1:
+		return firewall.Network{Prefix: sources[0]}
+	default:
+		return firewall.Network{Set: firewall.NewPrefixSet(sources)}
+	}
+}
+
+// applySourceMatches returns one source match fragment per iptables
+// rule needed for the sources: normally a single fragment (a set match,
+// a direct -s match, or nil for match-any), and one -s fragment per
+// prefix when a multi-source rule cannot use ipset. Per-prefix rules
+// are the only form a kernel without the ipset modules can express.
+func (r *family) applySourceMatches(sources []netip.Prefix, useIPSet bool) ([][]string, error) {
+	network := sourceNetwork(sources)
+	if !network.IsSet() || useIPSet {
+		match, err := r.applySourceMatch(network, sources)
+		if err != nil {
+			return nil, err
+		}
+		return [][]string{match}, nil
+	}
+
+	matches := make([][]string, 0, len(sources))
+	for _, source := range sources {
+		matches = append(matches, []string{"-s", source.String()})
+	}
+	return matches, nil
+}
+
+// applySourceMatch returns the iptables match fragment for the rule's
+// source. For a Set it increments the shared ipset's refcount; for a
+// Prefix it emits a direct -s match; for the wildcard it returns nil.
+func (r *family) applySourceMatch(network firewall.Network, prefixes []netip.Prefix) ([]string, error) {
+	switch {
+	case network.IsSet():
+		if r.ipsetCounter == nil {
+			return nil, fmt.Errorf("multi-source peer rule requires shared ipset counter")
+		}
+		name := r.ipsetName(network.Set.HashedName())
+		if _, err := r.ipsetCounter.Increment(name, prefixes); err != nil {
+			return nil, fmt.Errorf("ipset increment %s: %w", name, err)
+		}
+		return []string{"-m", "set", matchSet, name, "src"}, nil
+	case network.IsPrefix():
+		return []string{"-s", network.Prefix.String()}, nil
+	default:
+		return nil, nil
+	}
+}
+
+// dropSourceMatch undoes whatever applySourceMatch reserved when
+// installing a rule fails. Safe to call when the spec is empty or holds
+// only inline matchers. Decrement errors are logged but not returned:
+// the install error is what the caller needs to see.
+func (r *family) dropSourceMatch(srcMatch []string) {
+	if r.ipsetCounter == nil {
+		return
+	}
+	for _, name := range findSets(srcMatch) {
+		if _, err := r.ipsetCounter.Decrement(name); err != nil {
+			log.Errorf("rollback ipset decrement %s: %v", name, err)
+		}
+	}
+}
+
+// decrementSetCounter drops ipset references owned by a raw rule spec
+// stored in r.rules (NAT / legacy route entries). It returns an error
+// aggregate so the caller surfaces decrement failures.
+func (r *family) decrementSetCounter(rule []string) error {
+	if r.ipsetCounter == nil {
+		return nil
+	}
+	var merr *multierror.Error
+	for _, name := range findSets(rule) {
+		if _, err := r.ipsetCounter.Decrement(name); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("decrement counter: %w", err))
+		}
+	}
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+// installFilterRule assembles and writes the iptables filter-chain
+// rules for one filter rule, one per source match fragment. With
+// destination empty the rules land in the peer ACL input chain and each
+// gets a paired mangle PREROUTING rule for the redirect mark. With
+// destination set the rules land in the route ACL forward chain and
+// there is no mangle pairing.
+func (r *family) installFilterRule(
+	ruleID nbid.RuleID,
+	srcMatches [][]string,
+	destination firewall.Network,
+	protocol firewall.Protocol,
+	sPort, dPort *firewall.Port,
+	action firewall.Action,
+) (*Rule, error) {
+	isRoute := !destination.IsZero()
+
+	proto := protoForFamily(protocol, r.v6)
+
+	var destExp []string
+	if isRoute {
+		var err error
+		destExp, err = r.applyNetwork("-d", destination, nil)
+		if err != nil {
+			return nil, fmt.Errorf("apply network -d: %w", err)
+		}
+	}
+	matchSpecs := filterMatchSpecs(proto, sPort, dPort)
+
+	chain := chainACLInput
+	if isRoute {
+		chain = chainRTFwdIn
+	}
+
+	var installed []filterSpecs
+	for _, srcMatch := range srcMatches {
+		specs := slices.Clone(srcMatch)
+		specs = append(specs, destExp...)
+		specs = append(specs, matchSpecs...)
+
+		var mangleSpecs []string
+		if !isRoute {
+			mangleSpecs = slices.Clone(specs)
+			mangleSpecs = append(mangleSpecs,
+				"-i", r.wgIface.Name(),
+				"-m", "addrtype", "--dst-type", "LOCAL",
+				"-j", "MARK", "--set-xmark", fmt.Sprintf("%#x", nbnet.PreroutingFwmarkRedirected),
+			)
+		}
+
+		specs = append(specs, "-j", actionToStr(action))
+
+		if err := r.insertFilterRule(chain, action, specs); err != nil {
+			// Leave nothing half-installed: the caller sees an error, so a
+			// partial rule would silently keep matching without being tracked.
+			r.removeFilterSpecs(chain, installed)
+			r.dropSourceMatch(destExp)
+			return nil, fmt.Errorf("install filter rule on %s: %w", chain, err)
+		}
+
+		// The mangle redirect-mark rule is best effort: the filter rule itself
+		// is what enforces the ACL, so a mangle failure must not undo it. Drop
+		// the spec so teardown does not try to remove a rule that was not added.
+		if mangleSpecs != nil {
+			if err := r.iptablesClient.Append(tableMangle, chainRTPre, mangleSpecs...); err != nil {
+				log.Errorf("add mangle rule: %v", err)
+				mangleSpecs = nil
+			}
+		}
+
+		installed = append(installed, filterSpecs{specs: specs, mangleSpecs: mangleSpecs})
+	}
+
+	return &Rule{
+		id:          ruleID,
+		specs:       installed[0].specs,
+		mangleSpecs: installed[0].mangleSpecs,
+		extraRules:  installed[1:],
+		chain:       chain,
+		v6:          r.v6,
+	}, nil
+}
+
+// insertFilterRule writes one assembled rule spec into the given ACL
+// chain. Peer ACL drops are inserted at position 1 so they precede the
+// chain's catch-all; route ACL drops are inserted at position 2 to sit
+// immediately after the established/related accept rule.
+func (r *family) insertFilterRule(chain string, action firewall.Action, specs []string) error {
+	if action == firewall.ActionDrop {
+		pos := 1
+		if chain == chainRTFwdIn {
+			pos = 2
+		}
+		return r.iptablesClient.Insert(tableFilter, chain, pos, specs...)
+	}
+	return r.iptablesClient.Append(tableFilter, chain, specs...)
+}
+
+// removeFilterSpecs deletes the already-installed rules of a partially
+// applied filter rule.
+func (r *family) removeFilterSpecs(chain string, installed []filterSpecs) {
+	for _, fs := range installed {
+		if err := r.iptablesClient.DeleteIfExists(tableFilter, chain, fs.specs...); err != nil {
+			log.Debugf("delete partial filter rule: %v", err)
+		}
+		if fs.mangleSpecs != nil {
+			if err := r.iptablesClient.DeleteIfExists(tableMangle, chainRTPre, fs.mangleSpecs...); err != nil {
+				log.Debugf("delete partial mangle rule: %v", err)
+			}
+		}
+	}
+}
+
+// applyNetwork resolves a firewall.Network into the iptables match
+// fragment for the given direction flag (-s or -d). Set networks
+// increment the shared ipset refcount; prefixes emit a direct match;
+// an empty network returns no spec ("match any").
+func (r *family) applyNetwork(flag string, network firewall.Network, prefixes []netip.Prefix) ([]string, error) {
+	direction := "src"
+	if flag == "-d" {
+		direction = "dst"
+	}
+
+	if network.IsSet() {
+		// A destination set is populated later from DNS results, so unlike a
+		// source set it cannot be expanded into per-prefix rules. Without
+		// ipset such a rule is not expressible; report it instead of
+		// installing something broader than the policy allows.
+		if flag == "-d" && !r.ipsetSupported {
+			return nil, fmt.Errorf("destination set %s requires ipset (ip_set_hash_net and xt_set)", network.Set.HashedName())
+		}
+
+		name := r.ipsetName(network.Set.HashedName())
+		if _, err := r.ipsetCounter.Increment(name, prefixes); err != nil {
+			return nil, fmt.Errorf("create or get ipset: %w", err)
+		}
+
+		return []string{"-m", "set", matchSet, name, direction}, nil
+	}
+	if network.IsPrefix() {
+		return []string{flag, network.Prefix.String()}, nil
+	}
+
+	// nolint:nilnil
+	return nil, nil
+}
+
+// protoForFamily translates ICMP to ICMPv6 for ip6tables.
+// ip6tables requires "ipv6-icmp" (or "icmpv6") instead of "icmp".
+func protoForFamily(protocol firewall.Protocol, v6 bool) string {
+	if v6 && protocol == firewall.ProtocolICMP {
+		return "ipv6-icmp"
+	}
+	return string(protocol)
+}
+
+// filterMatchSpecs returns the proto/port match fragment for a
+// filtering rule. The source match (-s or -m set) is built by the
+// caller and prepended.
+func filterMatchSpecs(protocol string, sPort, dPort *firewall.Port) (specs []string) {
+	if protocol != "all" {
+		specs = append(specs, "-p", protocol)
+	}
+	specs = append(specs, applyPort("--sport", sPort)...)
+	specs = append(specs, applyPort("--dport", dPort)...)
+	return specs
+}
+
+func actionToStr(action firewall.Action) string {
+	if action == firewall.ActionAccept {
+		return "ACCEPT"
+	}
+	return "DROP"
+}
+
+func applyPort(flag string, port *firewall.Port) []string {
+	if port == nil {
+		return nil
+	}
+
+	if port.IsRange && len(port.Values) == 2 {
+		return []string{flag, fmt.Sprintf("%d:%d", port.Values[0], port.Values[1])}
+	}
+
+	if len(port.Values) > 1 {
+		portList := make([]string, len(port.Values))
+		for i, p := range port.Values {
+			portList[i] = strconv.Itoa(int(p))
+		}
+		return []string{"-m", "multiport", flag, strings.Join(portList, ",")}
+	}
+
+	return []string{flag, strconv.Itoa(int(port.Values[0]))}
+}

client/firewall/iptables/interface_allower_linux.go

@@ -0,0 +1,93 @@
+package iptables
+
+import (
+	"fmt"
+
+	"github.com/coreos/go-iptables/iptables"
+	"github.com/hashicorp/go-multierror"
+	log "github.com/sirupsen/logrus"
+
+	nberrors "github.com/netbirdio/netbird/client/errors"
+)
+
+// InterfaceAllower opens the NetBird interface on the iptables filter INPUT
+// chain so the host firewall doesn't drop traffic the userspace firewall
+// handles. It is the fallback used when nftables is unavailable (an
+// iptables-legacy host).
+//
+// It opens INPUT only: the userspace router never forwards in the kernel.
+// firewalld trust is handled by the uspfilter manager, not here.
+type InterfaceAllower struct {
+	ifaceName string
+	ipt4      *iptables.IPTables
+	// ipt6 is nil when the interface has no IPv6 overlay address.
+	ipt6 *iptables.IPTables
+}
+
+// NewInterfaceAllower builds an iptables allower for the interface. It returns
+// an error when iptables is unavailable, so the caller can fall back to
+// firewalld trust.
+func NewInterfaceAllower(wgIface iFaceMapper) (*InterfaceAllower, error) {
+	ipt4, err := iptables.NewWithProtocol(iptables.ProtocolIPv4)
+	if err != nil {
+		return nil, fmt.Errorf("iptables not available: %w", err)
+	}
+	if _, err := ipt4.ListChains(tableFilter); err != nil {
+		return nil, fmt.Errorf("iptables filter table not available: %w", err)
+	}
+
+	a := &InterfaceAllower{ifaceName: wgIface.Name(), ipt4: ipt4}
+
+	// Missing v6 must not break the v4 path: open v4 only and continue.
+	if wgIface.Address().HasIPv6() {
+		ipt6, err := iptables.NewWithProtocol(iptables.ProtocolIPv6)
+		if err != nil {
+			log.Warnf("ip6tables not available, opening interface on v4 only: %v", err)
+		} else if _, err := ipt6.ListChains(tableFilter); err != nil {
+			log.Warnf("ip6tables filter table not available, opening interface on v4 only: %v", err)
+		} else {
+			a.ipt6 = ipt6
+		}
+	}
+
+	return a, nil
+}
+
+// Apply inserts the interface accept rule on the filter INPUT chain. It removes
+// any stale rule first so an unclean exit (e.g. SIGKILL, where Close never ran)
+// is recovered deterministically rather than accumulating duplicates.
+func (a *InterfaceAllower) Apply() error {
+	var merr *multierror.Error
+	for _, ipt := range a.clients() {
+		if err := ipt.DeleteIfExists(tableFilter, chainInput, a.inputRule()...); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("clean stale interface accept rule: %w", err))
+		}
+		if err := ipt.Insert(tableFilter, chainInput, 1, a.inputRule()...); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("add interface accept rule: %w", err))
+		}
+	}
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+// Close removes the interface accept rule.
+func (a *InterfaceAllower) Close() error {
+	var merr *multierror.Error
+	for _, ipt := range a.clients() {
+		if err := ipt.DeleteIfExists(tableFilter, chainInput, a.inputRule()...); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("remove interface accept rule: %w", err))
+		}
+	}
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+func (a *InterfaceAllower) inputRule() []string {
+	return []string{"-i", a.ifaceName, "-j", "ACCEPT"}
+}
+
+func (a *InterfaceAllower) clients() []*iptables.IPTables {
+	clients := []*iptables.IPTables{a.ipt4}
+	if a.ipt6 != nil {
+		clients = append(clients, a.ipt6)
+	}
+	return clients
+}

client/firewall/iptables/ipset_linux.go

@@ -0,0 +1,131 @@
+//go:build !android
+
+package iptables
+
+import (
+	"fmt"
+	"net/netip"
+
+	"github.com/google/uuid"
+	"github.com/hashicorp/go-multierror"
+	"github.com/lrh3321/ipset-go"
+	log "github.com/sirupsen/logrus"
+
+	nberrors "github.com/netbirdio/netbird/client/errors"
+	firewall "github.com/netbirdio/netbird/client/firewall/manager"
+)
+
+// probeIPSetSupport checks whether the kernel can create the ipset type
+// used for source and destination matches. On kernels lacking the
+// required ipset hash module, set creation fails (e.g. "invalid
+// argument"), which would otherwise fail every multi-source rule and
+// leave traffic the policy permits blocked by the catch-all drop. When
+// unsupported, multi-source rules fall back to one rule per prefix.
+func (r *family) probeIPSetSupport() bool {
+	// Use a unique name so concurrent processes don't collide and we only ever
+	// destroy the set we created ourselves. ipset names are limited to 31 chars,
+	// so use a short random suffix.
+	probeName := "nb-probe-" + uuid.New().String()[:8]
+
+	if err := r.createIPSet(probeName); err != nil {
+		log.Warnf("ipset is not available (failed to create probe set: %v); "+
+			"falling back to per-IP iptables ACL rules. Ensure the kernel provides "+
+			"the ipset hash:net module (ip_set_hash_net) for better performance with large rule sets", err)
+		return false
+	}
+
+	if err := r.destroyIPSet(probeName); err != nil {
+		log.Debugf("destroy ipset probe set %q: %v", probeName, err)
+	}
+
+	return true
+}
+
+func (r *family) createIpSet(setName string, sources []netip.Prefix) error {
+	if err := r.createIPSet(setName); err != nil {
+		return fmt.Errorf("create set %s: %w", setName, err)
+	}
+
+	for _, prefix := range sources {
+		if err := r.addPrefixToIPSet(setName, prefix); err != nil {
+			// The refcounter records nothing when this callback errors,
+			// so destroy the set or it leaks in the kernel. A partial
+			// source set would also fail-open for deny rules, so the
+			// rule must fail rather than install with a missing source.
+			if derr := r.destroyIPSet(setName); derr != nil {
+				log.Warnf("rollback ipset %s after add failure: %v", setName, derr)
+			}
+			return fmt.Errorf("add element to set %s: %w", setName, err)
+		}
+	}
+
+	return nil
+}
+
+func (r *family) deleteIpSet(setName string) error {
+	if err := r.destroyIPSet(setName); err != nil {
+		return fmt.Errorf("destroy set %s: %w", setName, err)
+	}
+
+	log.Debugf("deleted unused ipset %s", setName)
+	return nil
+}
+
+func (r *family) UpdateSet(set firewall.Set, prefixes []netip.Prefix) error {
+	name := r.ipsetName(set.HashedName())
+	var merr *multierror.Error
+	for _, prefix := range prefixes {
+		if err := r.addPrefixToIPSet(name, prefix); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("add prefix to ipset: %w", err))
+		}
+	}
+	if merr == nil {
+		log.Debugf("updated set %s with prefixes %v", name, prefixes)
+	}
+
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+func (r *family) ipsetName(name string) string {
+	if r.v6 {
+		return name + "-v6"
+	}
+	return name
+}
+
+func (r *family) createIPSet(name string) error {
+	opts := ipset.CreateOptions{
+		Replace: true,
+	}
+	if r.v6 {
+		opts.Family = ipset.FamilyIPV6
+	}
+
+	if err := ipset.Create(name, ipset.TypeHashNet, opts); err != nil {
+		return fmt.Errorf("create ipset %s: %w", name, err)
+	}
+
+	log.Debugf("created ipset %s with type hash:net", name)
+	return nil
+}
+
+func (r *family) addPrefixToIPSet(name string, prefix netip.Prefix) error {
+	addr := prefix.Addr()
+	ip := addr.AsSlice()
+
+	entry := &ipset.Entry{
+		IP:      ip,
+		CIDR:    uint8(prefix.Bits()),
+		Replace: true,
+	}
+
+	if err := ipset.Add(name, entry); err != nil {
+		return fmt.Errorf("add prefix to ipset %s: %w", name, err)
+	}
+
+	return nil
+}
+
+func (r *family) destroyIPSet(name string) error {
+	return ipset.Destroy(name)
+}

client/firewall/iptables/manager_linux.go

@@ -3,7 +3,6 @@ package iptables
 import (
 	"context"
 	"fmt"
-	"net"
 	"net/netip"
 	"sync"
 
@@ -18,25 +17,21 @@ import (
 	"github.com/netbirdio/netbird/client/internal/statemanager"
 )
 
-type resetter interface {
+// Manager of iptables firewall. Per-family state (peer ACLs, route
-	Reset() error
+// ACLs, NAT, DNAT, MSS clamping) lives on family; Manager dispatches
-}
+// by family and provides the public firewall.Manager surface.
-
-// Manager of iptables firewall
 type Manager struct {
 	mutex sync.Mutex
 
 	wgIface iFaceMapper
 
 	ipv4Client   *iptables.IPTables
-	aclMgr       *aclManager
+	family4      *family
-	router       *router
 	rawSupported bool
 
 	// IPv6 counterparts, nil when no v6 overlay
 	ipv6Client *iptables.IPTables
-	aclMgr6    *aclManager
+	family6    *family
-	router6    *router
 }
 
 // iFaceMapper defines subset methods of interface required for manager
@@ -57,14 +52,9 @@ func Create(wgIface iFaceMapper, mtu uint16) (*Manager, error) {
 		ipv4Client: iptablesClient,
 	}
 
-	m.router, err = newRouter(iptablesClient, wgIface, mtu)
+	m.family4, err = newFamily(iptablesClient, wgIface, mtu)
 	if err != nil {
-		return nil, fmt.Errorf("create router: %w", err)
+		return nil, fmt.Errorf("create family: %w", err)
-	}
-
-	m.aclMgr, err = newAclManager(iptablesClient, wgIface)
-	if err != nil {
-		return nil, fmt.Errorf("create acl manager: %w", err)
 	}
 
 	if wgIface.Address().HasIPv6() {
@@ -81,21 +71,18 @@ func (m *Manager) createIPv6Components(wgIface iFaceMapper, mtu uint16) error {
 	if err != nil {
 		return fmt.Errorf("init ip6tables: %w", err)
 	}
+
+	family6, err := newFamily(ip6Client, wgIface, mtu)
+	if err != nil {
+		return fmt.Errorf("create v6 family: %w", err)
+	}
+
+	// Share the same IP forwarding state with the v4 family, since the
+	// forwarding refcounter is per-family but shared between both families.
+	family6.ipFwdState = m.family4.ipFwdState
+
 	m.ipv6Client = ip6Client
-
+	m.family6 = family6
-	m.router6, err = newRouter(ip6Client, wgIface, mtu)
-	if err != nil {
-		return fmt.Errorf("create v6 router: %w", err)
-	}
-
-	// Share the same IP forwarding state with the v4 router, since
-	// Forwarding refcounter is per-family but shared between v4 and v6 routers.
-	m.router6.ipFwdState = m.router.ipFwdState
-
-	m.aclMgr6, err = newAclManager(ip6Client, wgIface)
-	if err != nil {
-		return fmt.Errorf("create v6 acl manager: %w", err)
-	}
 
 	return nil
 }
@@ -109,7 +96,7 @@ func (m *Manager) Init(stateManager *statemanager.Manager) error {
 		InterfaceState: &InterfaceState{
 			NameStr:   m.wgIface.Name(),
 			WGAddress: m.wgIface.Address(),
-			MTU:       m.router.mtu,
+			MTU:       m.family4.mtu,
 		},
 	}
 	stateManager.RegisterState(state)
@@ -141,31 +128,24 @@ func (m *Manager) Init(stateManager *statemanager.Manager) error {
 	return nil
 }
 
-// initChains initializes router and ACL chains for both address families,
+// initChains initializes the per-family firewall state for both
-// rolling back on failure.
+// address families, rolling back on failure.
 func (m *Manager) initChains(stateManager *statemanager.Manager) error {
 	type initStep struct {
 		name string
-		init func(*statemanager.Manager) error
+		r    *family
-		mgr  resetter
 	}
 
-	steps := []initStep{
+	steps := []initStep{{"v4", m.family4}}
-		{"router", m.router.init, m.router},
-		{"acl manager", m.aclMgr.init, m.aclMgr},
-	}
 	if m.hasIPv6() {
-		steps = append(steps,
+		steps = append(steps, initStep{"v6", m.family6})
-			initStep{"v6 router", m.router6.init, m.router6},
-			initStep{"v6 acl manager", m.aclMgr6.init, m.aclMgr6},
-		)
 	}
 
 	var initialized []initStep
 	for _, s := range steps {
-		if err := s.init(stateManager); err != nil {
+		if err := s.r.init(stateManager); err != nil {
 			for i := len(initialized) - 1; i >= 0; i-- {
-				if rerr := initialized[i].mgr.Reset(); rerr != nil {
+				if rerr := initialized[i].r.Reset(); rerr != nil {
 					log.Warnf("rollback %s: %v", initialized[i].name, rerr)
 				}
 			}
@@ -176,84 +156,50 @@ func (m *Manager) initChains(stateManager *statemanager.Manager) error {
 	return nil
 }
 
-// AddPeerFiltering adds a rule to the firewall
+// AddFilterRule installs a packet-filtering rule. See firewall.Manager
-//
+// docs for destination semantics. Sources are a single address family;
-// Comment will be ignored because some system this feature is not supported
+// the rule is dispatched to the matching v4 / v6 backend.
-func (m *Manager) AddPeerFiltering(
+func (m *Manager) AddFilterRule(
-	id []byte,
-	ip net.IP,
-	proto firewall.Protocol,
-	sPort *firewall.Port,
-	dPort *firewall.Port,
-	action firewall.Action,
-	ipsetName string,
-) ([]firewall.Rule, error) {
-	m.mutex.Lock()
-	defer m.mutex.Unlock()
-
-	if ip.To4() != nil {
-		return m.aclMgr.AddPeerFiltering(id, ip, proto, sPort, dPort, action, ipsetName)
-	}
-	if !m.hasIPv6() {
-		return nil, fmt.Errorf("add peer filtering for %s: %w", ip, firewall.ErrIPv6NotInitialized)
-	}
-	return m.aclMgr6.AddPeerFiltering(id, ip, proto, sPort, dPort, action, ipsetName)
-}
-
-func (m *Manager) AddRouteFiltering(
 	id []byte,
 	sources []netip.Prefix,
 	destination firewall.Network,
 	proto firewall.Protocol,
-	sPort, dPort *firewall.Port,
+	sPort *firewall.Port,
+	dPort *firewall.Port,
 	action firewall.Action,
 ) (firewall.Rule, error) {
+	if len(sources) == 0 {
+		return nil, firewall.ErrNoSources
+	}
+
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if isIPv6RouteRule(sources, destination) {
+	fam := m.family4
+	if isIPv6Rule(sources, destination) {
 		if !m.hasIPv6() {
-			return nil, fmt.Errorf("add route filtering: %w", firewall.ErrIPv6NotInitialized)
+			return nil, fmt.Errorf("add filtering: %w", firewall.ErrIPv6NotInitialized)
 		}
-		return m.router6.AddRouteFiltering(id, sources, destination, proto, sPort, dPort, action)
+		fam = m.family6
 	}
-
+	return fam.AddFilterRule(id, sources, destination, proto, sPort, dPort, action)
-	return m.router.AddRouteFiltering(id, sources, destination, proto, sPort, dPort, action)
 }
 
-func isIPv6RouteRule(sources []netip.Prefix, destination firewall.Network) bool {
+// DeleteFilterRule removes a rule previously added via AddFilterRule.
-	if destination.IsPrefix() {
+// The rule is looked up by id in each family's filter cache.
-		return destination.Prefix.Addr().Is6()
+func (m *Manager) DeleteFilterRule(rule firewall.Rule) error {
-	}
-	return len(sources) > 0 && sources[0].Addr().Is6()
-}
-
-// DeletePeerRule from the firewall by rule definition
-func (m *Manager) DeletePeerRule(rule firewall.Rule) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if m.hasIPv6() && isIPv6IptRule(rule) {
+	id := rule.ID()
-		return m.aclMgr6.DeletePeerRule(rule)
+	if m.family4.hasRule(id) {
+		return m.family4.DeleteFilterRule(rule)
 	}
-	return m.aclMgr.DeletePeerRule(rule)
+	if m.hasIPv6() && m.family6.hasRule(id) {
-}
+		return m.family6.DeleteFilterRule(rule)
-
-func isIPv6IptRule(rule firewall.Rule) bool {
-	r, ok := rule.(*Rule)
-	return ok && r.v6
-}
-
-// DeleteRouteRule deletes a routing rule.
-// Route rules are keyed by content hash. Check v4 first, try v6 if not found.
-func (m *Manager) DeleteRouteRule(rule firewall.Rule) error {
-	m.mutex.Lock()
-	defer m.mutex.Unlock()
-
-	if m.hasIPv6() && !m.router.hasRule(rule.ID()) {
-		return m.router6.DeleteRouteRule(rule)
 	}
-	return m.router.DeleteRouteRule(rule)
+	log.Debugf("filter rule %s not found in any family", id)
+	return nil
 }
 
 func (m *Manager) IsServerRouteSupported() bool {
@@ -272,10 +218,10 @@ func (m *Manager) AddNatRule(pair firewall.RouterPair) error {
 		if !m.hasIPv6() {
 			return fmt.Errorf("add NAT rule: %w", firewall.ErrIPv6NotInitialized)
 		}
-		return m.router6.AddNatRule(pair)
+		return m.family6.AddNatRule(pair)
 	}
 
-	if err := m.router.AddNatRule(pair); err != nil {
+	if err := m.family4.AddNatRule(pair); err != nil {
 		return err
 	}
 
@@ -284,7 +230,7 @@ func (m *Manager) AddNatRule(pair firewall.RouterPair) error {
 	// wildcard 0.0.0.0/0 destination where the client resolves DNS.
 	if m.hasIPv6() && pair.Dynamic {
 		v6Pair := firewall.ToV6NatPair(pair)
-		if err := m.router6.AddNatRule(v6Pair); err != nil {
+		if err := m.family6.AddNatRule(v6Pair); err != nil {
 			return fmt.Errorf("add v6 NAT rule: %w", err)
 		}
 	}
@@ -300,18 +246,18 @@ func (m *Manager) RemoveNatRule(pair firewall.RouterPair) error {
 		if !m.hasIPv6() {
 			return nil
 		}
-		return m.router6.RemoveNatRule(pair)
+		return m.family6.RemoveNatRule(pair)
 	}
 
 	var merr *multierror.Error
 
-	if err := m.router.RemoveNatRule(pair); err != nil {
+	if err := m.family4.RemoveNatRule(pair); err != nil {
 		merr = multierror.Append(merr, fmt.Errorf("remove v4 NAT rule: %w", err))
 	}
 
 	if m.hasIPv6() && pair.Dynamic {
 		v6Pair := firewall.ToV6NatPair(pair)
-		if err := m.router6.RemoveNatRule(v6Pair); err != nil {
+		if err := m.family6.RemoveNatRule(v6Pair); err != nil {
 			merr = multierror.Append(merr, fmt.Errorf("remove v6 NAT rule: %w", err))
 		}
 	}
@@ -320,11 +266,14 @@ func (m *Manager) RemoveNatRule(pair firewall.RouterPair) error {
 }
 
 func (m *Manager) SetLegacyManagement(isLegacy bool) error {
-	if err := firewall.SetLegacyManagement(m.router, isLegacy); err != nil {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+
+	if err := firewall.SetLegacyManagement(m.family4, isLegacy); err != nil {
 		return err
 	}
 	if m.hasIPv6() {
-		return firewall.SetLegacyManagement(m.router6, isLegacy)
+		return firewall.SetLegacyManagement(m.family6, isLegacy)
 	}
 	return nil
 }
@@ -341,19 +290,13 @@ func (m *Manager) Close(stateManager *statemanager.Manager) error {
 	}
 
 	if m.hasIPv6() {
-		if err := m.aclMgr6.Reset(); err != nil {
+		if err := m.family6.Reset(); err != nil {
-			merr = multierror.Append(merr, fmt.Errorf("reset v6 acl manager: %w", err))
+			merr = multierror.Append(merr, fmt.Errorf("reset v6 family: %w", err))
-		}
-		if err := m.router6.Reset(); err != nil {
-			merr = multierror.Append(merr, fmt.Errorf("reset v6 router: %w", err))
 		}
 	}
 
-	if err := m.aclMgr.Reset(); err != nil {
+	if err := m.family4.Reset(); err != nil {
-		merr = multierror.Append(merr, fmt.Errorf("reset acl manager: %w", err))
+		merr = multierror.Append(merr, fmt.Errorf("reset family: %w", err))
-	}
-	if err := m.router.Reset(); err != nil {
-		merr = multierror.Append(merr, fmt.Errorf("reset router: %w", err))
 	}
 
 	// Appending to merr intentionally blocks DeleteState below so ShutdownState
@@ -372,27 +315,6 @@ func (m *Manager) Close(stateManager *statemanager.Manager) error {
 	return nberrors.FormatErrorOrNil(merr)
 }
 
-// AllowNetbird allows netbird interface traffic.
-// This is called when USPFilter wraps the native firewall, adding blanket accept
-// rules so that packet filtering is handled in userspace instead of by netfilter.
-func (m *Manager) AllowNetbird() error {
-	var merr *multierror.Error
-	if _, err := m.AddPeerFiltering(nil, net.IP{0, 0, 0, 0}, firewall.ProtocolALL, nil, nil, firewall.ActionAccept, ""); err != nil {
-		merr = multierror.Append(merr, fmt.Errorf("allow netbird v4 interface traffic: %w", err))
-	}
-	if m.hasIPv6() {
-		if _, err := m.AddPeerFiltering(nil, net.IPv6zero, firewall.ProtocolALL, nil, nil, firewall.ActionAccept, ""); err != nil {
-			merr = multierror.Append(merr, fmt.Errorf("allow netbird v6 interface traffic: %w", err))
-		}
-	}
-
-	if err := firewalld.TrustInterface(m.wgIface.Name()); err != nil {
-		log.Warnf("failed to trust interface in firewalld: %v", err)
-	}
-
-	return nberrors.FormatErrorOrNil(merr)
-}
-
 // Flush doesn't need to be implemented for this manager
 func (m *Manager) Flush() error { return nil }
 
@@ -403,11 +325,11 @@ func (m *Manager) SetLogLevel(log.Level) {
 
 func (m *Manager) EnableRouting() error {
 	// v6 only when the overlay actually has v6.
-	return m.router.ipFwdState.RequestRouting(m.router6 != nil)
+	return m.family4.ipFwdState.RequestRouting(m.hasIPv6())
 }
 
 func (m *Manager) DisableRouting() error {
-	return m.router.ipFwdState.ReleaseRouting()
+	return m.family4.ipFwdState.ReleaseRouting()
 }
 
 // AddDNATRule adds a DNAT rule
@@ -419,9 +341,9 @@ func (m *Manager) AddDNATRule(rule firewall.ForwardRule) (firewall.Rule, error)
 		if !m.hasIPv6() {
 			return nil, fmt.Errorf("add DNAT rule: %w", firewall.ErrIPv6NotInitialized)
 		}
-		return m.router6.AddDNATRule(rule)
+		return m.family6.AddDNATRule(rule)
 	}
-	return m.router.AddDNATRule(rule)
+	return m.family4.AddDNATRule(rule)
 }
 
 // DeleteDNATRule deletes a DNAT rule
@@ -429,10 +351,10 @@ func (m *Manager) DeleteDNATRule(rule firewall.Rule) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if m.hasIPv6() && !m.router.hasRule(rule.ID()+dnatSuffix) {
+	if m.hasIPv6() && !m.family4.hasDNATRule(rule.ID()) {
-		return m.router6.DeleteDNATRule(rule)
+		return m.family6.DeleteDNATRule(rule)
 	}
-	return m.router.DeleteDNATRule(rule)
+	return m.family4.DeleteDNATRule(rule)
 }
 
 // UpdateSet updates the set with the given prefixes
@@ -449,12 +371,12 @@ func (m *Manager) UpdateSet(set firewall.Set, prefixes []netip.Prefix) error {
 		}
 	}
 
-	if err := m.router.UpdateSet(set, v4Prefixes); err != nil {
+	if err := m.family4.UpdateSet(set, v4Prefixes); err != nil {
 		return err
 	}
 
 	if m.hasIPv6() && len(v6Prefixes) > 0 {
-		if err := m.router6.UpdateSet(set, v6Prefixes); err != nil {
+		if err := m.family6.UpdateSet(set, v6Prefixes); err != nil {
 			return fmt.Errorf("update v6 set: %w", err)
 		}
 	}
@@ -471,9 +393,9 @@ func (m *Manager) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protoco
 		if !m.hasIPv6() {
 			return fmt.Errorf("add inbound DNAT: %w", firewall.ErrIPv6NotInitialized)
 		}
-		return m.router6.AddInboundDNAT(localAddr, protocol, originalPort, translatedPort)
+		return m.family6.AddInboundDNAT(localAddr, protocol, originalPort, translatedPort)
 	}
-	return m.router.AddInboundDNAT(localAddr, protocol, originalPort, translatedPort)
+	return m.family4.AddInboundDNAT(localAddr, protocol, originalPort, translatedPort)
 }
 
 // RemoveInboundDNAT removes an inbound DNAT rule.
@@ -485,9 +407,9 @@ func (m *Manager) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Prot
 		if !m.hasIPv6() {
 			return fmt.Errorf("remove inbound DNAT: %w", firewall.ErrIPv6NotInitialized)
 		}
-		return m.router6.RemoveInboundDNAT(localAddr, protocol, originalPort, translatedPort)
+		return m.family6.RemoveInboundDNAT(localAddr, protocol, originalPort, translatedPort)
 	}
-	return m.router.RemoveInboundDNAT(localAddr, protocol, originalPort, translatedPort)
+	return m.family4.RemoveInboundDNAT(localAddr, protocol, originalPort, translatedPort)
 }
 
 // AddOutputDNAT adds an OUTPUT chain DNAT rule for locally-generated traffic.
@@ -499,9 +421,9 @@ func (m *Manager) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol
 		if !m.hasIPv6() {
 			return fmt.Errorf("add output DNAT: %w", firewall.ErrIPv6NotInitialized)
 		}
-		return m.router6.AddOutputDNAT(localAddr, protocol, originalPort, translatedPort)
+		return m.family6.AddOutputDNAT(localAddr, protocol, originalPort, translatedPort)
 	}
-	return m.router.AddOutputDNAT(localAddr, protocol, originalPort, translatedPort)
+	return m.family4.AddOutputDNAT(localAddr, protocol, originalPort, translatedPort)
 }
 
 // RemoveOutputDNAT removes an OUTPUT chain DNAT rule.
@@ -513,14 +435,14 @@ func (m *Manager) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Proto
 		if !m.hasIPv6() {
 			return fmt.Errorf("remove output DNAT: %w", firewall.ErrIPv6NotInitialized)
 		}
-		return m.router6.RemoveOutputDNAT(localAddr, protocol, originalPort, translatedPort)
+		return m.family6.RemoveOutputDNAT(localAddr, protocol, originalPort, translatedPort)
 	}
-	return m.router.RemoveOutputDNAT(localAddr, protocol, originalPort, translatedPort)
+	return m.family4.RemoveOutputDNAT(localAddr, protocol, originalPort, translatedPort)
 }
 
 const (
 	chainNameRaw = "NETBIRD-RAW"
-	chainOUTPUT  = "OUTPUT"
+	chainOutput  = "OUTPUT"
 	tableRaw     = "raw"
 )
 
@@ -595,15 +517,15 @@ func (m *Manager) initNoTrackChain() error {
 
 	jumpRule := []string{"-j", chainNameRaw}
 
-	if err := m.ipv4Client.InsertUnique(tableRaw, chainOUTPUT, 1, jumpRule...); err != nil {
+	if err := m.ipv4Client.InsertUnique(tableRaw, chainOutput, 1, jumpRule...); err != nil {
 		if delErr := m.ipv4Client.DeleteChain(tableRaw, chainNameRaw); delErr != nil {
 			log.Debugf("delete orphan chain: %v", delErr)
 		}
 		return fmt.Errorf("add output jump rule: %w", err)
 	}
 
-	if err := m.ipv4Client.InsertUnique(tableRaw, chainPREROUTING, 1, jumpRule...); err != nil {
+	if err := m.ipv4Client.InsertUnique(tableRaw, chainPrerouting, 1, jumpRule...); err != nil {
-		if delErr := m.ipv4Client.DeleteIfExists(tableRaw, chainOUTPUT, jumpRule...); delErr != nil {
+		if delErr := m.ipv4Client.DeleteIfExists(tableRaw, chainOutput, jumpRule...); delErr != nil {
 			log.Debugf("delete output jump rule: %v", delErr)
 		}
 		if delErr := m.ipv4Client.DeleteChain(tableRaw, chainNameRaw); delErr != nil {
@@ -630,11 +552,11 @@ func (m *Manager) cleanupNoTrackChain() error {
 
 	jumpRule := []string{"-j", chainNameRaw}
 
-	if err := m.ipv4Client.DeleteIfExists(tableRaw, chainOUTPUT, jumpRule...); err != nil {
+	if err := m.ipv4Client.DeleteIfExists(tableRaw, chainOutput, jumpRule...); err != nil {
 		return fmt.Errorf("remove output jump rule: %w", err)
 	}
 
-	if err := m.ipv4Client.DeleteIfExists(tableRaw, chainPREROUTING, jumpRule...); err != nil {
+	if err := m.ipv4Client.DeleteIfExists(tableRaw, chainPrerouting, jumpRule...); err != nil {
 		return fmt.Errorf("remove prerouting jump rule: %w", err)
 	}
 
@@ -649,3 +571,13 @@ func (m *Manager) cleanupNoTrackChain() error {
 func getConntrackEstablished() []string {
 	return []string{"-m", "conntrack", "--ctstate", "RELATED,ESTABLISHED", "-j", "ACCEPT"}
 }
+
+// isIPv6Rule reports whether the rule belongs to the IPv6 family, from
+// the destination prefix when set, otherwise from the (single-family)
+// sources.
+func isIPv6Rule(sources []netip.Prefix, destination firewall.Network) bool {
+	if destination.IsPrefix() {
+		return destination.Prefix.Addr().Is6()
+	}
+	return len(sources) > 0 && sources[0].Addr().Is6()
+}

client/firewall/iptables/manager_linux_test.go

@@ -5,16 +5,19 @@ package iptables
 import (
 	"fmt"
 	"net/netip"
+	"slices"
 	"strings"
 	"testing"
 	"time"
 
 	"github.com/coreos/go-iptables/iptables"
+	"github.com/lrh3321/ipset-go"
 	"github.com/stretchr/testify/require"
 
 	fw "github.com/netbirdio/netbird/client/firewall/manager"
 	"github.com/netbirdio/netbird/client/iface"
 	"github.com/netbirdio/netbird/client/iface/wgaddr"
+	"github.com/netbirdio/netbird/shared/management/domain"
 )
 
 var ifaceMock = &iFaceMock{
@@ -67,47 +70,37 @@ func TestIptablesManager(t *testing.T) {
 		time.Sleep(time.Second)
 	}()
 
-	var rule2 []fw.Rule
+	var rule2 fw.Rule
 	t.Run("add second rule", func(t *testing.T) {
 		ip := netip.MustParseAddr("10.20.0.3")
 		port := &fw.Port{
 			IsRange: true,
 			Values:  []uint16{8043, 8046},
 		}
-		rule2, err = manager.AddPeerFiltering(nil, ip.AsSlice(), "tcp", port, nil, fw.ActionAccept, "")
+		rule2, err = manager.AddFilterRule(nil, pfx(ip.AsSlice()), fw.Network{}, "tcp", port, nil, fw.ActionAccept)
 		require.NoError(t, err, "failed to add rule")
 
-		for _, r := range rule2 {
+		rr := rule2.(*Rule)
-			rr := r.(*Rule)
+		checkRuleSpecs(t, ipv4Client, rr.chain, true, rr.specs...)
-			checkRuleSpecs(t, ipv4Client, rr.chain, true, rr.specs...)
-		}
 	})
 
 	t.Run("delete second rule", func(t *testing.T) {
-		for _, r := range rule2 {
+		require.NoError(t, manager.DeleteFilterRule(rule2), "failed to delete rule")
-			err := manager.DeletePeerRule(r)
-			require.NoError(t, err, "failed to delete rule")
-		}
-
-		require.Empty(t, manager.aclMgr.ipsetStore.ipsets, "rulesets index after removed second rule must be empty")
 	})
 
 	t.Run("reset check", func(t *testing.T) {
 		// add second rule
 		ip := netip.MustParseAddr("10.20.0.3")
 		port := &fw.Port{Values: []uint16{5353}}
-		_, err = manager.AddPeerFiltering(nil, ip.AsSlice(), "udp", nil, port, fw.ActionAccept, "")
+		_, err = manager.AddFilterRule(nil, pfx(ip.AsSlice()), fw.Network{}, "udp", nil, port, fw.ActionAccept)
 		require.NoError(t, err, "failed to add rule")
 
 		err = manager.Close(nil)
 		require.NoError(t, err, "failed to reset")
 
-		ok, err := ipv4Client.ChainExists("filter", chainNameInputRules)
+		ok, err := ipv4Client.ChainExists("filter", chainACLInput)
 		require.NoError(t, err, "failed check chain exists")
-
+		require.Falsef(t, ok, "chain %q still exists after Close", chainACLInput)
-		if ok {
-			require.NoErrorf(t, err, "chain '%v' still exists after Close", chainNameInputRules)
-		}
 	})
 }
 
@@ -128,15 +121,13 @@ func TestIptablesManagerDenyRules(t *testing.T) {
 		ip := netip.MustParseAddr("10.20.0.3")
 		port := &fw.Port{Values: []uint16{22}}
 
-		rule, err := manager.AddPeerFiltering(nil, ip.AsSlice(), "tcp", nil, port, fw.ActionDrop, "deny-ssh")
+		rule, err := manager.AddFilterRule(nil, pfx(ip.AsSlice()), fw.Network{}, "tcp", nil, port, fw.ActionDrop)
 		require.NoError(t, err, "failed to add deny rule")
-		require.NotEmpty(t, rule, "deny rule should not be empty")
+		require.NotNil(t, rule, "deny rule should not be nil")
 
 		// Verify the rule was added by checking iptables
-		for _, r := range rule {
+		rr := rule.(*Rule)
-			rr := r.(*Rule)
+		checkRuleSpecs(t, ipv4Client, rr.chain, true, rr.specs...)
-			checkRuleSpecs(t, ipv4Client, rr.chain, true, rr.specs...)
-		}
 	})
 
 	t.Run("deny rule precedence test", func(t *testing.T) {
@@ -144,36 +135,40 @@ func TestIptablesManagerDenyRules(t *testing.T) {
 		port := &fw.Port{Values: []uint16{80}}
 
 		// Add accept rule first
-		_, err := manager.AddPeerFiltering(nil, ip.AsSlice(), "tcp", nil, port, fw.ActionAccept, "accept-http")
+		_, err := manager.AddFilterRule(nil, pfx(ip.AsSlice()), fw.Network{}, "tcp", nil, port, fw.ActionAccept)
 		require.NoError(t, err, "failed to add accept rule")
 
 		// Add deny rule second for same IP/port - this should take precedence
-		_, err = manager.AddPeerFiltering(nil, ip.AsSlice(), "tcp", nil, port, fw.ActionDrop, "deny-http")
+		_, err = manager.AddFilterRule(nil, pfx(ip.AsSlice()), fw.Network{}, "tcp", nil, port, fw.ActionDrop)
 		require.NoError(t, err, "failed to add deny rule")
 
 		// Inspect the actual iptables rules to verify deny rule comes before accept rule
-		rules, err := ipv4Client.List("filter", chainNameInputRules)
+		rules, err := ipv4Client.List("filter", chainACLInput)
 		require.NoError(t, err, "failed to list iptables rules")
 
 		// Debug: print all rules
-		t.Logf("All iptables rules in chain %s:", chainNameInputRules)
+		t.Logf("All iptables rules in chain %s:", chainACLInput)
 		for i, rule := range rules {
 			t.Logf("  [%d] %s", i, rule)
 		}
 
+		// Single-source rules emit a direct `-s <ip>/32 ... --dport 80`
+		// match. Match on that shape instead of the legacy
+		// per-(action,port) ipset names ("deny-http"/"accept-http")
+		// that this test predates.
+		srcMatch := fmt.Sprintf("-s %s/32", ip)
 		var denyRuleIndex, acceptRuleIndex = -1, -1
 		for i, rule := range rules {
-			if strings.Contains(rule, "DROP") {
+			if !strings.Contains(rule, srcMatch) || !strings.Contains(rule, "--dport 80") {
-				t.Logf("Found DROP rule at index %d: %s", i, rule)
+				continue
-				if strings.Contains(rule, "deny-http") && strings.Contains(rule, "80") {
-					denyRuleIndex = i
-				}
 			}
-			if strings.Contains(rule, "ACCEPT") {
+			if strings.Contains(rule, "-j DROP") {
+				t.Logf("Found DROP rule at index %d: %s", i, rule)
+				denyRuleIndex = i
+			}
+			if strings.Contains(rule, "-j ACCEPT") {
 				t.Logf("Found ACCEPT rule at index %d: %s", i, rule)
-				if strings.Contains(rule, "accept-http") && strings.Contains(rule, "80") {
+				acceptRuleIndex = i
-					acceptRuleIndex = i
-				}
 			}
 		}
 
@@ -198,7 +193,6 @@ func TestIptablesManagerIPSet(t *testing.T) {
 		},
 	}
 
-	// just check on the local interface
 	manager, err := Create(mock, iface.DefaultMTU)
 	require.NoError(t, err)
 	require.NoError(t, manager.Init(nil))
@@ -212,27 +206,39 @@ func TestIptablesManagerIPSet(t *testing.T) {
 		time.Sleep(time.Second)
 	}()
 
-	var rule2 []fw.Rule
+	var rule2 fw.Rule
-	t.Run("add second rule", func(t *testing.T) {
+	t.Run("single source uses direct -s match (no ipset)", func(t *testing.T) {
 		ip := netip.MustParseAddr("10.20.0.3")
 		port := &fw.Port{
 			Values: []uint16{443},
 		}
-		rule2, err = manager.AddPeerFiltering(nil, ip.AsSlice(), "tcp", port, nil, fw.ActionAccept, "default")
+		rule2, err = manager.AddFilterRule(nil, pfx(ip.AsSlice()), fw.Network{}, "tcp", port, nil, fw.ActionAccept)
-		for _, r := range rule2 {
+		require.NoError(t, err, "failed to add rule")
-			require.NoError(t, err, "failed to add rule")
+		require.NotNil(t, rule2)
-			require.Equal(t, r.(*Rule).ipsetName, "default-sport", "ipset name must be set")
+		require.Contains(t, rule2.(*Rule).specs, "-s",
-			require.Equal(t, r.(*Rule).ip, "10.20.0.3", "ipset IP must be set")
+			"single-source rule should use direct -s match, not an ipset")
-		}
+		require.Empty(t, findSets(rule2.(*Rule).specs),
+			"single-source rule should not allocate a shared ipset")
 	})
 
-	t.Run("delete second rule", func(t *testing.T) {
+	t.Run("delete single-source rule", func(t *testing.T) {
-		for _, r := range rule2 {
+		require.NoError(t, manager.DeleteFilterRule(rule2), "failed to delete rule")
-			err := manager.DeletePeerRule(r)
+	})
-			require.NoError(t, err, "failed to delete rule")
 
-			require.Empty(t, manager.aclMgr.ipsetStore.ipsets, "rulesets index after removed second rule must be empty")
+	t.Run("multi-source uses shared ipset", func(t *testing.T) {
+		sources := []netip.Prefix{
+			netip.PrefixFrom(netip.MustParseAddr("10.20.0.3"), 32),
+			netip.PrefixFrom(netip.MustParseAddr("10.20.0.4"), 32),
+			netip.PrefixFrom(netip.MustParseAddr("10.20.0.5"), 32),
 		}
+		port := &fw.Port{Values: []uint16{8080}}
+		multi, err := manager.AddFilterRule(nil, sources, fw.Network{}, "tcp", nil, port, fw.ActionAccept)
+		require.NoError(t, err, "failed to add multi-source rule")
+		require.NotNil(t, multi, "multi-source rule must produce one iptables rule")
+		sets := findSets(multi.(*Rule).specs)
+		require.Len(t, sets, 1, "multi-source rule must reference exactly one ipset")
+
+		require.NoError(t, manager.DeleteFilterRule(multi))
 	})
 
 	t.Run("reset check", func(t *testing.T) {
@@ -241,9 +247,324 @@ func TestIptablesManagerIPSet(t *testing.T) {
 	})
 }
 
+// TestIptablesFilterIPSetFallback verifies that when the kernel lacks
+// ipset support, a multi-source rule falls back to one iptables rule
+// per source prefix instead of silently leaving the chain empty. See
+// discussion #6125.
+func TestIptablesFilterIPSetFallback(t *testing.T) {
+	ipv4Client, err := iptables.NewWithProtocol(iptables.ProtocolIPv4)
+	require.NoError(t, err)
+
+	manager, err := Create(ifaceMock, iface.DefaultMTU)
+	require.NoError(t, err)
+	require.NoError(t, manager.Init(nil))
+
+	defer func() {
+		require.NoError(t, manager.Close(nil))
+	}()
+
+	// Simulate a kernel without the ipset hash module.
+	manager.family4.ipsetSupported = false
+
+	sources := []netip.Prefix{
+		netip.MustParsePrefix("10.20.0.42/32"),
+		netip.MustParsePrefix("10.20.0.43/32"),
+	}
+	port := &fw.Port{Values: []uint16{22}}
+
+	rule, err := manager.AddFilterRule(nil, sources, fw.Network{}, "tcp", nil, port, fw.ActionAccept)
+	require.NoError(t, err, "AddFilterRule should succeed via fallback")
+
+	rr := rule.(*Rule)
+	all := rr.allSpecs()
+	require.Len(t, all, len(sources), "each source prefix needs its own rule")
+	for i, fs := range all {
+		joined := strings.Join(fs.specs, " ")
+		require.Contains(t, joined, "-s "+sources[i].String(), "fallback rule must match by source prefix")
+		require.NotContains(t, joined, matchSet, "fallback rule must not use ipset matching")
+
+		// The rule must actually be present in the ACL chain (not silently dropped).
+		checkRuleSpecs(t, ipv4Client, rr.chain, true, fs.specs...)
+
+		// Every expanded peer rule keeps its own redirect-mark pairing.
+		require.NotNil(t, fs.mangleSpecs, "peer rule must carry a mangle pairing")
+		checkTableRuleSpecs(t, ipv4Client, tableMangle, chainRTPre, true, fs.mangleSpecs...)
+	}
+
+	require.NoError(t, manager.DeleteFilterRule(rule), "failed to delete fallback rule")
+	for _, fs := range all {
+		checkRuleSpecs(t, ipv4Client, rr.chain, false, fs.specs...)
+		checkTableRuleSpecs(t, ipv4Client, tableMangle, chainRTPre, false, fs.mangleSpecs...)
+	}
+}
+
+// TestIptablesFilterDestinationSetRequiresIPSet documents that a dynamic
+// (domain) destination cannot be expressed without ipset: its prefixes are only
+// known after DNS resolution, so there is nothing to expand into per-prefix
+// rules. The call must report that rather than install a broader rule than the
+// policy allows.
+func TestIptablesFilterDestinationSetRequiresIPSet(t *testing.T) {
+	manager, err := Create(ifaceMock, iface.DefaultMTU)
+	require.NoError(t, err)
+	require.NoError(t, manager.Init(nil))
+
+	defer func() {
+		require.NoError(t, manager.Close(nil))
+	}()
+
+	manager.family4.ipsetSupported = false
+
+	destination := fw.Network{Set: fw.NewDomainSet(domain.List{"example.com"})}
+
+	_, err = manager.AddFilterRule(nil, []netip.Prefix{netip.MustParsePrefix("172.16.0.0/16")},
+		destination, fw.ProtocolALL, nil, nil, fw.ActionAccept)
+	require.Error(t, err, "a domain destination is not expressible without ipset")
+	require.ErrorContains(t, err, "requires ipset")
+}
+
+// TestIptablesNatRuleDropsSourceSetOnDestinationFailure covers a marking rule
+// whose source set is created but whose destination set is not: the source
+// reference has to go back, or the set it created stays in the kernel with a
+// count nothing will ever drop.
+func TestIptablesNatRuleDropsSourceSetOnDestinationFailure(t *testing.T) {
+	manager, err := Create(ifaceMock, iface.DefaultMTU)
+	require.NoError(t, err)
+	require.NoError(t, manager.Init(nil))
+
+	defer func() {
+		require.NoError(t, manager.Close(nil))
+	}()
+
+	sourceSet := fw.NewPrefixSet([]netip.Prefix{
+		netip.MustParsePrefix("100.0.0.0/16"),
+		netip.MustParsePrefix("10.10.0.0/16"),
+	})
+	destSet := fw.NewDomainSet(domain.List{"example.org"})
+
+	// Poison the destination set's name so its hash:net creation fails after
+	// the source set has already been created.
+	poisoned := manager.family4.ipsetName(destSet.HashedName())
+	require.NoError(t, ipset.Create(poisoned, ipset.TypeHashIP, ipset.CreateOptions{}))
+	t.Cleanup(func() {
+		if err := ipset.Destroy(poisoned); err != nil {
+			t.Logf("destroy poisoned set %s: %v", poisoned, err)
+		}
+	})
+
+	pair := fw.RouterPair{
+		ID:          "nat-source-set-test",
+		Source:      fw.Network{Set: sourceSet},
+		Destination: fw.Network{Set: destSet},
+		Masquerade:  true,
+		Dynamic:     true,
+	}
+
+	require.Error(t, manager.AddNatRule(pair), "the destination set must fail to be created")
+
+	_, ok := manager.family4.ipsetCounter.Get(manager.family4.ipsetName(sourceSet.HashedName()))
+	require.False(t, ok, "the source set reference must be released")
+}
+
+// TestIptablesNatRuleReAddKeepsSetReferences re-adds the same NAT rule the way
+// a repeated network-map update does. The marking rule's set references must not
+// grow, or RemoveNatRule can never drop the count to zero and the set stays in
+// the kernel for the rest of the process lifetime.
+func TestIptablesNatRuleReAddKeepsSetReferences(t *testing.T) {
+	manager, err := Create(ifaceMock, iface.DefaultMTU)
+	require.NoError(t, err)
+	require.NoError(t, manager.Init(nil))
+
+	defer func() {
+		require.NoError(t, manager.Close(nil))
+	}()
+
+	set := fw.NewDomainSet(domain.List{"example.com"})
+	pair := fw.RouterPair{
+		ID:          "nat-reference-test",
+		Source:      fw.Network{Prefix: netip.MustParsePrefix("100.0.0.0/16")},
+		Destination: fw.Network{Set: set},
+		Masquerade:  true,
+		Dynamic:     true,
+	}
+
+	require.NoError(t, manager.AddNatRule(pair), "add nat rule")
+	name := manager.family4.ipsetName(set.HashedName())
+	first, ok := manager.family4.ipsetCounter.Get(name)
+	require.True(t, ok, "the marking rule must hold a reference to its set")
+
+	require.NoError(t, manager.AddNatRule(pair), "re-add nat rule")
+	second, ok := manager.family4.ipsetCounter.Get(name)
+	require.True(t, ok, "the set must still be referenced")
+	require.Equal(t, first.Count, second.Count, "re-adding the same rule must not add references")
+
+	require.NoError(t, manager.RemoveNatRule(pair), "remove nat rule")
+	_, ok = manager.family4.ipsetCounter.Get(name)
+	require.False(t, ok, "removing the rule must drop the last reference")
+}
+
+// TestIptablesRouteFilterIPSetFallback covers the route ACL side of the
+// fallback: with a destination set, the expanded per-source rules land
+// in the route forward chain and are all removed on delete.
+func TestIptablesRouteFilterIPSetFallback(t *testing.T) {
+	ipv4Client, err := iptables.NewWithProtocol(iptables.ProtocolIPv4)
+	require.NoError(t, err)
+
+	manager, err := Create(ifaceMock, iface.DefaultMTU)
+	require.NoError(t, err)
+	require.NoError(t, manager.Init(nil))
+
+	defer func() {
+		require.NoError(t, manager.Close(nil))
+	}()
+
+	manager.family4.ipsetSupported = false
+
+	sources := []netip.Prefix{
+		netip.MustParsePrefix("172.16.0.0/16"),
+		netip.MustParsePrefix("192.168.0.0/16"),
+	}
+	destination := fw.Network{Prefix: netip.MustParsePrefix("10.0.0.0/8")}
+	port := &fw.Port{Values: []uint16{443}}
+
+	rule, err := manager.AddFilterRule(nil, sources, destination, "tcp", nil, port, fw.ActionAccept)
+	require.NoError(t, err, "route ACL must install without ipset")
+
+	rr := rule.(*Rule)
+	require.Equal(t, chainRTFwdIn, rr.chain, "route rule must land in the forward chain")
+
+	all := rr.allSpecs()
+	require.Len(t, all, len(sources), "each source prefix needs its own rule")
+	for i, fs := range all {
+		joined := strings.Join(fs.specs, " ")
+		require.Contains(t, joined, "-s "+sources[i].String(), "fallback rule must match by source prefix")
+		require.NotContains(t, joined, matchSet, "fallback rule must not use ipset matching")
+		require.Nil(t, fs.mangleSpecs, "route rules have no mangle pairing")
+
+		checkRuleSpecs(t, ipv4Client, rr.chain, true, fs.specs...)
+	}
+
+	require.NoError(t, manager.DeleteFilterRule(rule), "failed to delete fallback rule")
+	for _, fs := range all {
+		checkRuleSpecs(t, ipv4Client, rr.chain, false, fs.specs...)
+	}
+}
+
+// TestIptablesCloseRemovesAllState exercises a spread of rule kinds and then
+// asserts Close puts every table it touches back exactly as it found it. A
+// leaked chain, jump, or ipset survives the daemon and nothing can remove it
+// afterwards, since the tracking that knew about it is gone.
+func TestIptablesCloseRemovesAllState(t *testing.T) {
+	ipv4Client, err := iptables.NewWithProtocol(iptables.ProtocolIPv4)
+	require.NoError(t, err)
+
+	before := snapshotIptables(t, ipv4Client)
+
+	manager, err := Create(ifaceMock, iface.DefaultMTU)
+	require.NoError(t, err)
+	require.NoError(t, manager.Init(nil))
+
+	// A failed assertion below returns before the Close under test, which would
+	// leave this test's chains and sets in the kernel for the next one.
+	t.Cleanup(func() {
+		if err := manager.Close(nil); err != nil {
+			t.Logf("close after failure: %v", err)
+		}
+	})
+
+	sources := []netip.Prefix{
+		netip.MustParsePrefix("10.20.0.42/32"),
+		netip.MustParsePrefix("10.20.0.43/32"),
+	}
+
+	// A multi-source peer rule: shared ipset plus the mangle redirect pairing.
+	_, err = manager.AddFilterRule(nil, sources, fw.Network{}, "tcp",
+		nil, &fw.Port{Values: []uint16{22}}, fw.ActionAccept)
+	require.NoError(t, err, "add peer rule")
+
+	// A route rule with a dynamic destination: a second set, in the forward chain.
+	_, err = manager.AddFilterRule(nil, sources,
+		fw.Network{Set: fw.NewDomainSet(domain.List{"example.com"})},
+		fw.ProtocolALL, nil, nil, fw.ActionDrop)
+	require.NoError(t, err, "add route rule")
+
+	// NAT marking for a routed destination, both directions.
+	pair := fw.RouterPair{
+		ID:          "cleanup-test",
+		Source:      fw.Network{Prefix: netip.MustParsePrefix("100.0.0.0/16")},
+		Destination: fw.Network{Prefix: netip.MustParsePrefix("192.168.55.0/24")},
+		Masquerade:  true,
+	}
+	require.NoError(t, manager.AddNatRule(pair), "add nat rule")
+	require.NoError(t, manager.EnableRouting(), "enable routing")
+
+	// A DNAT redirect, which also holds a forwarding reference.
+	dnat := fw.ForwardRule{
+		Protocol:          fw.ProtocolTCP,
+		DestinationPort:   fw.Port{Values: []uint16{8080}},
+		TranslatedAddress: netip.MustParseAddr("10.20.0.44"),
+		TranslatedPort:    fw.Port{Values: []uint16{80}},
+	}
+	_, err = manager.AddDNATRule(dnat)
+	require.NoError(t, err, "add dnat rule")
+
+	require.NotEqual(t, before, snapshotIptables(t, ipv4Client), "the manager must have installed state")
+
+	// Everything above stays in place, so Close is what has to remove it.
+	require.NoError(t, manager.Close(nil), "close")
+
+	after := snapshotIptables(t, ipv4Client)
+	require.Equal(t, before.chains, after.chains, "Close must remove every chain it created")
+	require.Equal(t, before.rules, after.rules, "Close must remove every rule it created")
+	require.Equal(t, before.sets, after.sets, "Close must destroy every ipset it created")
+}
+
+// iptablesState is a snapshot of the tables the manager writes to, used to
+// compare the kernel before and after a manager lifetime.
+type iptablesState struct {
+	chains map[string][]string
+	rules  map[string][]string
+	sets   []string
+}
+
+func snapshotIptables(t *testing.T, client *iptables.IPTables) iptablesState {
+	t.Helper()
+
+	state := iptablesState{
+		chains: map[string][]string{},
+		rules:  map[string][]string{},
+	}
+
+	for _, table := range []string{tableFilter, tableNat, tableMangle, tableRaw} {
+		chains, err := client.ListChains(table)
+		require.NoErrorf(t, err, "list chains in %s", table)
+		slices.Sort(chains)
+		state.chains[table] = chains
+
+		for _, chain := range chains {
+			rules, err := client.List(table, chain)
+			require.NoErrorf(t, err, "list rules in %s/%s", table, chain)
+			state.rules[table+"/"+chain] = rules
+		}
+	}
+
+	sets, err := ipset.ListAll()
+	require.NoError(t, err, "list ipsets")
+	for _, set := range sets {
+		state.sets = append(state.sets, set.SetName)
+	}
+	slices.Sort(state.sets)
+
+	return state
+}
+
 func checkRuleSpecs(t *testing.T, ipv4Client *iptables.IPTables, chainName string, mustExists bool, rulespec ...string) {
 	t.Helper()
-	exists, err := ipv4Client.Exists("filter", chainName, rulespec...)
+	checkTableRuleSpecs(t, ipv4Client, tableFilter, chainName, mustExists, rulespec...)
+}
+
+func checkTableRuleSpecs(t *testing.T, ipv4Client *iptables.IPTables, table, chainName string, mustExists bool, rulespec ...string) {
+	t.Helper()
+	exists, err := ipv4Client.Exists(table, chainName, rulespec...)
 	require.NoError(t, err, "failed to check rule")
 	require.Falsef(t, !exists && mustExists, "rule '%v' does not exist", rulespec)
 	require.Falsef(t, exists && !mustExists, "rule '%v' exist", rulespec)
@@ -283,7 +604,7 @@ func TestIptablesCreatePerformance(t *testing.T) {
 			start := time.Now()
 			for i := 0; i < testMax; i++ {
 				port := &fw.Port{Values: []uint16{uint16(1000 + i)}}
-				_, err = manager.AddPeerFiltering(nil, ip.AsSlice(), "tcp", nil, port, fw.ActionAccept, "")
+				_, err = manager.AddFilterRule(nil, pfx(ip.AsSlice()), fw.Network{}, "tcp", nil, port, fw.ActionAccept)
 
 				require.NoError(t, err, "failed to add rule")
 			}
@@ -291,40 +612,3 @@ func TestIptablesCreatePerformance(t *testing.T) {
 		})
 	}
 }
-
-// TestIptablesACLIPSetFallback verifies that when the kernel lacks ipset support,
-// the ACL manager falls back to per-IP iptables rules (-s <ip>) instead of
-// silently leaving the chain empty. See discussion #6125.
-func TestIptablesACLIPSetFallback(t *testing.T) {
-	ipv4Client, err := iptables.NewWithProtocol(iptables.ProtocolIPv4)
-	require.NoError(t, err)
-
-	// Use Create()/Init() so the router-owned chains (chainRTFWDIN/OUT) are
-	// created before the ACL manager's createDefaultChains() references them.
-	manager, err := Create(ifaceMock, iface.DefaultMTU)
-	require.NoError(t, err)
-	require.NoError(t, manager.Init(nil))
-
-	aclMgr := manager.aclMgr
-	// Simulate a kernel without the ipset hash module.
-	aclMgr.ipsetSupported = false
-
-	defer func() {
-		require.NoError(t, manager.Close(nil))
-	}()
-
-	ip := netip.MustParseAddr("10.20.0.42")
-	port := &fw.Port{Values: []uint16{22}}
-
-	rules, err := aclMgr.AddPeerFiltering(nil, ip.AsSlice(), "tcp", nil, port, fw.ActionAccept, "nb0000001")
-	require.NoError(t, err, "AddPeerFiltering should succeed via fallback")
-	require.NotEmpty(t, rules)
-
-	rule := rules[0].(*Rule)
-	require.Empty(t, rule.ipsetName, "fallback rule must not reference an ipset")
-	require.Contains(t, strings.Join(rule.specs, " "), "-s 10.20.0.42", "fallback rule must match by source IP")
-	require.NotContains(t, strings.Join(rule.specs, " "), "--match-set", "fallback rule must not use ipset matching")
-
-	// The rule must actually be present in the ACL chain (not silently dropped).
-	checkRuleSpecs(t, ipv4Client, rule.chain, true, rule.specs...)
-}

client/firewall/iptables/router_linux_test.go

@@ -31,7 +31,7 @@ func TestIptablesManager_RestoreOrCreateContainers(t *testing.T) {
 	iptablesClient, err := iptables.NewWithProtocol(iptables.ProtocolIPv4)
 	require.NoError(t, err, "failed to init iptables client")
 
-	manager, err := newRouter(iptablesClient, ifaceMock, iface.DefaultMTU)
+	manager, err := newFamily(iptablesClient, ifaceMock, iface.DefaultMTU)
 	require.NoError(t, err, "should return a valid iptables manager")
 	require.NoError(t, manager.init(nil))
 
@@ -52,12 +52,12 @@ func TestIptablesManager_RestoreOrCreateContainers(t *testing.T) {
 	// 11. MSS clamping rule for outbound traffic
 	require.Len(t, manager.rules, 11, "should have created rules map")
 
-	exists, err := manager.iptablesClient.Exists(tableNat, chainPOSTROUTING, "-j", chainRTNAT)
+	exists, err := manager.iptablesClient.Exists(tableNat, chainPostrouting, "-j", chainRTNAT)
-	require.NoError(t, err, "should be able to query the iptables %s table and %s chain", tableNat, chainPOSTROUTING)
+	require.NoError(t, err, "should be able to query the iptables %s table and %s chain", tableNat, chainPostrouting)
 	require.True(t, exists, "postrouting jump rule should exist")
 
-	exists, err = manager.iptablesClient.Exists(tableMangle, chainPREROUTING, "-j", chainRTPRE)
+	exists, err = manager.iptablesClient.Exists(tableMangle, chainPrerouting, "-j", chainRTPre)
-	require.NoError(t, err, "should be able to query the iptables %s table and %s chain", tableMangle, chainPREROUTING)
+	require.NoError(t, err, "should be able to query the iptables %s table and %s chain", tableMangle, chainPrerouting)
 	require.True(t, exists, "prerouting jump rule should exist")
 
 	pair := firewall.RouterPair{
@@ -84,7 +84,7 @@ func TestIptablesManager_AddNatRule(t *testing.T) {
 			iptablesClient, err := iptables.NewWithProtocol(iptables.ProtocolIPv4)
 			require.NoError(t, err, "failed to init iptables client")
 
-			manager, err := newRouter(iptablesClient, ifaceMock, iface.DefaultMTU)
+			manager, err := newFamily(iptablesClient, ifaceMock, iface.DefaultMTU)
 			require.NoError(t, err, "shouldn't return error")
 			require.NoError(t, manager.init(nil))
 
@@ -95,7 +95,7 @@ func TestIptablesManager_AddNatRule(t *testing.T) {
 			err = manager.AddNatRule(testCase.InputPair)
 			require.NoError(t, err, "marking rule should be inserted")
 
-			natRuleKey := firewall.GenKey(firewall.NatFormat, testCase.InputPair)
+			natRuleKey := testCase.InputPair.GenKey(firewall.NatFormat)
 			markingRule := []string{
 				"-i", ifaceMock.Name(),
 				"-m", "conntrack",
@@ -106,8 +106,8 @@ func TestIptablesManager_AddNatRule(t *testing.T) {
 				fmt.Sprintf("%#x", nbnet.PreroutingFwmarkMasquerade),
 			}
 
-			exists, err := iptablesClient.Exists(tableMangle, chainRTPRE, markingRule...)
+			exists, err := iptablesClient.Exists(tableMangle, chainRTPre, markingRule...)
-			require.NoError(t, err, "should be able to query the iptables %s table and %s chain", tableMangle, chainRTPRE)
+			require.NoError(t, err, "should be able to query the iptables %s table and %s chain", tableMangle, chainRTPre)
 			if testCase.InputPair.Masquerade {
 				require.True(t, exists, "marking rule should be created")
 				foundRule, found := manager.rules[natRuleKey]
@@ -121,7 +121,7 @@ func TestIptablesManager_AddNatRule(t *testing.T) {
 
 			// Check inverse rule
 			inversePair := firewall.GetInversePair(testCase.InputPair)
-			inverseRuleKey := firewall.GenKey(firewall.NatFormat, inversePair)
+			inverseRuleKey := inversePair.GenKey(firewall.NatFormat)
 			inverseMarkingRule := []string{
 				"!", "-i", ifaceMock.Name(),
 				"-m", "conntrack",
@@ -132,8 +132,8 @@ func TestIptablesManager_AddNatRule(t *testing.T) {
 				fmt.Sprintf("%#x", nbnet.PreroutingFwmarkMasqueradeReturn),
 			}
 
-			exists, err = iptablesClient.Exists(tableMangle, chainRTPRE, inverseMarkingRule...)
+			exists, err = iptablesClient.Exists(tableMangle, chainRTPre, inverseMarkingRule...)
-			require.NoError(t, err, "should be able to query the iptables %s table and %s chain", tableMangle, chainRTPRE)
+			require.NoError(t, err, "should be able to query the iptables %s table and %s chain", tableMangle, chainRTPre)
 			if testCase.InputPair.Masquerade {
 				require.True(t, exists, "inverse marking rule should be created")
 				foundRule, found := manager.rules[inverseRuleKey]
@@ -157,7 +157,7 @@ func TestIptablesManager_RemoveNatRule(t *testing.T) {
 		t.Run(testCase.Name, func(t *testing.T) {
 			iptablesClient, _ := iptables.NewWithProtocol(iptables.ProtocolIPv4)
 
-			manager, err := newRouter(iptablesClient, ifaceMock, iface.DefaultMTU)
+			manager, err := newFamily(iptablesClient, ifaceMock, iface.DefaultMTU)
 			require.NoError(t, err, "shouldn't return error")
 			require.NoError(t, manager.init(nil))
 			defer func() {
@@ -170,7 +170,7 @@ func TestIptablesManager_RemoveNatRule(t *testing.T) {
 			err = manager.RemoveNatRule(testCase.InputPair)
 			require.NoError(t, err, "shouldn't return error")
 
-			natRuleKey := firewall.GenKey(firewall.NatFormat, testCase.InputPair)
+			natRuleKey := testCase.InputPair.GenKey(firewall.NatFormat)
 			markingRule := []string{
 				"-i", ifaceMock.Name(),
 				"-m", "conntrack",
@@ -181,8 +181,8 @@ func TestIptablesManager_RemoveNatRule(t *testing.T) {
 				fmt.Sprintf("%#x", nbnet.PreroutingFwmarkMasquerade),
 			}
 
-			exists, err := iptablesClient.Exists(tableMangle, chainRTPRE, markingRule...)
+			exists, err := iptablesClient.Exists(tableMangle, chainRTPre, markingRule...)
-			require.NoError(t, err, "should be able to query the iptables %s table and %s chain", tableMangle, chainRTPRE)
+			require.NoError(t, err, "should be able to query the iptables %s table and %s chain", tableMangle, chainRTPre)
 			require.False(t, exists, "marking rule should not exist")
 
 			_, found := manager.rules[natRuleKey]
@@ -190,7 +190,7 @@ func TestIptablesManager_RemoveNatRule(t *testing.T) {
 
 			// Check inverse rule removal
 			inversePair := firewall.GetInversePair(testCase.InputPair)
-			inverseRuleKey := firewall.GenKey(firewall.NatFormat, inversePair)
+			inverseRuleKey := inversePair.GenKey(firewall.NatFormat)
 			inverseMarkingRule := []string{
 				"!", "-i", ifaceMock.Name(),
 				"-m", "conntrack",
@@ -201,8 +201,8 @@ func TestIptablesManager_RemoveNatRule(t *testing.T) {
 				fmt.Sprintf("%#x", nbnet.PreroutingFwmarkMasqueradeReturn),
 			}
 
-			exists, err = iptablesClient.Exists(tableMangle, chainRTPRE, inverseMarkingRule...)
+			exists, err = iptablesClient.Exists(tableMangle, chainRTPre, inverseMarkingRule...)
-			require.NoError(t, err, "should be able to query the iptables %s table and %s chain", tableMangle, chainRTPRE)
+			require.NoError(t, err, "should be able to query the iptables %s table and %s chain", tableMangle, chainRTPre)
 			require.False(t, exists, "inverse marking rule should not exist")
 
 			_, found = manager.rules[inverseRuleKey]
@@ -219,13 +219,13 @@ func TestRouter_AddRouteFiltering(t *testing.T) {
 	iptablesClient, err := iptables.NewWithProtocol(iptables.ProtocolIPv4)
 	require.NoError(t, err, "Failed to create iptables client")
 
-	r, err := newRouter(iptablesClient, ifaceMock, iface.DefaultMTU)
+	r, err := newFamily(iptablesClient, ifaceMock, iface.DefaultMTU)
-	require.NoError(t, err, "Failed to create router manager")
+	require.NoError(t, err, "Failed to create family manager")
 	require.NoError(t, r.init(nil))
 
 	defer func() {
 		err := r.Reset()
-		require.NoError(t, err, "Failed to reset router")
+		require.NoError(t, err, "Failed to reset family")
 	}()
 
 	tests := []struct {
@@ -334,62 +334,30 @@ func TestRouter_AddRouteFiltering(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			ruleKey, err := r.AddRouteFiltering(nil, tt.sources, firewall.Network{Prefix: tt.destination}, tt.proto, tt.sPort, tt.dPort, tt.action)
+			ruleKey, err := r.AddFilterRule(nil, tt.sources, firewall.Network{Prefix: tt.destination}, tt.proto, tt.sPort, tt.dPort, tt.action)
-			require.NoError(t, err, "AddRouteFiltering failed")
+			require.NoError(t, err, "AddFilterRule failed")
 
-			// Check if the rule is in the internal map
+			stored, ok := r.filters[ruleKey.ID()]
-			rule, ok := r.rules[ruleKey.ID()]
+			require.True(t, ok, "rule not stored in filters")
-			assert.True(t, ok, "Rule not found in internal map")
+			t.Logf("Internal rule: %v", stored.specs)
 
-			// Log the internal rule
+			exists, err := iptablesClient.Exists(tableFilter, chainRTFwdIn, stored.specs...)
-			t.Logf("Internal rule: %v", rule)
-
-			// Check if the rule exists in iptables
-			exists, err := iptablesClient.Exists(tableFilter, chainRTFWDIN, rule...)
 			assert.NoError(t, err, "Failed to check rule existence")
 			assert.True(t, exists, "Rule not found in iptables")
 
-			var source firewall.Network
-			if len(tt.sources) > 1 {
-				source.Set = firewall.NewPrefixSet(tt.sources)
-			} else if len(tt.sources) > 0 {
-				source.Prefix = tt.sources[0]
-			}
-			// Verify rule content
-			params := routeFilteringRuleParams{
-				Source:      source,
-				Destination: firewall.Network{Prefix: tt.destination},
-				Proto:       tt.proto,
-				SPort:       tt.sPort,
-				DPort:       tt.dPort,
-				Action:      tt.action,
-			}
-
-			expectedRule, err := r.genRouteRuleSpec(params, nil)
-			require.NoError(t, err, "Failed to generate expected rule spec")
-
 			if tt.expectSet {
 				setName := firewall.NewPrefixSet(tt.sources).HashedName()
-				expectedRule, err = r.genRouteRuleSpec(params, nil)
-				require.NoError(t, err, "Failed to generate expected rule spec with set")
-
-				// Check if the set was created
 				_, exists := r.ipsetCounter.Get(setName)
 				assert.True(t, exists, "IPSet not created")
+				assert.NotEmpty(t, findSets(stored.specs), "Rule should reference an ipset")
 			}
 
-			assert.Equal(t, expectedRule, rule, "Rule content mismatch")
+			require.NoError(t, r.DeleteFilterRule(ruleKey), "Failed to delete rule")
-
-			// Clean up
-			err = r.DeleteRouteRule(ruleKey)
-			require.NoError(t, err, "Failed to delete rule")
 		})
 	}
 }
 
 func TestFindSetNameInRule(t *testing.T) {
-	r := &router{}
-
 	testCases := []struct {
 		name     string
 		rule     []string
@@ -430,7 +398,7 @@ func TestFindSetNameInRule(t *testing.T) {
 
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
-			result := r.findSets(tc.rule)
+			result := findSets(tc.rule)
 
 			if len(result) != len(tc.expected) {
 				t.Errorf("Expected %d sets, got %d. Sets found: %v", len(tc.expected), len(result), result)

client/firewall/iptables/routing_linux.go

@@ -0,0 +1,273 @@
+//go:build !android
+
+package iptables
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/hashicorp/go-multierror"
+	log "github.com/sirupsen/logrus"
+
+	nberrors "github.com/netbirdio/netbird/client/errors"
+	firewall "github.com/netbirdio/netbird/client/firewall/manager"
+	nbnet "github.com/netbirdio/netbird/client/net"
+)
+
+func (r *family) AddNatRule(pair firewall.RouterPair) error {
+	if r.legacyManagement {
+		log.Warnf("This peer is connected to a NetBird Management service with an older version. Allowing all traffic for %s", pair.Destination)
+		if err := r.addLegacyRouteRule(pair); err != nil {
+			return fmt.Errorf("add legacy routing rule: %w", err)
+		}
+	}
+
+	if pair.Masquerade {
+		if err := r.addNatRule(pair); err != nil {
+			return fmt.Errorf("add nat rule: %w", err)
+		}
+
+		if err := r.addNatRule(firewall.GetInversePair(pair)); err != nil {
+			return fmt.Errorf("add inverse nat rule: %w", err)
+		}
+	}
+
+	r.updateState()
+
+	return nil
+}
+
+// RemoveNatRule removes an iptables rule pair from forwarding and nat chains
+func (r *family) RemoveNatRule(pair firewall.RouterPair) error {
+	if pair.Masquerade {
+		if err := r.removeNatRule(pair); err != nil {
+			return fmt.Errorf("remove nat rule: %w", err)
+		}
+
+		if err := r.removeNatRule(firewall.GetInversePair(pair)); err != nil {
+			return fmt.Errorf("remove inverse nat rule: %w", err)
+		}
+	}
+
+	if err := r.removeLegacyRouteRule(pair); err != nil {
+		return fmt.Errorf("remove legacy routing rule: %w", err)
+	}
+
+	r.updateState()
+
+	return nil
+}
+
+// addLegacyRouteRule adds a legacy routing rule for mgmt servers pre route acls
+func (r *family) addLegacyRouteRule(pair firewall.RouterPair) error {
+	ruleID := pair.GenKey(firewall.ForwardingFormat)
+
+	if err := r.removeLegacyRouteRule(pair); err != nil {
+		return err
+	}
+
+	rule := []string{"-s", pair.Source.String(), "-d", pair.Destination.String(), "-j", "ACCEPT"}
+	if err := r.iptablesClient.Append(tableFilter, chainRTFwdIn, rule...); err != nil {
+		return fmt.Errorf("add legacy forwarding rule %s -> %s: %w", pair.Source, pair.Destination, err)
+	}
+
+	r.rules[ruleID] = rule
+
+	return nil
+}
+
+func (r *family) removeLegacyRouteRule(pair firewall.RouterPair) error {
+	ruleID := pair.GenKey(firewall.ForwardingFormat)
+
+	if rule, exists := r.rules[ruleID]; exists {
+		if err := r.iptablesClient.DeleteIfExists(tableFilter, chainRTFwdIn, rule...); err != nil {
+			return fmt.Errorf("remove legacy forwarding rule %s -> %s: %w", pair.Source, pair.Destination, err)
+		}
+		delete(r.rules, ruleID)
+
+		if err := r.decrementSetCounter(rule); err != nil {
+			return fmt.Errorf("decrement ipset counter: %w", err)
+		}
+	}
+
+	return nil
+}
+
+// GetLegacyManagement returns the current legacy management mode
+func (r *family) GetLegacyManagement() bool {
+	return r.legacyManagement
+}
+
+// SetLegacyManagement sets the route manager to use legacy management mode
+func (r *family) SetLegacyManagement(isLegacy bool) {
+	r.legacyManagement = isLegacy
+}
+
+// RemoveAllLegacyRouteRules removes all legacy routing rules for mgmt servers pre route acls
+func (r *family) RemoveAllLegacyRouteRules() error {
+	var merr *multierror.Error
+	for k, rule := range r.rules {
+		if !strings.HasPrefix(string(k), firewall.ForwardingFormatPrefix) {
+			continue
+		}
+		if err := r.iptablesClient.DeleteIfExists(tableFilter, chainRTFwdIn, rule...); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("remove legacy forwarding rule: %w", err))
+		} else {
+			delete(r.rules, k)
+		}
+	}
+
+	r.updateState()
+
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+func (r *family) addPostroutingRules() error {
+	// First rule for outbound masquerade
+	rule1 := []string{
+		"-m", "mark", "--mark", fmt.Sprintf("%#x", nbnet.PreroutingFwmarkMasquerade),
+		"!", "-o", "lo",
+		"-j", "MASQUERADE",
+	}
+	if err := r.iptablesClient.Append(tableNat, chainRTNAT, rule1...); err != nil {
+		return fmt.Errorf("add outbound masquerade rule: %w", err)
+	}
+	r.rules["static-nat-outbound"] = rule1
+
+	// Second rule for return traffic masquerade
+	rule2 := []string{
+		"-m", "mark", "--mark", fmt.Sprintf("%#x", nbnet.PreroutingFwmarkMasqueradeReturn),
+		"-o", r.wgIface.Name(),
+		"-j", "MASQUERADE",
+	}
+	if err := r.iptablesClient.Append(tableNat, chainRTNAT, rule2...); err != nil {
+		return fmt.Errorf("add return masquerade rule: %w", err)
+	}
+	r.rules["static-nat-return"] = rule2
+
+	return nil
+}
+
+// addMSSClampingRules adds MSS clamping rules to prevent fragmentation for forwarded traffic.
+func (r *family) addMSSClampingRules() error {
+	overhead := uint16(ipv4TCPHeaderSize)
+	if r.v6 {
+		overhead = ipv6TCPHeaderSize
+	}
+	mss := r.mtu - overhead
+
+	// Add jump rule from FORWARD chain in mangle table to our custom chain
+	jumpRule := jumpRuleSpec(chainRTMSSClamp)
+	if err := r.iptablesClient.Insert(tableMangle, chainForward, 1, jumpRule...); err != nil {
+		return fmt.Errorf("add jump to MSS clamp chain: %w", err)
+	}
+	r.rules[jumpMSSClamp] = jumpRule
+
+	ruleOut := []string{
+		"-o", r.wgIface.Name(),
+		"-p", "tcp",
+		"--tcp-flags", "SYN,RST", "SYN",
+		"-j", "TCPMSS",
+		"--set-mss", fmt.Sprintf("%d", mss),
+	}
+	if err := r.iptablesClient.Append(tableMangle, chainRTMSSClamp, ruleOut...); err != nil {
+		return fmt.Errorf("add outbound MSS clamp rule: %w", err)
+	}
+	r.rules["mss-clamp-out"] = ruleOut
+
+	return nil
+}
+
+func (r *family) insertEstablishedRule(chain string) error {
+	establishedRule := getConntrackEstablished()
+
+	err := r.iptablesClient.Insert(tableFilter, chain, 1, establishedRule...)
+	if err != nil {
+		return fmt.Errorf("insert established rule: %w", err)
+	}
+
+	ruleID := firewall.RuleID("established-" + chain)
+	r.rules[ruleID] = establishedRule
+
+	return nil
+}
+
+func (r *family) addNatRule(pair firewall.RouterPair) (err error) {
+	ruleID := pair.GenKey(firewall.NatFormat)
+
+	if rule, exists := r.rules[ruleID]; exists {
+		if derr := r.iptablesClient.DeleteIfExists(tableMangle, chainRTPre, rule...); derr != nil {
+			return fmt.Errorf("remove existing marking rule for %s: %w", pair.Destination, derr)
+		}
+		delete(r.rules, ruleID)
+
+		// Drop the replaced spec's set references only once the new spec has
+		// taken its own, so a set both specs share is not destroyed and
+		// recreated, which would lose the prefixes UpdateSet put in it.
+		defer func() {
+			if derr := r.decrementSetCounter(rule); derr != nil && err == nil {
+				err = fmt.Errorf("decrement ipset counter: %w", derr)
+			}
+		}()
+	}
+
+	markValue := nbnet.PreroutingFwmarkMasquerade
+	if pair.Inverse {
+		markValue = nbnet.PreroutingFwmarkMasqueradeReturn
+	}
+
+	rule := []string{"-i", r.wgIface.Name()}
+	if pair.Inverse {
+		rule = []string{"!", "-i", r.wgIface.Name()}
+	}
+
+	rule = append(rule,
+		"-m", "conntrack",
+		"--ctstate", "NEW",
+	)
+	sourceExp, err := r.applyNetwork("-s", pair.Source, nil)
+	if err != nil {
+		return fmt.Errorf("apply network -s: %w", err)
+	}
+	destExp, err := r.applyNetwork("-d", pair.Destination, nil)
+	if err != nil {
+		r.dropSourceMatch(sourceExp)
+		return fmt.Errorf("apply network -d: %w", err)
+	}
+
+	rule = append(rule, sourceExp...)
+	rule = append(rule, destExp...)
+	rule = append(rule,
+		"-j", "MARK", "--set-mark", fmt.Sprintf("%#x", markValue),
+	)
+
+	// Ensure nat rules come first, so the mark can be overwritten.
+	// Currently overwritten by the dst-type LOCAL rules for redirected traffic.
+	if err := r.iptablesClient.Insert(tableMangle, chainRTPre, 1, rule...); err != nil {
+		r.dropSourceMatch(rule)
+		return fmt.Errorf("add marking rule for %s: %w", pair.Destination, err)
+	}
+
+	r.rules[ruleID] = rule
+
+	return nil
+}
+
+func (r *family) removeNatRule(pair firewall.RouterPair) error {
+	ruleID := pair.GenKey(firewall.NatFormat)
+
+	if rule, exists := r.rules[ruleID]; exists {
+		if err := r.iptablesClient.DeleteIfExists(tableMangle, chainRTPre, rule...); err != nil {
+			return fmt.Errorf("remove marking rule for %s: %w", pair.Destination, err)
+		}
+		delete(r.rules, ruleID)
+
+		if err := r.decrementSetCounter(rule); err != nil {
+			return fmt.Errorf("decrement ipset counter: %w", err)
+		}
+	} else {
+		log.Debugf("marking rule %s not found", ruleID)
+	}
+
+	return nil
+}

client/firewall/iptables/rule.go

@@ -1,18 +1,37 @@
 package iptables
 
-// Rule to handle management of rules
+import "github.com/netbirdio/netbird/client/firewall/manager"
-type Rule struct {
-	ruleID    string
-	ipsetName string
 
+// Rule to handle management of rules. Source set membership (when the
+// rule was built against a shared hash:net ipset) is encoded in specs;
+// DeleteFilterRule recovers it via findSets so the refcounter can drop
+// the right reference.
+type Rule struct {
+	id          manager.RuleID
 	specs       []string
 	mangleSpecs []string
-	ip          string
+	// extraRules holds the rules beyond the first when the ipset
-	chain       string
+	// fallback expands a multi-source rule into one rule per prefix.
-	v6          bool
+	extraRules []filterSpecs
+	chain      string
+	v6         bool
 }
 
-// GetRuleID returns the rule id
+// filterSpecs is one installed iptables rule: its filter-table spec and
-func (r *Rule) ID() string {
+// the paired mangle redirect-mark spec (nil for route rules or when the
-	return r.ruleID
+// mangle rule could not be added).
+type filterSpecs struct {
+	specs       []string
+	mangleSpecs []string
+}
+
+// allSpecs returns the spec pairs of every iptables rule backing this
+// Rule, the primary one first.
+func (r *Rule) allSpecs() []filterSpecs {
+	return append([]filterSpecs{{specs: r.specs, mangleSpecs: r.mangleSpecs}}, r.extraRules...)
+}
+
+// ID returns the rule id
+func (r *Rule) ID() manager.RuleID {
+	return r.id
 }

client/firewall/iptables/rulestore_linux.go

@@ -1,127 +0,0 @@
-package iptables
-
-import (
-	"encoding/json"
-	"maps"
-)
-
-type ipList struct {
-	ips map[string]struct{}
-}
-
-func newIpList(ip string) *ipList {
-	ips := make(map[string]struct{})
-	ips[ip] = struct{}{}
-
-	return &ipList{
-		ips: ips,
-	}
-}
-
-func (s *ipList) addIP(ip string) {
-	s.ips[ip] = struct{}{}
-}
-
-// clone returns a deep copy of the ipList with its own ips map.
-func (s *ipList) clone() *ipList {
-	if s == nil {
-		return nil
-	}
-	return &ipList{ips: maps.Clone(s.ips)}
-}
-
-// MarshalJSON implements json.Marshaler
-func (s *ipList) MarshalJSON() ([]byte, error) {
-	return json.Marshal(struct {
-		IPs map[string]struct{} `json:"ips"`
-	}{
-		IPs: s.ips,
-	})
-}
-
-// UnmarshalJSON implements json.Unmarshaler
-func (s *ipList) UnmarshalJSON(data []byte) error {
-	temp := struct {
-		IPs map[string]struct{} `json:"ips"`
-	}{}
-	if err := json.Unmarshal(data, &temp); err != nil {
-		return err
-	}
-	s.ips = temp.IPs
-
-	if temp.IPs == nil {
-		temp.IPs = make(map[string]struct{})
-	}
-
-	return nil
-}
-
-type ipsetStore struct {
-	ipsets map[string]*ipList
-}
-
-func newIpsetStore() *ipsetStore {
-	return &ipsetStore{
-		ipsets: make(map[string]*ipList),
-	}
-}
-
-// clone returns a deep copy of the ipsetStore with its own ipsets map and
-// independent ipList entries.
-func (s *ipsetStore) clone() *ipsetStore {
-	if s == nil {
-		return nil
-	}
-	cloned := &ipsetStore{ipsets: make(map[string]*ipList, len(s.ipsets))}
-	for name, list := range s.ipsets {
-		cloned.ipsets[name] = list.clone()
-	}
-	return cloned
-}
-
-func (s *ipsetStore) ipset(ipsetName string) (*ipList, bool) {
-	r, ok := s.ipsets[ipsetName]
-	return r, ok
-}
-
-func (s *ipsetStore) addIpList(ipsetName string, list *ipList) {
-	s.ipsets[ipsetName] = list
-}
-
-func (s *ipsetStore) deleteIpset(ipsetName string) {
-	delete(s.ipsets, ipsetName)
-}
-
-func (s *ipsetStore) ipsetNames() []string {
-	names := make([]string, 0, len(s.ipsets))
-	for name := range s.ipsets {
-		names = append(names, name)
-	}
-	return names
-}
-
-// MarshalJSON implements json.Marshaler
-func (s *ipsetStore) MarshalJSON() ([]byte, error) {
-	return json.Marshal(struct {
-		IPSets map[string]*ipList `json:"ipsets"`
-	}{
-		IPSets: s.ipsets,
-	})
-}
-
-// UnmarshalJSON implements json.Unmarshaler
-func (s *ipsetStore) UnmarshalJSON(data []byte) error {
-	temp := struct {
-		IPSets map[string]*ipList `json:"ipsets"`
-	}{}
-	if err := json.Unmarshal(data, &temp); err != nil {
-		return err
-	}
-	s.ipsets = temp.IPSets
-
-	if temp.IPSets == nil {
-		temp.IPSets = make(map[string]*ipList)
-	}
-
-	return nil
-}

client/firewall/iptables/state_linux.go

@@ -29,17 +29,13 @@ type ShutdownState struct {
 
 	InterfaceState *InterfaceState `json:"interface_state,omitempty"`
 
-	RouteRules        routeRules    `json:"route_rules,omitempty"`
+	RouteRules         routeRules    `json:"route_rules,omitempty"`
-	RouteIPsetCounter *ipsetCounter `json:"route_ipset_counter,omitempty"`
-
-	ACLEntries    aclEntries  `json:"acl_entries,omitempty"`
-	ACLIPsetStore *ipsetStore `json:"acl_ipset_store,omitempty"`
-
-	// IPv6 counterparts
 	RouteRules6        routeRules    `json:"route_rules_v6,omitempty"`
+	RouteIPsetCounter  *ipsetCounter `json:"route_ipset_counter,omitempty"`
 	RouteIPsetCounter6 *ipsetCounter `json:"route_ipset_counter_v6,omitempty"`
-	ACLEntries6        aclEntries    `json:"acl_entries_v6,omitempty"`
+
-	ACLIPsetStore6     *ipsetStore   `json:"acl_ipset_store_v6,omitempty"`
+	ACLEntries  aclEntries `json:"acl_entries,omitempty"`
+	ACLEntries6 aclEntries `json:"acl_entries_v6,omitempty"`
 }
 
 func (s *ShutdownState) Name() string {
@@ -57,17 +53,14 @@ func (s *ShutdownState) Cleanup() error {
 	}
 
 	if s.RouteRules != nil {
-		ipt.router.rules = s.RouteRules
+		ipt.family4.rules = s.RouteRules
 	}
 	if s.RouteIPsetCounter != nil {
-		ipt.router.ipsetCounter.LoadData(s.RouteIPsetCounter)
+		ipt.family4.ipsetCounter.LoadData(s.RouteIPsetCounter)
 	}
 
 	if s.ACLEntries != nil {
-		ipt.aclMgr.entries = s.ACLEntries
+		ipt.family4.entries = s.ACLEntries
-	}
-	if s.ACLIPsetStore != nil {
-		ipt.aclMgr.ipsetStore = s.ACLIPsetStore
 	}
 
 	// Clean up v6 state even if the current run has no IPv6.
@@ -79,16 +72,13 @@ func (s *ShutdownState) Cleanup() error {
 	}
 	if ipt.hasIPv6() {
 		if s.RouteRules6 != nil {
-			ipt.router6.rules = s.RouteRules6
+			ipt.family6.rules = s.RouteRules6
 		}
 		if s.RouteIPsetCounter6 != nil {
-			ipt.router6.ipsetCounter.LoadData(s.RouteIPsetCounter6)
+			ipt.family6.ipsetCounter.LoadData(s.RouteIPsetCounter6)
 		}
 		if s.ACLEntries6 != nil {
-			ipt.aclMgr6.entries = s.ACLEntries6
+			ipt.family6.entries = s.ACLEntries6
-		}
-		if s.ACLIPsetStore6 != nil {
-			ipt.aclMgr6.ipsetStore = s.ACLIPsetStore6
 		}
 	}
 

client/firewall/iptables/testhelpers_linux_test.go

@@ -0,0 +1,27 @@
+//go:build privileged
+
+package iptables
+
+import (
+	"fmt"
+	"net"
+	"net/netip"
+)
+
+func pfx(ip net.IP) []netip.Prefix {
+	if ip == nil {
+		return []netip.Prefix{netip.PrefixFrom(netip.IPv4Unspecified(), 0)}
+	}
+	if ip.IsUnspecified() {
+		if ip.To4() != nil {
+			return []netip.Prefix{netip.PrefixFrom(netip.IPv4Unspecified(), 0)}
+		}
+		return []netip.Prefix{netip.PrefixFrom(netip.IPv6Unspecified(), 0)}
+	}
+	a, ok := netip.AddrFromSlice(ip)
+	if !ok {
+		panic(fmt.Sprintf("invalid IP length: %d", len(ip)))
+	}
+	a = a.Unmap()
+	return []netip.Prefix{netip.PrefixFrom(a, a.BitLen())}
+}

client/firewall/manager/firewall.go

@@ -3,7 +3,6 @@ package manager
 import (
 	"errors"
 	"fmt"
-	"net"
 	"net/netip"
 	"sort"
 
@@ -16,6 +15,12 @@ import (
 // method but the IPv6 firewall components were not initialized.
 var ErrIPv6NotInitialized = errors.New("IPv6 firewall not initialized")
 
+// ErrNoSources is returned when AddFilterRule is called with an empty
+// source list. "Match any source" must be expressed explicitly with a
+// /0 prefix; an empty list is a caller error and is rejected rather
+// than silently widening the rule to every source.
+var ErrNoSources = errors.New("rule has no sources")
+
 const (
 	ForwardingFormatPrefix = "netbird-fwd-"
 	ForwardingFormat       = "netbird-fwd-%s-%t"
@@ -23,13 +28,18 @@ const (
 	NatFormat              = "netbird-nat-%s-%t"
 )
 
+// RuleID identifies a firewall rule. It is a typed string so the
+// compiler catches accidental mixing with arbitrary string keys. It is
+// only an identifier and does not implement Rule.
+type RuleID string
+
 // Rule abstraction should be implemented by each firewall manager
 //
 // Each firewall type for different OS can use different type
 // of the properties to hold data of the created rule
 type Rule interface {
 	// ID returns the rule id
-	ID() string
+	ID() RuleID
 }
 
 // RuleDirection is the traffic direction which a rule is applied
@@ -91,6 +101,13 @@ func (d Network) IsPrefix() bool {
 	return d.Prefix.IsValid()
 }
 
+// IsZero returns true if the network designates no destination, i.e. it
+// is the zero value. A zero Network is the peer-rule sentinel; a non-zero
+// one carries a prefix or set destination.
+func (d Network) IsZero() bool {
+	return !d.IsPrefix() && !d.IsSet()
+}
+
 // Manager is the high level abstraction of a firewall manager
 //
 // It declares methods which handle actions required by the
@@ -98,46 +115,42 @@ func (d Network) IsPrefix() bool {
 type Manager interface {
 	Init(stateManager *statemanager.Manager) error
 
-	// AllowNetbird allows netbird interface traffic
+	// AddFilterRule adds a packet-filtering rule to the firewall.
-	AllowNetbird() error
-
-	// AddPeerFiltering adds a rule to the firewall
 	//
-	// If comment argument is empty firewall manager should set
+	// If destination is the zero Network, the rule applies to traffic
-	// rule ID as comment for the rule
+	// inbound to this node, i.e. peer ACL semantics, installed in
+	// the kernel's input chain. If destination is set (prefix or
+	// set), the rule applies to forwarded traffic with that
+	// destination, route ACL semantics, installed in the forward
+	// chain.
 	//
-	// Note: Callers should call Flush() after adding rules to ensure
+	// sources must be a single address family; the caller splits mixed
-	// they are applied to the kernel and rule handles are refreshed.
+	// families and calls once per family. "Match any source" must be
-	AddPeerFiltering(
+	// expressed with an explicit /0 prefix; an empty sources list is
+	// rejected with ErrNoSources so a zeroed list can never widen a
+	// rule to every source.
+	//
+	// Note: callers should call Flush() after adding rules.
+	AddFilterRule(
 		id []byte,
-		ip net.IP,
+		sources []netip.Prefix,
+		destination Network,
 		proto Protocol,
 		sPort *Port,
 		dPort *Port,
 		action Action,
-		ipsetName string,
+	) (Rule, error)
-	) ([]Rule, error)
 
-	// DeletePeerRule from the firewall by rule definition
+	// DeleteFilterRule removes a filtering rule previously added via
-	DeletePeerRule(rule Rule) error
+	// AddFilterRule. The rule's own type identifies whether it lives
+	// in the peer (input) or route (forward) path.
+	DeleteFilterRule(rule Rule) error
 
 	// IsServerRouteSupported returns true if the firewall supports server side routing operations
 	IsServerRouteSupported() bool
 
 	IsStateful() bool
 
-	AddRouteFiltering(
-		id []byte,
-		sources []netip.Prefix,
-		destination Network,
-		proto Protocol,
-		sPort, dPort *Port,
-		action Action,
-	) (Rule, error)
-
-	// DeleteRouteRule deletes a routing rule
-	DeleteRouteRule(rule Rule) error
-
 	// AddNatRule inserts a routing NAT rule
 	AddNatRule(pair RouterPair) error
 
@@ -185,8 +198,9 @@ type Manager interface {
 	SetupEBPFProxyNoTrack(proxyPort, wgPort uint16) error
 }
 
-func GenKey(format string, pair RouterPair) string {
+// GenKey builds the rule id for this pair from the given format.
-	return fmt.Sprintf(format, pair.ID, pair.Inverse)
+func (p RouterPair) GenKey(format string) RuleID {
+	return RuleID(fmt.Sprintf(format, p.ID, p.Inverse))
 }
 
 // LegacyManager defines the interface for legacy management operations
@@ -242,6 +256,20 @@ func MergeIPRanges(prefixes []netip.Prefix) []netip.Prefix {
 	return merged
 }
 
+// UnmapPrefix normalizes a v4-mapped v6 prefix (::ffff:a.b.c.d) to its
+// plain v4 form, shifting the prefix length out of the 96-bit mapped
+// range. Other prefixes are returned unchanged. Keeping prefixes
+// unmapped ensures v4 rules match consistently and the match builders
+// read the correct address length.
+func UnmapPrefix(p netip.Prefix) netip.Prefix {
+	addr := p.Addr()
+	if !addr.Is4In6() {
+		return p
+	}
+	bits := max(p.Bits()-96, 0)
+	return netip.PrefixFrom(addr.Unmap(), bits)
+}
+
 // SortPrefixes sorts the given slice of netip.Prefix in place.
 // It sorts first by IP address, then by prefix length (most specific to least specific).
 func SortPrefixes(prefixes []netip.Prefix) {

client/firewall/manager/forward_rule.go

@@ -13,13 +13,13 @@ type ForwardRule struct {
 	TranslatedPort    Port
 }
 
-func (r ForwardRule) ID() string {
+func (r ForwardRule) ID() RuleID {
 	id := fmt.Sprintf("%s;%s;%s;%s",
 		r.Protocol,
 		r.DestinationPort.String(),
 		r.TranslatedAddress.String(),
 		r.TranslatedPort.String())
-	return id
+	return RuleID(id)
 }
 
 func (r ForwardRule) String() string {

client/firewall/manager/set.go

@@ -40,7 +40,7 @@ func (h Set) Comment() string {
 
 // NewPrefixSet generates a unique name for an ipset based on the given prefixes.
 func NewPrefixSet(prefixes []netip.Prefix) Set {
-	// sort for consistent naming
+	prefixes = slices.Clone(prefixes)
 	SortPrefixes(prefixes)
 
 	hash := sha256.New()

client/firewall/nftables/acl_linux.go

@@ -1,713 +0,0 @@
-package nftables
-
-import (
-	"bytes"
-	"fmt"
-	"net"
-	"slices"
-	"strconv"
-	"strings"
-	"time"
-
-	"github.com/google/nftables"
-	"github.com/google/nftables/binaryutil"
-	"github.com/google/nftables/expr"
-	log "github.com/sirupsen/logrus"
-	"golang.org/x/sys/unix"
-
-	firewall "github.com/netbirdio/netbird/client/firewall/manager"
-	nbnet "github.com/netbirdio/netbird/client/net"
-)
-
-const (
-
-	// rules chains contains the effective ACL rules
-	chainNameInputRules = "netbird-acl-input-rules"
-
-	// filter chains contains the rules that jump to the rules chains
-	chainNameInputFilter       = "netbird-acl-input-filter"
-	chainNameForwardFilter     = "netbird-acl-forward-filter"
-	chainNameManglePrerouting  = "netbird-mangle-prerouting"
-	chainNameManglePostrouting = "netbird-mangle-postrouting"
-)
-
-const flushError = "flush: %w"
-
-type AclManager struct {
-	rConn              *nftables.Conn
-	sConn              *nftables.Conn
-	wgIface            iFaceMapper
-	routingFwChainName string
-	af                 addrFamily
-
-	workTable       *nftables.Table
-	chainInputRules *nftables.Chain
-	chainPrerouting *nftables.Chain
-
-	ipsetStore *ipsetStore
-	rules      map[string]*Rule
-}
-
-func newAclManager(table *nftables.Table, wgIface iFaceMapper, routingFwChainName string) (*AclManager, error) {
-	// sConn is used for creating sets and adding/removing elements from them
-	// it's differ then rConn (which does create new conn for each flush operation)
-	// and is permanent. Using same connection for both type of operations
-	// overloads netlink with high amount of rules ( > 10000)
-	sConn, err := nftables.New(nftables.AsLasting())
-	if err != nil {
-		return nil, fmt.Errorf("create nf conn: %w", err)
-	}
-
-	return &AclManager{
-		rConn:              &nftables.Conn{},
-		sConn:              sConn,
-		wgIface:            wgIface,
-		workTable:          table,
-		routingFwChainName: routingFwChainName,
-		af:                 familyForAddr(table.Family == nftables.TableFamilyIPv4),
-
-		ipsetStore: newIpsetStore(),
-		rules:      make(map[string]*Rule),
-	}, nil
-}
-
-func (m *AclManager) init(workTable *nftables.Table) error {
-	m.workTable = workTable
-	return m.createDefaultChains()
-}
-
-// AddPeerFiltering rule to the firewall
-//
-// If comment argument is empty firewall manager should set
-// rule ID as comment for the rule
-func (m *AclManager) AddPeerFiltering(
-	id []byte,
-	ip net.IP,
-	proto firewall.Protocol,
-	sPort *firewall.Port,
-	dPort *firewall.Port,
-	action firewall.Action,
-	ipsetName string,
-) ([]firewall.Rule, error) {
-	var ipset *nftables.Set
-	if ipsetName != "" {
-		var err error
-		ipset, err = m.addIpToSet(ipsetName, ip)
-		if err != nil {
-			return nil, err
-		}
-	}
-
-	newRules := make([]firewall.Rule, 0, 2)
-	ioRule, err := m.addIOFiltering(ip, proto, sPort, dPort, action, ipset)
-	if err != nil {
-		return nil, err
-	}
-
-	newRules = append(newRules, ioRule)
-	return newRules, nil
-}
-
-// DeletePeerRule from the firewall by rule definition
-func (m *AclManager) DeletePeerRule(rule firewall.Rule) error {
-	r, ok := rule.(*Rule)
-	if !ok {
-		return fmt.Errorf("invalid rule type")
-	}
-
-	if r.nftSet == nil {
-		if err := m.rConn.DelRule(r.nftRule); err != nil {
-			log.Errorf("failed to delete rule: %v", err)
-		}
-		if r.mangleRule != nil {
-			if err := m.rConn.DelRule(r.mangleRule); err != nil {
-				log.Errorf("failed to delete mangle rule: %v", err)
-			}
-		}
-		delete(m.rules, r.ID())
-		return m.rConn.Flush()
-	}
-
-	ips, ok := m.ipsetStore.ips(r.nftSet.Name)
-	if !ok {
-		if err := m.rConn.DelRule(r.nftRule); err != nil {
-			log.Errorf("failed to delete rule: %v", err)
-		}
-		if r.mangleRule != nil {
-			if err := m.rConn.DelRule(r.mangleRule); err != nil {
-				log.Errorf("failed to delete mangle rule: %v", err)
-			}
-		}
-		delete(m.rules, r.ID())
-		return m.rConn.Flush()
-	}
-
-	if _, ok := ips[r.ip.String()]; ok {
-		err := m.sConn.SetDeleteElements(r.nftSet, []nftables.SetElement{{Key: ipToBytes(r.ip, m.af)}})
-		if err != nil {
-			log.Errorf("delete elements for set %q: %v", r.nftSet.Name, err)
-		}
-		if err := m.sConn.Flush(); err != nil {
-			log.Debugf("flush error of set delete element, %s", r.nftSet.Name)
-			return err
-		}
-		m.ipsetStore.DeleteIpFromSet(r.nftSet.Name, r.ip)
-	}
-
-	// if after delete, set still contains other IPs,
-	// no need to delete firewall rule and we should exit here
-	if len(ips) > 0 {
-		return nil
-	}
-
-	if err := m.rConn.DelRule(r.nftRule); err != nil {
-		log.Errorf("failed to delete rule: %v", err)
-	}
-	if r.mangleRule != nil {
-		if err := m.rConn.DelRule(r.mangleRule); err != nil {
-			log.Errorf("failed to delete mangle rule: %v", err)
-		}
-	}
-
-	if err := m.rConn.Flush(); err != nil {
-		return err
-	}
-
-	delete(m.rules, r.ID())
-	m.ipsetStore.DeleteReferenceFromIpSet(r.nftSet.Name)
-
-	if m.ipsetStore.HasReferenceToSet(r.nftSet.Name) {
-		return nil
-	}
-
-	// we delete last IP from the set, that means we need to delete
-	// set itself and associated firewall rule too
-	m.rConn.FlushSet(r.nftSet)
-	m.rConn.DelSet(r.nftSet)
-	m.ipsetStore.deleteIpset(r.nftSet.Name)
-	return nil
-}
-
-// createDefaultAllowRules creates default allow rules for the input and output chains
-func (m *AclManager) createDefaultAllowRules() error {
-	expIn := []expr.Any{
-		&expr.Verdict{
-			Kind: expr.VerdictAccept,
-		},
-	}
-
-	_ = m.rConn.InsertRule(&nftables.Rule{
-		Table:    m.workTable,
-		Chain:    m.chainInputRules,
-		Position: 0,
-		Exprs:    expIn,
-	})
-
-	if err := m.rConn.Flush(); err != nil {
-		return fmt.Errorf(flushError, err)
-	}
-	return nil
-}
-
-// Flush rule/chain/set operations from the buffer
-//
-// Method also get all rules after flush and refreshes handle values in the rulesets
-func (m *AclManager) Flush() error {
-	if err := m.flushWithBackoff(); err != nil {
-		return err
-	}
-
-	if err := m.refreshRuleHandles(m.chainInputRules, false); err != nil {
-		log.Errorf("failed to refresh rule handles ipv4 input chain: %v", err)
-	}
-	if err := m.refreshRuleHandles(m.chainPrerouting, true); err != nil {
-		log.Errorf("failed to refresh rule handles prerouting chain: %v", err)
-	}
-
-	return nil
-}
-
-func (m *AclManager) addIOFiltering(
-	ip net.IP,
-	proto firewall.Protocol,
-	sPort *firewall.Port,
-	dPort *firewall.Port,
-	action firewall.Action,
-	ipset *nftables.Set,
-) (*Rule, error) {
-	ruleId := generatePeerRuleId(ip, proto, sPort, dPort, action, ipset)
-	if r, ok := m.rules[ruleId]; ok {
-		return &Rule{
-			nftRule:    r.nftRule,
-			mangleRule: r.mangleRule,
-			nftSet:     r.nftSet,
-			ruleID:     r.ruleID,
-			ip:         ip,
-		}, nil
-	}
-
-	var expressions []expr.Any
-
-	if proto != firewall.ProtocolALL {
-		expressions = append(expressions, &expr.Payload{
-			DestRegister: 1,
-			Base:         expr.PayloadBaseNetworkHeader,
-			Offset:       m.af.protoOffset,
-			Len:          uint32(1),
-		})
-
-		protoData, err := m.af.protoNum(proto)
-		if err != nil {
-			return nil, fmt.Errorf("convert protocol to number: %v", err)
-		}
-
-		expressions = append(expressions, &expr.Cmp{
-			Register: 1,
-			Op:       expr.CmpOpEq,
-			Data:     []byte{protoData},
-		})
-	}
-
-	rawIP := ipToBytes(ip, m.af)
-	// check if rawIP contains zeroed IPv4 0.0.0.0 value
-	// in that case not add IP match expression into the rule definition
-	if slices.ContainsFunc(rawIP, func(v byte) bool { return v != 0 }) {
-		expressions = append(expressions,
-			&expr.Payload{
-				DestRegister: 1,
-				Base:         expr.PayloadBaseNetworkHeader,
-				Offset:       m.af.srcAddrOffset,
-				Len:          m.af.addrLen,
-			},
-		)
-		// add individual IP for match if no ipset defined
-		if ipset == nil {
-			expressions = append(expressions,
-				&expr.Cmp{
-					Op:       expr.CmpOpEq,
-					Register: 1,
-					Data:     rawIP,
-				},
-			)
-		} else {
-			expressions = append(expressions,
-				&expr.Lookup{
-					SourceRegister: 1,
-					SetName:        ipset.Name,
-					SetID:          ipset.ID,
-				},
-			)
-		}
-	}
-
-	expressions = append(expressions, applyPort(sPort, true)...)
-	expressions = append(expressions, applyPort(dPort, false)...)
-
-	mainExpressions := slices.Clone(expressions)
-
-	switch action {
-	case firewall.ActionAccept:
-		mainExpressions = append(mainExpressions, &expr.Verdict{Kind: expr.VerdictAccept})
-	case firewall.ActionDrop:
-		mainExpressions = append(mainExpressions, &expr.Verdict{Kind: expr.VerdictDrop})
-	}
-
-	userData := []byte(ruleId)
-
-	chain := m.chainInputRules
-	rule := &nftables.Rule{
-		Table:    m.workTable,
-		Chain:    chain,
-		Exprs:    mainExpressions,
-		UserData: userData,
-	}
-
-	// Insert DROP rules at the beginning, append ACCEPT rules at the end
-	var nftRule *nftables.Rule
-	if action == firewall.ActionDrop {
-		nftRule = m.rConn.InsertRule(rule)
-	} else {
-		nftRule = m.rConn.AddRule(rule)
-	}
-
-	if err := m.rConn.Flush(); err != nil {
-		return nil, fmt.Errorf("flush input rule %s: %v", ruleId, err)
-	}
-
-	ruleStruct := &Rule{
-		nftRule: nftRule,
-		// best effort mangle rule
-		mangleRule: m.createPreroutingRule(expressions, userData),
-		nftSet:     ipset,
-		ruleID:     ruleId,
-		ip:         ip,
-	}
-	m.rules[ruleId] = ruleStruct
-	if ipset != nil {
-		m.ipsetStore.AddReferenceToIpset(ipset.Name)
-	}
-
-	return ruleStruct, nil
-}
-
-func (m *AclManager) createPreroutingRule(expressions []expr.Any, userData []byte) *nftables.Rule {
-	if m.chainPrerouting == nil {
-		log.Warn("prerouting chain is not created")
-		return nil
-	}
-
-	preroutingExprs := slices.Clone(expressions)
-
-	// interface
-	preroutingExprs = append([]expr.Any{
-		&expr.Meta{
-			Key:      expr.MetaKeyIIFNAME,
-			Register: 1,
-		},
-		&expr.Cmp{
-			Op:       expr.CmpOpEq,
-			Register: 1,
-			Data:     ifname(m.wgIface.Name()),
-		},
-	}, preroutingExprs...)
-
-	// local destination and mark
-	preroutingExprs = append(preroutingExprs,
-		&expr.Fib{
-			Register:       1,
-			ResultADDRTYPE: true,
-			FlagDADDR:      true,
-		},
-		&expr.Cmp{
-			Op:       expr.CmpOpEq,
-			Register: 1,
-			Data:     binaryutil.NativeEndian.PutUint32(unix.RTN_LOCAL),
-		},
-
-		&expr.Immediate{
-			Register: 1,
-			Data:     binaryutil.NativeEndian.PutUint32(nbnet.PreroutingFwmarkRedirected),
-		},
-		&expr.Meta{
-			Key:            expr.MetaKeyMARK,
-			Register:       1,
-			SourceRegister: true,
-		},
-	)
-
-	nfRule := m.rConn.AddRule(&nftables.Rule{
-		Table:    m.workTable,
-		Chain:    m.chainPrerouting,
-		Exprs:    preroutingExprs,
-		UserData: userData,
-	})
-
-	if err := m.rConn.Flush(); err != nil {
-		log.Errorf("failed to flush mangle rule %s: %v", string(userData), err)
-		return nil
-	}
-
-	return nfRule
-}
-
-func (m *AclManager) createDefaultChains() (err error) {
-	// chainNameInputRules
-	chain := m.createChain(chainNameInputRules)
-	err = m.rConn.Flush()
-	if err != nil {
-		log.Debugf("failed to create chain (%s): %s", chain.Name, err)
-		return fmt.Errorf(flushError, err)
-	}
-	m.chainInputRules = chain
-
-	// netbird-acl-input-filter
-	// type filter hook input priority filter; policy accept;
-	chain = m.createFilterChainWithHook(chainNameInputFilter, nftables.ChainHookInput)
-	m.addJumpRule(chain, m.chainInputRules.Name, expr.MetaKeyIIFNAME) // to netbird-acl-input-rules
-	m.addDropExpressions(chain, expr.MetaKeyIIFNAME)
-	err = m.rConn.Flush()
-	if err != nil {
-		log.Debugf("failed to create chain (%s): %s", chain.Name, err)
-		return err
-	}
-
-	// netbird-acl-forward-filter
-	chainFwFilter := m.createFilterChainWithHook(chainNameForwardFilter, nftables.ChainHookForward)
-	m.addJumpRulesToRtForward(chainFwFilter) // to netbird-rt-fwd
-	m.addDropExpressions(chainFwFilter, expr.MetaKeyIIFNAME)
-
-	err = m.rConn.Flush()
-	if err != nil {
-		log.Debugf("failed to create chain (%s): %s", chainNameForwardFilter, err)
-		return fmt.Errorf(flushError, err)
-	}
-
-	if err := m.allowRedirectedTraffic(chainFwFilter); err != nil {
-		log.Errorf("failed to allow redirected traffic: %s", err)
-	}
-
-	return nil
-}
-
-// Makes redirected traffic originally destined for the host itself (now subject to the forward filter)
-// go through the input filter as well. This will enable e.g. Docker services to keep working by accessing the
-// netbird peer IP.
-func (m *AclManager) allowRedirectedTraffic(chainFwFilter *nftables.Chain) error {
-	// Chain is created by route manager
-	// TODO: move creation to a common place
-	m.chainPrerouting = &nftables.Chain{
-		Name:     chainNameManglePrerouting,
-		Table:    m.workTable,
-		Type:     nftables.ChainTypeFilter,
-		Hooknum:  nftables.ChainHookPrerouting,
-		Priority: nftables.ChainPriorityMangle,
-	}
-
-	m.addFwmarkToForward(chainFwFilter)
-
-	if err := m.rConn.Flush(); err != nil {
-		return fmt.Errorf(flushError, err)
-	}
-
-	return nil
-}
-
-func (m *AclManager) addFwmarkToForward(chainFwFilter *nftables.Chain) {
-	m.rConn.InsertRule(&nftables.Rule{
-		Table: m.workTable,
-		Chain: chainFwFilter,
-		Exprs: []expr.Any{
-			&expr.Meta{
-				Key:      expr.MetaKeyMARK,
-				Register: 1,
-			},
-			&expr.Cmp{
-				Op:       expr.CmpOpEq,
-				Register: 1,
-				Data:     binaryutil.NativeEndian.PutUint32(nbnet.PreroutingFwmarkRedirected),
-			},
-			&expr.Verdict{
-				Kind: expr.VerdictAccept,
-			},
-		},
-	})
-}
-
-func (m *AclManager) addJumpRulesToRtForward(chainFwFilter *nftables.Chain) {
-	expressions := []expr.Any{
-		&expr.Meta{Key: expr.MetaKeyIIFNAME, Register: 1},
-		&expr.Cmp{
-			Op:       expr.CmpOpEq,
-			Register: 1,
-			Data:     ifname(m.wgIface.Name()),
-		},
-		&expr.Verdict{
-			Kind:  expr.VerdictJump,
-			Chain: m.routingFwChainName,
-		},
-	}
-
-	_ = m.rConn.AddRule(&nftables.Rule{
-		Table: m.workTable,
-		Chain: chainFwFilter,
-		Exprs: expressions,
-	})
-}
-
-func (m *AclManager) createChain(name string) *nftables.Chain {
-	chain := &nftables.Chain{
-		Name:  name,
-		Table: m.workTable,
-	}
-
-	chain = m.rConn.AddChain(chain)
-
-	insertReturnTrafficRule(m.rConn, m.workTable, chain)
-
-	return chain
-}
-
-func (m *AclManager) createFilterChainWithHook(name string, hookNum *nftables.ChainHook) *nftables.Chain {
-	polAccept := nftables.ChainPolicyAccept
-	chain := &nftables.Chain{
-		Name:     name,
-		Table:    m.workTable,
-		Hooknum:  hookNum,
-		Priority: nftables.ChainPriorityFilter,
-		Type:     nftables.ChainTypeFilter,
-		Policy:   &polAccept,
-	}
-
-	return m.rConn.AddChain(chain)
-}
-
-func (m *AclManager) addDropExpressions(chain *nftables.Chain, ifaceKey expr.MetaKey) []expr.Any {
-	expressions := []expr.Any{
-		&expr.Meta{Key: ifaceKey, Register: 1},
-		&expr.Cmp{
-			Op:       expr.CmpOpEq,
-			Register: 1,
-			Data:     ifname(m.wgIface.Name()),
-		},
-		&expr.Verdict{Kind: expr.VerdictDrop},
-	}
-	_ = m.rConn.AddRule(&nftables.Rule{
-		Table: m.workTable,
-		Chain: chain,
-		Exprs: expressions,
-	})
-	return nil
-}
-
-func (m *AclManager) addJumpRule(chain *nftables.Chain, to string, ifaceKey expr.MetaKey) {
-	expressions := []expr.Any{
-		&expr.Meta{Key: ifaceKey, Register: 1},
-		&expr.Cmp{
-			Op:       expr.CmpOpEq,
-			Register: 1,
-			Data:     ifname(m.wgIface.Name()),
-		},
-		&expr.Verdict{
-			Kind:  expr.VerdictJump,
-			Chain: to,
-		},
-	}
-
-	_ = m.rConn.AddRule(&nftables.Rule{
-		Table: chain.Table,
-		Chain: chain,
-		Exprs: expressions,
-	})
-}
-
-func (m *AclManager) addIpToSet(ipsetName string, ip net.IP) (*nftables.Set, error) {
-	ipset, err := m.rConn.GetSetByName(m.workTable, ipsetName)
-	rawIP := ipToBytes(ip, m.af)
-	if err != nil {
-		if ipset, err = m.createSet(m.workTable, ipsetName); err != nil {
-			return nil, fmt.Errorf("get set name: %v", err)
-		}
-
-		m.ipsetStore.newIpset(ipset.Name)
-	}
-
-	if m.ipsetStore.IsIpInSet(ipset.Name, ip) {
-		return ipset, nil
-	}
-
-	if err := m.sConn.SetAddElements(ipset, []nftables.SetElement{{Key: rawIP}}); err != nil {
-		return nil, fmt.Errorf("add set element for the first time: %v", err)
-	}
-
-	m.ipsetStore.AddIpToSet(ipset.Name, ip)
-
-	if err := m.sConn.Flush(); err != nil {
-		return nil, fmt.Errorf("flush add elements: %v", err)
-	}
-
-	return ipset, nil
-}
-
-// createSet in given table by name
-func (m *AclManager) createSet(table *nftables.Table, name string) (*nftables.Set, error) {
-	ipset := &nftables.Set{
-		Name:    name,
-		Table:   table,
-		Dynamic: true,
-		KeyType: m.af.setKeyType,
-	}
-
-	if err := m.rConn.AddSet(ipset, nil); err != nil {
-		return nil, fmt.Errorf("create set: %v", err)
-	}
-
-	if err := m.rConn.Flush(); err != nil {
-		return nil, fmt.Errorf("flush created set: %v", err)
-	}
-
-	return ipset, nil
-}
-
-func (m *AclManager) flushWithBackoff() (err error) {
-	backoff := 4
-	backoffTime := 1000 * time.Millisecond
-	for i := 0; ; i++ {
-		err = m.rConn.Flush()
-		if err != nil {
-			log.Debugf("failed to flush nftables: %v", err)
-			if !strings.Contains(err.Error(), "busy") {
-				return
-			}
-			log.Error("failed to flush nftables, retrying...")
-			if i == backoff-1 {
-				return err
-			}
-			time.Sleep(backoffTime)
-			backoffTime *= 2
-			continue
-		}
-		break
-	}
-	return
-}
-
-func (m *AclManager) refreshRuleHandles(chain *nftables.Chain, mangle bool) error {
-	if m.workTable == nil || chain == nil {
-		return nil
-	}
-
-	list, err := m.rConn.GetRules(m.workTable, chain)
-	if err != nil {
-		return err
-	}
-
-	for _, rule := range list {
-		if len(rule.UserData) == 0 {
-			continue
-		}
-		split := bytes.Split(rule.UserData, []byte(" "))
-		r, ok := m.rules[string(split[0])]
-		if ok {
-			if mangle {
-				*r.mangleRule = *rule
-			} else {
-				*r.nftRule = *rule
-			}
-		}
-	}
-
-	return nil
-}
-
-func generatePeerRuleId(ip net.IP, proto firewall.Protocol, sPort *firewall.Port, dPort *firewall.Port, action firewall.Action, ipset *nftables.Set) string {
-	rulesetID := ":" + string(proto) + ":"
-	if sPort != nil {
-		rulesetID += sPort.String()
-	}
-	rulesetID += ":"
-	if dPort != nil {
-		rulesetID += dPort.String()
-	}
-	rulesetID += ":"
-	rulesetID += strconv.Itoa(int(action))
-	if ipset == nil {
-		return "ip:" + ip.String() + rulesetID
-	}
-	return "set:" + ipset.Name + rulesetID
-}
-
-func ifname(n string) []byte {
-	b := make([]byte, 16)
-	copy(b, n+"\x00")
-	return b
-}
-
-
-// ipToBytes converts net.IP to the correct byte length for the address family.
-func ipToBytes(ip net.IP, af addrFamily) []byte {
-	if af.addrLen == 4 {
-		return ip.To4()
-	}
-	return ip.To16()
-}
-

client/firewall/nftables/chains_linux.go

@@ -0,0 +1,880 @@
+//go:build !android
+
+package nftables
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"slices"
+	"strings"
+	"time"
+
+	"github.com/coreos/go-iptables/iptables"
+	"github.com/google/nftables"
+	"github.com/google/nftables/binaryutil"
+	"github.com/google/nftables/expr"
+	"github.com/hashicorp/go-multierror"
+	log "github.com/sirupsen/logrus"
+	"golang.org/x/sys/unix"
+
+	nberrors "github.com/netbirdio/netbird/client/errors"
+	"github.com/netbirdio/netbird/client/firewall/firewalld"
+	firewall "github.com/netbirdio/netbird/client/firewall/manager"
+	nbnet "github.com/netbirdio/netbird/client/net"
+)
+
+func (r *family) createContainers() error {
+	r.chains[chainNameRoutingFw] = r.conn.AddChain(&nftables.Chain{
+		Name:  chainNameRoutingFw,
+		Table: r.workTable,
+	})
+
+	prio := *nftables.ChainPriorityNATSource - 1
+	r.chains[chainNameRoutingNat] = r.conn.AddChain(&nftables.Chain{
+		Name:     chainNameRoutingNat,
+		Table:    r.workTable,
+		Hooknum:  nftables.ChainHookPostrouting,
+		Priority: &prio,
+		Type:     nftables.ChainTypeNAT,
+	})
+
+	r.chains[chainNameRoutingRdr] = r.conn.AddChain(&nftables.Chain{
+		Name:     chainNameRoutingRdr,
+		Table:    r.workTable,
+		Hooknum:  nftables.ChainHookPrerouting,
+		Priority: nftables.ChainPriorityNATDest,
+		Type:     nftables.ChainTypeNAT,
+	})
+
+	r.chains[chainNameManglePostrouting] = r.conn.AddChain(&nftables.Chain{
+		Name:     chainNameManglePostrouting,
+		Table:    r.workTable,
+		Hooknum:  nftables.ChainHookPostrouting,
+		Priority: nftables.ChainPriorityMangle,
+		Type:     nftables.ChainTypeFilter,
+	})
+
+	r.chains[chainNameManglePrerouting] = r.conn.AddChain(&nftables.Chain{
+		Name:     chainNameManglePrerouting,
+		Table:    r.workTable,
+		Hooknum:  nftables.ChainHookPrerouting,
+		Priority: nftables.ChainPriorityMangle,
+		Type:     nftables.ChainTypeFilter,
+	})
+
+	r.chains[chainNameMangleForward] = r.conn.AddChain(&nftables.Chain{
+		Name:     chainNameMangleForward,
+		Table:    r.workTable,
+		Hooknum:  nftables.ChainHookForward,
+		Priority: nftables.ChainPriorityMangle,
+		Type:     nftables.ChainTypeFilter,
+	})
+
+	insertReturnTrafficRule(r.conn, r.workTable, r.chains[chainNameRoutingFw])
+
+	r.addPostroutingRules()
+
+	if err := r.conn.Flush(); err != nil {
+		return fmt.Errorf("initialize tables: %v", err)
+	}
+
+	if err := r.addMSSClampingRules(); err != nil {
+		log.Errorf("failed to add MSS clamping rules: %s", err)
+	}
+
+	// Kernel routing opens both INPUT and FORWARD.
+	if err := r.openInterface(true); err != nil {
+		log.Errorf("failed to open interface in foreign chains: %s", err)
+	}
+
+	if err := firewalld.TrustInterface(r.wgIface.Name()); err != nil {
+		log.Warnf("failed to trust interface in firewalld: %v", err)
+	}
+
+	if err := r.refreshRulesMap(); err != nil {
+		log.Errorf("failed to refresh rules: %s", err)
+	}
+
+	return nil
+}
+
+// setupDataPlaneMark configures the fwmark for the data plane
+func (r *family) setupDataPlaneMark() error {
+	if r.chains[chainNameManglePrerouting] == nil || r.chains[chainNameManglePostrouting] == nil {
+		return errors.New("no mangle chains found")
+	}
+
+	ctNew := getCtNewExprs()
+	preExprs := []expr.Any{
+		&expr.Meta{
+			Key:      expr.MetaKeyIIFNAME,
+			Register: 1,
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     ifname(r.wgIface.Name()),
+		},
+	}
+	preExprs = append(preExprs, ctNew...)
+	preExprs = append(preExprs,
+		&expr.Immediate{
+			Register: 1,
+			Data:     binaryutil.NativeEndian.PutUint32(nbnet.DataPlaneMarkIn),
+		},
+		&expr.Ct{
+			Key:            expr.CtKeyMARK,
+			Register:       1,
+			SourceRegister: true,
+		},
+	)
+
+	preNftRule := &nftables.Rule{
+		Table: r.workTable,
+		Chain: r.chains[chainNameManglePrerouting],
+		Exprs: preExprs,
+	}
+	r.conn.AddRule(preNftRule)
+
+	postExprs := []expr.Any{
+		&expr.Meta{
+			Key:      expr.MetaKeyOIFNAME,
+			Register: 1,
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     ifname(r.wgIface.Name()),
+		},
+	}
+	postExprs = append(postExprs, ctNew...)
+	postExprs = append(postExprs,
+		&expr.Immediate{
+			Register: 1,
+			Data:     binaryutil.NativeEndian.PutUint32(nbnet.DataPlaneMarkOut),
+		},
+		&expr.Ct{
+			Key:            expr.CtKeyMARK,
+			Register:       1,
+			SourceRegister: true,
+		},
+	)
+
+	postNftRule := &nftables.Rule{
+		Table: r.workTable,
+		Chain: r.chains[chainNameManglePostrouting],
+		Exprs: postExprs,
+	}
+	r.conn.AddRule(postNftRule)
+
+	if err := r.conn.Flush(); err != nil {
+		return fmt.Errorf("flush: %w", err)
+	}
+
+	return nil
+}
+
+// openInterface adds passthrough accept rules for the NetBird interface to the
+// kernel's filter table and external chains so they don't drop our traffic.
+// includeForward also opens the FORWARD chains (kernel routing); when false only
+// INPUT is opened, which is all the userspace router needs since it never
+// forwards in the kernel.
+func (r *family) openInterface(includeForward bool) error {
+	var merr *multierror.Error
+
+	if err := r.acceptFilterTableRules(includeForward); err != nil {
+		merr = multierror.Append(merr, err)
+	}
+
+	if err := r.acceptExternalChainsRules(includeForward); err != nil {
+		merr = multierror.Append(merr, fmt.Errorf("add accept rules to external chains: %w", err))
+	}
+
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+func (r *family) acceptFilterTableRules(includeForward bool) error {
+	if r.filterTable == nil {
+		return nil
+	}
+
+	fw := "iptables"
+
+	defer func() {
+		log.Debugf("Used %s to add accept input/forward rules", fw)
+	}()
+
+	// Try iptables first and fallback to nftables if iptables is not available.
+	// Use the correct protocol (iptables vs ip6tables) for the address family.
+	ipt, err := iptables.NewWithProtocol(r.iptablesProto())
+	if err != nil {
+		log.Warnf("Will use nftables to manipulate the filter table because iptables is not available: %v", err)
+
+		fw = "nftables"
+		return r.acceptFilterRulesNftables(r.filterTable, includeForward)
+	}
+
+	if err := r.acceptFilterRulesIptables(ipt, includeForward); err != nil {
+		log.Warnf("iptables failed (table may be incompatible), falling back to nftables: %v", err)
+		fw = "nftables"
+		return r.acceptFilterRulesNftables(r.filterTable, includeForward)
+	}
+	return nil
+}
+
+func (r *family) acceptFilterRulesIptables(ipt *iptables.IPTables, includeForward bool) error {
+	var merr *multierror.Error
+
+	if includeForward {
+		for _, rule := range r.getAcceptForwardRules() {
+			if err := ipt.Insert("filter", chainNameForward, 1, rule...); err != nil {
+				merr = multierror.Append(merr, fmt.Errorf("add iptables forward rule: %v", err))
+			} else {
+				log.Debugf("added iptables forward rule: %v", rule)
+			}
+		}
+	}
+
+	inputRule := r.getAcceptInputRule()
+	if err := ipt.Insert("filter", chainNameInput, 1, inputRule...); err != nil {
+		merr = multierror.Append(merr, fmt.Errorf("add iptables input rule: %v", err))
+	} else {
+		log.Debugf("added iptables input rule: %v", inputRule)
+	}
+
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+func (r *family) getAcceptForwardRules() [][]string {
+	intf := r.wgIface.Name()
+	return [][]string{
+		{"-i", intf, "-j", "ACCEPT"},
+		{"-o", intf, "-m", "conntrack", "--ctstate", "RELATED,ESTABLISHED", "-j", "ACCEPT"},
+	}
+}
+
+func (r *family) getAcceptInputRule() []string {
+	return []string{"-i", r.wgIface.Name(), "-j", "ACCEPT"}
+}
+
+// acceptFilterRulesNftables adds accept rules to the ip filter table using nftables.
+// This is used when iptables is not available.
+func (r *family) acceptFilterRulesNftables(table *nftables.Table, includeForward bool) error {
+	intf := ifname(r.wgIface.Name())
+
+	if includeForward {
+		forwardChain := &nftables.Chain{
+			Name:     chainNameForward,
+			Table:    table,
+			Type:     nftables.ChainTypeFilter,
+			Hooknum:  nftables.ChainHookForward,
+			Priority: nftables.ChainPriorityFilter,
+		}
+		r.insertForwardAcceptRules(forwardChain, intf)
+	}
+
+	inputChain := &nftables.Chain{
+		Name:     chainNameInput,
+		Table:    table,
+		Type:     nftables.ChainTypeFilter,
+		Hooknum:  nftables.ChainHookInput,
+		Priority: nftables.ChainPriorityFilter,
+	}
+	r.insertInputAcceptRule(inputChain, intf)
+
+	return r.conn.Flush()
+}
+
+// acceptExternalChainsRules adds accept rules to external chains (non-netbird, non-iptables tables).
+// It dynamically finds chains at call time to handle chains that may have been created after startup.
+func (r *family) acceptExternalChainsRules(includeForward bool) error {
+	chains := r.findExternalChains()
+	if len(chains) == 0 {
+		return nil
+	}
+
+	intf := ifname(r.wgIface.Name())
+	for _, chain := range chains {
+		r.applyExternalChainAccept(chain, intf, includeForward)
+	}
+
+	if err := r.conn.Flush(); err != nil {
+		return fmt.Errorf("flush external chain rules: %w", err)
+	}
+	return nil
+}
+
+func (r *family) applyExternalChainAccept(chain *nftables.Chain, intf []byte, includeForward bool) {
+	if chain.Hooknum == nil {
+		log.Debugf("skipping external chain %s/%s: hooknum is nil", chain.Table.Name, chain.Name)
+		return
+	}
+
+	log.Debugf("adding accept rules to external %s chain: %s %s/%s",
+		hookName(chain.Hooknum), familyName(chain.Table.Family), chain.Table.Name, chain.Name)
+
+	switch *chain.Hooknum {
+	case *nftables.ChainHookForward:
+		if includeForward {
+			r.insertForwardAcceptRules(chain, intf)
+		}
+	case *nftables.ChainHookInput:
+		r.insertInputAcceptRule(chain, intf)
+	}
+}
+
+func (r *family) insertForwardAcceptRules(chain *nftables.Chain, intf []byte) {
+	existing, err := r.existingNetbirdRulesInChain(chain)
+	if err != nil {
+		log.Warnf("skip forward accept rules in %s/%s: %v", chain.Table.Name, chain.Name, err)
+		return
+	}
+	r.insertForwardIifRule(chain, intf, existing)
+	r.insertForwardOifEstablishedRule(chain, intf, existing)
+}
+
+func (r *family) insertForwardIifRule(chain *nftables.Chain, intf []byte, existing map[string]bool) {
+	if existing[userDataAcceptForwardRuleIif] {
+		return
+	}
+	r.conn.InsertRule(&nftables.Rule{
+		Table: chain.Table,
+		Chain: chain,
+		Exprs: []expr.Any{
+			&expr.Meta{Key: expr.MetaKeyIIFNAME, Register: 1},
+			&expr.Cmp{Op: expr.CmpOpEq, Register: 1, Data: intf},
+			&expr.Counter{},
+			&expr.Verdict{Kind: expr.VerdictAccept},
+		},
+		UserData: []byte(userDataAcceptForwardRuleIif),
+	})
+}
+
+func (r *family) insertForwardOifEstablishedRule(chain *nftables.Chain, intf []byte, existing map[string]bool) {
+	if existing[userDataAcceptForwardRuleOif] {
+		return
+	}
+	exprs := []expr.Any{
+		&expr.Meta{Key: expr.MetaKeyOIFNAME, Register: 1},
+		&expr.Cmp{Op: expr.CmpOpEq, Register: 1, Data: intf},
+	}
+	r.conn.InsertRule(&nftables.Rule{
+		Table:    chain.Table,
+		Chain:    chain,
+		Exprs:    append(exprs, getEstablishedExprs(2)...),
+		UserData: []byte(userDataAcceptForwardRuleOif),
+	})
+}
+
+func (r *family) insertInputAcceptRule(chain *nftables.Chain, intf []byte) {
+	existing, err := r.existingNetbirdRulesInChain(chain)
+	if err != nil {
+		log.Warnf("skip input accept rule in %s/%s: %v", chain.Table.Name, chain.Name, err)
+		return
+	}
+	if existing[userDataAcceptInputRule] {
+		return
+	}
+	r.conn.InsertRule(&nftables.Rule{
+		Table: chain.Table,
+		Chain: chain,
+		Exprs: []expr.Any{
+			&expr.Meta{Key: expr.MetaKeyIIFNAME, Register: 1},
+			&expr.Cmp{Op: expr.CmpOpEq, Register: 1, Data: intf},
+			&expr.Counter{},
+			&expr.Verdict{Kind: expr.VerdictAccept},
+		},
+		UserData: []byte(userDataAcceptInputRule),
+	})
+}
+
+// existingNetbirdRulesInChain returns the set of netbird-owned UserData tags present in a chain; callers must bail on error since InsertRule is additive.
+func (r *family) existingNetbirdRulesInChain(chain *nftables.Chain) (map[string]bool, error) {
+	rules, err := r.conn.GetRules(chain.Table, chain)
+	if err != nil {
+		return nil, fmt.Errorf("list rules: %w", err)
+	}
+	present := map[string]bool{}
+	for _, rule := range rules {
+		if !isNetbirdAcceptRuleTag(rule.UserData) {
+			continue
+		}
+		present[string(rule.UserData)] = true
+	}
+	return present, nil
+}
+
+func isNetbirdAcceptRuleTag(userData []byte) bool {
+	switch string(userData) {
+	case userDataAcceptForwardRuleIif,
+		userDataAcceptForwardRuleOif,
+		userDataAcceptInputRule:
+		return true
+	}
+	return false
+}
+
+func (r *family) removeAcceptFilterRules() error {
+	var merr *multierror.Error
+
+	if err := r.removeFilterTableRules(); err != nil {
+		merr = multierror.Append(merr, err)
+	}
+
+	if err := r.removeExternalChainsRules(); err != nil {
+		merr = multierror.Append(merr, fmt.Errorf("remove external chain rules: %w", err))
+	}
+
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+func (r *family) removeFilterTableRules() error {
+	if r.filterTable == nil {
+		return nil
+	}
+
+	ipt, err := iptables.NewWithProtocol(r.iptablesProto())
+	if err != nil {
+		log.Debugf("iptables not available, using nftables to remove filter rules: %v", err)
+		return r.removeAcceptRulesFromTable(r.filterTable)
+	}
+
+	if err := r.removeAcceptFilterRulesIptables(ipt); err != nil {
+		log.Debugf("iptables removal failed (table may be incompatible), falling back to nftables: %v", err)
+		return r.removeAcceptRulesFromTable(r.filterTable)
+	}
+	return nil
+}
+
+func (r *family) removeAcceptRulesFromTable(table *nftables.Table) error {
+	chains, err := r.conn.ListChainsOfTableFamily(table.Family)
+	if err != nil {
+		return fmt.Errorf("list chains: %v", err)
+	}
+
+	for _, chain := range chains {
+		if chain.Table.Name != table.Name {
+			continue
+		}
+
+		if chain.Name != chainNameForward && chain.Name != chainNameInput {
+			continue
+		}
+
+		if err := r.removeAcceptRulesFromChain(table, chain); err != nil {
+			return err
+		}
+	}
+
+	return r.conn.Flush()
+}
+
+func (r *family) removeAcceptRulesFromChain(table *nftables.Table, chain *nftables.Chain) error {
+	rules, err := r.conn.GetRules(table, chain)
+	if err != nil {
+		return fmt.Errorf("get rules from %s/%s: %v", table.Name, chain.Name, err)
+	}
+
+	for _, rule := range rules {
+		if bytes.Equal(rule.UserData, []byte(userDataAcceptForwardRuleIif)) ||
+			bytes.Equal(rule.UserData, []byte(userDataAcceptForwardRuleOif)) ||
+			bytes.Equal(rule.UserData, []byte(userDataAcceptInputRule)) {
+			if err := r.conn.DelRule(rule); err != nil {
+				return fmt.Errorf("delete rule from %s/%s: %v", table.Name, chain.Name, err)
+			}
+		}
+	}
+	return nil
+}
+
+// removeExternalChainsRules removes our accept rules from all external chains.
+// This is deterministic - it scans for chains at removal time rather than relying on saved state,
+// ensuring cleanup works even after a crash or if chains changed.
+func (r *family) removeExternalChainsRules() error {
+	chains := r.findExternalChains()
+	if len(chains) == 0 {
+		return nil
+	}
+
+	var merr *multierror.Error
+	for _, chain := range chains {
+		if err := r.removeAcceptRulesFromChain(chain.Table, chain); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("remove rules from external chain %s/%s: %w", chain.Table.Name, chain.Name, err))
+			continue
+		}
+		if err := r.conn.Flush(); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("flush external chain %s/%s: %w", chain.Table.Name, chain.Name, err))
+		}
+	}
+
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+// findExternalChains scans for chains from non-netbird tables that have FORWARD or INPUT hooks.
+// This is used both at startup (to know where to add rules) and at cleanup (to ensure deterministic removal).
+func (r *family) findExternalChains() []*nftables.Chain {
+	var chains []*nftables.Chain
+
+	families := []nftables.TableFamily{r.af.tableFamily, nftables.TableFamilyINet}
+
+	for _, family := range families {
+		allChains, err := r.conn.ListChainsOfTableFamily(family)
+		if err != nil {
+			log.Debugf("list chains for family %d: %v", family, err)
+			continue
+		}
+
+		for _, chain := range allChains {
+			if r.isExternalChain(chain) {
+				chains = append(chains, chain)
+			}
+		}
+	}
+
+	return chains
+}
+
+func (r *family) isExternalChain(chain *nftables.Chain) bool {
+	if r.workTable != nil && chain.Table.Name == r.workTable.Name {
+		return false
+	}
+
+	// Skip firewalld-owned chains. Firewalld creates its chains with the
+	// NFT_CHAIN_OWNER flag, so inserting rules into them returns EPERM.
+	// We delegate acceptance to firewalld by trusting the interface instead.
+	if chain.Table.Name == firewalldTableName {
+		return false
+	}
+
+	// Skip iptables/ip6tables-managed tables (adding nft-native rules breaks iptables-save compat)
+	if (chain.Table.Family == nftables.TableFamilyIPv4 || chain.Table.Family == nftables.TableFamilyIPv6) && isIptablesTable(chain.Table.Name) {
+		return false
+	}
+
+	if chain.Type != nftables.ChainTypeFilter {
+		return false
+	}
+
+	if chain.Hooknum == nil {
+		return false
+	}
+
+	return *chain.Hooknum == *nftables.ChainHookForward || *chain.Hooknum == *nftables.ChainHookInput
+}
+
+func isIptablesTable(name string) bool {
+	switch name {
+	case tableNameFilter, tableNat, tableMangle, tableRaw, tableSecurity:
+		return true
+	}
+	return false
+}
+
+func (r *family) removeAcceptFilterRulesIptables(ipt *iptables.IPTables) error {
+	var merr *multierror.Error
+
+	for _, rule := range r.getAcceptForwardRules() {
+		if err := ipt.DeleteIfExists("filter", chainNameForward, rule...); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("remove iptables forward rule: %v", err))
+		}
+	}
+
+	inputRule := r.getAcceptInputRule()
+	if err := ipt.DeleteIfExists("filter", chainNameInput, inputRule...); err != nil {
+		merr = multierror.Append(merr, fmt.Errorf("remove iptables input rule: %v", err))
+	}
+
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+// Flush rule/chain/set operations from the buffer
+//
+// Method also get all rules after flush and refreshes handle values in the rulesets
+func (r *family) Flush() error {
+	if err := r.flushWithBackoff(); err != nil {
+		return err
+	}
+
+	if err := r.refreshRuleHandles(r.chainInputRules, false); err != nil {
+		log.Errorf("failed to refresh rule handles ipv4 input chain: %v", err)
+	}
+	if err := r.refreshRuleHandles(r.chainPrerouting, true); err != nil {
+		log.Errorf("failed to refresh rule handles prerouting chain: %v", err)
+	}
+
+	return nil
+}
+
+// queuePreroutingRule builds the prerouting mangle rule that marks
+// redirected traffic and queues it on the connection without flushing,
+// so the caller can commit it in the same transaction as the rule it
+// pairs with. Returns nil when the prerouting chain is absent, in which
+// case nothing is queued.
+func (r *family) queuePreroutingRule(expressions []expr.Any, userData []byte) *nftables.Rule {
+	if r.chainPrerouting == nil {
+		log.Warn("prerouting chain is not created")
+		return nil
+	}
+
+	preroutingExprs := slices.Clone(expressions)
+
+	// interface
+	preroutingExprs = append([]expr.Any{
+		&expr.Meta{
+			Key:      expr.MetaKeyIIFNAME,
+			Register: 1,
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     ifname(r.wgIface.Name()),
+		},
+	}, preroutingExprs...)
+
+	// local destination and mark
+	preroutingExprs = append(preroutingExprs,
+		&expr.Fib{
+			Register:       1,
+			ResultADDRTYPE: true,
+			FlagDADDR:      true,
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     binaryutil.NativeEndian.PutUint32(unix.RTN_LOCAL),
+		},
+
+		&expr.Immediate{
+			Register: 1,
+			Data:     binaryutil.NativeEndian.PutUint32(nbnet.PreroutingFwmarkRedirected),
+		},
+		&expr.Meta{
+			Key:            expr.MetaKeyMARK,
+			Register:       1,
+			SourceRegister: true,
+		},
+	)
+
+	return r.conn.AddRule(&nftables.Rule{
+		Table:    r.workTable,
+		Chain:    r.chainPrerouting,
+		Exprs:    preroutingExprs,
+		UserData: userData,
+	})
+}
+
+func (r *family) createDefaultChains() (err error) {
+	// chainNameInputRules
+	chain := r.createChain(chainNameInputRules)
+	err = r.conn.Flush()
+	if err != nil {
+		log.Debugf("failed to create chain (%s): %s", chain.Name, err)
+		return fmt.Errorf(flushError, err)
+	}
+	r.chainInputRules = chain
+
+	// netbird-acl-input-filter
+	// type filter hook input priority filter; policy accept;
+	chain = r.createFilterChainWithHook(chainNameInputFilter, nftables.ChainHookInput)
+	r.addJumpRule(chain, r.chainInputRules.Name, expr.MetaKeyIIFNAME) // to netbird-acl-input-rules
+	r.addDropExpressions(chain, expr.MetaKeyIIFNAME)
+	err = r.conn.Flush()
+	if err != nil {
+		log.Debugf("failed to create chain (%s): %s", chain.Name, err)
+		return err
+	}
+
+	// netbird-acl-forward-filter
+	chainFwFilter := r.createFilterChainWithHook(chainNameForwardFilter, nftables.ChainHookForward)
+	r.addJumpRulesToRtForward(chainFwFilter) // to netbird-rt-fwd
+	r.addDropExpressions(chainFwFilter, expr.MetaKeyIIFNAME)
+
+	err = r.conn.Flush()
+	if err != nil {
+		log.Debugf("failed to create chain (%s): %s", chainNameForwardFilter, err)
+		return fmt.Errorf(flushError, err)
+	}
+
+	if err := r.allowRedirectedTraffic(chainFwFilter); err != nil {
+		log.Errorf("failed to allow redirected traffic: %s", err)
+	}
+
+	return nil
+}
+
+// Makes redirected traffic originally destined for the host itself (now subject to the forward filter)
+// go through the input filter as well. This will enable e.g. Docker services to keep working by accessing the
+// netbird peer IP.
+func (r *family) allowRedirectedTraffic(chainFwFilter *nftables.Chain) error {
+	r.chainPrerouting = r.chains[chainNameManglePrerouting]
+
+	r.addFwmarkToForward(chainFwFilter)
+
+	if err := r.conn.Flush(); err != nil {
+		return fmt.Errorf(flushError, err)
+	}
+
+	return nil
+}
+
+func (r *family) addFwmarkToForward(chainFwFilter *nftables.Chain) {
+	r.conn.InsertRule(&nftables.Rule{
+		Table: r.workTable,
+		Chain: chainFwFilter,
+		Exprs: []expr.Any{
+			&expr.Meta{
+				Key:      expr.MetaKeyMARK,
+				Register: 1,
+			},
+			&expr.Cmp{
+				Op:       expr.CmpOpEq,
+				Register: 1,
+				Data:     binaryutil.NativeEndian.PutUint32(nbnet.PreroutingFwmarkRedirected),
+			},
+			&expr.Verdict{
+				Kind: expr.VerdictAccept,
+			},
+		},
+	})
+}
+
+func (r *family) addJumpRulesToRtForward(chainFwFilter *nftables.Chain) {
+	expressions := []expr.Any{
+		&expr.Meta{Key: expr.MetaKeyIIFNAME, Register: 1},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     ifname(r.wgIface.Name()),
+		},
+		&expr.Verdict{
+			Kind:  expr.VerdictJump,
+			Chain: r.routingFwChainName,
+		},
+	}
+
+	_ = r.conn.AddRule(&nftables.Rule{
+		Table: r.workTable,
+		Chain: chainFwFilter,
+		Exprs: expressions,
+	})
+}
+
+func (r *family) createChain(name string) *nftables.Chain {
+	chain := &nftables.Chain{
+		Name:  name,
+		Table: r.workTable,
+	}
+
+	chain = r.conn.AddChain(chain)
+
+	insertReturnTrafficRule(r.conn, r.workTable, chain)
+
+	return chain
+}
+
+func (r *family) createFilterChainWithHook(name string, hookNum *nftables.ChainHook) *nftables.Chain {
+	polAccept := nftables.ChainPolicyAccept
+	chain := &nftables.Chain{
+		Name:     name,
+		Table:    r.workTable,
+		Hooknum:  hookNum,
+		Priority: nftables.ChainPriorityFilter,
+		Type:     nftables.ChainTypeFilter,
+		Policy:   &polAccept,
+	}
+
+	return r.conn.AddChain(chain)
+}
+
+func (r *family) addDropExpressions(chain *nftables.Chain, ifaceKey expr.MetaKey) []expr.Any {
+	expressions := []expr.Any{
+		&expr.Meta{Key: ifaceKey, Register: 1},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     ifname(r.wgIface.Name()),
+		},
+		&expr.Verdict{Kind: expr.VerdictDrop},
+	}
+	_ = r.conn.AddRule(&nftables.Rule{
+		Table: r.workTable,
+		Chain: chain,
+		Exprs: expressions,
+	})
+	return nil
+}
+
+func (r *family) addJumpRule(chain *nftables.Chain, to string, ifaceKey expr.MetaKey) {
+	expressions := []expr.Any{
+		&expr.Meta{Key: ifaceKey, Register: 1},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     ifname(r.wgIface.Name()),
+		},
+		&expr.Verdict{
+			Kind:  expr.VerdictJump,
+			Chain: to,
+		},
+	}
+
+	_ = r.conn.AddRule(&nftables.Rule{
+		Table: chain.Table,
+		Chain: chain,
+		Exprs: expressions,
+	})
+}
+
+func (r *family) flushWithBackoff() (err error) {
+	backoff := 4
+	backoffTime := 1000 * time.Millisecond
+	for i := 0; ; i++ {
+		err = r.conn.Flush()
+		if err != nil {
+			log.Debugf("failed to flush nftables: %v", err)
+			if !strings.Contains(err.Error(), "busy") {
+				return
+			}
+			log.Error("failed to flush nftables, retrying...")
+			if i == backoff-1 {
+				return err
+			}
+			time.Sleep(backoffTime)
+			backoffTime *= 2
+			continue
+		}
+		break
+	}
+	return
+}
+
+func (r *family) refreshRuleHandles(chain *nftables.Chain, mangle bool) error {
+	if r.workTable == nil || chain == nil {
+		return nil
+	}
+
+	list, err := r.conn.GetRules(r.workTable, chain)
+	if err != nil {
+		return err
+	}
+
+	for _, rule := range list {
+		if len(rule.UserData) == 0 {
+			continue
+		}
+		pr, ok := r.filters[firewall.RuleID(rule.UserData)]
+		if !ok {
+			continue
+		}
+		if mangle {
+			if pr.mangleRule != nil {
+				*pr.mangleRule = *rule
+			}
+		} else {
+			*pr.nftRule = *rule
+		}
+	}
+
+	return nil
+}

client/firewall/nftables/dnat_linux.go

@@ -0,0 +1,573 @@
+//go:build !android
+
+package nftables
+
+import (
+	"fmt"
+	"net/netip"
+
+	"github.com/google/nftables"
+	"github.com/google/nftables/binaryutil"
+	"github.com/google/nftables/expr"
+	"github.com/google/nftables/xt"
+	"github.com/hashicorp/go-multierror"
+	log "github.com/sirupsen/logrus"
+
+	nberrors "github.com/netbirdio/netbird/client/errors"
+	firewall "github.com/netbirdio/netbird/client/firewall/manager"
+)
+
+func (r *family) AddDNATRule(rule firewall.ForwardRule) (firewall.Rule, error) {
+	ruleID := rule.ID()
+	if _, exists := r.rules[ruleID+dnatSuffix]; exists {
+		return rule, nil
+	}
+
+	protoNum, err := r.af.protoNum(rule.Protocol)
+	if err != nil {
+		return nil, fmt.Errorf("convert protocol to number: %w", err)
+	}
+
+	// Request forwarding before queueing rules: addDnatRedirect/addDnatMasq
+	// buffer netlink messages on r.conn that the next caller's Flush would
+	// commit if we returned without flushing them ourselves.
+	if err := r.ipFwdState.RequestForwarding(r.isV6()); err != nil {
+		return nil, fmt.Errorf("enable forwarding: %w", err)
+	}
+
+	if err := r.addDnatRedirect(rule, protoNum, ruleID); err != nil {
+		r.releaseForwarding()
+		return nil, err
+	}
+
+	if err := r.addDnatMasq(rule, protoNum, ruleID); err != nil {
+		r.releaseForwarding()
+		delete(r.rules, ruleID+dnatSuffix)
+		return nil, err
+	}
+
+	// Unlike iptables, there's no point in adding "out" rules in the forward chain here as our policy is ACCEPT.
+	// To overcome DROP policies in other chains, we'd have to add rules to the chains there.
+	// We also cannot just add "oif <iface> accept" there and filter in our own table as we don't know what is supposed to be allowed.
+	// TODO: find chains with drop policies and add rules there
+
+	if err := r.conn.Flush(); err != nil {
+		r.releaseForwarding()
+		delete(r.rules, ruleID+dnatSuffix)
+		delete(r.rules, ruleID+snatSuffix)
+		return nil, fmt.Errorf("flush rules: %w", err)
+	}
+
+	return &rule, nil
+}
+
+func (r *family) addDnatRedirect(rule firewall.ForwardRule, protoNum uint8, ruleID firewall.RuleID) error {
+	dnatExprs := []expr.Any{
+		&expr.Meta{Key: expr.MetaKeyIIFNAME, Register: 1},
+		&expr.Cmp{
+			Op:       expr.CmpOpNeq,
+			Register: 1,
+			Data:     ifname(r.wgIface.Name()),
+		},
+		&expr.Meta{Key: expr.MetaKeyL4PROTO, Register: 1},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     []byte{protoNum},
+		},
+		&expr.Payload{
+			DestRegister: 1,
+			Base:         expr.PayloadBaseTransportHeader,
+			Offset:       2,
+			Len:          2,
+		},
+	}
+	portExprs, err := r.applyPort(&rule.DestinationPort, false)
+	if err != nil {
+		return fmt.Errorf("apply destination port: %w", err)
+	}
+	dnatExprs = append(dnatExprs, portExprs...)
+
+	// shifted translated port is not supported in nftables, so we hand this over to xtables
+	if rule.TranslatedPort.IsRange && len(rule.TranslatedPort.Values) == 2 {
+		if rule.TranslatedPort.Values[0] != rule.DestinationPort.Values[0] ||
+			rule.TranslatedPort.Values[1] != rule.DestinationPort.Values[1] {
+			return r.addXTablesRedirect(dnatExprs, ruleID, rule)
+		}
+	}
+
+	additionalExprs, regProtoMin, regProtoMax, err := r.handleTranslatedPort(rule)
+	if err != nil {
+		return err
+	}
+	dnatExprs = append(dnatExprs, additionalExprs...)
+
+	dnatExprs = append(dnatExprs,
+		&expr.NAT{
+			Type:        expr.NATTypeDestNAT,
+			Family:      uint32(r.af.tableFamily),
+			RegAddrMin:  1,
+			RegProtoMin: regProtoMin,
+			RegProtoMax: regProtoMax,
+		},
+	)
+
+	dnatRule := &nftables.Rule{
+		Table:    r.workTable,
+		Chain:    r.chains[chainNameRoutingRdr],
+		Exprs:    dnatExprs,
+		UserData: []byte(ruleID + dnatSuffix),
+	}
+	r.conn.AddRule(dnatRule)
+	r.rules[ruleID+dnatSuffix] = dnatRule
+
+	return nil
+}
+
+func (r *family) handleTranslatedPort(rule firewall.ForwardRule) ([]expr.Any, uint32, uint32, error) {
+	switch {
+	case rule.TranslatedPort.IsRange && len(rule.TranslatedPort.Values) == 2:
+		return r.handlePortRange(rule)
+	case len(rule.TranslatedPort.Values) == 0:
+		return r.handleAddressOnly(rule)
+	case len(rule.TranslatedPort.Values) == 1:
+		return r.handleSinglePort(rule)
+	default:
+		return nil, 0, 0, fmt.Errorf("invalid translated port: %v", rule.TranslatedPort)
+	}
+}
+
+func (r *family) handlePortRange(rule firewall.ForwardRule) ([]expr.Any, uint32, uint32, error) {
+	exprs := []expr.Any{
+		&expr.Immediate{
+			Register: 1,
+			Data:     rule.TranslatedAddress.AsSlice(),
+		},
+		&expr.Immediate{
+			Register: 2,
+			Data:     binaryutil.BigEndian.PutUint16(rule.TranslatedPort.Values[0]),
+		},
+		&expr.Immediate{
+			Register: 3,
+			Data:     binaryutil.BigEndian.PutUint16(rule.TranslatedPort.Values[1]),
+		},
+	}
+	return exprs, 2, 3, nil
+}
+
+func (r *family) handleAddressOnly(rule firewall.ForwardRule) ([]expr.Any, uint32, uint32, error) {
+	exprs := []expr.Any{
+		&expr.Immediate{
+			Register: 1,
+			Data:     rule.TranslatedAddress.AsSlice(),
+		},
+	}
+	return exprs, 0, 0, nil
+}
+
+func (r *family) handleSinglePort(rule firewall.ForwardRule) ([]expr.Any, uint32, uint32, error) {
+	exprs := []expr.Any{
+		&expr.Immediate{
+			Register: 1,
+			Data:     rule.TranslatedAddress.AsSlice(),
+		},
+		&expr.Immediate{
+			Register: 2,
+			Data:     binaryutil.BigEndian.PutUint16(rule.TranslatedPort.Values[0]),
+		},
+	}
+	return exprs, 2, 0, nil
+}
+
+func (r *family) addXTablesRedirect(dnatExprs []expr.Any, ruleID firewall.RuleID, rule firewall.ForwardRule) error {
+	dnatExprs = append(dnatExprs,
+		&expr.Counter{},
+		&expr.Target{
+			Name: "DNAT",
+			Rev:  2,
+			Info: &xt.NatRange2{
+				NatRange: xt.NatRange{
+					Flags:   uint(xt.NatRangeMapIPs | xt.NatRangeProtoSpecified | xt.NatRangeProtoOffset),
+					MinIP:   rule.TranslatedAddress.AsSlice(),
+					MaxIP:   rule.TranslatedAddress.AsSlice(),
+					MinPort: rule.TranslatedPort.Values[0],
+					MaxPort: rule.TranslatedPort.Values[1],
+				},
+				BasePort: rule.DestinationPort.Values[0],
+			},
+		},
+	)
+
+	natTable := &nftables.Table{
+		Name:   tableNat,
+		Family: r.af.tableFamily,
+	}
+	dnatRule := &nftables.Rule{
+		Table: natTable,
+		Chain: &nftables.Chain{
+			Name:     chainNameNatPrerouting,
+			Table:    natTable,
+			Type:     nftables.ChainTypeNAT,
+			Hooknum:  nftables.ChainHookPrerouting,
+			Priority: nftables.ChainPriorityNATDest,
+		},
+		Exprs:    dnatExprs,
+		UserData: []byte(ruleID + dnatSuffix),
+	}
+	r.conn.AddRule(dnatRule)
+	r.rules[ruleID+dnatSuffix] = dnatRule
+
+	return nil
+}
+
+func (r *family) addDnatMasq(rule firewall.ForwardRule, protoNum uint8, ruleID firewall.RuleID) error {
+	portExprs, err := r.applyPort(&rule.TranslatedPort, false)
+	if err != nil {
+		return fmt.Errorf("apply translated port: %w", err)
+	}
+
+	masqExprs := []expr.Any{
+		&expr.Meta{Key: expr.MetaKeyOIFNAME, Register: 1},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     ifname(r.wgIface.Name()),
+		},
+		&expr.Meta{Key: expr.MetaKeyL4PROTO, Register: 1},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     []byte{protoNum},
+		},
+		&expr.Payload{
+			DestRegister: 1,
+			Base:         expr.PayloadBaseNetworkHeader,
+			Offset:       r.af.dstAddrOffset,
+			Len:          r.af.addrLen,
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     rule.TranslatedAddress.AsSlice(),
+		},
+	}
+
+	masqExprs = append(masqExprs, portExprs...)
+	masqExprs = append(masqExprs, &expr.Masq{})
+
+	masqRule := &nftables.Rule{
+		Table:    r.workTable,
+		Chain:    r.chains[chainNameRoutingNat],
+		Exprs:    masqExprs,
+		UserData: []byte(ruleID + snatSuffix),
+	}
+	r.conn.AddRule(masqRule)
+	r.rules[ruleID+snatSuffix] = masqRule
+
+	return nil
+}
+
+func (r *family) DeleteDNATRule(rule firewall.Rule) error {
+	ruleID := rule.ID()
+
+	if err := r.refreshRulesMap(); err != nil {
+		return fmt.Errorf(refreshRulesMapError, err)
+	}
+
+	var merr *multierror.Error
+	var needsFlush bool
+	var found bool
+
+	if dnatRule, exists := r.rules[ruleID+dnatSuffix]; exists {
+		found = true
+		if dnatRule.Handle == 0 {
+			log.Warnf("dnat rule %s has no handle, removing stale entry", ruleID+dnatSuffix)
+			delete(r.rules, ruleID+dnatSuffix)
+		} else if err := r.conn.DelRule(dnatRule); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("delete dnat rule: %w", err))
+		} else {
+			needsFlush = true
+		}
+	}
+
+	if masqRule, exists := r.rules[ruleID+snatSuffix]; exists {
+		found = true
+		if masqRule.Handle == 0 {
+			log.Warnf("snat rule %s has no handle, removing stale entry", ruleID+snatSuffix)
+			delete(r.rules, ruleID+snatSuffix)
+		} else if err := r.conn.DelRule(masqRule); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("delete snat rule: %w", err))
+		} else {
+			needsFlush = true
+		}
+	}
+
+	if needsFlush {
+		if err := r.conn.Flush(); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf(flushError, err))
+		}
+	}
+
+	if merr != nil {
+		return nberrors.FormatErrorOrNil(merr)
+	}
+
+	delete(r.rules, ruleID+dnatSuffix)
+	delete(r.rules, ruleID+snatSuffix)
+
+	// Release once, only if the rule was present and removed.
+	if found {
+		r.releaseForwarding()
+	}
+
+	return nil
+}
+
+// releaseForwarding drops one IP forwarding reference, logging any error.
+func (r *family) releaseForwarding() {
+	if err := r.ipFwdState.ReleaseForwarding(r.isV6()); err != nil {
+		log.Errorf("release IP forwarding: %v", err)
+	}
+}
+
+// isV6 reports whether this family handles the IPv6 table.
+func (r *family) isV6() bool {
+	return r.af.tableFamily == nftables.TableFamilyIPv6
+}
+
+func (r *family) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+	ruleID := firewall.RuleID(fmt.Sprintf("inbound-dnat-%s-%s-%d-%d", localAddr.String(), protocol, originalPort, translatedPort))
+
+	if _, exists := r.rules[ruleID]; exists {
+		return nil
+	}
+
+	protoNum, err := r.af.protoNum(protocol)
+	if err != nil {
+		return fmt.Errorf("convert protocol to number: %w", err)
+	}
+
+	exprs := []expr.Any{
+		&expr.Meta{Key: expr.MetaKeyIIFNAME, Register: 1},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     ifname(r.wgIface.Name()),
+		},
+		&expr.Meta{Key: expr.MetaKeyL4PROTO, Register: 2},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 2,
+			Data:     []byte{protoNum},
+		},
+		&expr.Payload{
+			DestRegister: 3,
+			Base:         expr.PayloadBaseTransportHeader,
+			Offset:       2,
+			Len:          2,
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 3,
+			Data:     binaryutil.BigEndian.PutUint16(originalPort),
+		},
+	}
+
+	bits := 32
+	if localAddr.Is6() {
+		bits = 128
+	}
+	exprs = append(exprs, prefixMatchExprs(r.af, netip.PrefixFrom(localAddr, bits), false)...)
+
+	exprs = append(exprs,
+		&expr.Immediate{
+			Register: 1,
+			Data:     localAddr.AsSlice(),
+		},
+		&expr.Immediate{
+			Register: 2,
+			Data:     binaryutil.BigEndian.PutUint16(translatedPort),
+		},
+		&expr.NAT{
+			Type:        expr.NATTypeDestNAT,
+			Family:      uint32(r.af.tableFamily),
+			RegAddrMin:  1,
+			RegProtoMin: 2,
+			RegProtoMax: 0,
+		},
+	)
+
+	dnatRule := &nftables.Rule{
+		Table:    r.workTable,
+		Chain:    r.chains[chainNameRoutingRdr],
+		Exprs:    exprs,
+		UserData: []byte(ruleID),
+	}
+	r.conn.AddRule(dnatRule)
+
+	if err := r.conn.Flush(); err != nil {
+		return fmt.Errorf("add inbound DNAT rule: %w", err)
+	}
+
+	r.rules[ruleID] = dnatRule
+
+	return nil
+}
+
+// RemoveInboundDNAT removes an inbound DNAT rule.
+func (r *family) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+	if err := r.refreshRulesMap(); err != nil {
+		return fmt.Errorf(refreshRulesMapError, err)
+	}
+
+	ruleID := firewall.RuleID(fmt.Sprintf("inbound-dnat-%s-%s-%d-%d", localAddr.String(), protocol, originalPort, translatedPort))
+
+	rule, exists := r.rules[ruleID]
+	if !exists {
+		return nil
+	}
+
+	if rule.Handle == 0 {
+		log.Warnf("inbound DNAT rule %s has no handle, removing stale entry", ruleID)
+		delete(r.rules, ruleID)
+		return nil
+	}
+
+	if err := r.conn.DelRule(rule); err != nil {
+		return fmt.Errorf("delete inbound DNAT rule %s: %w", ruleID, err)
+	}
+	if err := r.conn.Flush(); err != nil {
+		return fmt.Errorf("flush delete inbound DNAT rule: %w", err)
+	}
+	delete(r.rules, ruleID)
+
+	return nil
+}
+
+// ensureNATOutputChain lazily creates the OUTPUT NAT chain on first use.
+func (r *family) ensureNATOutputChain() error {
+	if _, exists := r.chains[chainNameNATOutput]; exists {
+		return nil
+	}
+
+	r.chains[chainNameNATOutput] = r.conn.AddChain(&nftables.Chain{
+		Name:     chainNameNATOutput,
+		Table:    r.workTable,
+		Hooknum:  nftables.ChainHookOutput,
+		Priority: nftables.ChainPriorityNATDest,
+		Type:     nftables.ChainTypeNAT,
+	})
+
+	if err := r.conn.Flush(); err != nil {
+		delete(r.chains, chainNameNATOutput)
+		return fmt.Errorf("create NAT output chain: %w", err)
+	}
+	return nil
+}
+
+// AddOutputDNAT adds an OUTPUT chain DNAT rule for locally-generated traffic.
+func (r *family) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+	ruleID := firewall.RuleID(fmt.Sprintf("output-dnat-%s-%s-%d-%d", localAddr.String(), protocol, originalPort, translatedPort))
+
+	if _, exists := r.rules[ruleID]; exists {
+		return nil
+	}
+
+	if err := r.ensureNATOutputChain(); err != nil {
+		return err
+	}
+
+	protoNum, err := r.af.protoNum(protocol)
+	if err != nil {
+		return fmt.Errorf("convert protocol to number: %w", err)
+	}
+
+	exprs := []expr.Any{
+		&expr.Meta{Key: expr.MetaKeyL4PROTO, Register: 1},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     []byte{protoNum},
+		},
+		&expr.Payload{
+			DestRegister: 2,
+			Base:         expr.PayloadBaseTransportHeader,
+			Offset:       2,
+			Len:          2,
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 2,
+			Data:     binaryutil.BigEndian.PutUint16(originalPort),
+		},
+	}
+
+	bits := 32
+	if localAddr.Is6() {
+		bits = 128
+	}
+	exprs = append(exprs, prefixMatchExprs(r.af, netip.PrefixFrom(localAddr, bits), false)...)
+
+	exprs = append(exprs,
+		&expr.Immediate{
+			Register: 1,
+			Data:     localAddr.AsSlice(),
+		},
+		&expr.Immediate{
+			Register: 2,
+			Data:     binaryutil.BigEndian.PutUint16(translatedPort),
+		},
+		&expr.NAT{
+			Type:        expr.NATTypeDestNAT,
+			Family:      uint32(r.af.tableFamily),
+			RegAddrMin:  1,
+			RegProtoMin: 2,
+		},
+	)
+
+	dnatRule := &nftables.Rule{
+		Table:    r.workTable,
+		Chain:    r.chains[chainNameNATOutput],
+		Exprs:    exprs,
+		UserData: []byte(ruleID),
+	}
+	r.conn.AddRule(dnatRule)
+
+	if err := r.conn.Flush(); err != nil {
+		return fmt.Errorf("add output DNAT rule: %w", err)
+	}
+
+	r.rules[ruleID] = dnatRule
+
+	return nil
+}
+
+// RemoveOutputDNAT removes an OUTPUT chain DNAT rule.
+func (r *family) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+	if err := r.refreshRulesMap(); err != nil {
+		return fmt.Errorf(refreshRulesMapError, err)
+	}
+
+	ruleID := firewall.RuleID(fmt.Sprintf("output-dnat-%s-%s-%d-%d", localAddr.String(), protocol, originalPort, translatedPort))
+
+	rule, exists := r.rules[ruleID]
+	if !exists {
+		return nil
+	}
+
+	if rule.Handle == 0 {
+		log.Warnf("output DNAT rule %s has no handle, removing stale entry", ruleID)
+		delete(r.rules, ruleID)
+		return nil
+	}
+
+	if err := r.conn.DelRule(rule); err != nil {
+		return fmt.Errorf("delete output DNAT rule %s: %w", ruleID, err)
+	}
+	if err := r.conn.Flush(); err != nil {
+		return fmt.Errorf("flush delete output DNAT rule: %w", err)
+	}
+	delete(r.rules, ruleID)
+
+	return nil
+}

client/firewall/nftables/dnat_refcount_linux_test.go

@@ -82,7 +82,7 @@ func dnatV6(port uint16) fw.ForwardRule {
 // v4 refcount at zero.
 func TestNftablesDNAT_RefcountBalancedV4(t *testing.T) {
 	m := newNftRefcountManager(t, false)
-	state := m.router.ipFwdState
+	state := m.family4.ipFwdState
 
 	r1, err := m.AddDNATRule(dnatV4(8081))
 	require.NoError(t, err, "add v4 dnat 1")
@@ -111,9 +111,9 @@ func TestNftablesDNAT_RefcountBalancedV4(t *testing.T) {
 // and decrements back to zero on Delete.
 func TestNftablesDNAT_RefcountBalancedV6(t *testing.T) {
 	m := newNftRefcountManager(t, true)
-	require.NotNil(t, m.router6, "v6 router")
+	require.NotNil(t, m.family6, "v6 family")
-	require.Same(t, m.router.ipFwdState, m.router6.ipFwdState, "shared state")
+	require.Same(t, m.family4.ipFwdState, m.family6.ipFwdState, "shared state")
-	state := m.router.ipFwdState
+	state := m.family4.ipFwdState
 
 	r1, err := m.AddDNATRule(dnatV6(9091))
 	require.NoError(t, err, "add v6 dnat 1")
@@ -142,7 +142,7 @@ func TestNftablesDNAT_RefcountBalancedV6(t *testing.T) {
 // ForwardRule) does not double-increment the refcount.
 func TestNftablesDNAT_DuplicateAddNoLeak(t *testing.T) {
 	m := newNftRefcountManager(t, true)
-	state := m.router.ipFwdState
+	state := m.family4.ipFwdState
 
 	rule := dnatV4(8083)
 	r1, err := m.AddDNATRule(rule)
@@ -165,7 +165,7 @@ func TestNftablesDNAT_DuplicateAddNoLeak(t *testing.T) {
 // never added does not underflow the refcount.
 func TestNftablesDNAT_DeleteMissingNoUnderflow(t *testing.T) {
 	m := newNftRefcountManager(t, true)
-	state := m.router.ipFwdState
+	state := m.family4.ipFwdState
 
 	// Construct a Rule reference for something never added. The router stores
 	// rules by ID(), and DeleteDNATRule looks them up in r.rules; a missing
@@ -195,7 +195,7 @@ func TestNftablesDNAT_DeleteMissingNoUnderflow(t *testing.T) {
 // and a single DisableRouting drops both back to zero.
 func TestNftablesRouting_RepeatedEnableSingleReference(t *testing.T) {
 	m := newNftRefcountManager(t, true)
-	state := m.router.ipFwdState
+	state := m.family4.ipFwdState
 
 	require.NoError(t, m.EnableRouting(), "first enable")
 	require.NoError(t, m.EnableRouting(), "second enable")
@@ -214,7 +214,7 @@ func TestNftablesRouting_RepeatedEnableSingleReference(t *testing.T) {
 // DisableRouting does not release references held by active DNAT rules.
 func TestNftablesRouting_DisableKeepsDNATReference(t *testing.T) {
 	m := newNftRefcountManager(t, true)
-	state := m.router.ipFwdState
+	state := m.family4.ipFwdState
 
 	r1, err := m.AddDNATRule(dnatV6(9095))
 	require.NoError(t, err, "add v6 dnat")
@@ -232,7 +232,7 @@ func TestNftablesRouting_DisableKeepsDNATReference(t *testing.T) {
 // twice does not underflow the refcount (the second delete is a no-op).
 func TestNftablesDNAT_DoubleDeleteNoUnderflow(t *testing.T) {
 	m := newNftRefcountManager(t, true)
-	state := m.router.ipFwdState
+	state := m.family4.ipFwdState
 
 	r1, err := m.AddDNATRule(dnatV6(9093))
 	require.NoError(t, err)

client/firewall/nftables/family_linux.go

@@ -0,0 +1,249 @@
+//go:build !android
+
+package nftables
+
+import (
+	"fmt"
+	"net/netip"
+
+	"github.com/coreos/go-iptables/iptables"
+	"github.com/google/nftables"
+	"github.com/hashicorp/go-multierror"
+	log "github.com/sirupsen/logrus"
+
+	nberrors "github.com/netbirdio/netbird/client/errors"
+	"github.com/netbirdio/netbird/client/firewall/firewalld"
+	firewall "github.com/netbirdio/netbird/client/firewall/manager"
+	"github.com/netbirdio/netbird/client/internal/routemanager/ipfwdstate"
+	"github.com/netbirdio/netbird/client/internal/routemanager/refcounter"
+)
+
+const (
+	tableNat      = "nat"
+	tableMangle   = "mangle"
+	tableRaw      = "raw"
+	tableSecurity = "security"
+
+	chainNameNatPrerouting = "PREROUTING"
+	chainNameRoutingFw     = "netbird-rt-fwd"
+	chainNameRoutingNat    = "netbird-rt-postrouting"
+	chainNameRoutingRdr    = "netbird-rt-redirect"
+	chainNameNATOutput     = "netbird-nat-output"
+	chainNameForward       = "FORWARD"
+	chainNameMangleForward = "netbird-mangle-forward"
+
+	// Peer ACL chain names.
+	chainNameInputRules        = "netbird-acl-input-rules"
+	chainNameInputFilter       = "netbird-acl-input-filter"
+	chainNameForwardFilter     = "netbird-acl-forward-filter"
+	chainNameManglePrerouting  = "netbird-mangle-prerouting"
+	chainNameManglePostrouting = "netbird-mangle-postrouting"
+
+	flushError = "flush: %w"
+
+	firewalldTableName = "firewalld"
+
+	userDataAcceptForwardRuleIif = "frwacceptiif"
+	userDataAcceptForwardRuleOif = "frwacceptoif"
+	userDataAcceptInputRule      = "inputaccept"
+
+	dnatSuffix firewall.RuleID = "_dnat"
+	snatSuffix firewall.RuleID = "_snat"
+
+	// ipv4TCPHeaderSize is the minimum IPv4 (20) + TCP (20) header size for MSS calculation.
+	ipv4TCPHeaderSize = 40
+	// ipv6TCPHeaderSize is the minimum IPv6 (40) + TCP (20) header size for MSS calculation.
+	ipv6TCPHeaderSize = 60
+
+	// maxPrefixesSet 1638 prefixes start to fail, taking some margin
+	maxPrefixesSet       = 1500
+	refreshRulesMapError = "refresh rules map: %w"
+)
+
+var (
+	errFilterTableNotFound = fmt.Errorf("'filter' table not found")
+)
+
+type setInput struct {
+	set      firewall.Set
+	prefixes []netip.Prefix
+}
+
+// family holds the per-address-family nftables state. One instance
+// handles route ACLs, peer ACLs, NAT, DNAT, and MSS clamping for a
+// single family; the top-level Manager owns one for v4 and another
+// for v6. The name predates the peer-ACL absorption; it's effectively
+// the per-family backend now.
+type family struct {
+	conn        *nftables.Conn
+	workTable   *nftables.Table
+	filterTable *nftables.Table
+	chains      map[string]*nftables.Chain
+
+	// filters holds peer + route filter rules keyed by content hash.
+	// AddFilterRule writes here; DeleteFilterRule looks up by id.
+	filters map[firewall.RuleID]*Rule
+
+	// rules holds NAT, DNAT, and external accept rules (auxiliary
+	// plumbing that isn't a filter rule).
+	rules map[firewall.RuleID]*nftables.Rule
+
+	// Peer ACL chain handles.
+	chainInputRules    *nftables.Chain
+	chainPrerouting    *nftables.Chain
+	routingFwChainName string
+
+	ipsetCounter *refcounter.Counter[string, setInput, *nftables.Set]
+
+	af               addrFamily
+	wgIface          iFaceMapper
+	ipFwdState       *ipfwdstate.IPForwardingState
+	legacyManagement bool
+	mtu              uint16
+}
+
+func newFamily(workTable *nftables.Table, wgIface iFaceMapper, mtu uint16) *family {
+	r := &family{
+		conn:               &nftables.Conn{},
+		workTable:          workTable,
+		chains:             make(map[string]*nftables.Chain),
+		filters:            make(map[firewall.RuleID]*Rule),
+		rules:              make(map[firewall.RuleID]*nftables.Rule),
+		routingFwChainName: chainNameRoutingFw,
+		af:                 familyForAddr(workTable.Family == nftables.TableFamilyIPv4),
+		wgIface:            wgIface,
+		ipFwdState:         ipfwdstate.NewIPForwardingState(wgIface.Name()),
+		mtu:                mtu,
+	}
+
+	r.ipsetCounter = refcounter.New(
+		r.createIpSet,
+		r.deleteIpSet,
+	)
+
+	var err error
+	r.filterTable, err = r.loadFilterTable()
+	if err != nil {
+		log.Debugf("ip filter table not found: %v", err)
+	}
+
+	return r
+}
+
+func (r *family) init(workTable *nftables.Table) error {
+	r.workTable = workTable
+
+	if err := r.removeAcceptFilterRules(); err != nil {
+		log.Errorf("failed to clean up rules from filter table: %s", err)
+	}
+
+	if err := r.createContainers(); err != nil {
+		return fmt.Errorf("create containers: %w", err)
+	}
+
+	if err := r.setupDataPlaneMark(); err != nil {
+		log.Errorf("failed to set up data plane mark: %v", err)
+	}
+
+	if err := r.createDefaultChains(); err != nil {
+		return fmt.Errorf("create default acl chains: %w", err)
+	}
+
+	return nil
+}
+
+// Reset cleans existing nftables filter table rules from the system
+func (r *family) Reset() error {
+	// clear without deleting the ipsets, the nf table will be deleted by the caller
+	r.ipsetCounter.Clear()
+
+	var merr *multierror.Error
+
+	if err := r.removeAcceptFilterRules(); err != nil {
+		merr = multierror.Append(merr, fmt.Errorf("remove accept filter rules: %w", err))
+	}
+
+	if err := firewalld.UntrustInterface(r.wgIface.Name()); err != nil {
+		merr = multierror.Append(merr, err)
+	}
+
+	if err := r.removeNatPreroutingRules(); err != nil {
+		merr = multierror.Append(merr, fmt.Errorf("remove filter prerouting rules: %w", err))
+	}
+
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+func (r *family) loadFilterTable() (*nftables.Table, error) {
+	tables, err := r.conn.ListTablesOfFamily(r.af.tableFamily)
+	if err != nil {
+		return nil, fmt.Errorf("list tables: %w", err)
+	}
+
+	for _, table := range tables {
+		if table.Name == "filter" {
+			return table, nil
+		}
+	}
+
+	return nil, errFilterTableNotFound
+}
+
+func hookName(hook *nftables.ChainHook) string {
+	if hook == nil {
+		return "unknown"
+	}
+	switch *hook {
+	case *nftables.ChainHookForward:
+		return chainNameForward
+	case *nftables.ChainHookInput:
+		return chainNameInput
+	default:
+		return fmt.Sprintf("hook(%d)", *hook)
+	}
+}
+
+func familyName(family nftables.TableFamily) string {
+	switch family {
+	case nftables.TableFamilyIPv4:
+		return "ip"
+	case nftables.TableFamilyIPv6:
+		return "ip6"
+	case nftables.TableFamilyINet:
+		return "inet"
+	default:
+		return fmt.Sprintf("family(%d)", family)
+	}
+}
+
+func (r *family) iptablesProto() iptables.Protocol {
+	if r.af.tableFamily == nftables.TableFamilyIPv6 {
+		return iptables.ProtocolIPv6
+	}
+	return iptables.ProtocolIPv4
+}
+
+func (r *family) refreshRulesMap() error {
+	var merr *multierror.Error
+	newRules := make(map[firewall.RuleID]*nftables.Rule)
+	for _, chain := range r.chains {
+		rules, err := r.conn.GetRules(chain.Table, chain)
+		if err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("list rules for chain %s: %w", chain.Name, err))
+			// preserve existing entries for this chain since we can't verify their state
+			for k, v := range r.rules {
+				if v.Chain != nil && v.Chain.Name == chain.Name {
+					newRules[k] = v
+				}
+			}
+			continue
+		}
+		for _, rule := range rules {
+			if len(rule.UserData) > 0 {
+				newRules[firewall.RuleID(rule.UserData)] = rule
+			}
+		}
+	}
+	r.rules = newRules
+	return nberrors.FormatErrorOrNil(merr)
+}

client/firewall/nftables/filter_linux.go

@@ -0,0 +1,540 @@
+//go:build !android
+
+package nftables
+
+import (
+	"fmt"
+	"net"
+	"net/netip"
+	"slices"
+
+	"github.com/google/nftables"
+	"github.com/google/nftables/binaryutil"
+	"github.com/google/nftables/expr"
+	"github.com/hashicorp/go-multierror"
+	log "github.com/sirupsen/logrus"
+
+	nberrors "github.com/netbirdio/netbird/client/errors"
+	firewall "github.com/netbirdio/netbird/client/firewall/manager"
+	nbid "github.com/netbirdio/netbird/client/internal/acl/id"
+)
+
+// AddFilterRule installs one nftables packet-filter rule. With
+// destination empty the rule goes to the peer ACL input chain plus a
+// paired prerouting mangle rule for the redirect mark. With
+// destination set (prefix or named set) it goes to the route ACL
+// forward chain. Multi-source rules collapse to one nftables rule
+// backed by the shared refcounted hash:net set.
+func (r *family) AddFilterRule(
+	id []byte,
+	sources []netip.Prefix,
+	destination firewall.Network,
+	proto firewall.Protocol,
+	sPort *firewall.Port,
+	dPort *firewall.Port,
+	action firewall.Action,
+) (firewall.Rule, error) {
+	isRoute := !destination.IsZero()
+
+	ruleID := nbid.GenerateRuleID(sources, destination, proto, sPort, dPort, action)
+	if existing, ok := r.filters[ruleID]; ok {
+		return existing, nil
+	}
+
+	srcExprs, err := r.applyNetwork(sourceNetwork(sources), sources, true)
+	if err != nil {
+		return nil, fmt.Errorf("apply source: %w", err)
+	}
+
+	var exprs []expr.Any
+	if isRoute {
+		exprs, err = r.buildRouteFilterExprs(srcExprs, destination, proto, sPort, dPort)
+	} else {
+		exprs, err = r.buildPeerFilterExprs(srcExprs, proto, sPort, dPort)
+	}
+	if err != nil {
+		r.dropNetworkMatch(srcExprs)
+		return nil, err
+	}
+
+	mainExprs := slices.Clone(exprs)
+	verdict := expr.VerdictAccept
+	if action == firewall.ActionDrop {
+		verdict = expr.VerdictDrop
+	}
+	mainExprs = append(mainExprs, &expr.Verdict{Kind: verdict})
+
+	chain := r.chainInputRules
+	if isRoute {
+		chain = r.chains[chainNameRoutingFw]
+	}
+
+	userData := []byte(ruleID)
+
+	// Build the paired prerouting mangle rule before flushing so both
+	// rules commit in one transaction. An anonymous port set binds to
+	// exactly one rule, so the mangle rule needs its own expression list
+	// with fresh sets, not a clone of the main rule's. Guard on the
+	// prerouting chain first: building the expressions queues the port
+	// set, so skipping the build when there is no chain to bind it to
+	// keeps an unbound set out of the connection batch.
+	var mangleRule *nftables.Rule
+	if !isRoute && r.chainPrerouting != nil {
+		mangleExprs, err := r.buildPeerFilterExprs(srcExprs, proto, sPort, dPort)
+		if err != nil {
+			r.dropNetworkMatch(exprs)
+			return nil, fmt.Errorf("build mangle rule: %w", err)
+		}
+		mangleRule = r.queuePreroutingRule(mangleExprs, userData)
+	}
+
+	nftRule := &nftables.Rule{
+		Table:    r.workTable,
+		Chain:    chain,
+		Exprs:    mainExprs,
+		UserData: userData,
+	}
+	if action == firewall.ActionDrop {
+		nftRule = r.conn.InsertRule(nftRule)
+	} else {
+		nftRule = r.conn.AddRule(nftRule)
+	}
+	if err := r.conn.Flush(); err != nil {
+		r.dropNetworkMatch(exprs)
+		return nil, fmt.Errorf(flushError, err)
+	}
+
+	rule := &Rule{
+		nftRule:    nftRule,
+		mangleRule: mangleRule,
+		sources:    sources,
+		id:         ruleID,
+	}
+	r.filters[ruleID] = rule
+
+	log.Debugf("added filter rule: sources=%v, destination=%v, proto=%v, sPort=%v, dPort=%v, action=%v",
+		sources, destination, proto, sPort, dPort, action)
+	return rule, nil
+}
+
+// buildPeerFilterExprs assembles the input-chain (peer ACL) match: the
+// IP-header protocol byte read via Payload, then source, then ports
+// (no counter), matching the historical peer shape so per-rule kernel
+// state is identical to pre-unification.
+func (r *family) buildPeerFilterExprs(
+	srcExprs []expr.Any,
+	proto firewall.Protocol,
+	sPort, dPort *firewall.Port,
+) ([]expr.Any, error) {
+	var exprs []expr.Any
+
+	if proto != firewall.ProtocolALL {
+		protoNum, err := r.af.protoNum(proto)
+		if err != nil {
+			return nil, fmt.Errorf("convert protocol to number: %w", err)
+		}
+		exprs = append(exprs,
+			&expr.Payload{
+				DestRegister: 1,
+				Base:         expr.PayloadBaseNetworkHeader,
+				Offset:       r.af.protoOffset,
+				Len:          1,
+			},
+			&expr.Cmp{Op: expr.CmpOpEq, Register: 1, Data: []byte{protoNum}},
+		)
+	}
+	exprs = append(exprs, srcExprs...)
+
+	portExprs, err := r.applyPorts(sPort, dPort)
+	if err != nil {
+		return nil, err
+	}
+	exprs = append(exprs, portExprs...)
+	return exprs, nil
+}
+
+// buildRouteFilterExprs assembles the forward-chain (route ACL) match:
+// source, then destination, then optional proto/ports, then a counter.
+func (r *family) buildRouteFilterExprs(
+	srcExprs []expr.Any,
+	destination firewall.Network,
+	proto firewall.Protocol,
+	sPort, dPort *firewall.Port,
+) ([]expr.Any, error) {
+	exprs := append([]expr.Any{}, srcExprs...)
+
+	destExprs, err := r.applyNetwork(destination, nil, false)
+	if err != nil {
+		return nil, fmt.Errorf("apply destination: %w", err)
+	}
+	exprs = append(exprs, destExprs...)
+
+	if proto != firewall.ProtocolALL {
+		protoNum, err := r.af.protoNum(proto)
+		if err != nil {
+			r.dropNetworkMatch(destExprs)
+			return nil, fmt.Errorf("convert protocol to number: %w", err)
+		}
+		exprs = append(exprs,
+			&expr.Meta{Key: expr.MetaKeyL4PROTO, Register: 1},
+			&expr.Cmp{Op: expr.CmpOpEq, Register: 1, Data: []byte{protoNum}},
+		)
+
+		portExprs, err := r.applyPorts(sPort, dPort)
+		if err != nil {
+			r.dropNetworkMatch(destExprs)
+			return nil, err
+		}
+		exprs = append(exprs, portExprs...)
+	}
+
+	exprs = append(exprs, &expr.Counter{})
+	return exprs, nil
+}
+
+func (r *family) hasRule(id firewall.RuleID) bool {
+	_, ok := r.filters[id]
+	return ok
+}
+
+func (r *family) hasDNATRule(id firewall.RuleID) bool {
+	_, ok := r.rules[id+dnatSuffix]
+	return ok
+}
+
+// DeleteFilterRule removes a previously installed filter rule. Source
+// set references are recovered from the stored rule's expressions via
+// findSets and dropped from the shared refcounter.
+func (r *family) DeleteFilterRule(rule firewall.Rule) error {
+	ruleID := rule.ID()
+	pr, ok := r.filters[ruleID]
+	if !ok {
+		log.Debugf("filter rule %s not found", ruleID)
+		return nil
+	}
+
+	// A freshly added rule carries no handle until it is read back from
+	// the kernel, and Flush only refreshes the peer chains. Pull live
+	// handles for this rule's chain before deciding it is stale so route
+	// rules (which Flush never refreshes) can actually be deleted. A
+	// refresh failure aborts the delete without touching tracking state,
+	// so the caller can retry while the rule may still exist in the kernel.
+	if pr.nftRule.Handle == 0 {
+		if err := r.refreshRuleHandles(pr.nftRule.Chain, false); err != nil {
+			return fmt.Errorf("refresh handles for chain %s: %w", pr.nftRule.Chain.Name, err)
+		}
+	}
+	// Refresh the mangle handle independently: the main rule's handle can
+	// be populated while the prerouting refresh during Flush failed, and
+	// gating the mangle refresh on the main handle would leak the mangle
+	// rule on delete.
+	if pr.mangleRule != nil && pr.mangleRule.Handle == 0 {
+		if err := r.refreshRuleHandles(r.chainPrerouting, true); err != nil {
+			return fmt.Errorf("refresh mangle handles: %w", err)
+		}
+	}
+
+	if pr.nftRule.Handle == 0 {
+		log.Warnf("filter rule %s has no handle, removing stale entry", ruleID)
+		// The paired mangle rule can still be in the kernel with a live
+		// handle. Dropping the tracking entry without removing it would
+		// leave a prerouting rule that nothing can find again.
+		if err := r.deleteMangleRule(pr, ruleID); err != nil {
+			return err
+		}
+		r.dropNetworkMatch(pr.nftRule.Exprs)
+		delete(r.filters, ruleID)
+		return nil
+	}
+
+	if err := r.conn.DelRule(pr.nftRule); err != nil {
+		log.Errorf("queue rule delete: %v", err)
+	}
+	r.queueMangleDelete(pr)
+	if err := r.conn.Flush(); err != nil {
+		return fmt.Errorf("flush delete %s: %w", ruleID, err)
+	}
+
+	r.dropNetworkMatch(pr.nftRule.Exprs)
+	delete(r.filters, ruleID)
+	return nil
+}
+
+// deleteMangleRule removes the prerouting rule paired with a filter rule on
+// its own, for the paths that drop the filter rule's tracking without queueing
+// a delete for it.
+func (r *family) deleteMangleRule(pr *Rule, ruleID firewall.RuleID) error {
+	if pr.mangleRule == nil || pr.mangleRule.Handle == 0 {
+		return nil
+	}
+
+	r.queueMangleDelete(pr)
+	if err := r.conn.Flush(); err != nil {
+		return fmt.Errorf("flush mangle delete %s: %w", ruleID, err)
+	}
+	return nil
+}
+
+// queueMangleDelete queues the delete of the rule's prerouting counterpart, if
+// it has one. The caller commits it.
+func (r *family) queueMangleDelete(pr *Rule) {
+	if pr.mangleRule == nil {
+		return
+	}
+	if err := r.conn.DelRule(pr.mangleRule); err != nil {
+		log.Errorf("queue mangle rule delete: %v", err)
+	}
+}
+
+func (r *family) decrementSetCounter(rule *nftables.Rule) error {
+	if r.ipsetCounter == nil {
+		return nil
+	}
+	sets := findSets(rule)
+
+	var merr *multierror.Error
+	for _, setName := range sets {
+		if _, err := r.ipsetCounter.Decrement(setName); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("decrement set counter: %w", err))
+		}
+	}
+
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+// dropNetworkMatch undoes whatever the source/destination match
+// reserved. Safe to call when the spec is empty or holds only inline
+// matchers.
+func (r *family) dropNetworkMatch(exprs []expr.Any) {
+	if r.ipsetCounter == nil {
+		return
+	}
+	for _, e := range exprs {
+		lookup, ok := e.(*expr.Lookup)
+		if !ok {
+			continue
+		}
+		if _, err := r.ipsetCounter.Decrement(lookup.SetName); err != nil {
+			log.Errorf("rollback ipset decrement %s: %v", lookup.SetName, err)
+		}
+	}
+}
+
+func (r *family) applyNetwork(
+	network firewall.Network,
+	setPrefixes []netip.Prefix,
+	isSource bool,
+) ([]expr.Any, error) {
+	if network.IsSet() {
+		exprs, err := r.getIpSet(network.Set, setPrefixes, isSource)
+		if err != nil {
+			side := "destination"
+			if isSource {
+				side = "source"
+			}
+			return nil, fmt.Errorf("%s set: %w", side, err)
+		}
+		return exprs, nil
+	}
+
+	if network.IsPrefix() {
+		return prefixMatchExprs(r.af, network.Prefix, isSource), nil
+	}
+
+	return nil, nil
+}
+
+// applyPort builds the transport-header port match. A single value
+// compares directly, a range uses a range expression, and multiple
+// values go through an anonymous constant set: consecutive cmp
+// expressions AND together, so chained equality comparisons could
+// never match more than one port. The set is queued on the
+// connection and committed by the caller's flush together with the
+// rule that binds it.
+func (r *family) applyPort(port *firewall.Port, isSource bool) ([]expr.Any, error) {
+	if port == nil || len(port.Values) == 0 {
+		return nil, nil
+	}
+
+	// dst port
+	offset := uint32(2)
+	if isSource {
+		// src port
+		offset = 0
+	}
+
+	exprs := []expr.Any{
+		&expr.Payload{
+			DestRegister: 1,
+			Base:         expr.PayloadBaseTransportHeader,
+			Offset:       offset,
+			Len:          2,
+		},
+	}
+
+	switch {
+	case port.IsRange && len(port.Values) == 2:
+		exprs = append(exprs, &expr.Range{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			FromData: binaryutil.BigEndian.PutUint16(port.Values[0]),
+			ToData:   binaryutil.BigEndian.PutUint16(port.Values[1]),
+		})
+	case len(port.Values) == 1:
+		exprs = append(exprs, &expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     binaryutil.BigEndian.PutUint16(port.Values[0]),
+		})
+	default:
+		lookup, err := r.anonymousPortSet(port.Values)
+		if err != nil {
+			return nil, err
+		}
+		exprs = append(exprs, lookup)
+	}
+
+	return exprs, nil
+}
+
+// anonymousPortSet queues an anonymous constant set holding the given
+// ports on the connection and returns a lookup against it. The set is
+// committed by the caller's flush together with the rule that binds it.
+func (r *family) anonymousPortSet(values []uint16) (*expr.Lookup, error) {
+	set := &nftables.Set{
+		Anonymous: true,
+		Constant:  true,
+		Table:     r.workTable,
+		KeyType:   nftables.TypeInetService,
+	}
+	elements := make([]nftables.SetElement, 0, len(values))
+	for _, p := range values {
+		elements = append(elements, nftables.SetElement{Key: binaryutil.BigEndian.PutUint16(p)})
+	}
+	if err := r.conn.AddSet(set, elements); err != nil {
+		return nil, fmt.Errorf("add anonymous port set: %w", err)
+	}
+	return &expr.Lookup{
+		SourceRegister: 1,
+		SetID:          set.ID,
+		SetName:        set.Name,
+	}, nil
+}
+
+// applyPorts builds the source then destination port matches.
+func (r *family) applyPorts(sPort, dPort *firewall.Port) ([]expr.Any, error) {
+	sPortExprs, err := r.applyPort(sPort, true)
+	if err != nil {
+		return nil, fmt.Errorf("apply source port: %w", err)
+	}
+
+	dPortExprs, err := r.applyPort(dPort, false)
+	if err != nil {
+		return nil, fmt.Errorf("apply destination port: %w", err)
+	}
+
+	return append(sPortExprs, dPortExprs...), nil
+}
+
+// prefixMatchExprs is the family-aware match sequence for a CIDR
+// prefix. /0 returns nil; a host prefix (full bit length for the
+// family) skips the bitwise step since the mask is all-ones. Shared
+// between family and aclManager so both treat single prefixes
+// identically.
+func prefixMatchExprs(af addrFamily, prefix netip.Prefix, isSource bool) []expr.Any {
+	offset := af.dstAddrOffset
+	if isSource {
+		offset = af.srcAddrOffset
+	}
+
+	ones := prefix.Bits()
+	if ones == 0 {
+		return nil
+	}
+
+	payload := &expr.Payload{
+		DestRegister: 1,
+		Base:         expr.PayloadBaseNetworkHeader,
+		Offset:       offset,
+		Len:          af.addrLen,
+	}
+	cmp := &expr.Cmp{
+		Op:       expr.CmpOpEq,
+		Register: 1,
+		Data:     prefix.Masked().Addr().AsSlice(),
+	}
+
+	if ones == af.totalBits {
+		return []expr.Any{payload, cmp}
+	}
+
+	mask := net.CIDRMask(ones, af.totalBits)
+	xor := make([]byte, af.addrLen)
+	return []expr.Any{
+		payload,
+		&expr.Bitwise{
+			DestRegister:   1,
+			SourceRegister: 1,
+			Len:            af.addrLen,
+			Mask:           mask,
+			Xor:            xor,
+		},
+		cmp,
+	}
+}
+
+func getCtNewExprs() []expr.Any {
+	return []expr.Any{
+		&expr.Ct{
+			Key:      expr.CtKeySTATE,
+			Register: 1,
+		},
+		&expr.Bitwise{
+			SourceRegister: 1,
+			DestRegister:   1,
+			Len:            4,
+			Mask:           binaryutil.NativeEndian.PutUint32(expr.CtStateBitNEW),
+			Xor:            binaryutil.NativeEndian.PutUint32(0),
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpNeq,
+			Register: 1,
+			Data:     []byte{0, 0, 0, 0},
+		},
+	}
+}
+
+// sourceNetwork classifies a source-prefix list into the firewall.Network
+// shape the rest of the spec-builder consumes: empty for match-any, a
+// single prefix inline, or an ipset for multiple sources.
+func sourceNetwork(sources []netip.Prefix) firewall.Network {
+	switch {
+	case len(sources) == 0:
+		return firewall.Network{}
+	case len(sources) == 1 && sources[0].Bits() == 0:
+		return firewall.Network{}
+	case len(sources) == 1:
+		return firewall.Network{Prefix: sources[0]}
+	default:
+		return firewall.Network{Set: firewall.NewPrefixSet(sources)}
+	}
+}
+
+func ifname(n string) []byte {
+	b := make([]byte, 16)
+	copy(b, n+"\x00")
+	return b
+}
+
+// findSets scans an nftables rule's expressions for expr.Lookup and
+// returns the named sets in occurrence order. Used at delete time to
+// drop ipsetCounter references; peer and route ACLs go through it.
+func findSets(rule *nftables.Rule) []string {
+	var sets []string
+	for _, e := range rule.Exprs {
+		if lookup, ok := e.(*expr.Lookup); ok {
+			sets = append(sets, lookup.SetName)
+		}
+	}
+	return sets
+}

client/firewall/nftables/interface_allower_integration_linux_test.go

@@ -0,0 +1,90 @@
+//go:build privileged
+
+package nftables
+
+import (
+	"bytes"
+	"os"
+	"testing"
+
+	"github.com/google/nftables"
+	"github.com/stretchr/testify/require"
+
+	"github.com/netbirdio/netbird/client/iface"
+)
+
+// TestInterfaceAllowerInputOnly verifies the userspace-mode allower opens the
+// interface on the INPUT hook of foreign chains only (not FORWARD, since the
+// userspace router never forwards in the kernel), creates no netbird work
+// table, and removes its rules on Close.
+func TestInterfaceAllowerInputOnly(t *testing.T) {
+	if os.Geteuid() != 0 {
+		t.Skip("root required")
+	}
+
+	require.False(t, ipTableExists(t, getTableName()), "precondition: no stale netbird table")
+
+	conn := &nftables.Conn{}
+	extTable := conn.AddTable(&nftables.Table{Name: "nbtest_extchains", Family: nftables.TableFamilyINet})
+	inputChain := conn.AddChain(&nftables.Chain{
+		Name: "ext_input", Table: extTable,
+		Hooknum: nftables.ChainHookInput, Priority: nftables.ChainPriorityFilter, Type: nftables.ChainTypeFilter,
+	})
+	forwardChain := conn.AddChain(&nftables.Chain{
+		Name: "ext_forward", Table: extTable,
+		Hooknum: nftables.ChainHookForward, Priority: nftables.ChainPriorityFilter, Type: nftables.ChainTypeFilter,
+	})
+	require.NoError(t, conn.Flush(), "create external table and chains")
+	t.Cleanup(func() {
+		c := &nftables.Conn{}
+		c.DelTable(extTable)
+		_ = c.Flush()
+	})
+
+	allower, err := NewInterfaceAllower(ifaceMock, iface.DefaultMTU)
+	require.NoError(t, err, "create allower")
+	require.NoError(t, allower.Apply(), "apply")
+
+	require.True(t, chainHasUserData(t, extTable, inputChain, userDataAcceptInputRule),
+		"external INPUT chain should get the accept rule")
+	require.Len(t, listRules(t, extTable, forwardChain), 0,
+		"external FORWARD chain must not be opened in userspace mode")
+	require.False(t, ipTableExists(t, getTableName()),
+		"allower must not create a netbird work table")
+
+	require.NoError(t, allower.Close(), "close")
+	require.False(t, chainHasUserData(t, extTable, inputChain, userDataAcceptInputRule),
+		"accept rule should be removed on close")
+}
+
+func listRules(t *testing.T, table *nftables.Table, chain *nftables.Chain) []*nftables.Rule {
+	t.Helper()
+	c := &nftables.Conn{}
+	rules, err := c.GetRules(table, chain)
+	require.NoError(t, err)
+	return rules
+}
+
+func chainHasUserData(t *testing.T, table *nftables.Table, chain *nftables.Chain, ud string) bool {
+	for _, r := range listRules(t, table, chain) {
+		if bytes.Equal(r.UserData, []byte(ud)) {
+			return true
+		}
+	}
+	return false
+}
+
+func ipTableExists(t *testing.T, name string) bool {
+	t.Helper()
+	c := &nftables.Conn{}
+	for _, fam := range []nftables.TableFamily{nftables.TableFamilyIPv4, nftables.TableFamilyIPv6} {
+		tbls, err := c.ListTablesOfFamily(fam)
+		require.NoError(t, err)
+		for _, tb := range tbls {
+			if tb.Name == name {
+				return true
+			}
+		}
+	}
+	return false
+}

client/firewall/nftables/interface_allower_linux.go

@@ -0,0 +1,107 @@
+package nftables
+
+import (
+	"fmt"
+
+	"github.com/google/nftables"
+	"github.com/hashicorp/go-multierror"
+
+	nberrors "github.com/netbirdio/netbird/client/errors"
+)
+
+// InterfaceAllower opens the NetBird interface in the kernel's filter table and
+// external chains and keeps them reconciled via a netlink monitor, so the host
+// firewall doesn't drop traffic the NetBird firewall handles. It is used by the
+// userspace firewall, where routing happens in the forwarder, so only INPUT is
+// opened (the userspace router never forwards in the kernel).
+//
+// It owns its own families/connection and never creates a netbird work table.
+// firewalld trust is handled by the caller, not here. Its operations are serial
+// (Apply before the monitor starts; reconciles run on the single monitor
+// goroutine; Close stops the monitor before removing), so it needs no locking.
+//
+// TODO: this opens nftables and the iptables-nft filter table (detected via
+// nft), but not a legacy-iptables ruleset running in parallel with nftables.
+// Such a host would keep its legacy filter chains closed for the interface.
+type InterfaceAllower struct {
+	family4    *family
+	family6    *family
+	extMonitor *externalChainMonitor
+}
+
+// NewInterfaceAllower builds an allower for the given interface. It returns an
+// error when nftables is unavailable (e.g. an iptables-legacy host), so the
+// caller can fall back to firewalld trust.
+func NewInterfaceAllower(wgIface iFaceMapper, mtu uint16) (*InterfaceAllower, error) {
+	tableName := getTableName()
+
+	family4 := newFamily(&nftables.Table{Name: tableName, Family: nftables.TableFamilyIPv4}, wgIface, mtu)
+
+	// Probe nftables availability before committing to this backend.
+	if _, err := family4.conn.ListChainsOfTableFamily(nftables.TableFamilyINet); err != nil {
+		return nil, fmt.Errorf("nftables not available: %w", err)
+	}
+
+	a := &InterfaceAllower{family4: family4}
+
+	if wgIface.Address().HasIPv6() {
+		a.family6 = newFamily(&nftables.Table{Name: tableName, Family: nftables.TableFamilyIPv6}, wgIface, mtu)
+	}
+
+	a.extMonitor = newExternalChainMonitor(a)
+	return a, nil
+}
+
+// Apply opens the interface (INPUT only) in the foreign filter chains and starts
+// reconciling them on nftables changes.
+func (a *InterfaceAllower) Apply() error {
+	var merr *multierror.Error
+	for _, f := range a.families() {
+		// Remove any stale accepts first so a prior unclean exit (e.g. SIGKILL,
+		// where Close never ran) is recovered deterministically rather than
+		// accumulating duplicate rules on the iptables filter table.
+		if err := f.removeAcceptFilterRules(); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("clean stale accept rules: %w", err))
+		}
+		if err := f.openInterface(false); err != nil {
+			merr = multierror.Append(merr, err)
+		}
+	}
+
+	a.extMonitor.start()
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+// families returns the configured address families (v4, and v6 when present).
+func (a *InterfaceAllower) families() []*family {
+	families := []*family{a.family4}
+	if a.family6 != nil {
+		families = append(families, a.family6)
+	}
+	return families
+}
+
+// reconcileExternalChains re-applies the INPUT accepts to external chains. It
+// implements externalChainReconciler for the monitor.
+func (a *InterfaceAllower) reconcileExternalChains() error {
+	var merr *multierror.Error
+	for _, f := range a.families() {
+		if err := f.acceptExternalChainsRules(false); err != nil {
+			merr = multierror.Append(merr, err)
+		}
+	}
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+// Close stops the monitor and removes the accept rules.
+func (a *InterfaceAllower) Close() error {
+	a.extMonitor.stop()
+
+	var merr *multierror.Error
+	for _, f := range a.families() {
+		if err := f.removeAcceptFilterRules(); err != nil {
+			merr = multierror.Append(merr, err)
+		}
+	}
+	return nberrors.FormatErrorOrNil(merr)
+}

client/firewall/nftables/ipset_linux.go

@@ -0,0 +1,210 @@
+//go:build !android
+
+package nftables
+
+import (
+	"encoding/binary"
+	"fmt"
+	"net/netip"
+
+	"github.com/google/nftables"
+	"github.com/google/nftables/expr"
+	log "github.com/sirupsen/logrus"
+
+	firewall "github.com/netbirdio/netbird/client/firewall/manager"
+	"github.com/netbirdio/netbird/client/internal/routemanager/refcounter"
+)
+
+func (r *family) getIpSet(set firewall.Set, prefixes []netip.Prefix, isSource bool) ([]expr.Any, error) {
+	ref, err := r.ipsetCounter.Increment(set.HashedName(), setInput{
+		set:      set,
+		prefixes: prefixes,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("create or get ipset: %w", err)
+	}
+
+	return r.getIpSetExprs(ref, isSource)
+}
+
+func (r *family) createIpSet(setName string, input setInput) (*nftables.Set, error) {
+	// overlapping prefixes will result in an error, so we need to merge them
+	prefixes := firewall.MergeIPRanges(input.prefixes)
+
+	nfset := &nftables.Set{
+		Name:    setName,
+		Comment: input.set.Comment(),
+		Table:   r.workTable,
+		// required for prefixes
+		Interval: true,
+		KeyType:  r.af.setKeyType,
+	}
+
+	elements := r.convertPrefixesToSet(prefixes)
+	nElements := len(elements)
+
+	maxElements := maxPrefixesSet * 2
+	initialElements := elements[:min(maxElements, nElements)]
+
+	if err := r.conn.AddSet(nfset, initialElements); err != nil {
+		return nil, fmt.Errorf("error adding set %s: %w", setName, err)
+	}
+	if err := r.conn.Flush(); err != nil {
+		return nil, fmt.Errorf("flush error: %w", err)
+	}
+	log.Debugf("Created new ipset: %s with %d initial prefixes (total prefixes %d)", setName, len(initialElements)/2, len(prefixes))
+
+	// The set is committed now. If a later batch fails, destroy it: the
+	// refcounter records nothing on a create-callback error, so it would
+	// otherwise leak, and a partial source set fails-open for deny rules.
+	if err := r.addRemainingElements(nfset, elements, maxElements); err != nil {
+		if derr := r.deleteIpSet(setName, nfset); derr != nil {
+			log.Warnf("rollback ipset %s after add failure: %v", setName, derr)
+		}
+		return nil, err
+	}
+
+	log.Infof("Created new ipset: %s with %d prefixes", setName, len(prefixes))
+	return nfset, nil
+}
+
+// addRemainingElements adds element batches beyond the initial one in
+// maxElements-sized chunks, flushing each. Called after the set has been
+// created with its first batch.
+func (r *family) addRemainingElements(nfset *nftables.Set, elements []nftables.SetElement, maxElements int) error {
+	nElements := len(elements)
+	for subStart := maxElements; subStart < nElements; subStart += maxElements {
+		subEnd := min(subStart+maxElements, nElements)
+		subElement := elements[subStart:subEnd]
+		nSubPrefixes := len(subElement) / 2
+		log.Tracef("Adding new prefixes (%d) in ipset: %s", nSubPrefixes, nfset.Name)
+		if err := r.conn.SetAddElements(nfset, subElement); err != nil {
+			return fmt.Errorf("error adding prefixes (%d) to set %s: %w", nSubPrefixes, nfset.Name, err)
+		}
+		if err := r.conn.Flush(); err != nil {
+			return fmt.Errorf("flush error: %w", err)
+		}
+		log.Debugf("Added new prefixes (%d) in ipset: %s", nSubPrefixes, nfset.Name)
+	}
+	return nil
+}
+
+func (r *family) convertPrefixesToSet(prefixes []netip.Prefix) []nftables.SetElement {
+	var elements []nftables.SetElement
+	for _, prefix := range prefixes {
+		// nftables needs half-open intervals [firstIP, lastIP) for prefixes
+		// e.g. 10.0.0.0/24 becomes [10.0.0.0, 10.0.1.0), 10.1.1.1/32 becomes [10.1.1.1, 10.1.1.2) etc
+		firstIP := prefix.Addr()
+
+		// For a /0 the last address is the broadcast and its Next() overflows
+		// to an invalid Addr with an empty key, so wrap to the zero address,
+		// which nftables reads as the open end of a full-range interval.
+		var lastKey []byte
+		if prefix.Bits() == 0 {
+			lastKey = make([]byte, r.af.addrLen)
+		} else {
+			lastKey = calculateLastIP(prefix).Next().AsSlice()
+		}
+
+		// the nft tool also adds a zero-address IntervalEnd element, see https://github.com/google/nftables/issues/247
+		// nftables.SetElement{Key: make([]byte, r.af.addrLen), IntervalEnd: true},
+		elements = append(elements,
+			nftables.SetElement{Key: firstIP.AsSlice()},
+			nftables.SetElement{Key: lastKey, IntervalEnd: true},
+		)
+	}
+	return elements
+}
+
+// calculateLastIP determines the last IP in a given prefix.
+func calculateLastIP(prefix netip.Prefix) netip.Addr {
+	masked := prefix.Masked()
+	if masked.Addr().Is4() {
+		hostMask := ^uint32(0) >> masked.Bits()
+		lastIP := uint32FromNetipAddr(masked.Addr()) | hostMask
+		return netip.AddrFrom4(uint32ToBytes(lastIP))
+	}
+
+	// IPv6: set host bits to all 1s
+	b := masked.Addr().As16()
+	bits := masked.Bits()
+	for i := bits; i < 128; i++ {
+		b[i/8] |= 1 << (7 - i%8)
+	}
+	return netip.AddrFrom16(b)
+}
+
+// Utility function to convert netip.Addr to uint32.
+func uint32FromNetipAddr(addr netip.Addr) uint32 {
+	b := addr.As4()
+	return binary.BigEndian.Uint32(b[:])
+}
+
+// Utility function to convert uint32 to a netip-compatible byte slice.
+func uint32ToBytes(ip uint32) [4]byte {
+	var b [4]byte
+	binary.BigEndian.PutUint32(b[:], ip)
+	return b
+}
+
+func (r *family) deleteIpSet(setName string, nfset *nftables.Set) error {
+	r.conn.DelSet(nfset)
+	if err := r.conn.Flush(); err != nil {
+		return fmt.Errorf(flushError, err)
+	}
+
+	log.Debugf("Deleted unused ipset %s", setName)
+	return nil
+}
+
+func (r *family) UpdateSet(set firewall.Set, prefixes []netip.Prefix) error {
+	nfset, err := r.conn.GetSetByName(r.workTable, set.HashedName())
+	if err != nil {
+		return fmt.Errorf("get set %s: %w", set.HashedName(), err)
+	}
+
+	// Overlapping prefixes (e.g. duplicate resolved addresses) make the
+	// interval set reject the batch, so merge them as createIpSet does.
+	prefixes = firewall.MergeIPRanges(prefixes)
+	elements := r.convertPrefixesToSet(prefixes)
+
+	// Add in batches sized like createIpSet so a large update does not
+	// exceed the netlink message size limit.
+	maxElements := maxPrefixesSet * 2
+	for start := 0; start < len(elements); start += maxElements {
+		end := min(start+maxElements, len(elements))
+		if err := r.conn.SetAddElements(nfset, elements[start:end]); err != nil {
+			return fmt.Errorf("add elements to set %s: %w", set.HashedName(), err)
+		}
+		if err := r.conn.Flush(); err != nil {
+			return fmt.Errorf(flushError, err)
+		}
+	}
+
+	log.Debugf("updated set %s with %d prefixes", set.HashedName(), len(prefixes))
+
+	return nil
+}
+
+func (r *family) getIpSetExprs(ref refcounter.Ref[*nftables.Set], isSource bool) ([]expr.Any, error) {
+	// dst offset by default
+	offset := r.af.dstAddrOffset
+	if isSource {
+		// src offset
+		offset = r.af.srcAddrOffset
+	}
+
+	return []expr.Any{
+		&expr.Payload{
+			DestRegister: 1,
+			Base:         expr.PayloadBaseNetworkHeader,
+			Offset:       offset,
+			Len:          r.af.addrLen,
+		},
+		&expr.Lookup{
+			SourceRegister: 1,
+			SetName:        ref.Out.Name,
+			SetID:          ref.Out.ID,
+		},
+	}, nil
+}

client/firewall/nftables/ipset_linux_test.go

@@ -0,0 +1,36 @@
+package nftables
+
+import (
+	"net/netip"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// TestConvertPrefixesToSetWildcard verifies that a /0 prefix produces a
+// usable interval. The last address of a /0 is the broadcast, whose Next()
+// overflows to an invalid Addr with an empty key; the IntervalEnd must wrap
+// to the zero address instead so nftables sees a full-range interval.
+func TestConvertPrefixesToSetWildcard(t *testing.T) {
+	tests := []struct {
+		name   string
+		af     addrFamily
+		prefix string
+	}{
+		{"IPv4 /0", afIPv4, "0.0.0.0/0"},
+		{"IPv6 /0", afIPv6, "::/0"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			r := &family{af: tt.af}
+			elements := r.convertPrefixesToSet([]netip.Prefix{netip.MustParsePrefix(tt.prefix)})
+
+			require.Len(t, elements, 2, "expected start and interval-end element")
+			assert.False(t, elements[0].IntervalEnd, "first element is the interval start")
+			assert.True(t, elements[1].IntervalEnd, "second element is the interval end")
+			assert.Len(t, elements[1].Key, int(tt.af.addrLen), "interval-end key must be a zero address, not empty")
+		})
+	}
+}

client/firewall/nftables/ipsetstore_linux.go

@@ -1,85 +0,0 @@
-package nftables
-
-import (
-	"net"
-)
-
-type ipsetStore struct {
-	ipsetReference map[string]int
-	ipsets         map[string]map[string]struct{} // ipsetName -> list of ips
-}
-
-func newIpsetStore() *ipsetStore {
-	return &ipsetStore{
-		ipsetReference: make(map[string]int),
-		ipsets:         make(map[string]map[string]struct{}),
-	}
-}
-
-func (s *ipsetStore) ips(ipsetName string) (map[string]struct{}, bool) {
-	r, ok := s.ipsets[ipsetName]
-	return r, ok
-}
-
-func (s *ipsetStore) newIpset(ipsetName string) map[string]struct{} {
-	s.ipsetReference[ipsetName] = 0
-	ipList := make(map[string]struct{})
-	s.ipsets[ipsetName] = ipList
-	return ipList
-}
-
-func (s *ipsetStore) deleteIpset(ipsetName string) {
-	delete(s.ipsetReference, ipsetName)
-	delete(s.ipsets, ipsetName)
-}
-
-func (s *ipsetStore) DeleteIpFromSet(ipsetName string, ip net.IP) {
-	ipList, ok := s.ipsets[ipsetName]
-	if !ok {
-		return
-	}
-	delete(ipList, ip.String())
-}
-
-func (s *ipsetStore) AddIpToSet(ipsetName string, ip net.IP) {
-	ipList, ok := s.ipsets[ipsetName]
-	if !ok {
-		return
-	}
-	ipList[ip.String()] = struct{}{}
-}
-
-func (s *ipsetStore) IsIpInSet(ipsetName string, ip net.IP) bool {
-	ipList, ok := s.ipsets[ipsetName]
-	if !ok {
-		return false
-	}
-	_, ok = ipList[ip.String()]
-	return ok
-}
-
-func (s *ipsetStore) AddReferenceToIpset(ipsetName string) {
-	s.ipsetReference[ipsetName]++
-}
-
-func (s *ipsetStore) DeleteReferenceFromIpSet(ipsetName string) {
-	r, ok := s.ipsetReference[ipsetName]
-	if !ok {
-		return
-	}
-	if r == 0 {
-		return
-	}
-	s.ipsetReference[ipsetName]--
-}
-
-func (s *ipsetStore) HasReferenceToSet(ipsetName string) bool {
-	if _, ok := s.ipsetReference[ipsetName]; !ok {
-		return false
-	}
-	if s.ipsetReference[ipsetName] == 0 {
-		return false
-	}
-
-	return true
-}

client/firewall/nftables/manager_linux.go

@@ -3,7 +3,6 @@ package nftables
 import (
 	"context"
 	"fmt"
-	"net"
 	"net/netip"
 	"os"
 	"sync"
@@ -16,7 +15,6 @@ import (
 	"golang.org/x/sys/unix"
 
 	nberrors "github.com/netbirdio/netbird/client/errors"
-	"github.com/netbirdio/netbird/client/firewall/firewalld"
 	firewall "github.com/netbirdio/netbird/client/firewall/manager"
 	"github.com/netbirdio/netbird/client/iface/wgaddr"
 	"github.com/netbirdio/netbird/client/internal/statemanager"
@@ -45,18 +43,17 @@ type iFaceMapper interface {
 	Address() wgaddr.Address
 }
 
-// Manager of iptables firewall
+// Manager of nftables firewall. Per-family state (peer ACLs, route
+// ACLs, NAT, DNAT, MSS clamping) lives on family; Manager dispatches
+// by family and provides the public firewall.Manager surface.
 type Manager struct {
 	mutex   sync.Mutex
 	rConn   *nftables.Conn
 	wgIface iFaceMapper
 
-	router     *router
+	family4 *family
-	aclManager *AclManager
+	// IPv6 counterpart, nil when no v6 overlay.
-
+	family6 *family
-	// IPv6 counterparts, nil when no v6 overlay
-	router6     *router
-	aclManager6 *AclManager
 
 	notrackOutputChain     *nftables.Chain
 	notrackPreroutingChain *nftables.Chain
@@ -74,21 +71,10 @@ func Create(wgIface iFaceMapper, mtu uint16) (*Manager, error) {
 	tableName := getTableName()
 	workTable := &nftables.Table{Name: tableName, Family: nftables.TableFamilyIPv4}
 
-	var err error
+	m.family4 = newFamily(workTable, wgIface, mtu)
-	m.router, err = newRouter(workTable, wgIface, mtu)
-	if err != nil {
-		return nil, fmt.Errorf("create router: %w", err)
-	}
-
-	m.aclManager, err = newAclManager(workTable, wgIface, chainNameRoutingFw)
-	if err != nil {
-		return nil, fmt.Errorf("create acl manager: %w", err)
-	}
 
 	if wgIface.Address().HasIPv6() {
-		if err := m.createIPv6Components(tableName, wgIface, mtu); err != nil {
+		m.createIPv6Components(tableName, wgIface, mtu)
-			return nil, fmt.Errorf("create IPv6 firewall: %w", err)
-		}
 	}
 
 	m.extMonitor = newExternalChainMonitor(m)
@@ -96,30 +82,19 @@ func Create(wgIface iFaceMapper, mtu uint16) (*Manager, error) {
 	return m, nil
 }
 
-func (m *Manager) createIPv6Components(tableName string, wgIface iFaceMapper, mtu uint16) error {
+func (m *Manager) createIPv6Components(tableName string, wgIface iFaceMapper, mtu uint16) {
 	workTable6 := &nftables.Table{Name: tableName, Family: nftables.TableFamilyIPv6}
 
-	var err error
+	m.family6 = newFamily(workTable6, wgIface, mtu)
-	m.router6, err = newRouter(workTable6, wgIface, mtu)
-	if err != nil {
-		return fmt.Errorf("create v6 router: %w", err)
-	}
 
-	// Share the per-family forwarding refcounter with the v4 router so a v4
+	// Share the per-family forwarding refcounter with the v4 family so a v4
 	// rule and a v6 rule against the same state machine cooperate cleanly.
-	m.router6.ipFwdState = m.router.ipFwdState
+	m.family6.ipFwdState = m.family4.ipFwdState
-
-	m.aclManager6, err = newAclManager(workTable6, wgIface, chainNameRoutingFw)
-	if err != nil {
-		return fmt.Errorf("create v6 acl manager: %w", err)
-	}
-
-	return nil
 }
 
 // hasIPv6 reports whether the manager has IPv6 components initialized.
 func (m *Manager) hasIPv6() bool {
-	return m.router6 != nil
+	return m.family6 != nil
 }
 
 func (m *Manager) initIPv6() error {
@@ -128,12 +103,8 @@ func (m *Manager) initIPv6() error {
 		return fmt.Errorf("create v6 work table: %w", err)
 	}
 
-	if err := m.router6.init(workTable6); err != nil {
+	if err := m.family6.init(workTable6); err != nil {
-		return fmt.Errorf("v6 router init: %w", err)
+		return fmt.Errorf("v6 family init: %w", err)
-	}
-
-	if err := m.aclManager6.init(workTable6); err != nil {
-		return fmt.Errorf("v6 acl manager init: %w", err)
 	}
 
 	return nil
@@ -156,19 +127,20 @@ func (m *Manager) Init(stateManager *statemanager.Manager) error {
 
 // reconcileExternalChains re-applies passthrough accept rules to external
 // filter chains for both IPv4 and IPv6 routers. Called by the monitor when
-// tables or chains appear (e.g. after firewalld reloads).
+// tables or chains appear (e.g. after firewalld reloads). Kernel routing opens
+// both INPUT and FORWARD.
 func (m *Manager) reconcileExternalChains() error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
 	var merr *multierror.Error
-	if m.router != nil {
+	if m.family4 != nil {
-		if err := m.router.acceptExternalChainsRules(); err != nil {
+		if err := m.family4.acceptExternalChainsRules(true); err != nil {
 			merr = multierror.Append(merr, fmt.Errorf("v4: %w", err))
 		}
 	}
 	if m.hasIPv6() {
-		if err := m.router6.acceptExternalChainsRules(); err != nil {
+		if err := m.family6.acceptExternalChainsRules(true); err != nil {
 			merr = multierror.Append(merr, fmt.Errorf("v6: %w", err))
 		}
 	}
@@ -187,12 +159,8 @@ func (m *Manager) initFirewall() (err error) {
 		}
 	}()
 
-	if err := m.router.init(workTable); err != nil {
+	if err := m.family4.init(workTable); err != nil {
-		return fmt.Errorf("router init: %w", err)
+		return fmt.Errorf("family init: %w", err)
-	}
-
-	if err := m.aclManager.init(workTable); err != nil {
-		return fmt.Errorf("acl manager init: %w", err)
 	}
 
 	if m.hasIPv6() {
@@ -220,7 +188,7 @@ func (m *Manager) persistState(stateManager *statemanager.Manager) {
 		InterfaceState: &InterfaceState{
 			NameStr:   m.wgIface.Name(),
 			WGAddress: m.wgIface.Address(),
-			MTU:       m.router.mtu,
+			MTU:       m.family4.mtu,
 		},
 	}); err != nil {
 		log.Errorf("failed to update state: %v", err)
@@ -235,12 +203,12 @@ func (m *Manager) persistState(stateManager *statemanager.Manager) {
 
 // rollbackInit performs best-effort cleanup of already-initialized state when Init fails partway through.
 func (m *Manager) rollbackInit() {
-	if err := m.router.Reset(); err != nil {
+	if err := m.family4.Reset(); err != nil {
-		log.Warnf("rollback router: %v", err)
+		log.Warnf("rollback family: %v", err)
 	}
 	if m.hasIPv6() {
-		if err := m.router6.Reset(); err != nil {
+		if err := m.family6.Reset(); err != nil {
-			log.Warnf("rollback v6 router: %v", err)
+			log.Warnf("rollback v6 family: %v", err)
 		}
 	}
 	if err := m.cleanupNetbirdTables(); err != nil {
@@ -251,118 +219,82 @@ func (m *Manager) rollbackInit() {
 	}
 }
 
-// AddPeerFiltering rule to the firewall
+// AddFilterRule installs a packet-filtering rule.
 //
-// If comment argument is empty firewall manager should set
+// Destination semantics: zero Network → input chain (peer ACL);
-// rule ID as comment for the rule
+// set Network → forward chain (route ACL).
-func (m *Manager) AddPeerFiltering(
+//
-	id []byte,
+// Sources are a single address family; the rule is dispatched to the
-	ip net.IP,
+// matching per-family backend.
-	proto firewall.Protocol,
+func (m *Manager) AddFilterRule(
-	sPort *firewall.Port,
-	dPort *firewall.Port,
-	action firewall.Action,
-	ipsetName string,
-) ([]firewall.Rule, error) {
-	m.mutex.Lock()
-	defer m.mutex.Unlock()
-
-	if ip.To4() != nil {
-		return m.aclManager.AddPeerFiltering(id, ip, proto, sPort, dPort, action, ipsetName)
-	}
-
-	if !m.hasIPv6() {
-		return nil, fmt.Errorf("add peer filtering for %s: %w", ip, firewall.ErrIPv6NotInitialized)
-	}
-	return m.aclManager6.AddPeerFiltering(id, ip, proto, sPort, dPort, action, ipsetName)
-}
-
-func (m *Manager) AddRouteFiltering(
 	id []byte,
 	sources []netip.Prefix,
 	destination firewall.Network,
 	proto firewall.Protocol,
-	sPort, dPort *firewall.Port,
+	sPort *firewall.Port,
+	dPort *firewall.Port,
 	action firewall.Action,
 ) (firewall.Rule, error) {
+	if len(sources) == 0 {
+		return nil, firewall.ErrNoSources
+	}
+
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if isIPv6RouteRule(sources, destination) {
+	fam := m.family4
+	if isIPv6Rule(sources, destination) {
 		if !m.hasIPv6() {
-			return nil, fmt.Errorf("add route filtering: %w", firewall.ErrIPv6NotInitialized)
+			return nil, fmt.Errorf("add filtering: %w", firewall.ErrIPv6NotInitialized)
 		}
-		return m.router6.AddRouteFiltering(id, sources, destination, proto, sPort, dPort, action)
+		fam = m.family6
 	}
-
+	return fam.AddFilterRule(id, sources, destination, proto, sPort, dPort, action)
-	return m.router.AddRouteFiltering(id, sources, destination, proto, sPort, dPort, action)
 }
 
-// DeletePeerRule from the firewall by rule definition
+// DeleteFilterRule removes a filtering rule. The owning family is found
-func (m *Manager) DeletePeerRule(rule firewall.Rule) error {
+// by id in the in-memory filter maps, which are the only tracking for
+// filter rules. family.DeleteFilterRule is idempotent when the id is
+// absent.
+func (m *Manager) DeleteFilterRule(rule firewall.Rule) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if m.hasIPv6() && isIPv6Rule(rule) {
+	fam, err := m.familyForRuleID(rule.ID(), (*family).hasRule, false)
-		return m.aclManager6.DeletePeerRule(rule)
-	}
-	return m.aclManager.DeletePeerRule(rule)
-}
-
-func isIPv6Rule(rule firewall.Rule) bool {
-	r, ok := rule.(*Rule)
-	return ok && r.nftRule != nil && r.nftRule.Table != nil && r.nftRule.Table.Family == nftables.TableFamilyIPv6
-}
-
-// isIPv6RouteRule determines whether a route rule belongs to the v6 table.
-// For static routes, the destination prefix determines the family. For dynamic
-// routes (DomainSet), the sources determine the family since management
-// duplicates dynamic rules per family.
-func isIPv6RouteRule(sources []netip.Prefix, destination firewall.Network) bool {
-	if destination.IsPrefix() {
-		return destination.Prefix.Addr().Is6()
-	}
-	return len(sources) > 0 && sources[0].Addr().Is6()
-}
-
-// DeleteRouteRule deletes a routing rule. Route rules live in exactly one
-// router; the cached maps are normally authoritative, so the kernel is only
-// consulted when neither map knows about the rule.
-func (m *Manager) DeleteRouteRule(rule firewall.Rule) error {
-	m.mutex.Lock()
-	defer m.mutex.Unlock()
-
-	id := rule.ID()
-	r, err := m.routerForRuleID(id, (*router).hasRule)
 	if err != nil {
 		return err
 	}
-	return r.DeleteRouteRule(rule)
+	return fam.DeleteFilterRule(rule)
 }
 
-// routerForRuleID picks the router holding the rule with the given id, using
+// familyForRuleID picks the family holding the rule with the given id, using
-// the supplied lookup. If the cached maps disagree (or both miss), it refreshes
+// the supplied lookup. With refresh set, a miss in both cached maps reloads
-// from the kernel once and re-checks before falling back to the v4 router.
+// the NAT/DNAT rule maps from the kernel once and re-checks before falling
-func (m *Manager) routerForRuleID(id string, has func(*router, string) bool) (*router, error) {
+// back to the v4 family. Filter rules are tracked only in memory and have no
-	if has(m.router, id) {
+// kernel-backed reload, so their callers pass refresh as false.
-		return m.router, nil
+func (m *Manager) familyForRuleID(id firewall.RuleID, has func(*family, firewall.RuleID) bool, refresh bool) (*family, error) {
-	}
+	if has(m.family4, id) {
-	if m.hasIPv6() && has(m.router6, id) {
+		return m.family4, nil
-		return m.router6, nil
 	}
 	if !m.hasIPv6() {
-		return m.router, nil
+		return m.family4, nil
 	}
-	if err := m.router.refreshRulesMap(); err != nil {
+	if has(m.family6, id) {
+		return m.family6, nil
+	}
+	if !refresh {
+		return m.family4, nil
+	}
+	if err := m.family4.refreshRulesMap(); err != nil {
 		return nil, fmt.Errorf("refresh v4 rules: %w", err)
 	}
-	if err := m.router6.refreshRulesMap(); err != nil {
+	if err := m.family6.refreshRulesMap(); err != nil {
 		return nil, fmt.Errorf("refresh v6 rules: %w", err)
 	}
-	if has(m.router6, id) && !has(m.router, id) {
+	if has(m.family6, id) && !has(m.family4, id) {
-		return m.router6, nil
+		return m.family6, nil
 	}
-	return m.router, nil
+	return m.family4, nil
 }
 
 func (m *Manager) IsServerRouteSupported() bool {
@@ -381,10 +313,10 @@ func (m *Manager) AddNatRule(pair firewall.RouterPair) error {
 		if !m.hasIPv6() {
 			return fmt.Errorf("add NAT rule: %w", firewall.ErrIPv6NotInitialized)
 		}
-		return m.router6.AddNatRule(pair)
+		return m.family6.AddNatRule(pair)
 	}
 
-	if err := m.router.AddNatRule(pair); err != nil {
+	if err := m.family4.AddNatRule(pair); err != nil {
 		return err
 	}
 
@@ -396,7 +328,7 @@ func (m *Manager) AddNatRule(pair firewall.RouterPair) error {
 	// so the eventual cleanup still works.
 	if m.hasIPv6() && pair.Dynamic {
 		v6Pair := firewall.ToV6NatPair(pair)
-		if err := m.router6.AddNatRule(v6Pair); err != nil {
+		if err := m.family6.AddNatRule(v6Pair); err != nil {
 			return fmt.Errorf("add v6 NAT rule: %w", err)
 		}
 	}
@@ -412,18 +344,18 @@ func (m *Manager) RemoveNatRule(pair firewall.RouterPair) error {
 		if !m.hasIPv6() {
 			return nil
 		}
-		return m.router6.RemoveNatRule(pair)
+		return m.family6.RemoveNatRule(pair)
 	}
 
 	var merr *multierror.Error
 
-	if err := m.router.RemoveNatRule(pair); err != nil {
+	if err := m.family4.RemoveNatRule(pair); err != nil {
 		merr = multierror.Append(merr, fmt.Errorf("remove v4 NAT rule: %w", err))
 	}
 
 	if m.hasIPv6() && pair.Dynamic {
 		v6Pair := firewall.ToV6NatPair(pair)
-		if err := m.router6.RemoveNatRule(v6Pair); err != nil {
+		if err := m.family6.RemoveNatRule(v6Pair); err != nil {
 			merr = multierror.Append(merr, fmt.Errorf("remove v6 NAT rule: %w", err))
 		}
 	}
@@ -431,46 +363,13 @@ func (m *Manager) RemoveNatRule(pair firewall.RouterPair) error {
 	return nberrors.FormatErrorOrNil(merr)
 }
 
-// AllowNetbird allows netbird interface traffic.
-// This is called when USPFilter wraps the native firewall, adding blanket accept
-// rules so that packet filtering is handled in userspace instead of by netfilter.
-//
-// TODO: In USP mode this only adds ACCEPT to the netbird table's own chains,
-// which doesn't override DROP rules in external tables (e.g. firewalld).
-// Should add passthrough rules to external chains (like the native mode router's
-// addExternalChainsRules does) for both the netbird table family and inet tables.
-// The netbird table itself is fine (routing chains already exist there), but
-// non-netbird tables with INPUT/FORWARD hooks can still DROP our WG traffic.
-func (m *Manager) AllowNetbird() error {
-	m.mutex.Lock()
-	defer m.mutex.Unlock()
-
-	if err := m.aclManager.createDefaultAllowRules(); err != nil {
-		return fmt.Errorf("create default allow rules: %w", err)
-	}
-	if m.hasIPv6() {
-		if err := m.aclManager6.createDefaultAllowRules(); err != nil {
-			return fmt.Errorf("create v6 default allow rules: %w", err)
-		}
-	}
-	if err := m.rConn.Flush(); err != nil {
-		return fmt.Errorf("flush allow input netbird rules: %w", err)
-	}
-
-	if err := firewalld.TrustInterface(m.wgIface.Name()); err != nil {
-		log.Warnf("failed to trust interface in firewalld: %v", err)
-	}
-
-	return nil
-}
-
 // SetLegacyManagement sets the route manager to use legacy management
 func (m *Manager) SetLegacyManagement(isLegacy bool) error {
-	if err := firewall.SetLegacyManagement(m.router, isLegacy); err != nil {
+	if err := firewall.SetLegacyManagement(m.family4, isLegacy); err != nil {
 		return err
 	}
 	if m.hasIPv6() {
-		return firewall.SetLegacyManagement(m.router6, isLegacy)
+		return firewall.SetLegacyManagement(m.family6, isLegacy)
 	}
 	return nil
 }
@@ -484,13 +383,13 @@ func (m *Manager) Close(stateManager *statemanager.Manager) error {
 
 	var merr *multierror.Error
 
-	if err := m.router.Reset(); err != nil {
+	if err := m.family4.Reset(); err != nil {
-		merr = multierror.Append(merr, fmt.Errorf("reset router: %v", err))
+		merr = multierror.Append(merr, fmt.Errorf("reset family: %w", err))
 	}
 
 	if m.hasIPv6() {
-		if err := m.router6.Reset(); err != nil {
+		if err := m.family6.Reset(); err != nil {
-			merr = multierror.Append(merr, fmt.Errorf("reset v6 router: %v", err))
+			merr = multierror.Append(merr, fmt.Errorf("reset v6 family: %w", err))
 		}
 	}
 
@@ -531,11 +430,11 @@ func (m *Manager) SetLogLevel(log.Level) {
 
 func (m *Manager) EnableRouting() error {
 	// v6 only when the overlay actually has v6.
-	return m.router.ipFwdState.RequestRouting(m.router6 != nil)
+	return m.family4.ipFwdState.RequestRouting(m.hasIPv6())
 }
 
 func (m *Manager) DisableRouting() error {
-	return m.router.ipFwdState.ReleaseRouting()
+	return m.family4.ipFwdState.ReleaseRouting()
 }
 
 // Flush rule/chain/set operations from the buffer
@@ -546,13 +445,13 @@ func (m *Manager) Flush() error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if err := m.aclManager.Flush(); err != nil {
+	if err := m.family4.Flush(); err != nil {
 		return err
 	}
 
 	if m.hasIPv6() {
-		if err := m.aclManager6.Flush(); err != nil {
+		if err := m.family6.Flush(); err != nil {
-			return fmt.Errorf("flush v6 acl: %w", err)
+			return fmt.Errorf("flush v6 family: %w", err)
 		}
 	}
 
@@ -572,9 +471,9 @@ func (m *Manager) AddDNATRule(rule firewall.ForwardRule) (firewall.Rule, error)
 		if !m.hasIPv6() {
 			return nil, fmt.Errorf("add DNAT rule: %w", firewall.ErrIPv6NotInitialized)
 		}
-		return m.router6.AddDNATRule(rule)
+		return m.family6.AddDNATRule(rule)
 	}
-	return m.router.AddDNATRule(rule)
+	return m.family4.AddDNATRule(rule)
 }
 
 // DeleteDNATRule deletes a DNAT rule
@@ -582,7 +481,7 @@ func (m *Manager) DeleteDNATRule(rule firewall.Rule) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	r, err := m.routerForRuleID(rule.ID(), (*router).hasDNATRule)
+	r, err := m.familyForRuleID(rule.ID(), (*family).hasDNATRule, true)
 	if err != nil {
 		return err
 	}
@@ -603,12 +502,12 @@ func (m *Manager) UpdateSet(set firewall.Set, prefixes []netip.Prefix) error {
 		}
 	}
 
-	if err := m.router.UpdateSet(set, v4Prefixes); err != nil {
+	if err := m.family4.UpdateSet(set, v4Prefixes); err != nil {
 		return err
 	}
 
 	if m.hasIPv6() && len(v6Prefixes) > 0 {
-		if err := m.router6.UpdateSet(set, v6Prefixes); err != nil {
+		if err := m.family6.UpdateSet(set, v6Prefixes); err != nil {
 			return fmt.Errorf("update v6 set: %w", err)
 		}
 	}
@@ -625,9 +524,9 @@ func (m *Manager) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protoco
 		if !m.hasIPv6() {
 			return fmt.Errorf("add inbound DNAT: %w", firewall.ErrIPv6NotInitialized)
 		}
-		return m.router6.AddInboundDNAT(localAddr, protocol, originalPort, translatedPort)
+		return m.family6.AddInboundDNAT(localAddr, protocol, originalPort, translatedPort)
 	}
-	return m.router.AddInboundDNAT(localAddr, protocol, originalPort, translatedPort)
+	return m.family4.AddInboundDNAT(localAddr, protocol, originalPort, translatedPort)
 }
 
 // RemoveInboundDNAT removes an inbound DNAT rule.
@@ -639,9 +538,9 @@ func (m *Manager) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Prot
 		if !m.hasIPv6() {
 			return fmt.Errorf("remove inbound DNAT: %w", firewall.ErrIPv6NotInitialized)
 		}
-		return m.router6.RemoveInboundDNAT(localAddr, protocol, originalPort, translatedPort)
+		return m.family6.RemoveInboundDNAT(localAddr, protocol, originalPort, translatedPort)
 	}
-	return m.router.RemoveInboundDNAT(localAddr, protocol, originalPort, translatedPort)
+	return m.family4.RemoveInboundDNAT(localAddr, protocol, originalPort, translatedPort)
 }
 
 // AddOutputDNAT adds an OUTPUT chain DNAT rule for locally-generated traffic.
@@ -653,9 +552,9 @@ func (m *Manager) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol
 		if !m.hasIPv6() {
 			return fmt.Errorf("add output DNAT: %w", firewall.ErrIPv6NotInitialized)
 		}
-		return m.router6.AddOutputDNAT(localAddr, protocol, originalPort, translatedPort)
+		return m.family6.AddOutputDNAT(localAddr, protocol, originalPort, translatedPort)
 	}
-	return m.router.AddOutputDNAT(localAddr, protocol, originalPort, translatedPort)
+	return m.family4.AddOutputDNAT(localAddr, protocol, originalPort, translatedPort)
 }
 
 // RemoveOutputDNAT removes an OUTPUT chain DNAT rule.
@@ -667,9 +566,9 @@ func (m *Manager) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Proto
 		if !m.hasIPv6() {
 			return fmt.Errorf("remove output DNAT: %w", firewall.ErrIPv6NotInitialized)
 		}
-		return m.router6.RemoveOutputDNAT(localAddr, protocol, originalPort, translatedPort)
+		return m.family6.RemoveOutputDNAT(localAddr, protocol, originalPort, translatedPort)
 	}
-	return m.router.RemoveOutputDNAT(localAddr, protocol, originalPort, translatedPort)
+	return m.family4.RemoveOutputDNAT(localAddr, protocol, originalPort, translatedPort)
 }
 
 const (
@@ -898,3 +797,14 @@ func getEstablishedExprs(register uint32) []expr.Any {
 		},
 	}
 }
+
+// isIPv6Rule reports whether the rule belongs to the v6 table. For a
+// prefix destination the destination family decides; otherwise the
+// (single-family) sources do, since management duplicates rules per
+// family.
+func isIPv6Rule(sources []netip.Prefix, destination firewall.Network) bool {
+	if destination.IsPrefix() {
+		return destination.Prefix.Addr().Is6()
+	}
+	return len(sources) > 0 && sources[0].Addr().Is6()
+}

client/firewall/nftables/manager_linux_test.go

@@ -72,13 +72,13 @@ func TestNftablesManager(t *testing.T) {
 
 	testClient := &nftables.Conn{}
 
-	rule, err := manager.AddPeerFiltering(nil, ip.AsSlice(), fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{53}}, fw.ActionDrop, "")
+	rule, err := manager.AddFilterRule(nil, pfx(ip.AsSlice()), fw.Network{}, fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{53}}, fw.ActionDrop)
 	require.NoError(t, err, "failed to add rule")
 
 	err = manager.Flush()
 	require.NoError(t, err, "failed to flush")
 
-	rules, err := testClient.GetRules(manager.aclManager.workTable, manager.aclManager.chainInputRules)
+	rules, err := testClient.GetRules(manager.family4.workTable, manager.family4.chainInputRules)
 	require.NoError(t, err, "failed to get rules")
 
 	require.Len(t, rules, 2, "expected 2 rules")
@@ -149,15 +149,12 @@ func TestNftablesManager(t *testing.T) {
 	// Compare connection tracking rule at position 1 (pushed down by DROP rule insertion)
 	compareExprsIgnoringCounters(t, rules[1].Exprs, expectedExprs1)
 
-	for _, r := range rule {
+	require.NoError(t, manager.DeleteFilterRule(rule), "failed to delete rule")
-		err = manager.DeletePeerRule(r)
-		require.NoError(t, err, "failed to delete rule")
-	}
 
 	err = manager.Flush()
 	require.NoError(t, err, "failed to flush")
 
-	rules, err = testClient.GetRules(manager.aclManager.workTable, manager.aclManager.chainInputRules)
+	rules, err = testClient.GetRules(manager.family4.workTable, manager.family4.chainInputRules)
 	require.NoError(t, err, "failed to get rules")
 	// established rule remains
 	require.Len(t, rules, 1, "expected 1 rules after deletion")
@@ -182,47 +179,39 @@ func TestNftablesManagerRuleOrder(t *testing.T) {
 	testClient := &nftables.Conn{}
 
 	// Add accept rule first
-	_, err = manager.AddPeerFiltering(nil, ip.AsSlice(), fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80}}, fw.ActionAccept, "accept-http")
+	_, err = manager.AddFilterRule(nil, pfx(ip.AsSlice()), fw.Network{}, fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80}}, fw.ActionAccept)
 	require.NoError(t, err, "failed to add accept rule")
 
 	// Add deny rule second for the same traffic
-	_, err = manager.AddPeerFiltering(nil, ip.AsSlice(), fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80}}, fw.ActionDrop, "deny-http")
+	_, err = manager.AddFilterRule(nil, pfx(ip.AsSlice()), fw.Network{}, fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80}}, fw.ActionDrop)
 	require.NoError(t, err, "failed to add deny rule")
 
 	err = manager.Flush()
 	require.NoError(t, err, "failed to flush")
 
-	rules, err := testClient.GetRules(manager.aclManager.workTable, manager.aclManager.chainInputRules)
+	rules, err := testClient.GetRules(manager.family4.workTable, manager.family4.chainInputRules)
 	require.NoError(t, err, "failed to get rules")
 
 	t.Logf("Found %d rules in nftables chain", len(rules))
 
-	// Find the accept and deny rules and verify deny comes before accept
+	// Single-source rules emit a direct payload+cmp on the source IP
+	// (no set lookup). Match by source-IP + port + verdict instead of
+	// the legacy per-(action,port) set names ("deny-http"/"accept-http")
+	// that this test predates.
+	wantSrc := ip.AsSlice()
 	var acceptRuleIndex, denyRuleIndex = -1, -1
 	for i, rule := range rules {
-		hasAcceptHTTPSet := false
+		var hasSrc, hasPort80 bool
-		hasDenyHTTPSet := false
-		hasPort80 := false
 		var action string
-
 		for _, e := range rule.Exprs {
-			// Check for set lookup
+			if cmp, ok := e.(*expr.Cmp); ok && cmp.Op == expr.CmpOpEq {
-			if lookup, ok := e.(*expr.Lookup); ok {
+				if bytes.Equal(cmp.Data, wantSrc) {
-				switch lookup.SetName {
+					hasSrc = true
-				case "accept-http":
-					hasAcceptHTTPSet = true
-				case "deny-http":
-					hasDenyHTTPSet = true
 				}
-
+				if len(cmp.Data) == 2 && binary.BigEndian.Uint16(cmp.Data) == 80 {
-			}
-			// Check for port 80
-			if cmp, ok := e.(*expr.Cmp); ok {
-				if cmp.Op == expr.CmpOpEq && len(cmp.Data) == 2 && binary.BigEndian.Uint16(cmp.Data) == 80 {
 					hasPort80 = true
 				}
 			}
-			// Check for verdict
 			if verdict, ok := e.(*expr.Verdict); ok {
 				switch verdict.Kind {
 				case expr.VerdictAccept:
@@ -233,11 +222,15 @@ func TestNftablesManagerRuleOrder(t *testing.T) {
 			}
 		}
 
-		if hasAcceptHTTPSet && hasPort80 && action == "ACCEPT" {
+		if !hasSrc || !hasPort80 {
-			t.Logf("Rule [%d]: accept-http set + Port 80 + ACCEPT", i)
+			continue
+		}
+		switch action {
+		case "ACCEPT":
+			t.Logf("Rule [%d]: src=%s port=80 ACCEPT", i, ip)
 			acceptRuleIndex = i
-		} else if hasDenyHTTPSet && hasPort80 && action == "DROP" {
+		case "DROP":
-			t.Logf("Rule [%d]: deny-http set + Port 80 + DROP", i)
+			t.Logf("Rule [%d]: src=%s port=80 DROP", i, ip)
 			denyRuleIndex = i
 		}
 	}
@@ -281,7 +274,7 @@ func TestNFtablesCreatePerformance(t *testing.T) {
 			start := time.Now()
 			for i := 0; i < testMax; i++ {
 				port := &fw.Port{Values: []uint16{uint16(1000 + i)}}
-				_, err = manager.AddPeerFiltering(nil, ip.AsSlice(), "tcp", nil, port, fw.ActionAccept, "")
+				_, err = manager.AddFilterRule(nil, pfx(ip.AsSlice()), fw.Network{}, "tcp", nil, port, fw.ActionAccept)
 				require.NoError(t, err, "failed to add rule")
 
 				if i%100 == 0 {
@@ -363,10 +356,10 @@ func TestNftablesManagerCompatibilityWithIptables(t *testing.T) {
 	})
 
 	ip := netip.MustParseAddr("100.96.0.1")
-	_, err = manager.AddPeerFiltering(nil, ip.AsSlice(), fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80}}, fw.ActionAccept, "")
+	_, err = manager.AddFilterRule(nil, pfx(ip.AsSlice()), fw.Network{}, fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80}}, fw.ActionAccept)
 	require.NoError(t, err, "failed to add peer filtering rule")
 
-	_, err = manager.AddRouteFiltering(
+	_, err = manager.AddFilterRule(
 		nil,
 		[]netip.Prefix{netip.MustParsePrefix("192.168.2.0/24")},
 		fw.Network{Prefix: netip.MustParsePrefix("10.1.0.0/24")},
@@ -439,10 +432,10 @@ func TestNftablesManagerIPv6CompatibilityWithIp6tables(t *testing.T) {
 	})
 
 	ip := netip.MustParseAddr("fd00::2")
-	_, err = manager.AddPeerFiltering(nil, ip.AsSlice(), fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80}}, fw.ActionAccept, "")
+	_, err = manager.AddFilterRule(nil, pfx(ip.AsSlice()), fw.Network{}, fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80}}, fw.ActionAccept)
 	require.NoError(t, err, "add v6 peer filtering rule")
 
-	_, err = manager.AddRouteFiltering(
+	_, err = manager.AddFilterRule(
 		nil,
 		[]netip.Prefix{netip.MustParsePrefix("fd00:1::/64")},
 		fw.Network{Prefix: netip.MustParsePrefix("2001:db8::/48")},
@@ -552,7 +545,7 @@ func TestNftablesManagerCompatibilityWithIptablesFor6kPrefixes(t *testing.T) {
 			prefixes = append(prefixes, netip.PrefixFrom(addr, 24))
 		}
 	}
-	_, err = manager.AddRouteFiltering(
+	_, err = manager.AddFilterRule(
 		nil,
 		prefixes,
 		fw.Network{Prefix: netip.MustParsePrefix("10.2.0.0/24")},
@@ -567,7 +560,7 @@ func TestNftablesManagerCompatibilityWithIptablesFor6kPrefixes(t *testing.T) {
 	verifyIptablesOutput(t, stdout, stderr)
 }
 
-func TestNftablesManagerCompatibilityWithIptablesForEmptyPrefixes(t *testing.T) {
+func TestNftablesManagerCompatibilityWithIptablesForWildcardSource(t *testing.T) {
 	if check() != NFTABLES {
 		t.Skip("nftables not supported on this system")
 	}
@@ -593,9 +586,9 @@ func TestNftablesManagerCompatibilityWithIptablesForEmptyPrefixes(t *testing.T)
 		verifyIptablesOutput(t, stdout, stderr)
 	})
 
-	_, err = manager.AddRouteFiltering(
+	_, err = manager.AddFilterRule(
 		nil,
-		[]netip.Prefix{},
+		[]netip.Prefix{netip.MustParsePrefix("0.0.0.0/0")},
 		fw.Network{Prefix: netip.MustParsePrefix("10.2.0.0/24")},
 		fw.ProtocolTCP,
 		nil,
@@ -608,6 +601,73 @@ func TestNftablesManagerCompatibilityWithIptablesForEmptyPrefixes(t *testing.T)
 	verifyIptablesOutput(t, stdout, stderr)
 }
 
+func TestNftablesManagerMultiPortFilter(t *testing.T) {
+	if check() != NFTABLES {
+		t.Skip("nftables not supported on this system")
+	}
+
+	manager, err := Create(ifaceMock, iface.DefaultMTU)
+	require.NoError(t, err)
+	require.NoError(t, manager.Init(nil))
+
+	t.Cleanup(func() {
+		require.NoError(t, manager.Close(nil), "failed to reset manager state")
+	})
+
+	ip := netip.MustParseAddr("100.96.0.1")
+
+	rule, err := manager.AddFilterRule(nil, pfx(ip.AsSlice()), fw.Network{}, fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80, 443}}, fw.ActionAccept)
+	require.NoError(t, err, "failed to add multi-port rule")
+
+	testClient := &nftables.Conn{}
+	rules, err := testClient.GetRules(manager.family4.workTable, manager.family4.chainInputRules)
+	require.NoError(t, err, "failed to get rules")
+
+	var lookup *expr.Lookup
+	for _, kernelRule := range rules {
+		if string(kernelRule.UserData) != string(rule.ID()) {
+			continue
+		}
+		for _, e := range kernelRule.Exprs {
+			if l, ok := e.(*expr.Lookup); ok {
+				lookup = l
+			}
+		}
+	}
+	require.NotNil(t, lookup, "multi-port rule must match ports via a set lookup")
+
+	sets, err := testClient.GetSets(manager.family4.workTable)
+	require.NoError(t, err, "failed to get sets")
+
+	var portSet *nftables.Set
+	for _, s := range sets {
+		if s.Name == lookup.SetName {
+			portSet = s
+		}
+	}
+	require.NotNil(t, portSet, "anonymous port set not found in kernel")
+
+	portSet.Table = manager.family4.workTable
+	elements, err := testClient.GetSetElements(portSet)
+	require.NoError(t, err, "failed to get set elements")
+
+	ports := make(map[uint16]bool)
+	for _, e := range elements {
+		require.Len(t, e.Key, 2, "port set element key should be 2 bytes")
+		ports[binary.BigEndian.Uint16(e.Key)] = true
+	}
+	require.True(t, ports[80], "port set should contain port 80")
+	require.True(t, ports[443], "port set should contain port 443")
+
+	require.NoError(t, manager.DeleteFilterRule(rule), "failed to delete rule")
+
+	rules, err = testClient.GetRules(manager.family4.workTable, manager.family4.chainInputRules)
+	require.NoError(t, err, "failed to get rules after delete")
+	for _, kernelRule := range rules {
+		require.NotEqual(t, string(rule.ID()), string(kernelRule.UserData), "rule should be removed from kernel")
+	}
+}
+
 func compareExprsIgnoringCounters(t *testing.T, got, want []expr.Any) {
 	t.Helper()
 	require.Equal(t, len(got), len(want), "expression count mismatch")

client/firewall/nftables/router_linux_test.go

@@ -37,7 +37,7 @@ func TestNftablesManager_AddNatRule(t *testing.T) {
 
 	for _, testCase := range test.InsertRuleTestCases {
 		t.Run(testCase.Name, func(t *testing.T) {
-			// need fw manager to init both acl mgr and router for all chains to be present
+			// need fw manager to init both acl mgr and family for all chains to be present
 			manager, err := Create(ifaceMock, iface.DefaultMTU)
 			t.Cleanup(func() {
 				require.NoError(t, manager.Close(nil))
@@ -47,7 +47,7 @@ func TestNftablesManager_AddNatRule(t *testing.T) {
 
 			nftablesTestingClient := &nftables.Conn{}
 
-			rtr := manager.router
+			rtr := manager.family4
 			err = rtr.AddNatRule(testCase.InputPair)
 			require.NoError(t, err, "pair should be inserted")
 
@@ -90,9 +90,9 @@ func TestNftablesManager_AddNatRule(t *testing.T) {
 				}
 
 				// Build CIDR matching expressions
-				testRouter := &router{af: afIPv4}
+				testRouter := &family{af: afIPv4}
-				sourceExp := testRouter.applyPrefix(testCase.InputPair.Source.Prefix, true)
+				sourceExp := prefixMatchExprs(testRouter.af, testCase.InputPair.Source.Prefix, true)
-				destExp := testRouter.applyPrefix(testCase.InputPair.Destination.Prefix, false)
+				destExp := prefixMatchExprs(testRouter.af, testCase.InputPair.Destination.Prefix, false)
 
 				// Combine all expressions in the correct order
 				// nolint:gocritic
@@ -100,14 +100,14 @@ func TestNftablesManager_AddNatRule(t *testing.T) {
 				testingExpression = append(testingExpression, sourceExp...)
 				testingExpression = append(testingExpression, destExp...)
 
-				natRuleKey := firewall.GenKey(firewall.PreroutingFormat, testCase.InputPair)
+				natRuleKey := testCase.InputPair.GenKey(firewall.PreroutingFormat)
 				found := 0
 				for _, chain := range rtr.chains {
 					if chain.Name == chainNameManglePrerouting {
 						rules, err := nftablesTestingClient.GetRules(chain.Table, chain)
 						require.NoError(t, err, "should list rules for %s table and %s chain", chain.Table.Name, chain.Name)
 						for _, rule := range rules {
-							if len(rule.UserData) > 0 && string(rule.UserData) == natRuleKey {
+							if len(rule.UserData) > 0 && firewall.RuleID(rule.UserData) == natRuleKey {
 								// Compare expressions up to the mark setting expressions
 								require.ElementsMatchf(t, rule.Exprs[:len(testingExpression)], testingExpression, "prerouting nat rule elements should match")
 								found = 1
@@ -135,19 +135,19 @@ func TestNftablesManager_RemoveNatRule(t *testing.T) {
 			require.NoError(t, err)
 			require.NoError(t, manager.Init(nil))
 
-			rtr := manager.router
+			rtr := manager.family4
 
-			// First add the NAT rule using the router's method
+			// First add the NAT rule using the family's method
 			err = rtr.AddNatRule(testCase.InputPair)
 			require.NoError(t, err, "should add NAT rule")
 
 			// Verify the rule was added
-			natRuleKey := firewall.GenKey(firewall.PreroutingFormat, testCase.InputPair)
+			natRuleKey := testCase.InputPair.GenKey(firewall.PreroutingFormat)
 			found := false
 			rules, err := rtr.conn.GetRules(rtr.workTable, rtr.chains[chainNameManglePrerouting])
 			require.NoError(t, err, "should list rules")
 			for _, rule := range rules {
-				if len(rule.UserData) > 0 && string(rule.UserData) == natRuleKey {
+				if len(rule.UserData) > 0 && firewall.RuleID(rule.UserData) == natRuleKey {
 					found = true
 					break
 				}
@@ -163,7 +163,7 @@ func TestNftablesManager_RemoveNatRule(t *testing.T) {
 			rules, err = rtr.conn.GetRules(rtr.workTable, rtr.chains[chainNameManglePrerouting])
 			require.NoError(t, err, "should list rules after removal")
 			for _, rule := range rules {
-				if len(rule.UserData) > 0 && string(rule.UserData) == natRuleKey {
+				if len(rule.UserData) > 0 && firewall.RuleID(rule.UserData) == natRuleKey {
 					found = true
 					break
 				}
@@ -200,11 +200,10 @@ func TestRouter_AddRouteFiltering(t *testing.T) {
 
 	defer deleteWorkTable()
 
-	r, err := newRouter(workTable, ifaceMock, iface.DefaultMTU)
+	r := newFamily(workTable, ifaceMock, iface.DefaultMTU)
-	require.NoError(t, err, "Failed to create router")
 	require.NoError(t, r.init(workTable))
 
-	defer func(r *router) {
+	defer func(r *family) {
 		require.NoError(t, r.Reset(), "Failed to reset rules")
 	}(r)
 
@@ -314,16 +313,16 @@ func TestRouter_AddRouteFiltering(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			ruleKey, err := r.AddRouteFiltering(nil, tt.sources, firewall.Network{Prefix: tt.destination}, tt.proto, tt.sPort, tt.dPort, tt.action)
+			ruleKey, err := r.AddFilterRule(nil, tt.sources, firewall.Network{Prefix: tt.destination}, tt.proto, tt.sPort, tt.dPort, tt.action)
-			require.NoError(t, err, "AddRouteFiltering failed")
+			require.NoError(t, err, "AddFilterRule failed")
 
 			t.Cleanup(func() {
-				require.NoError(t, r.DeleteRouteRule(ruleKey), "Failed to delete rule")
+				require.NoError(t, r.DeleteFilterRule(ruleKey), "Failed to delete rule")
 			})
 
-			// Check if the rule is in the internal map
+			stored, ok := r.filters[id.RuleID(ruleKey.ID())]
-			rule, ok := r.rules[ruleKey.ID()]
+			require.True(t, ok, "Rule not found in filters map")
-			assert.True(t, ok, "Rule not found in internal map")
+			rule := stored.nftRule
 
 			t.Log("Internal rule expressions:")
 			for i, expr := range rule.Exprs {
@@ -339,7 +338,7 @@ func TestRouter_AddRouteFiltering(t *testing.T) {
 
 			var nftRule *nftables.Rule
 			for _, rule := range rules {
-				if string(rule.UserData) == ruleKey.ID() {
+				if firewall.RuleID(rule.UserData) == ruleKey.ID() {
 					nftRule = rule
 					break
 				}
@@ -367,12 +366,11 @@ func TestNftablesCreateIpSet(t *testing.T) {
 
 	defer deleteWorkTable()
 
-	r, err := newRouter(workTable, ifaceMock, iface.DefaultMTU)
+	r := newFamily(workTable, ifaceMock, iface.DefaultMTU)
-	require.NoError(t, err, "Failed to create router")
 	require.NoError(t, r.init(workTable))
 
 	defer func() {
-		require.NoError(t, r.Reset(), "Failed to reset router")
+		require.NoError(t, r.Reset(), "Failed to reset family")
 	}()
 
 	tests := []struct {
@@ -509,6 +507,58 @@ func TestNftablesCreateIpSet(t *testing.T) {
 	}
 }
 
+// TestNftablesUpdateSetMergesOverlapping verifies that UpdateSet merges
+// overlapping prefixes before adding them. An interval set rejects
+// overlapping elements, so without the merge a batch holding a /32 already
+// covered by a /24, or a duplicate address as DNS resolution can produce,
+// would fail.
+func TestNftablesUpdateSetMergesOverlapping(t *testing.T) {
+	if check() != NFTABLES {
+		t.Skip("nftables not supported on this system")
+	}
+
+	workTable, err := createWorkTable()
+	require.NoError(t, err, "create work table")
+	defer deleteWorkTable()
+
+	r := newFamily(workTable, ifaceMock, iface.DefaultMTU)
+	require.NoError(t, r.init(workTable))
+	defer func() {
+		require.NoError(t, r.Reset(), "reset family")
+	}()
+
+	initial := []netip.Prefix{netip.MustParsePrefix("10.0.0.0/24")}
+	set := firewall.NewPrefixSet(initial)
+
+	created, err := r.createIpSet(set.HashedName(), setInput{prefixes: initial})
+	require.NoError(t, err, "create ip set")
+	require.NotNil(t, created)
+
+	overlapping := []netip.Prefix{
+		netip.MustParsePrefix("192.168.1.0/24"),
+		netip.MustParsePrefix("192.168.1.1/32"),
+		netip.MustParsePrefix("192.168.1.1/32"),
+	}
+	require.NoError(t, r.UpdateSet(set, overlapping), "UpdateSet must merge overlapping prefixes")
+
+	fetchedSet, err := r.conn.GetSetByName(r.workTable, set.HashedName())
+	require.NoError(t, err, "fetch updated set")
+	elements, err := r.conn.GetSetElements(fetchedSet)
+	require.NoError(t, err, "get set elements")
+
+	starts := make(map[string]bool)
+	for _, elem := range elements {
+		if elem.IntervalEnd {
+			continue
+		}
+		starts[netip.AddrFrom4(*(*[4]byte)(elem.Key)).String()] = true
+	}
+	// The /32s are covered by the /24, so the update adds one interval and
+	// leaves the one created earlier in place.
+	assert.Equal(t, map[string]bool{"10.0.0.0": true, "192.168.1.0": true}, starts,
+		"merged set must hold the original and the merged interval")
+}
+
 func TestNftablesCreateIpSet_IPv6(t *testing.T) {
 	if check() != NFTABLES {
 		t.Skip("nftables not supported on this system")
@@ -518,11 +568,10 @@ func TestNftablesCreateIpSet_IPv6(t *testing.T) {
 	require.NoError(t, err, "Failed to create v6 work table")
 	defer deleteWorkTableIPv6()
 
-	r, err := newRouter(workTable, ifaceMock, iface.DefaultMTU)
+	r := newFamily(workTable, ifaceMock, iface.DefaultMTU)
-	require.NoError(t, err, "Failed to create router")
 	require.NoError(t, r.init(workTable))
 	defer func() {
-		require.NoError(t, r.Reset(), "Failed to reset router")
+		require.NoError(t, r.Reset(), "Failed to reset family")
 	}()
 
 	tests := []struct {
@@ -748,6 +797,14 @@ func containsPort(exprs []expr.Any, port *firewall.Port, isSource bool) bool {
 					}
 				}
 			}
+		case *expr.Lookup:
+			// Multiple discrete ports compile to an anonymous set lookup
+			// rather than a chain of comparisons. The set's id and name are
+			// assigned dynamically, so matching the lookup is enough here;
+			// the set elements are verified separately.
+			if !port.IsRange && len(port.Values) > 1 {
+				portMatchFound = true
+			}
 		}
 		if payloadFound && portMatchFound {
 			return true
@@ -861,13 +918,12 @@ func TestRouter_RefreshRulesMap_RemovesStaleEntries(t *testing.T) {
 	require.NoError(t, err)
 	defer deleteWorkTable()
 
-	r, err := newRouter(workTable, ifaceMock, iface.DefaultMTU)
+	r := newFamily(workTable, ifaceMock, iface.DefaultMTU)
-	require.NoError(t, err)
 	require.NoError(t, r.init(workTable))
 	defer func() { require.NoError(t, r.Reset()) }()
 
 	// Add a real rule to the kernel
-	ruleKey, err := r.AddRouteFiltering(
+	ruleKey, err := r.AddFilterRule(
 		nil,
 		[]netip.Prefix{netip.MustParsePrefix("192.168.1.0/24")},
 		firewall.Network{Prefix: netip.MustParsePrefix("10.0.0.0/24")},
@@ -878,11 +934,11 @@ func TestRouter_RefreshRulesMap_RemovesStaleEntries(t *testing.T) {
 	)
 	require.NoError(t, err)
 	t.Cleanup(func() {
-		require.NoError(t, r.DeleteRouteRule(ruleKey))
+		require.NoError(t, r.DeleteFilterRule(ruleKey))
 	})
 
 	// Inject a stale entry with Handle=0 (simulates store-before-flush failure)
-	staleKey := "stale-rule-that-does-not-exist"
+	staleKey := firewall.RuleID("stale-rule-that-does-not-exist")
 	r.rules[staleKey] = &nftables.Rule{
 		Table:    r.workTable,
 		Chain:    r.chains[chainNameRoutingFw],
@@ -902,6 +958,54 @@ func TestRouter_RefreshRulesMap_RemovesStaleEntries(t *testing.T) {
 	assert.NotZero(t, realRule.Handle, "real rule should have a valid handle")
 }
 
+// TestRouter_DeleteRouteRule_RemovesKernelRule verifies a route filter
+// rule is actually removed from the kernel on delete. The route chain is
+// not refreshed by Flush, so the stored rule carries a zero handle;
+// DeleteFilterRule must pull live handles itself before issuing the
+// delete or the kernel rule leaks. Regression test for that path.
+func TestRouter_DeleteRouteRule_RemovesKernelRule(t *testing.T) {
+	if check() != NFTABLES {
+		t.Skip("nftables not supported on this system")
+	}
+
+	workTable, err := createWorkTable()
+	require.NoError(t, err)
+	defer deleteWorkTable()
+
+	r := newFamily(workTable, ifaceMock, iface.DefaultMTU)
+	require.NoError(t, r.init(workTable))
+	defer func() { require.NoError(t, r.Reset()) }()
+
+	ruleKey, err := r.AddFilterRule(
+		nil,
+		[]netip.Prefix{netip.MustParsePrefix("192.168.1.0/24")},
+		firewall.Network{Prefix: netip.MustParsePrefix("10.0.0.0/24")},
+		firewall.ProtocolTCP,
+		nil,
+		&firewall.Port{Values: []uint16{80}},
+		firewall.ActionAccept,
+	)
+	require.NoError(t, err)
+
+	countKernelRules := func() int {
+		list, err := r.conn.GetRules(r.workTable, r.chains[chainNameRoutingFw])
+		require.NoError(t, err)
+		n := 0
+		for _, rule := range list {
+			if string(rule.UserData) == string(ruleKey.ID()) {
+				n++
+			}
+		}
+		return n
+	}
+
+	require.Equal(t, 1, countKernelRules(), "rule should be present in the kernel after add")
+
+	require.NoError(t, r.DeleteFilterRule(ruleKey))
+	assert.Equal(t, 0, countKernelRules(), "rule must be removed from the kernel after delete")
+	assert.NotContains(t, r.filters, ruleKey.ID(), "filters map entry should be cleared")
+}
+
 func TestRouter_DeleteRouteRule_StaleHandle(t *testing.T) {
 	if check() != NFTABLES {
 		t.Skip("nftables not supported on this system")
@@ -911,24 +1015,27 @@ func TestRouter_DeleteRouteRule_StaleHandle(t *testing.T) {
 	require.NoError(t, err)
 	defer deleteWorkTable()
 
-	r, err := newRouter(workTable, ifaceMock, iface.DefaultMTU)
+	r := newFamily(workTable, ifaceMock, iface.DefaultMTU)
-	require.NoError(t, err)
 	require.NoError(t, r.init(workTable))
 	defer func() { require.NoError(t, r.Reset()) }()
 
 	// Inject a stale entry with Handle=0
-	staleKey := "stale-route-rule"
+	staleKey := id.RuleID("stale-route-rule")
-	r.rules[staleKey] = &nftables.Rule{
+	staleRule := &Rule{
-		Table:    r.workTable,
+		nftRule: &nftables.Rule{
-		Chain:    r.chains[chainNameRoutingFw],
+			Table:    r.workTable,
-		Handle:   0,
+			Chain:    r.chains[chainNameRoutingFw],
-		UserData: []byte(staleKey),
+			Handle:   0,
+			UserData: []byte(staleKey),
+		},
+		id: staleKey,
 	}
+	r.filters[staleKey] = staleRule
 
-	// DeleteRouteRule should not return an error for stale handles
+	// DeleteFilterRule should not return an error for stale handles
-	err = r.DeleteRouteRule(id.RuleID(staleKey))
+	err = r.DeleteFilterRule(staleRule)
 	assert.NoError(t, err, "deleting a stale rule should not error")
-	assert.NotContains(t, r.rules, staleKey, "stale entry should be cleaned up")
+	assert.NotContains(t, r.filters, staleKey, "stale entry should be cleaned up")
 }
 
 func TestRouter_AddNatRule_WithStaleEntry(t *testing.T) {
@@ -950,7 +1057,7 @@ func TestRouter_AddNatRule_WithStaleEntry(t *testing.T) {
 		Masquerade:  true,
 	}
 
-	rtr := manager.router
+	rtr := manager.family4
 
 	// First add succeeds
 	err = rtr.AddNatRule(pair)
@@ -960,11 +1067,11 @@ func TestRouter_AddNatRule_WithStaleEntry(t *testing.T) {
 	})
 
 	// Corrupt the handle to simulate stale state
-	natRuleKey := firewall.GenKey(firewall.PreroutingFormat, pair)
+	natRuleKey := pair.GenKey(firewall.PreroutingFormat)
 	if rule, exists := rtr.rules[natRuleKey]; exists {
 		rule.Handle = 0
 	}
-	inverseKey := firewall.GenKey(firewall.PreroutingFormat, firewall.GetInversePair(pair))
+	inverseKey := firewall.GetInversePair(pair).GenKey(firewall.PreroutingFormat)
 	if rule, exists := rtr.rules[inverseKey]; exists {
 		rule.Handle = 0
 	}
@@ -979,7 +1086,7 @@ func TestRouter_AddNatRule_WithStaleEntry(t *testing.T) {
 
 	found := 0
 	for _, rule := range rules {
-		if len(rule.UserData) > 0 && string(rule.UserData) == natRuleKey {
+		if len(rule.UserData) > 0 && firewall.RuleID(rule.UserData) == natRuleKey {
 			found++
 		}
 	}
@@ -1010,7 +1117,7 @@ func TestCalculateLastIP(t *testing.T) {
 }
 
 func TestConvertPrefixesToSet_IPv6(t *testing.T) {
-	r := &router{af: afIPv6}
+	r := &family{af: afIPv6}
 	prefixes := []netip.Prefix{
 		netip.MustParsePrefix("fd00::/64"),
 		netip.MustParsePrefix("2001:db8::1/128"),

client/firewall/nftables/routing_linux.go

@@ -0,0 +1,558 @@
+//go:build !android
+
+package nftables
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/google/nftables"
+	"github.com/google/nftables/binaryutil"
+	"github.com/google/nftables/expr"
+	"github.com/hashicorp/go-multierror"
+	log "github.com/sirupsen/logrus"
+	"golang.org/x/sys/unix"
+
+	nberrors "github.com/netbirdio/netbird/client/errors"
+	firewall "github.com/netbirdio/netbird/client/firewall/manager"
+	nbnet "github.com/netbirdio/netbird/client/net"
+)
+
+func (r *family) AddNatRule(pair firewall.RouterPair) error {
+	if err := r.refreshRulesMap(); err != nil {
+		return fmt.Errorf(refreshRulesMapError, err)
+	}
+
+	// Resolve every rule's match expressions before queueing any of them: a
+	// message buffered on the shared connection cannot be un-queued, so
+	// returning an error after queueing would leave the next caller's Flush
+	// to commit a rule nothing tracks.
+	var legacyExprs []expr.Any
+	if r.legacyManagement {
+		log.Warnf("This peer is connected to a NetBird Management service with an older version. Allowing all traffic for %s", pair.Destination)
+
+		var err error
+		legacyExprs, err = r.legacyRouteRuleExprs(pair)
+		if err != nil {
+			return fmt.Errorf("build legacy routing rule: %w", err)
+		}
+	}
+
+	inverse := firewall.GetInversePair(pair)
+	var natExprs, inverseExprs []expr.Any
+	if pair.Masquerade {
+		var err error
+		natExprs, err = r.natRuleExprs(pair)
+		if err != nil {
+			r.dropNetworkMatch(legacyExprs)
+			return fmt.Errorf("build nat rule: %w", err)
+		}
+
+		inverseExprs, err = r.natRuleExprs(inverse)
+		if err != nil {
+			r.dropNetworkMatch(legacyExprs)
+			r.dropNetworkMatch(natExprs)
+			return fmt.Errorf("build inverse nat rule: %w", err)
+		}
+	}
+
+	if legacyExprs != nil {
+		r.queueLegacyRouteRule(pair, legacyExprs)
+	}
+	if pair.Masquerade {
+		r.queueNatRule(pair, natExprs)
+		r.queueNatRule(inverse, inverseExprs)
+	}
+
+	if err := r.conn.Flush(); err != nil {
+		r.rollbackRules(pair)
+		return fmt.Errorf("insert rules for %s: %w", pair.Destination, err)
+	}
+
+	return nil
+}
+
+// rollbackRules cleans up unflushed rules and their set counters after a flush failure.
+func (r *family) rollbackRules(pair firewall.RouterPair) {
+	keys := []firewall.RuleID{
+		pair.GenKey(firewall.ForwardingFormat),
+		pair.GenKey(firewall.PreroutingFormat),
+		firewall.GetInversePair(pair).GenKey(firewall.PreroutingFormat),
+	}
+	for _, key := range keys {
+		rule, ok := r.rules[key]
+		if !ok {
+			continue
+		}
+		if err := r.decrementSetCounter(rule); err != nil {
+			log.Warnf("rollback set counter for %s: %v", key, err)
+		}
+		delete(r.rules, key)
+	}
+}
+
+// natRuleExprs resolves the match expressions of the pair's prerouting
+// marking rule. It reserves the ipset references the matches need but queues
+// nothing on the connection, so its error paths leave the connection clean.
+func (r *family) natRuleExprs(pair firewall.RouterPair) ([]expr.Any, error) {
+	sourceExp, err := r.applyNetwork(pair.Source, nil, true)
+	if err != nil {
+		return nil, fmt.Errorf("apply source: %w", err)
+	}
+
+	destExp, err := r.applyNetwork(pair.Destination, nil, false)
+	if err != nil {
+		r.dropNetworkMatch(sourceExp)
+		return nil, fmt.Errorf("apply destination: %w", err)
+	}
+
+	op := expr.CmpOpEq
+	if pair.Inverse {
+		op = expr.CmpOpNeq
+	}
+
+	exprs := []expr.Any{
+		&expr.Meta{
+			Key:      expr.MetaKeyIIFNAME,
+			Register: 1,
+		},
+		&expr.Cmp{
+			Op:       op,
+			Register: 1,
+			Data:     ifname(r.wgIface.Name()),
+		},
+	}
+	// We only care about NEW connections to mark them and later identify them in the postrouting chain for masquerading.
+	// Masquerading will take care of the conntrack state, which means we won't need to mark established connections.
+	exprs = append(exprs, getCtNewExprs()...)
+
+	exprs = append(exprs, sourceExp...)
+	exprs = append(exprs, destExp...)
+
+	markValue := nbnet.PreroutingFwmarkMasquerade
+	if pair.Inverse {
+		markValue = nbnet.PreroutingFwmarkMasqueradeReturn
+	}
+
+	exprs = append(exprs,
+		&expr.Immediate{
+			Register: 1,
+			Data:     binaryutil.NativeEndian.PutUint32(markValue),
+		},
+		&expr.Meta{
+			Key:            expr.MetaKeyMARK,
+			SourceRegister: true,
+			Register:       1,
+		},
+	)
+
+	return exprs, nil
+}
+
+// queueNatRule replaces any tracked rule for the pair and queues the new
+// prerouting marking rule on the connection. Failures are logged rather than
+// returned: the caller has already queued messages that only a Flush can
+// commit, so it must not return early.
+func (r *family) queueNatRule(pair firewall.RouterPair, exprs []expr.Any) {
+	ruleID := pair.GenKey(firewall.PreroutingFormat)
+
+	if _, exists := r.rules[ruleID]; exists {
+		if err := r.removeNatRule(pair); err != nil {
+			// The rule this replaces may still be in the kernel. Keep tracking
+			// it and skip the new one: overwriting the entry would leave the old
+			// rule installed with nothing that can find it again, while keeping
+			// it lets the next update retry the whole replacement.
+			log.Errorf("replace prerouting rule %s: %v", ruleID, err)
+			r.dropNetworkMatch(exprs)
+			return
+		}
+	}
+
+	// Ensure nat rules come first, so the mark can be overwritten.
+	// Currently overwritten by the dst-type LOCAL rules for redirected traffic.
+	r.rules[ruleID] = r.conn.InsertRule(&nftables.Rule{
+		Table:    r.workTable,
+		Chain:    r.chains[chainNameManglePrerouting],
+		Exprs:    exprs,
+		UserData: []byte(ruleID),
+	})
+}
+
+func (r *family) addPostroutingRules() {
+	// First masquerade rule for traffic coming in from WireGuard interface
+	exprs := []expr.Any{
+		// Match on the first fwmark
+		&expr.Meta{
+			Key:      expr.MetaKeyMARK,
+			Register: 1,
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     binaryutil.NativeEndian.PutUint32(nbnet.PreroutingFwmarkMasquerade),
+		},
+
+		// We need to exclude the loopback interface as this changes the ebpf proxy port
+		&expr.Meta{
+			Key:      expr.MetaKeyOIFNAME,
+			Register: 1,
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpNeq,
+			Register: 1,
+			Data:     ifname("lo"),
+		},
+		&expr.Counter{},
+		&expr.Masq{},
+	}
+
+	r.conn.AddRule(&nftables.Rule{
+		Table: r.workTable,
+		Chain: r.chains[chainNameRoutingNat],
+		Exprs: exprs,
+	})
+
+	// Second masquerade rule for traffic going out through WireGuard interface
+	exprs2 := []expr.Any{
+		// Match on the second fwmark
+		&expr.Meta{
+			Key:      expr.MetaKeyMARK,
+			Register: 1,
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     binaryutil.NativeEndian.PutUint32(nbnet.PreroutingFwmarkMasqueradeReturn),
+		},
+
+		// Match WireGuard interface
+		&expr.Meta{
+			Key:      expr.MetaKeyOIFNAME,
+			Register: 1,
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     ifname(r.wgIface.Name()),
+		},
+		&expr.Counter{},
+		&expr.Masq{},
+	}
+
+	r.conn.AddRule(&nftables.Rule{
+		Table: r.workTable,
+		Chain: r.chains[chainNameRoutingNat],
+		Exprs: exprs2,
+	})
+}
+
+// addMSSClampingRules adds MSS clamping rules to prevent fragmentation for forwarded traffic.
+func (r *family) addMSSClampingRules() error {
+	overhead := uint16(ipv4TCPHeaderSize)
+	if r.af.tableFamily == nftables.TableFamilyIPv6 {
+		overhead = ipv6TCPHeaderSize
+	}
+	if r.mtu <= overhead {
+		log.Debugf("MTU %d too small for MSS clamping (overhead %d), skipping", r.mtu, overhead)
+		return nil
+	}
+	mss := r.mtu - overhead
+
+	exprsOut := []expr.Any{
+		&expr.Meta{
+			Key:      expr.MetaKeyOIFNAME,
+			Register: 1,
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     ifname(r.wgIface.Name()),
+		},
+		&expr.Meta{
+			Key:      expr.MetaKeyL4PROTO,
+			Register: 1,
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     []byte{unix.IPPROTO_TCP},
+		},
+		&expr.Payload{
+			DestRegister: 1,
+			Base:         expr.PayloadBaseTransportHeader,
+			Offset:       13,
+			Len:          1,
+		},
+		&expr.Bitwise{
+			DestRegister:   1,
+			SourceRegister: 1,
+			Len:            1,
+			Mask:           []byte{0x02},
+			Xor:            []byte{0x00},
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpNeq,
+			Register: 1,
+			Data:     []byte{0x00},
+		},
+		&expr.Counter{},
+		&expr.Exthdr{
+			DestRegister: 1,
+			Type:         2,
+			Offset:       2,
+			Len:          2,
+			Op:           expr.ExthdrOpTcpopt,
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpGt,
+			Register: 1,
+			Data:     binaryutil.BigEndian.PutUint16(uint16(mss)),
+		},
+		&expr.Immediate{
+			Register: 1,
+			Data:     binaryutil.BigEndian.PutUint16(uint16(mss)),
+		},
+		&expr.Exthdr{
+			SourceRegister: 1,
+			Type:           2,
+			Offset:         2,
+			Len:            2,
+			Op:             expr.ExthdrOpTcpopt,
+		},
+	}
+
+	r.conn.AddRule(&nftables.Rule{
+		Table: r.workTable,
+		Chain: r.chains[chainNameMangleForward],
+		Exprs: exprsOut,
+	})
+
+	return r.conn.Flush()
+}
+
+func buildLegacyRouteRuleExpressions(sourceExp, destExp []expr.Any) []expr.Any {
+	exprs := make([]expr.Any, 0, len(sourceExp)+len(destExp)+2)
+	exprs = append(exprs, sourceExp...)
+	exprs = append(exprs, destExp...)
+	exprs = append(exprs,
+		&expr.Counter{},
+		&expr.Verdict{Kind: expr.VerdictAccept},
+	)
+	return exprs
+}
+
+// legacyRouteRuleExprs resolves the match expressions of the pair's legacy
+// forwarding rule, queueing nothing on the connection.
+func (r *family) legacyRouteRuleExprs(pair firewall.RouterPair) ([]expr.Any, error) {
+	sourceExp, err := r.applyNetwork(pair.Source, nil, true)
+	if err != nil {
+		return nil, fmt.Errorf("apply source: %w", err)
+	}
+
+	destExp, err := r.applyNetwork(pair.Destination, nil, false)
+	if err != nil {
+		r.dropNetworkMatch(sourceExp)
+		return nil, fmt.Errorf("apply destination: %w", err)
+	}
+
+	return buildLegacyRouteRuleExpressions(sourceExp, destExp), nil
+}
+
+// queueLegacyRouteRule replaces any tracked rule for the pair and queues the
+// new legacy forwarding rule. Failures are logged for the same reason as in
+// queueNatRule.
+func (r *family) queueLegacyRouteRule(pair firewall.RouterPair, exprs []expr.Any) {
+	ruleID := pair.GenKey(firewall.ForwardingFormat)
+
+	if _, exists := r.rules[ruleID]; exists {
+		if err := r.removeLegacyRouteRule(pair); err != nil {
+			// Keep the old rule tracked instead of losing it, as in queueNatRule.
+			log.Errorf("replace legacy forwarding rule %s: %v", ruleID, err)
+			r.dropNetworkMatch(exprs)
+			return
+		}
+	}
+
+	r.rules[ruleID] = r.conn.AddRule(&nftables.Rule{
+		Table:    r.workTable,
+		Chain:    r.chains[chainNameRoutingFw],
+		Exprs:    exprs,
+		UserData: []byte(ruleID),
+	})
+}
+
+// removeLegacyRouteRule removes a legacy routing rule for mgmt servers pre route acls
+func (r *family) removeLegacyRouteRule(pair firewall.RouterPair) error {
+	ruleID := pair.GenKey(firewall.ForwardingFormat)
+
+	rule, exists := r.rules[ruleID]
+	if !exists {
+		return nil
+	}
+
+	return r.deleteLegacyRuleEntry(ruleID, rule)
+}
+
+// deleteLegacyRuleEntry removes one legacy forwarding rule and drops its
+// ipset references. It also clears stale entries that never got a handle.
+func (r *family) deleteLegacyRuleEntry(ruleID firewall.RuleID, rule *nftables.Rule) error {
+	if rule.Handle == 0 {
+		log.Warnf("legacy forwarding rule %s has no handle, removing stale entry", ruleID)
+		if err := r.decrementSetCounter(rule); err != nil {
+			log.Warnf("decrement set counter for stale rule %s: %v", ruleID, err)
+		}
+		delete(r.rules, ruleID)
+		return nil
+	}
+
+	if err := r.conn.DelRule(rule); err != nil {
+		return fmt.Errorf("remove legacy forwarding rule %s: %w", ruleID, err)
+	}
+
+	delete(r.rules, ruleID)
+
+	if err := r.decrementSetCounter(rule); err != nil {
+		return fmt.Errorf("decrement set counter: %w", err)
+	}
+
+	return nil
+}
+
+// GetLegacyManagement returns the route manager's legacy management mode
+func (r *family) GetLegacyManagement() bool {
+	return r.legacyManagement
+}
+
+// SetLegacyManagement sets the route manager to use legacy management mode
+func (r *family) SetLegacyManagement(isLegacy bool) {
+	r.legacyManagement = isLegacy
+}
+
+// RemoveAllLegacyRouteRules removes all legacy routing rules for mgmt servers pre route acls
+func (r *family) RemoveAllLegacyRouteRules() error {
+	if err := r.refreshRulesMap(); err != nil {
+		return fmt.Errorf(refreshRulesMapError, err)
+	}
+
+	var merr *multierror.Error
+	var found bool
+	for k, rule := range r.rules {
+		if !strings.HasPrefix(string(k), firewall.ForwardingFormatPrefix) {
+			continue
+		}
+		found = true
+		if err := r.deleteLegacyRuleEntry(k, rule); err != nil {
+			merr = multierror.Append(merr, err)
+		}
+	}
+
+	// Commit the queued deletes here instead of leaving them for whichever
+	// caller flushes next: the tracking entries are already gone, so an
+	// uncommitted delete would leave a rule in the kernel that nothing can
+	// find again.
+	if found {
+		if err := r.conn.Flush(); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf(flushError, err))
+		}
+	}
+
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+func (r *family) removeNatPreroutingRules() error {
+	table := &nftables.Table{
+		Name:   tableNat,
+		Family: r.af.tableFamily,
+	}
+	chain := &nftables.Chain{
+		Name:     chainNameNatPrerouting,
+		Table:    table,
+		Hooknum:  nftables.ChainHookPrerouting,
+		Priority: nftables.ChainPriorityNATDest,
+		Type:     nftables.ChainTypeNAT,
+	}
+	rules, err := r.conn.GetRules(table, chain)
+	if err != nil {
+		return fmt.Errorf("get rules from nat table: %w", err)
+	}
+
+	var merr *multierror.Error
+
+	// Delete rules that have our UserData suffix
+	for _, rule := range rules {
+		if len(rule.UserData) == 0 || !strings.HasSuffix(string(rule.UserData), string(dnatSuffix)) {
+			continue
+		}
+		if err := r.conn.DelRule(rule); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("delete rule %s: %w", rule.UserData, err))
+		}
+	}
+
+	if err := r.conn.Flush(); err != nil {
+		merr = multierror.Append(merr, fmt.Errorf(flushError, err))
+	}
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+func (r *family) RemoveNatRule(pair firewall.RouterPair) error {
+	if err := r.refreshRulesMap(); err != nil {
+		return fmt.Errorf(refreshRulesMapError, err)
+	}
+
+	var merr *multierror.Error
+
+	if pair.Masquerade {
+		if err := r.removeNatRule(pair); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("remove prerouting rule: %w", err))
+		}
+
+		if err := r.removeNatRule(firewall.GetInversePair(pair)); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("remove inverse prerouting rule: %w", err))
+		}
+	}
+
+	if err := r.removeLegacyRouteRule(pair); err != nil {
+		merr = multierror.Append(merr, fmt.Errorf("remove legacy routing rule: %w", err))
+	}
+
+	// Set counters are decremented in the sub-methods above before flush. If flush fails,
+	// counters will be off until the next successful removal or refresh cycle.
+	if err := r.conn.Flush(); err != nil {
+		merr = multierror.Append(merr, fmt.Errorf("flush remove nat rules %s: %w", pair.Destination, err))
+	}
+
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+func (r *family) removeNatRule(pair firewall.RouterPair) error {
+	ruleID := pair.GenKey(firewall.PreroutingFormat)
+
+	rule, exists := r.rules[ruleID]
+	if !exists {
+		log.Debugf("prerouting rule %s not found", ruleID)
+		return nil
+	}
+
+	if rule.Handle == 0 {
+		log.Warnf("prerouting rule %s has no handle, removing stale entry", ruleID)
+		if err := r.decrementSetCounter(rule); err != nil {
+			log.Warnf("decrement set counter for stale rule %s: %v", ruleID, err)
+		}
+		delete(r.rules, ruleID)
+		return nil
+	}
+
+	if err := r.conn.DelRule(rule); err != nil {
+		return fmt.Errorf("remove prerouting rule %s -> %s: %w", pair.Source, pair.Destination, err)
+	}
+
+	log.Debugf("removed prerouting rule %s -> %s", pair.Source, pair.Destination)
+
+	delete(r.rules, ruleID)
+
+	if err := r.decrementSetCounter(rule); err != nil {
+		return fmt.Errorf("decrement set counter: %w", err)
+	}
+
+	return nil
+}

client/firewall/nftables/rule_linux.go

@@ -1,21 +1,26 @@
 package nftables
 
 import (
-	"net"
+	"net/netip"
 
 	"github.com/google/nftables"
+
+	"github.com/netbirdio/netbird/client/firewall/manager"
 )
 
-// Rule to handle management of rules
+// Rule wraps an installed filter rule (peer or route). Source set
+// membership is encoded in the rule's expressions; DeleteFilterRule
+// recovers the set name via findSets so the refcounter can drop the
+// right reference. mangleRule is set only for peer rules.
 type Rule struct {
 	nftRule    *nftables.Rule
 	mangleRule *nftables.Rule
-	nftSet     *nftables.Set
+	// sources is the canonical source list this rule was created for.
-	ruleID     string
+	sources []netip.Prefix
-	ip         net.IP
+	id      manager.RuleID
 }
 
-// GetRuleID returns the rule id
+// ID returns the rule id
-func (r *Rule) ID() string {
+func (r *Rule) ID() manager.RuleID {
-	return r.ruleID
+	return r.id
 }

client/firewall/nftables/testhelpers_linux_test.go

@@ -0,0 +1,27 @@
+//go:build privileged
+
+package nftables
+
+import (
+	"fmt"
+	"net"
+	"net/netip"
+)
+
+func pfx(ip net.IP) []netip.Prefix {
+	if ip == nil {
+		return []netip.Prefix{netip.PrefixFrom(netip.IPv4Unspecified(), 0)}
+	}
+	if ip.IsUnspecified() {
+		if ip.To4() != nil {
+			return []netip.Prefix{netip.PrefixFrom(netip.IPv4Unspecified(), 0)}
+		}
+		return []netip.Prefix{netip.PrefixFrom(netip.IPv6Unspecified(), 0)}
+	}
+	a, ok := netip.AddrFromSlice(ip)
+	if !ok {
+		panic(fmt.Sprintf("invalid IP length: %d", len(ip)))
+	}
+	a = a.Unmap()
+	return []netip.Prefix{netip.PrefixFrom(a, a.BitLen())}
+}

client/firewall/uspfilter/allow_netbird.go

@@ -1,37 +0,0 @@
-//go:build !windows
-
-package uspfilter
-
-import (
-	log "github.com/sirupsen/logrus"
-
-	"github.com/netbirdio/netbird/client/firewall/firewalld"
-	"github.com/netbirdio/netbird/client/internal/statemanager"
-)
-
-// Close cleans up the firewall manager by removing all rules and closing trackers
-func (m *Manager) Close(stateManager *statemanager.Manager) error {
-	m.mutex.Lock()
-	defer m.mutex.Unlock()
-
-	m.resetState()
-
-	if m.nativeFirewall != nil {
-		return m.nativeFirewall.Close(stateManager)
-	}
-	if err := firewalld.UntrustInterface(m.wgIface.Name()); err != nil {
-		log.Warnf("failed to untrust interface in firewalld: %v", err)
-	}
-	return nil
-}
-
-// AllowNetbird allows netbird interface traffic
-func (m *Manager) AllowNetbird() error {
-	if m.nativeFirewall != nil {
-		return m.nativeFirewall.AllowNetbird()
-	}
-	if err := firewalld.TrustInterface(m.wgIface.Name()); err != nil {
-		log.Warnf("failed to trust interface in firewalld: %v", err)
-	}
-	return nil
-}

client/firewall/uspfilter/common/iface.go

@@ -1,17 +0,0 @@
-package common
-
-import (
-	wgdevice "golang.zx2c4.com/wireguard/device"
-
-	"github.com/netbirdio/netbird/client/iface/device"
-	"github.com/netbirdio/netbird/client/iface/wgaddr"
-)
-
-// IFaceMapper defines subset methods of interface required for manager
-type IFaceMapper interface {
-	Name() string
-	SetFilter(device.PacketFilter) error
-	Address() wgaddr.Address
-	GetWGDevice() *wgdevice.Device
-	GetDevice() *device.FilteredDevice
-}

client/firewall/uspfilter/filter.go

@@ -5,7 +5,6 @@ import (
 	"encoding/binary"
 	"errors"
 	"fmt"
-	"net"
 	"net/netip"
 	"os"
 	"slices"
@@ -20,14 +19,18 @@ import (
 	"github.com/google/uuid"
 	"github.com/hashicorp/go-multierror"
 	log "github.com/sirupsen/logrus"
+	wgdevice "golang.zx2c4.com/wireguard/device"
 
 	nberrors "github.com/netbirdio/netbird/client/errors"
+	"github.com/netbirdio/netbird/client/firewall/firewalld"
 	firewall "github.com/netbirdio/netbird/client/firewall/manager"
 	"github.com/netbirdio/netbird/client/firewall/uspfilter/common"
 	"github.com/netbirdio/netbird/client/firewall/uspfilter/conntrack"
 	"github.com/netbirdio/netbird/client/firewall/uspfilter/forwarder"
 	nblog "github.com/netbirdio/netbird/client/firewall/uspfilter/log"
+	"github.com/netbirdio/netbird/client/iface/device"
 	"github.com/netbirdio/netbird/client/iface/netstack"
+	"github.com/netbirdio/netbird/client/iface/wgaddr"
 	nbid "github.com/netbirdio/netbird/client/internal/acl/id"
 	nftypes "github.com/netbirdio/netbird/client/internal/netflow/types"
 	"github.com/netbirdio/netbird/client/internal/statemanager"
@@ -58,7 +61,10 @@ const (
 	// EnvDisableMSSClamping disables TCP MSS clamping for forwarded traffic.
 	EnvDisableMSSClamping = "NB_DISABLE_MSS_CLAMPING"
 
-	// EnvForceUserspaceRouter forces userspace routing even if native routing is available.
+	// EnvForceUserspaceRouter is a deprecated alias for
+	// NB_FORCE_USERSPACE_FIREWALL: the userspace firewall always routes in
+	// userspace, so forcing one forces the other. Kept for backward
+	// compatibility.
 	EnvForceUserspaceRouter = "NB_FORCE_USERSPACE_ROUTER"
 
 	// EnvEnableLocalForwarding enables forwarding of local traffic to the native stack for internal (non-NetBird) interfaces.
@@ -70,14 +76,20 @@ const (
 	EnvEnableNetstackLocalForwarding = "NB_ENABLE_NETSTACK_LOCAL_FORWARDING"
 )
 
-var errNatNotSupported = errors.New("nat not supported with userspace firewall")
+// errNotSupported is returned by firewall operations that only make sense with
+// a kernel firewall (kernel NAT/DNAT, eBPF) and are not implemented in
+// userspace mode, where they should not be called.
+var errNotSupported = errors.New("not supported with userspace firewall")
 
-// RuleSet is a set of rules grouped by a string key
+// peerRules is the canonical list-based storage for peer ACL rules.
-type RuleSet map[string]PeerRule
+// Drop and accept rules live in separate slices; drop-before-accept
+// ordering comes from consulting the deny slice (and its index) before
+// the accept one.
+type peerRules []*PeerRule
 
-type RouteRules []*RouteRule
+type routeRules []*RouteRule
 
-func (r RouteRules) Sort() {
+func (r routeRules) Sort() {
 	slices.SortStableFunc(r, func(a, b *RouteRule) int {
 		// Deny rules come first
 		if a.action == firewall.ActionDrop && b.action != firewall.ActionDrop {
@@ -86,22 +98,74 @@ func (r RouteRules) Sort() {
 		if a.action != firewall.ActionDrop && b.action == firewall.ActionDrop {
 			return 1
 		}
-		return strings.Compare(a.id, b.id)
+		return strings.Compare(string(a.id), string(b.id))
 	})
 }
 
+// peerRuleSpec carries the parameters that define a peer filter rule,
+// threaded together through the build path so the builders take a single
+// argument instead of a long parameter list.
+type peerRuleSpec struct {
+	mgmtID  []byte
+	sources []netip.Prefix
+	ipLayer gopacket.LayerType
+	proto   firewall.Protocol
+	sPort   *firewall.Port
+	dPort   *firewall.Port
+	action  firewall.Action
+}
+
+// Iface is the network interface the userspace firewall attaches to: the
+// methods of the WireGuard device it actually uses.
+type Iface interface {
+	Name() string
+	Address() wgaddr.Address
+	SetFilter(device.PacketFilter) error
+	GetWGDevice() *wgdevice.Device
+}
+
+// InterfaceAllower opens the NetBird interface in the host firewall so it
+// doesn't drop traffic the userspace firewall handles, without taking over
+// packet filtering. Implementations (nftables, iptables, firewalld, the windows
+// netsh rule) are selected per platform and injected into Create; Apply runs at
+// creation and Close on teardown.
+type InterfaceAllower interface {
+	Apply() error
+	Close() error
+}
+
+// Config holds the dependencies and options for the userspace firewall.
+type Config struct {
+	// IFace is the overlay interface the filter attaches to.
+	IFace Iface
+	// InterfaceAllower opens the NetBird interface in foreign kernel filter
+	// chains so the kernel doesn't drop traffic the userspace firewall handles.
+	// Nil in netstack mode, on non-Linux platforms without a backend, or when
+	// neither nftables nor iptables is available. firewalld trust is applied by
+	// the manager regardless, since firewalld owns its own chains and we cannot
+	// insert into them.
+	InterfaceAllower InterfaceAllower
+	// DisableServerRoutes indicates whether server routes are disabled.
+	DisableServerRoutes bool
+	FlowLogger          nftypes.FlowLogger
+	MTU                 uint16
+}
+
 // Manager userspace firewall manager
 type Manager struct {
-	outgoingRules     map[netip.Addr]RuleSet
+	decoders     sync.Pool
-	incomingDenyRules map[netip.Addr]RuleSet
+	wgIface      Iface
-	incomingRules     map[netip.Addr]RuleSet
+	ifaceAllower InterfaceAllower
-	routeRules        RouteRules
+	mutex        sync.RWMutex
-	routeRulesMap     map[nbid.RuleID]*RouteRule
-	decoders          sync.Pool
-	wgIface           common.IFaceMapper
-	nativeFirewall    firewall.Manager
 
-	mutex sync.RWMutex
+	incomingDenyRules   peerRules
+	incomingAcceptRules peerRules
+	incomingDenyIndex   peerRuleIndex
+	incomingAcceptIndex peerRuleIndex
+	peerRulesMap        map[nbid.RuleID]*PeerRule
+
+	routeRules    routeRules
+	routeRulesMap map[nbid.RuleID]*RouteRule
 
 	// indicates whether server routes are disabled
 	disableServerRoutes bool
@@ -219,24 +283,6 @@ func (d *decoder) decodeTransport(proto layers.IPProtocol, payload []byte) bool
 	return true
 }
 
-// Create userspace firewall manager constructor
-func Create(iface common.IFaceMapper, disableServerRoutes bool, flowLogger nftypes.FlowLogger, mtu uint16) (*Manager, error) {
-	return create(iface, nil, disableServerRoutes, flowLogger, mtu)
-}
-
-func CreateWithNativeFirewall(iface common.IFaceMapper, nativeFirewall firewall.Manager, disableServerRoutes bool, flowLogger nftypes.FlowLogger, mtu uint16) (*Manager, error) {
-	if nativeFirewall == nil {
-		return nil, errors.New("native firewall is nil")
-	}
-
-	mgr, err := create(iface, nativeFirewall, disableServerRoutes, flowLogger, mtu)
-	if err != nil {
-		return nil, err
-	}
-
-	return mgr, nil
-}
-
 func parseCreateEnv() (bool, bool, bool) {
 	var disableConntrack, enableLocalForwarding, disableMSSClamping bool
 	var err error
@@ -267,7 +313,7 @@ func parseCreateEnv() (bool, bool, bool) {
 	return disableConntrack, enableLocalForwarding, disableMSSClamping
 }
 
-func create(iface common.IFaceMapper, nativeFirewall firewall.Manager, disableServerRoutes bool, flowLogger nftypes.FlowLogger, mtu uint16) (*Manager, error) {
+func Create(cfg Config) (_ *Manager, err error) {
 	disableConntrack, enableLocalForwarding, disableMSSClamping := parseCreateEnv()
 
 	m := &Manager{
@@ -290,65 +336,133 @@ func create(iface common.IFaceMapper, nativeFirewall firewall.Manager, disableSe
 				return d
 			},
 		},
-		nativeFirewall:      nativeFirewall,
+		wgIface:             cfg.IFace,
-		outgoingRules:       make(map[netip.Addr]RuleSet),
+		ifaceAllower:        cfg.InterfaceAllower,
-		incomingDenyRules:   make(map[netip.Addr]RuleSet),
-		incomingRules:       make(map[netip.Addr]RuleSet),
-		wgIface:             iface,
 		localipmanager:      newLocalIPManager(),
-		disableServerRoutes: disableServerRoutes,
+		disableServerRoutes: cfg.DisableServerRoutes,
 		stateful:            !disableConntrack,
 		logger:              nblog.NewFromLogrus(log.StandardLogger()),
-		flowLogger:          flowLogger,
+		flowLogger:          cfg.FlowLogger,
 		netstack:            netstack.IsEnabled(),
 		localForwarding:     enableLocalForwarding,
+		peerRulesMap:        make(map[nbid.RuleID]*PeerRule),
 		routeRulesMap:       make(map[nbid.RuleID]*RouteRule),
 		dnatMappings:        make(map[netip.Addr]netip.Addr),
 		portDNATRules:       []portDNATRule{},
 		netstackServices:    make(map[serviceKey]struct{}),
-		mtu:                 mtu,
+		mtu:                 cfg.MTU,
 	}
 	m.routingEnabled.Store(false)
 
+	// Release the allower (and its monitor) if setup fails after it was wired in.
+	defer func() {
+		if err != nil {
+			m.closeAllowerOnError()
+		}
+	}()
+
 	if !disableMSSClamping {
-		m.mssClampEnabled = true
+		m.enableMSSClamping(cfg.MTU)
-		if mtu > ipv4TCPHeaderMinSize {
-			m.mssClampValueIPv4 = mtu - ipv4TCPHeaderMinSize
-		}
-		if mtu > ipv6TCPHeaderMinSize {
-			m.mssClampValueIPv6 = mtu - ipv6TCPHeaderMinSize
-		}
 	}
-	if err := m.localipmanager.UpdateLocalIPs(iface); err != nil {
+	if err := m.localipmanager.UpdateLocalIPs(cfg.IFace); err != nil {
 		return nil, fmt.Errorf("update local IPs: %w", err)
 	}
 	m.fragments = newFragmentTracker(m.logger)
-
+	m.setupConntrack(disableConntrack)
-	if disableConntrack {
-		log.Info("conntrack is disabled")
-	} else {
-		m.udpTracker = conntrack.NewUDPTracker(conntrack.DefaultUDPTimeout, m.logger, flowLogger)
-		m.icmpTracker = conntrack.NewICMPTracker(conntrack.DefaultICMPTimeout, m.logger, flowLogger)
-		m.tcpTracker = conntrack.NewTCPTracker(conntrack.DefaultTCPTimeout, m.logger, flowLogger)
-	}
 	if m.netstack && m.localForwarding {
 		if err := m.initForwarder(); err != nil {
 			log.Errorf("failed to initialize forwarder: %v", err)
 		}
 	}
-	if err := iface.SetFilter(m); err != nil {
+	if err := cfg.IFace.SetFilter(m); err != nil {
 		m.fragments.Close()
 		return nil, fmt.Errorf("set filter: %w", err)
 	}
+
+	m.openHostFirewall(cfg.IFace.Name())
+
 	return m, nil
 }
 
+// closeAllowerOnError releases the allower (and its monitor) when Create fails
+// after the allower was wired in.
+func (m *Manager) closeAllowerOnError() {
+	if m.ifaceAllower == nil {
+		return
+	}
+	if err := m.ifaceAllower.Close(); err != nil {
+		log.Warnf("close interface allower after failed firewall setup: %v", err)
+	}
+}
+
+// enableMSSClamping enables MSS clamping and computes the per-family clamp values.
+func (m *Manager) enableMSSClamping(mtu uint16) {
+	m.mssClampEnabled = true
+	if mtu > ipv4TCPHeaderMinSize {
+		m.mssClampValueIPv4 = mtu - ipv4TCPHeaderMinSize
+	}
+	if mtu > ipv6TCPHeaderMinSize {
+		m.mssClampValueIPv6 = mtu - ipv6TCPHeaderMinSize
+	}
+}
+
+// setupConntrack initializes the stateful trackers unless conntrack is disabled.
+func (m *Manager) setupConntrack(disabled bool) {
+	if disabled {
+		log.Info("conntrack is disabled")
+		return
+	}
+	m.udpTracker = conntrack.NewUDPTracker(conntrack.DefaultUDPTimeout, m.logger, m.flowLogger)
+	m.icmpTracker = conntrack.NewICMPTracker(conntrack.DefaultICMPTimeout, m.logger, m.flowLogger)
+	m.tcpTracker = conntrack.NewTCPTracker(conntrack.DefaultTCPTimeout, m.logger, m.flowLogger)
+}
+
+// openHostFirewall opens the NetBird interface in the kernel firewall so it
+// doesn't drop traffic the userspace firewall handles. Best-effort: failures
+// here shouldn't prevent the firewall from coming up.
+func (m *Manager) openHostFirewall(ifaceName string) {
+	if m.ifaceAllower != nil {
+		if err := m.ifaceAllower.Apply(); err != nil {
+			log.Errorf("failed to allow netbird interface traffic: %v", err)
+		}
+	}
+	// firewalld owns its own chains we can't insert into, so trust the interface
+	// there in addition to the allower. Netstack has no kernel interface.
+	if !m.netstack {
+		if err := firewalld.TrustInterface(ifaceName); err != nil {
+			log.Warnf("failed to trust interface in firewalld: %v", err)
+		}
+	}
+}
+
+// Close cleans up the firewall manager: removes rules, closes trackers, and
+// closes the interface allower.
+func (m *Manager) Close(*statemanager.Manager) error {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+
+	m.resetState()
+
+	var merr *multierror.Error
+	if m.ifaceAllower != nil {
+		if err := m.ifaceAllower.Close(); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("close interface allower: %w", err))
+		}
+	}
+	if !m.netstack {
+		if err := firewalld.UntrustInterface(m.wgIface.Name()); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("untrust interface in firewalld: %w", err))
+		}
+	}
+	return nberrors.FormatErrorOrNil(merr)
+}
+
 // blockInvalidRouted installs drop rules for traffic to the wg overlay that
 // arrives via the routing path. v4 and v6 are independent: a v6 install
 // failure leaves v4 protection in place (and vice versa) so the returned
 // slice always contains whatever was successfully installed, even on error.
 // Callers must persist the slice so DisableRouting can clean partial state.
-func (m *Manager) blockInvalidRouted(iface common.IFaceMapper) ([]firewall.Rule, error) {
+func (m *Manager) blockInvalidRouted(iface Iface) ([]firewall.Rule, error) {
 	wgPrefix := iface.Address().Network
 	log.Debugf("blocking invalid routed traffic for %s", wgPrefix)
 
@@ -359,7 +473,7 @@ func (m *Manager) blockInvalidRouted(iface common.IFaceMapper) ([]firewall.Rule,
 	}
 
 	var rules []firewall.Rule
-	v4Rule, err := m.addRouteFiltering(
+	v4Rule, err := m.addRouteRule(
 		nil,
 		sources,
 		firewall.Network{Prefix: wgPrefix},
@@ -375,7 +489,7 @@ func (m *Manager) blockInvalidRouted(iface common.IFaceMapper) ([]firewall.Rule,
 
 	if v6Net.IsValid() {
 		log.Debugf("blocking invalid routed traffic for %s", v6Net)
-		v6Rule, err := m.addRouteFiltering(
+		v6Rule, err := m.addRouteRule(
 			nil,
 			sources,
 			firewall.Network{Prefix: v6Net},
@@ -396,20 +510,14 @@ func (m *Manager) blockInvalidRouted(iface common.IFaceMapper) ([]firewall.Rule,
 }
 
 func (m *Manager) determineRouting() error {
-	var disableUspRouting, forceUserspaceRouter bool
+	var disableUspRouting bool
-	var err error
 	if val := os.Getenv(EnvDisableUserspaceRouting); val != "" {
+		var err error
 		disableUspRouting, err = strconv.ParseBool(val)
 		if err != nil {
 			log.Warnf("failed to parse %s: %v", EnvDisableUserspaceRouting, err)
 		}
 	}
-	if val := os.Getenv(EnvForceUserspaceRouter); val != "" {
-		forceUserspaceRouter, err = strconv.ParseBool(val)
-		if err != nil {
-			log.Warnf("failed to parse %s: %v", EnvForceUserspaceRouter, err)
-		}
-	}
 
 	switch {
 	case disableUspRouting:
@@ -424,26 +532,11 @@ func (m *Manager) determineRouting() error {
 
 		log.Info("server routes are disabled")
 
-	case forceUserspaceRouter:
-		m.routingEnabled.Store(true)
-		m.nativeRouter.Store(false)
-
-		log.Info("userspace routing is forced")
-
-	case !m.netstack && m.nativeFirewall != nil:
-		// if the OS supports routing natively, then we don't need to filter/route ourselves
-		// netstack mode won't support native routing as there is no interface
-
-		m.routingEnabled.Store(true)
-		m.nativeRouter.Store(true)
-
-		log.Info("native routing is enabled")
-
 	default:
 		m.routingEnabled.Store(true)
 		m.nativeRouter.Store(false)
 
-		log.Info("userspace routing enabled by default")
+		log.Info("userspace routing enabled")
 	}
 
 	if m.routingEnabled.Load() && !m.nativeRouter.Load() {
@@ -509,96 +602,118 @@ func (m *Manager) IsStateful() bool {
 	return m.stateful
 }
 
-func (m *Manager) AddNatRule(pair firewall.RouterPair) error {
+func (m *Manager) AddNatRule(firewall.RouterPair) error {
-	if m.nativeRouter.Load() && m.nativeFirewall != nil {
-		return m.nativeFirewall.AddNatRule(pair)
-	}
-
 	// userspace routed packets are always SNATed to the inbound direction
 	// TODO: implement outbound SNAT
 	return nil
 }
 
 // RemoveNatRule removes a routing firewall rule
-func (m *Manager) RemoveNatRule(pair firewall.RouterPair) error {
+func (m *Manager) RemoveNatRule(firewall.RouterPair) error {
-	if m.nativeRouter.Load() && m.nativeFirewall != nil {
-		return m.nativeFirewall.RemoveNatRule(pair)
-	}
 	return nil
 }
 
-// AddPeerFiltering rule to the firewall
+// addPeerRule installs an input-chain rule that matches packets
-//
+// by source only. Called from AddFilterRule when the caller doesn't
-// If comment argument is empty firewall manager should set
+// specify a destination. Sources are expected to share one address
-// rule ID as comment for the rule
+// family; the family selects the ipLayer so the ICMP variant matches
-func (m *Manager) AddPeerFiltering(
+// what the decoder produces.
+func (m *Manager) addPeerRule(
 	id []byte,
-	ip net.IP,
+	sources []netip.Prefix,
 	proto firewall.Protocol,
 	sPort *firewall.Port,
 	dPort *firewall.Port,
 	action firewall.Action,
-	_ string,
-) ([]firewall.Rule, error) {
-	// TODO: fix in upper layers
-	i, ok := netip.AddrFromSlice(ip)
-	if !ok {
-		return nil, fmt.Errorf("invalid IP: %s", ip)
-	}
-
-	i = i.Unmap()
-	r := PeerRule{
-		id:        uuid.New().String(),
-		mgmtId:    id,
-		ip:        i,
-		ipLayer:   layers.LayerTypeIPv6,
-		matchByIP: true,
-		drop:      action == firewall.ActionDrop,
-	}
-	if i.Is4() {
-		r.ipLayer = layers.LayerTypeIPv4
-	}
-
-	if s := r.ip.String(); s == "0.0.0.0" || s == "::" {
-		r.matchByIP = false
-	}
-
-	r.sPort = sPort
-	r.dPort = dPort
-
-	r.protoLayer = protoToLayer(proto, r.ipLayer)
-
-	m.mutex.Lock()
-	var targetMap map[netip.Addr]RuleSet
-	if r.drop {
-		targetMap = m.incomingDenyRules
-	} else {
-		targetMap = m.incomingRules
-	}
-
-	if _, ok := targetMap[r.ip]; !ok {
-		targetMap[r.ip] = make(RuleSet)
-	}
-	targetMap[r.ip][r.id] = r
-	m.mutex.Unlock()
-	return []firewall.Rule{&r}, nil
-}
-
-func (m *Manager) AddRouteFiltering(
-	id []byte,
-	sources []netip.Prefix,
-	destination firewall.Network,
-	proto firewall.Protocol,
-	sPort, dPort *firewall.Port,
-	action firewall.Action,
 ) (firewall.Rule, error) {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	return m.addRouteFiltering(id, sources, destination, proto, sPort, dPort, action)
+	// Sources are a single family; normalize v4-mapped prefixes to plain
+	// v4 and pick the matching IP layer. A /0 source matches any address
+	// of its own family only, mirroring the kernel backends.
+	normalized := make([]netip.Prefix, len(sources))
+	ipLayer := layers.LayerTypeIPv4
+	for i, p := range sources {
+		normalized[i] = firewall.UnmapPrefix(p)
+		if normalized[i].Addr().Is6() {
+			ipLayer = layers.LayerTypeIPv6
+		}
+	}
+	spec := peerRuleSpec{
+		mgmtID:  id,
+		sources: normalized,
+		ipLayer: ipLayer,
+		proto:   proto,
+		sPort:   sPort,
+		dPort:   dPort,
+		action:  action,
+	}
+	return m.addOnePeerRule(spec), nil
 }
 
-func (m *Manager) addRouteFiltering(
+// addOnePeerRule builds and registers a single-family peer rule, or
+// returns the existing rule when one with the same content key is
+// already installed. The caller must hold m.mutex. The content key is
+// the shared GenerateRuleID with an empty destination, so peer rules
+// dedup the same way route rules and the kernel backends do; it is
+// order-independent, so callers passing the same sources in any order
+// dedup to one rule.
+//
+// There is no refcount: a content key is installed once and deleted on
+// the first DeleteFilterRule for that key. The caller must therefore
+// key its own tracking by the returned rule id so add and delete stay
+// balanced per content key; the acl manager does this via
+// peerRulesPairs.
+func (m *Manager) addOnePeerRule(spec peerRuleSpec) *PeerRule {
+	ruleID := nbid.GenerateRuleID(spec.sources, firewall.Network{}, spec.proto, spec.sPort, spec.dPort, spec.action)
+	if existing, ok := m.peerRulesMap[ruleID]; ok {
+		return existing
+	}
+
+	rule := m.buildPeerRule(ruleID, spec)
+	m.registerPeerRule(rule)
+	return rule
+}
+
+func (m *Manager) buildPeerRule(ruleID nbid.RuleID, spec peerRuleSpec) *PeerRule {
+	r := &PeerRule{
+		id:      ruleID,
+		mgmtId:  spec.mgmtID,
+		sources: spec.sources,
+		action:  spec.action,
+		srcPort: spec.sPort,
+		dstPort: spec.dPort,
+	}
+	r.sourceAddrs = make(map[netip.Addr]struct{}, len(spec.sources))
+	for _, p := range spec.sources {
+		if p.Bits() == p.Addr().BitLen() {
+			r.sourceAddrs[p.Addr()] = struct{}{}
+		}
+	}
+	r.protoLayer = protoToLayer(spec.proto, spec.ipLayer)
+	return r
+}
+
+// registerPeerRule records a freshly built peer rule in the matching
+// slice, index, and dedup map. The caller must hold m.mutex.
+func (m *Manager) registerPeerRule(r *PeerRule) {
+	if r.action == firewall.ActionDrop {
+		m.incomingDenyRules = append(m.incomingDenyRules, r)
+		m.incomingDenyIndex.add(r)
+	} else {
+		m.incomingAcceptRules = append(m.incomingAcceptRules, r)
+		m.incomingAcceptIndex.add(r)
+	}
+	m.peerRulesMap[r.id] = r
+}
+
+// AddFilterRule is the unified entry point for both peer (input chain)
+// and route (forward chain) filtering rules. The destination
+// distinguishes the two semantics: a zero Network installs an
+// input-side rule that matches by source only; a set Network installs
+// a forward-side rule that also matches the destination.
+func (m *Manager) AddFilterRule(
 	id []byte,
 	sources []netip.Prefix,
 	destination firewall.Network,
@@ -606,19 +721,49 @@ func (m *Manager) addRouteFiltering(
 	sPort, dPort *firewall.Port,
 	action firewall.Action,
 ) (firewall.Rule, error) {
-	if m.nativeRouter.Load() && m.nativeFirewall != nil {
+	if len(sources) == 0 {
-		return m.nativeFirewall.AddRouteFiltering(id, sources, destination, proto, sPort, dPort, action)
+		return nil, firewall.ErrNoSources
 	}
 
-	ruleKey := nbid.GenerateRouteRuleKey(sources, destination, proto, sPort, dPort, action)
+	if destination.IsZero() {
+		return m.addPeerRule(id, sources, proto, sPort, dPort, action)
+	}
 
-	if existingRule, ok := m.routeRulesMap[ruleKey]; ok {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+	return m.addRouteRule(id, sources, destination, proto, sPort, dPort, action)
+}
+
+// DeleteFilterRule deletes a filtering rule. The rule's underlying type
+// is used to route to the correct internal path.
+func (m *Manager) DeleteFilterRule(rule firewall.Rule) error {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+
+	if r, ok := rule.(*PeerRule); ok {
+		return m.deletePeerRuleLocked(r)
+	}
+
+	// Anything else is a route rule (matched on the forward path).
+	return m.deleteRouteRule(rule)
+}
+
+func (m *Manager) addRouteRule(
+	id []byte,
+	sources []netip.Prefix,
+	destination firewall.Network,
+	proto firewall.Protocol,
+	sPort, dPort *firewall.Port,
+	action firewall.Action,
+) (firewall.Rule, error) {
+	ruleID := nbid.GenerateRuleID(sources, destination, proto, sPort, dPort, action)
+
+	if existingRule, ok := m.routeRulesMap[ruleID]; ok {
 		return existingRule, nil
 	}
 
 	rule := RouteRule{
-		// TODO: consolidate these IDs
+		id:         ruleID,
-		id:         string(ruleKey),
 		mgmtId:     id,
 		sources:    sources,
 		dstSet:     destination.Set,
@@ -633,78 +778,58 @@ func (m *Manager) addRouteFiltering(
 
 	m.routeRules = append(m.routeRules, &rule)
 	m.routeRules.Sort()
-	m.routeRulesMap[ruleKey] = &rule
+	m.routeRulesMap[ruleID] = &rule
 
 	return &rule, nil
 }
 
-func (m *Manager) DeleteRouteRule(rule firewall.Rule) error {
-	m.mutex.Lock()
-	defer m.mutex.Unlock()
-
-	return m.deleteRouteRule(rule)
-}
-
 func (m *Manager) deleteRouteRule(rule firewall.Rule) error {
-	if m.nativeRouter.Load() && m.nativeFirewall != nil {
+	ruleID := rule.ID()
-		return m.nativeFirewall.DeleteRouteRule(rule)
+	trimmed, _, ok := removeRuleByID(m.routeRules, ruleID)
+	if !ok {
+		return fmt.Errorf("route rule not found: %s", ruleID)
 	}
-
+	m.routeRules = trimmed
-	ruleKey := nbid.RuleID(rule.ID())
+	delete(m.routeRulesMap, ruleID)
-	if _, ok := m.routeRulesMap[ruleKey]; !ok {
-		return fmt.Errorf("route rule not found: %s", ruleKey)
-	}
-
-	idx := slices.IndexFunc(m.routeRules, func(r *RouteRule) bool {
-		return r.id == string(ruleKey)
-	})
-	if idx < 0 {
-		return fmt.Errorf("route rule not found in slice: %s", ruleKey)
-	}
-
-	m.routeRules = slices.Delete(m.routeRules, idx, idx+1)
-	delete(m.routeRulesMap, ruleKey)
 	return nil
 }
 
-// DeletePeerRule from the firewall by rule definition
+// deletePeerRuleLocked removes a peer rule from the matching slice,
-func (m *Manager) DeletePeerRule(rule firewall.Rule) error {
+// index, and dedup map. The caller must hold m.mutex.
-	m.mutex.Lock()
+func (m *Manager) deletePeerRuleLocked(r *PeerRule) error {
-	defer m.mutex.Unlock()
+	target, index := &m.incomingAcceptRules, &m.incomingAcceptIndex
+	if r.action == firewall.ActionDrop {
+		target, index = &m.incomingDenyRules, &m.incomingDenyIndex
+	}
 
-	r, ok := rule.(*PeerRule)
+	trimmed, stored, ok := removeRuleByID(*target, r.id)
 	if !ok {
-		return fmt.Errorf("delete rule: invalid rule type: %T", rule)
-	}
-
-	var sourceMap map[netip.Addr]RuleSet
-	if r.drop {
-		sourceMap = m.incomingDenyRules
-	} else {
-		sourceMap = m.incomingRules
-	}
-
-	if ruleset, ok := sourceMap[r.ip]; ok {
-		if _, exists := ruleset[r.id]; !exists {
-			return fmt.Errorf("delete rule: no rule with such id: %v", r.id)
-		}
-		delete(ruleset, r.id)
-		if len(ruleset) == 0 {
-			delete(sourceMap, r.ip)
-		}
-	} else {
 		return fmt.Errorf("delete rule: no rule with such id: %v", r.id)
 	}
-
+	*target = trimmed
+	index.remove(stored)
+	delete(m.peerRulesMap, r.id)
 	return nil
 }
 
-// SetLegacyManagement doesn't need to be implemented for this manager
+// removeRuleByID removes the first rule whose id matches ruleID from
-func (m *Manager) SetLegacyManagement(isLegacy bool) error {
+// rules, preserving order. It returns the trimmed slice, the removed
-	if m.nativeFirewall == nil {
+// rule, and whether a match was found.
-		return nil
+func removeRuleByID[S ~[]T, T firewall.Rule](rules S, ruleID firewall.RuleID) (S, T, bool) {
+	idx := slices.IndexFunc(rules, func(r T) bool { return r.ID() == ruleID })
+	var removed T
+	if idx < 0 {
+		return rules, removed, false
 	}
-	return m.nativeFirewall.SetLegacyManagement(isLegacy)
+	removed = rules[idx]
+	return slices.Delete(rules, idx, idx+1), removed, true
+}
+
+// SetLegacyManagement is a no-op for the userspace firewall: it only matters
+// when an old management server can't send route firewall rules, which the
+// userspace router doesn't rely on.
+func (m *Manager) SetLegacyManagement(bool) error {
+	return nil
 }
 
 // Flush doesn't need to be implemented for this manager
@@ -713,11 +838,14 @@ func (m *Manager) Flush() error { return nil }
 // resetState clears all firewall rules and closes connection trackers.
 // Must be called with m.mutex held.
 func (m *Manager) resetState() {
-	clear(m.outgoingRules)
+	m.incomingDenyRules = m.incomingDenyRules[:0]
-	clear(m.incomingDenyRules)
+	m.incomingAcceptRules = m.incomingAcceptRules[:0]
-	clear(m.incomingRules)
+	m.incomingDenyIndex.reset()
+	m.incomingAcceptIndex.reset()
+	clear(m.peerRulesMap)
 	clear(m.routeRulesMap)
 	m.routeRules = m.routeRules[:0]
+	m.blockRules = nil
 	m.udpHookOut.Store(nil)
 	m.tcpHookOut.Store(nil)
 
@@ -751,21 +879,15 @@ func (m *Manager) resetState() {
 	}
 }
 
-// SetupEBPFProxyNoTrack creates notrack rules for eBPF proxy loopback traffic.
+// SetupEBPFProxyNoTrack is not supported by the userspace firewall: eBPF isn't
-func (m *Manager) SetupEBPFProxyNoTrack(proxyPort, wgPort uint16) error {
+// used in userspace mode, so this should never be called.
-	if m.nativeFirewall == nil {
+func (m *Manager) SetupEBPFProxyNoTrack(uint16, uint16) error {
-		return nil
+	return errNotSupported
-	}
-	return m.nativeFirewall.SetupEBPFProxyNoTrack(proxyPort, wgPort)
 }
 
 // UpdateSet updates the rule destinations associated with the given set
 // by merging the existing prefixes with the new ones, then deduplicating.
 func (m *Manager) UpdateSet(set firewall.Set, prefixes []netip.Prefix) error {
-	if m.nativeRouter.Load() && m.nativeFirewall != nil {
-		return m.nativeFirewall.UpdateSet(set, prefixes)
-	}
-
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
@@ -863,11 +985,11 @@ func (m *Manager) extractIPs(d *decoder) (srcIP, dstIP netip.Addr) {
 	case layers.LayerTypeIPv4:
 		src, _ := netip.AddrFromSlice(d.ip4.SrcIP)
 		dst, _ := netip.AddrFromSlice(d.ip4.DstIP)
-		return src, dst
+		return src.Unmap(), dst.Unmap()
 	case layers.LayerTypeIPv6:
 		src, _ := netip.AddrFromSlice(d.ip6.SrcIP)
 		dst, _ := netip.AddrFromSlice(d.ip6.DstIP)
-		return src, dst
+		return src.Unmap(), dst.Unmap()
 	default:
 		return netip.Addr{}, netip.Addr{}
 	}
@@ -1622,20 +1744,12 @@ func (m *Manager) peerACLsBlock(srcIP netip.Addr, d *decoder, packetData []byte)
 		return nil, false
 	}
 
-	if mgmtId, filter, ok := validateRule(srcIP, packetData, m.incomingDenyRules[srcIP], d); ok {
+	if mgmtId, filter, ok := m.incomingDenyIndex.match(srcIP, d); ok {
 		return mgmtId, filter
 	}
-
+	if mgmtId, filter, ok := m.incomingAcceptIndex.match(srcIP, d); ok {
-	if mgmtId, filter, ok := validateRule(srcIP, packetData, m.incomingRules[srcIP], d); ok {
 		return mgmtId, filter
 	}
-	if mgmtId, filter, ok := validateRule(srcIP, packetData, m.incomingRules[netip.IPv4Unspecified()], d); ok {
-		return mgmtId, filter
-	}
-	if mgmtId, filter, ok := validateRule(srcIP, packetData, m.incomingRules[netip.IPv6Unspecified()], d); ok {
-		return mgmtId, filter
-	}
-
 	return nil, true
 }
 
@@ -1656,39 +1770,6 @@ func portsMatch(rulePort *firewall.Port, packetPort uint16) bool {
 	return false
 }
 
-func validateRule(ip netip.Addr, packetData []byte, rules map[string]PeerRule, d *decoder) ([]byte, bool, bool) {
-	payloadLayer := d.decoded[1]
-
-	for _, rule := range rules {
-		if rule.matchByIP && ip.Compare(rule.ip) != 0 {
-			continue
-		}
-
-		if rule.protoLayer == layerTypeAll {
-			return rule.mgmtId, rule.drop, true
-		}
-
-		if !protoLayerMatches(rule.protoLayer, payloadLayer) {
-			continue
-		}
-
-		switch payloadLayer {
-		case layers.LayerTypeTCP:
-			if portsMatch(rule.sPort, uint16(d.tcp.SrcPort)) && portsMatch(rule.dPort, uint16(d.tcp.DstPort)) {
-				return rule.mgmtId, rule.drop, true
-			}
-		case layers.LayerTypeUDP:
-			if portsMatch(rule.sPort, uint16(d.udp.SrcPort)) && portsMatch(rule.dPort, uint16(d.udp.DstPort)) {
-				return rule.mgmtId, rule.drop, true
-			}
-		case layers.LayerTypeICMPv4, layers.LayerTypeICMPv6:
-			return rule.mgmtId, rule.drop, true
-		}
-	}
-
-	return nil, false, false
-}
-
 // routeACLsPass returns true if the packet is allowed by the route ACLs
 func (m *Manager) routeACLsPass(srcIP, dstIP netip.Addr, protoLayer gopacket.LayerType, srcPort, dstPort uint16) ([]byte, bool) {
 	m.mutex.RLock()
@@ -1765,10 +1846,13 @@ func (m *Manager) EnableRouting() error {
 	}
 
 	rules, err := m.blockInvalidRouted(m.wgIface)
-	// Persist whatever was installed even on partial failure, so DisableRouting
-	// can clean it up later.
 	m.blockRules = rules
 	if err != nil {
+		// Roll back so forwarding can't stay active without the full set of
+		// block rules.
+		if derr := m.disableRouting(); derr != nil {
+			log.Warnf("roll back routing after block rule failure: %v", derr)
+		}
 		return fmt.Errorf("block invalid routed: %w", err)
 	}
 
@@ -1779,6 +1863,10 @@ func (m *Manager) DisableRouting() error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
+	return m.disableRouting()
+}
+
+func (m *Manager) disableRouting() error {
 	fwder := m.forwarder.Load()
 	if fwder == nil {
 		return nil

client/firewall/uspfilter/filter_bench_test.go

@@ -94,7 +94,7 @@ func BenchmarkCoreFiltering(b *testing.B) {
 			stateful: false,
 			setupFunc: func(m *Manager) {
 				// Single rule allowing all traffic
-				_, err := m.AddPeerFiltering(nil, net.ParseIP("0.0.0.0"), fw.ProtocolALL, nil, nil, fw.ActionAccept, "")
+				_, err := m.AddFilterRule(nil, pfx(net.ParseIP("0.0.0.0")), fw.Network{}, fw.ProtocolALL, nil, nil, fw.ActionAccept)
 				require.NoError(b, err)
 			},
 			desc: "Baseline: Single 'allow all' rule without connection tracking",
@@ -114,15 +114,13 @@ func BenchmarkCoreFiltering(b *testing.B) {
 				// Add explicit rules matching return traffic pattern
 				for i := 0; i < 1000; i++ { // Simulate realistic ruleset size
 					ip := generateRandomIPs(1)[0]
-					_, err := m.AddPeerFiltering(
+					_, err := m.AddFilterRule(
 						nil,
-						ip,
+						pfx(ip), fw.Network{},
 						fw.ProtocolTCP,
 						&fw.Port{Values: []uint16{uint16(1024 + i)}},
 						&fw.Port{Values: []uint16{80}},
-						fw.ActionAccept,
+						fw.ActionAccept)
-						"",
-					)
 					require.NoError(b, err)
 				}
 			},
@@ -133,15 +131,13 @@ func BenchmarkCoreFiltering(b *testing.B) {
 			stateful: true,
 			setupFunc: func(m *Manager) {
 				// Add some basic rules but rely on state for established connections
-				_, err := m.AddPeerFiltering(
+				_, err := m.AddFilterRule(
 					nil,
-					net.ParseIP("0.0.0.0"),
+					pfx(net.ParseIP("0.0.0.0")), fw.Network{},
 					fw.ProtocolTCP,
 					nil,
 					nil,
-					fw.ActionDrop,
+					fw.ActionDrop)
-					"",
-				)
 				require.NoError(b, err)
 			},
 			desc: "Connection tracking with established connections",
@@ -168,9 +164,12 @@ func BenchmarkCoreFiltering(b *testing.B) {
 				}
 
 				// Create manager and basic setup
-				manager, _ := Create(&IFaceMock{
+				manager, err := Create(Config{
-					SetFilterFunc: func(device.PacketFilter) error { return nil },
+					IFace: &IFaceMock{
-				}, false, flowLogger, iface.DefaultMTU)
+						SetFilterFunc: func(device.PacketFilter) error { return nil },
+					},
+					FlowLogger: flowLogger, MTU: iface.DefaultMTU})
+				require.NoError(b, err)
 				defer b.Cleanup(func() {
 					require.NoError(b, manager.Close(nil))
 				})
@@ -208,9 +207,12 @@ func BenchmarkStateScaling(b *testing.B) {
 
 	for _, count := range connCounts {
 		b.Run(fmt.Sprintf("conns_%d", count), func(b *testing.B) {
-			manager, _ := Create(&IFaceMock{
+			manager, err := Create(Config{
-				SetFilterFunc: func(device.PacketFilter) error { return nil },
+				IFace: &IFaceMock{
-			}, false, flowLogger, iface.DefaultMTU)
+					SetFilterFunc: func(device.PacketFilter) error { return nil },
+				},
+				FlowLogger: flowLogger, MTU: iface.DefaultMTU})
+			require.NoError(b, err)
 			b.Cleanup(func() {
 				require.NoError(b, manager.Close(nil))
 			})
@@ -251,9 +253,12 @@ func BenchmarkEstablishmentOverhead(b *testing.B) {
 
 	for _, sc := range scenarios {
 		b.Run(sc.name, func(b *testing.B) {
-			manager, _ := Create(&IFaceMock{
+			manager, err := Create(Config{
-				SetFilterFunc: func(device.PacketFilter) error { return nil },
+				IFace: &IFaceMock{
-			}, false, flowLogger, iface.DefaultMTU)
+					SetFilterFunc: func(device.PacketFilter) error { return nil },
+				},
+				FlowLogger: flowLogger, MTU: iface.DefaultMTU})
+			require.NoError(b, err)
 			b.Cleanup(func() {
 				require.NoError(b, manager.Close(nil))
 			})
@@ -409,9 +414,12 @@ func BenchmarkRoutedNetworkReturn(b *testing.B) {
 
 	for _, sc := range scenarios {
 		b.Run(sc.name, func(b *testing.B) {
-			manager, _ := Create(&IFaceMock{
+			manager, err := Create(Config{
-				SetFilterFunc: func(device.PacketFilter) error { return nil },
+				IFace: &IFaceMock{
-			}, false, flowLogger, iface.DefaultMTU)
+					SetFilterFunc: func(device.PacketFilter) error { return nil },
+				},
+				FlowLogger: flowLogger, MTU: iface.DefaultMTU})
+			require.NoError(b, err)
 			b.Cleanup(func() {
 				require.NoError(b, manager.Close(nil))
 			})
@@ -536,9 +544,12 @@ func BenchmarkLongLivedConnections(b *testing.B) {
 				require.NoError(b, os.Unsetenv("NB_DISABLE_CONNTRACK"))
 			}
 
-			manager, _ := Create(&IFaceMock{
+			manager, err := Create(Config{
-				SetFilterFunc: func(device.PacketFilter) error { return nil },
+				IFace: &IFaceMock{
-			}, false, flowLogger, iface.DefaultMTU)
+					SetFilterFunc: func(device.PacketFilter) error { return nil },
+				},
+				FlowLogger: flowLogger, MTU: iface.DefaultMTU})
+			require.NoError(b, err)
 			defer b.Cleanup(func() {
 				require.NoError(b, manager.Close(nil))
 			})
@@ -546,7 +557,7 @@ func BenchmarkLongLivedConnections(b *testing.B) {
 			// Setup initial state based on scenario
 			if sc.rules {
 				// Single rule to allow all return traffic from port 80
-				_, err := manager.AddPeerFiltering(nil, net.ParseIP("0.0.0.0"), fw.ProtocolTCP, &fw.Port{Values: []uint16{80}}, nil, fw.ActionAccept, "")
+				_, err := manager.AddFilterRule(nil, pfx(net.ParseIP("0.0.0.0")), fw.Network{}, fw.ProtocolTCP, &fw.Port{Values: []uint16{80}}, nil, fw.ActionAccept)
 				require.NoError(b, err)
 			}
 
@@ -619,9 +630,12 @@ func BenchmarkShortLivedConnections(b *testing.B) {
 				require.NoError(b, os.Unsetenv("NB_DISABLE_CONNTRACK"))
 			}
 
-			manager, _ := Create(&IFaceMock{
+			manager, err := Create(Config{
-				SetFilterFunc: func(device.PacketFilter) error { return nil },
+				IFace: &IFaceMock{
-			}, false, flowLogger, iface.DefaultMTU)
+					SetFilterFunc: func(device.PacketFilter) error { return nil },
+				},
+				FlowLogger: flowLogger, MTU: iface.DefaultMTU})
+			require.NoError(b, err)
 			defer b.Cleanup(func() {
 				require.NoError(b, manager.Close(nil))
 			})
@@ -629,7 +643,7 @@ func BenchmarkShortLivedConnections(b *testing.B) {
 			// Setup initial state based on scenario
 			if sc.rules {
 				// Single rule to allow all return traffic from port 80
-				_, err := manager.AddPeerFiltering(nil, net.ParseIP("0.0.0.0"), fw.ProtocolTCP, &fw.Port{Values: []uint16{80}}, nil, fw.ActionAccept, "")
+				_, err := manager.AddFilterRule(nil, pfx(net.ParseIP("0.0.0.0")), fw.Network{}, fw.ProtocolTCP, &fw.Port{Values: []uint16{80}}, nil, fw.ActionAccept)
 				require.NoError(b, err)
 			}
 
@@ -730,16 +744,19 @@ func BenchmarkParallelLongLivedConnections(b *testing.B) {
 				require.NoError(b, os.Unsetenv("NB_DISABLE_CONNTRACK"))
 			}
 
-			manager, _ := Create(&IFaceMock{
+			manager, err := Create(Config{
-				SetFilterFunc: func(device.PacketFilter) error { return nil },
+				IFace: &IFaceMock{
-			}, false, flowLogger, iface.DefaultMTU)
+					SetFilterFunc: func(device.PacketFilter) error { return nil },
+				},
+				FlowLogger: flowLogger, MTU: iface.DefaultMTU})
+			require.NoError(b, err)
 			defer b.Cleanup(func() {
 				require.NoError(b, manager.Close(nil))
 			})
 
 			// Setup initial state based on scenario
 			if sc.rules {
-				_, err := manager.AddPeerFiltering(nil, net.ParseIP("0.0.0.0"), fw.ProtocolTCP, &fw.Port{Values: []uint16{80}}, nil, fw.ActionAccept, "")
+				_, err := manager.AddFilterRule(nil, pfx(net.ParseIP("0.0.0.0")), fw.Network{}, fw.ProtocolTCP, &fw.Port{Values: []uint16{80}}, nil, fw.ActionAccept)
 				require.NoError(b, err)
 			}
 
@@ -810,15 +827,18 @@ func BenchmarkParallelShortLivedConnections(b *testing.B) {
 				require.NoError(b, os.Unsetenv("NB_DISABLE_CONNTRACK"))
 			}
 
-			manager, _ := Create(&IFaceMock{
+			manager, err := Create(Config{
-				SetFilterFunc: func(device.PacketFilter) error { return nil },
+				IFace: &IFaceMock{
-			}, false, flowLogger, iface.DefaultMTU)
+					SetFilterFunc: func(device.PacketFilter) error { return nil },
+				},
+				FlowLogger: flowLogger, MTU: iface.DefaultMTU})
+			require.NoError(b, err)
 			defer b.Cleanup(func() {
 				require.NoError(b, manager.Close(nil))
 			})
 
 			if sc.rules {
-				_, err := manager.AddPeerFiltering(nil, net.ParseIP("0.0.0.0"), fw.ProtocolTCP, &fw.Port{Values: []uint16{80}}, nil, fw.ActionAccept, "")
+				_, err := manager.AddFilterRule(nil, pfx(net.ParseIP("0.0.0.0")), fw.Network{}, fw.ProtocolTCP, &fw.Port{Values: []uint16{80}}, nil, fw.ActionAccept)
 				require.NoError(b, err)
 			}
 
@@ -931,7 +951,7 @@ func BenchmarkRouteACLs(b *testing.B) {
 
 	for _, r := range rules {
 		dst := fw.Network{Prefix: r.dest}
-		_, err := manager.AddRouteFiltering(nil, r.sources, dst, r.proto, nil, r.port, fw.ActionAccept)
+		_, err := manager.AddFilterRule(nil, r.sources, dst, r.proto, nil, r.port, fw.ActionAccept)
 		if err != nil {
 			b.Fatal(err)
 		}
@@ -1014,9 +1034,11 @@ func BenchmarkMSSClamping(b *testing.B) {
 
 	for _, sc := range scenarios {
 		b.Run(sc.name, func(b *testing.B) {
-			manager, err := Create(&IFaceMock{
+			manager, err := Create(Config{
-				SetFilterFunc: func(device.PacketFilter) error { return nil },
+				IFace: &IFaceMock{
-			}, false, flowLogger, iface.DefaultMTU)
+					SetFilterFunc: func(device.PacketFilter) error { return nil },
+				},
+				FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 			require.NoError(b, err)
 			defer func() {
 				require.NoError(b, manager.Close(nil))
@@ -1079,9 +1101,11 @@ func BenchmarkMSSClampingOverhead(b *testing.B) {
 
 	for _, sc := range scenarios {
 		b.Run(sc.name, func(b *testing.B) {
-			manager, err := Create(&IFaceMock{
+			manager, err := Create(Config{
-				SetFilterFunc: func(device.PacketFilter) error { return nil },
+				IFace: &IFaceMock{
-			}, false, flowLogger, iface.DefaultMTU)
+					SetFilterFunc: func(device.PacketFilter) error { return nil },
+				},
+				FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 			require.NoError(b, err)
 			defer func() {
 				require.NoError(b, manager.Close(nil))
@@ -1134,9 +1158,11 @@ func BenchmarkMSSClampingMemory(b *testing.B) {
 
 	for _, sc := range scenarios {
 		b.Run(sc.name, func(b *testing.B) {
-			manager, err := Create(&IFaceMock{
+			manager, err := Create(Config{
-				SetFilterFunc: func(device.PacketFilter) error { return nil },
+				IFace: &IFaceMock{
-			}, false, flowLogger, iface.DefaultMTU)
+					SetFilterFunc: func(device.PacketFilter) error { return nil },
+				},
+				FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 			require.NoError(b, err)
 			defer func() {
 				require.NoError(b, manager.Close(nil))

client/firewall/uspfilter/filter_filter_test.go

@@ -32,7 +32,7 @@ func TestPeerACLFiltering(t *testing.T) {
 		},
 	}
 
-	manager, err := Create(ifaceMock, false, flowLogger, iface.DefaultMTU)
+	manager, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 	require.NoError(t, err)
 	require.NotNil(t, manager)
 
@@ -496,40 +496,32 @@ func TestPeerACLFiltering(t *testing.T) {
 		t.Run(tc.name, func(t *testing.T) {
 			if tc.ruleAction == fw.ActionDrop {
 				// add general accept rule for the same IP to test drop rule precedence
-				rules, err := manager.AddPeerFiltering(
+				rules, err := manager.AddFilterRule(
 					nil,
-					net.ParseIP(tc.ruleIP),
+					pfx(net.ParseIP(tc.ruleIP)), fw.Network{},
 					fw.ProtocolALL,
 					nil,
 					nil,
-					fw.ActionAccept,
+					fw.ActionAccept)
-					"",
-				)
 				require.NoError(t, err)
-				require.NotEmpty(t, rules)
+				require.NotNil(t, rules)
 				t.Cleanup(func() {
-					for _, rule := range rules {
+					require.NoError(t, manager.DeleteFilterRule(rules))
-						require.NoError(t, manager.DeletePeerRule(rule))
-					}
 				})
 			}
 
-			rules, err := manager.AddPeerFiltering(
+			rules, err := manager.AddFilterRule(
 				nil,
-				net.ParseIP(tc.ruleIP),
+				pfx(net.ParseIP(tc.ruleIP)), fw.Network{},
 				tc.ruleProto,
 				tc.ruleSrcPort,
 				tc.ruleDstPort,
-				tc.ruleAction,
+				tc.ruleAction)
-				"",
-			)
 			require.NoError(t, err)
-			require.NotEmpty(t, rules)
+			require.NotNil(t, rules)
 
 			t.Cleanup(func() {
-				for _, rule := range rules {
+				require.NoError(t, manager.DeleteFilterRule(rules))
-					require.NoError(t, manager.DeletePeerRule(rule))
-				}
 			})
 
 			packet := createTestPacket(t, tc.srcIP, tc.dstIP, tc.proto, tc.srcPort, tc.dstPort)
@@ -557,7 +549,7 @@ func TestPeerACLFilteringIPv6(t *testing.T) {
 		},
 	}
 
-	manager, err := Create(ifaceMock, false, flowLogger, iface.DefaultMTU)
+	manager, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 	require.NoError(t, err)
 	t.Cleanup(func() { require.NoError(t, manager.Close(nil)) })
 
@@ -652,14 +644,24 @@ func TestPeerACLFilteringIPv6(t *testing.T) {
 			shouldBeBlocked: false,
 		},
 		{
-			name:            "IPv6: v4 wildcard ICMP rule matches ICMPv6 via protoLayerMatches",
+			name:            "IPv6: v4 wildcard ICMP rule does not match ICMPv6",
 			srcIP:           "fd00::1",
 			dstIP:           "fd00::100",
 			proto:           fw.ProtocolICMP,
 			ruleIP:          "0.0.0.0",
 			ruleProto:       fw.ProtocolICMP,
 			ruleAction:      fw.ActionAccept,
-			shouldBeBlocked: false,
+			shouldBeBlocked: true,
+		},
+		{
+			name:            "IPv4: v6 wildcard ICMP rule does not match ICMPv4",
+			srcIP:           "100.10.0.1",
+			dstIP:           "100.10.0.100",
+			proto:           fw.ProtocolICMP,
+			ruleIP:          "::",
+			ruleProto:       fw.ProtocolICMP,
+			ruleAction:      fw.ActionAccept,
+			shouldBeBlocked: true,
 		},
 	}
 
@@ -672,22 +674,18 @@ func TestPeerACLFilteringIPv6(t *testing.T) {
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
 			if tc.ruleAction == fw.ActionDrop {
-				rules, err := manager.AddPeerFiltering(nil, net.ParseIP(tc.ruleIP), fw.ProtocolALL, nil, nil, fw.ActionAccept, "")
+				rules, err := manager.AddFilterRule(nil, pfx(net.ParseIP(tc.ruleIP)), fw.Network{}, fw.ProtocolALL, nil, nil, fw.ActionAccept)
 				require.NoError(t, err)
 				t.Cleanup(func() {
-					for _, rule := range rules {
+					require.NoError(t, manager.DeleteFilterRule(rules))
-						require.NoError(t, manager.DeletePeerRule(rule))
-					}
 				})
 			}
 
-			rules, err := manager.AddPeerFiltering(nil, net.ParseIP(tc.ruleIP), tc.ruleProto, nil, tc.ruleDstPort, tc.ruleAction, "")
+			rules, err := manager.AddFilterRule(nil, pfx(net.ParseIP(tc.ruleIP)), fw.Network{}, tc.ruleProto, nil, tc.ruleDstPort, tc.ruleAction)
 			require.NoError(t, err)
-			require.NotEmpty(t, rules)
+			require.NotNil(t, rules)
 			t.Cleanup(func() {
-				for _, rule := range rules {
+				require.NoError(t, manager.DeleteFilterRule(rules))
-					require.NoError(t, manager.DeletePeerRule(rule))
-				}
 			})
 
 			packet := createTestPacket(t, tc.srcIP, tc.dstIP, tc.proto, tc.srcPort, tc.dstPort)
@@ -800,7 +798,7 @@ func setupRoutedManager(tb testing.TB, network string) *Manager {
 		},
 	}
 
-	manager, err := Create(ifaceMock, false, flowLogger, iface.DefaultMTU)
+	manager, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 	require.NoError(tb, err)
 	require.NoError(tb, manager.EnableRouting())
 	require.NotNil(tb, manager)
@@ -1405,7 +1403,7 @@ func TestRouteACLFiltering(t *testing.T) {
 		t.Run(tc.name, func(t *testing.T) {
 			if tc.rule.action == fw.ActionDrop {
 				// add general accept rule to test drop rule
-				rule, err := manager.AddRouteFiltering(
+				rule, err := manager.AddFilterRule(
 					nil,
 					[]netip.Prefix{netip.MustParsePrefix("0.0.0.0/0")},
 					fw.Network{Prefix: netip.MustParsePrefix("0.0.0.0/0")},
@@ -1415,13 +1413,13 @@ func TestRouteACLFiltering(t *testing.T) {
 					fw.ActionAccept,
 				)
 				require.NoError(t, err)
-				require.NotNil(t, rule)
+				require.NotEmpty(t, rule)
 				t.Cleanup(func() {
-					require.NoError(t, manager.DeleteRouteRule(rule))
+					require.NoError(t, manager.DeleteFilterRule(rule))
 				})
 			}
 
-			rule, err := manager.AddRouteFiltering(
+			rule, err := manager.AddFilterRule(
 				nil,
 				tc.rule.sources,
 				tc.rule.dest,
@@ -1431,10 +1429,10 @@ func TestRouteACLFiltering(t *testing.T) {
 				tc.rule.action,
 			)
 			require.NoError(t, err)
-			require.NotNil(t, rule)
+			require.NotEmpty(t, rule)
 
 			t.Cleanup(func() {
-				require.NoError(t, manager.DeleteRouteRule(rule))
+				require.NoError(t, manager.DeleteFilterRule(rule))
 			})
 
 			srcIP := netip.MustParseAddr(tc.srcIP)
@@ -1602,9 +1600,9 @@ func TestRouteACLOrder(t *testing.T) {
 
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
-			var rules []fw.Rule
+			var addedRules []fw.Rule
 			for _, r := range tc.rules {
-				rule, err := manager.AddRouteFiltering(
+				rule, err := manager.AddFilterRule(
 					nil,
 					r.sources,
 					r.dest,
@@ -1615,12 +1613,12 @@ func TestRouteACLOrder(t *testing.T) {
 				)
 				require.NoError(t, err)
 				require.NotNil(t, rule)
-				rules = append(rules, rule)
+				addedRules = append(addedRules, rule)
 			}
 
 			t.Cleanup(func() {
-				for _, rule := range rules {
+				for _, rule := range addedRules {
-					require.NoError(t, manager.DeleteRouteRule(rule))
+					require.NoError(t, manager.DeleteFilterRule(rule))
 				}
 			})
 
@@ -1646,7 +1644,7 @@ func TestRouteACLSet(t *testing.T) {
 		},
 	}
 
-	manager, err := Create(ifaceMock, false, flowLogger, iface.DefaultMTU)
+	manager, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 	require.NoError(t, err)
 	t.Cleanup(func() {
 		require.NoError(t, manager.Close(nil))
@@ -1655,7 +1653,7 @@ func TestRouteACLSet(t *testing.T) {
 	set := fw.NewDomainSet(domain.List{"example.org"})
 
 	// Add rule that uses the set (initially empty)
-	rule, err := manager.AddRouteFiltering(
+	rule, err := manager.AddFilterRule(
 		nil,
 		[]netip.Prefix{netip.MustParsePrefix("0.0.0.0/0")},
 		fw.Network{Set: set},
@@ -1689,7 +1687,7 @@ func TestRouteACLFilteringIPv6(t *testing.T) {
 	manager := setupRoutedManager(t, "10.10.0.100/16")
 
 	v6Dst := netip.MustParsePrefix("fd00:dead:beef::/48")
-	_, err := manager.AddRouteFiltering(
+	_, err := manager.AddFilterRule(
 		nil,
 		[]netip.Prefix{netip.MustParsePrefix("fd00::/16")},
 		fw.Network{Prefix: v6Dst},
@@ -1700,7 +1698,7 @@ func TestRouteACLFilteringIPv6(t *testing.T) {
 	)
 	require.NoError(t, err)
 
-	_, err = manager.AddRouteFiltering(
+	_, err = manager.AddFilterRule(
 		nil,
 		[]netip.Prefix{netip.MustParsePrefix("fd00::/16")},
 		fw.Network{Prefix: netip.MustParsePrefix("fd00:dead:beef:1::/64")},

client/firewall/uspfilter/filter_routeacl_test.go

@@ -29,7 +29,7 @@ func TestAddRouteFilteringReturnsExistingRule(t *testing.T) {
 	destination := fw.Network{Prefix: netip.MustParsePrefix("192.168.1.0/24")}
 
 	// Add rule first time
-	rule1, err := manager.AddRouteFiltering(
+	rule1, err := manager.AddFilterRule(
 		[]byte("policy-1"),
 		sources,
 		destination,
@@ -42,7 +42,7 @@ func TestAddRouteFilteringReturnsExistingRule(t *testing.T) {
 	require.NotNil(t, rule1)
 
 	// Add the same rule again
-	rule2, err := manager.AddRouteFiltering(
+	rule2, err := manager.AddFilterRule(
 		[]byte("policy-1"),
 		sources,
 		destination,
@@ -74,7 +74,7 @@ func TestAddRouteFilteringDifferentRulesGetDifferentIDs(t *testing.T) {
 	sources := []netip.Prefix{netip.MustParsePrefix("100.64.1.0/24")}
 
 	// Add first rule
-	rule1, err := manager.AddRouteFiltering(
+	rule1, err := manager.AddFilterRule(
 		[]byte("policy-1"),
 		sources,
 		fw.Network{Prefix: netip.MustParsePrefix("192.168.1.0/24")},
@@ -86,7 +86,7 @@ func TestAddRouteFilteringDifferentRulesGetDifferentIDs(t *testing.T) {
 	require.NoError(t, err)
 
 	// Add different rule (different destination)
-	rule2, err := manager.AddRouteFiltering(
+	rule2, err := manager.AddFilterRule(
 		[]byte("policy-2"),
 		sources,
 		fw.Network{Prefix: netip.MustParsePrefix("192.168.2.0/24")}, // Different!
@@ -115,7 +115,7 @@ func TestRouteRuleUpdateDoesNotCauseGap(t *testing.T) {
 	sources := []netip.Prefix{netip.MustParsePrefix("100.64.1.0/24")}
 	destination := fw.Network{Prefix: netip.MustParsePrefix("192.168.1.0/24")}
 
-	rule1, err := manager.AddRouteFiltering(
+	rule1, err := manager.AddFilterRule(
 		[]byte("policy-1"),
 		sources,
 		destination,
@@ -132,7 +132,7 @@ func TestRouteRuleUpdateDoesNotCauseGap(t *testing.T) {
 	require.True(t, pass, "Traffic should pass with rule in place")
 
 	// Re-add same rule (simulates network map update)
-	rule2, err := manager.AddRouteFiltering(
+	rule2, err := manager.AddFilterRule(
 		[]byte("policy-1"),
 		sources,
 		destination,
@@ -147,7 +147,7 @@ func TestRouteRuleUpdateDoesNotCauseGap(t *testing.T) {
 	// won't delete rule1 during cleanup. If IDs differed, deleting rule1
 	// would remove the only matching rule and cause a traffic gap.
 	if rule1.ID() != rule2.ID() {
-		err = manager.DeleteRouteRule(rule1)
+		err = manager.DeleteFilterRule(rule1)
 		require.NoError(t, err)
 	}
 
@@ -156,6 +156,59 @@ func TestRouteRuleUpdateDoesNotCauseGap(t *testing.T) {
 		"Traffic should still pass after rule update - no gap should occur")
 }
 
+// TestBlockInvalidRoutedDualStack verifies that when the interface has an
+// IPv6 overlay address, blockInvalidRouted installs a block rule for both
+// the v4 and v6 WG prefixes and that routed traffic to the v6 prefix is
+// denied. The v4-only soft-skip path is covered by
+// TestBlockInvalidRoutedIdempotent, whose mock leaves IPv6Net invalid.
+func TestBlockInvalidRoutedDualStack(t *testing.T) {
+	ctrl := gomock.NewController(t)
+	dev := mocks.NewMockDevice(ctrl)
+	dev.EXPECT().MTU().Return(1500, nil).AnyTimes()
+
+	wgNet := netip.MustParsePrefix("100.64.0.1/16")
+	wgNet6 := netip.MustParsePrefix("fd00:1234::1/64")
+
+	ifaceMock := &IFaceMock{
+		SetFilterFunc: func(device.PacketFilter) error { return nil },
+		AddressFunc: func() wgaddr.Address {
+			return wgaddr.Address{
+				IP:      wgNet.Addr(),
+				Network: wgNet,
+				IPv6:    wgNet6.Addr(),
+				IPv6Net: wgNet6,
+			}
+		},
+		GetDeviceFunc: func() *device.FilteredDevice {
+			return &device.FilteredDevice{Device: dev}
+		},
+		GetWGDeviceFunc: func() *wgdevice.Device {
+			return &wgdevice.Device{}
+		},
+	}
+
+	manager, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: iface.DefaultMTU})
+	require.NoError(t, err)
+	t.Cleanup(func() {
+		require.NoError(t, manager.Close(nil))
+	})
+
+	rules, err := manager.blockInvalidRouted(ifaceMock)
+	require.NoError(t, err)
+	require.Len(t, rules, 2, "dual-stack interface must produce a v4 and a v6 block rule")
+
+	manager.mutex.RLock()
+	ruleCount := len(manager.routeRules)
+	manager.mutex.RUnlock()
+	assert.Equal(t, 2, ruleCount, "should have one block rule per family")
+
+	// v6 routed traffic to the WG prefix must be denied.
+	srcIP := netip.MustParseAddr("2001:db8::1")
+	dstIP := netip.MustParseAddr("fd00:1234::50")
+	_, pass := manager.routeACLsPass(srcIP, dstIP, layers.LayerTypeTCP, 12345, 80)
+	assert.False(t, pass, "block rule should deny routed traffic to the v6 WG prefix")
+}
+
 // TestBlockInvalidRoutedIdempotent verifies that blockInvalidRouted creates
 // exactly one drop rule for the WireGuard network prefix, and calling it again
 // returns the same rule without duplicating.
@@ -182,7 +235,7 @@ func TestBlockInvalidRoutedIdempotent(t *testing.T) {
 		},
 	}
 
-	manager, err := Create(ifaceMock, false, flowLogger, iface.DefaultMTU)
+	manager, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 	require.NoError(t, err)
 	t.Cleanup(func() {
 		require.NoError(t, manager.Close(nil))
@@ -245,7 +298,7 @@ func TestBlockRuleNotAccumulatedOnRepeatedEnableRouting(t *testing.T) {
 		},
 	}
 
-	manager, err := Create(ifaceMock, false, flowLogger, iface.DefaultMTU)
+	manager, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 	require.NoError(t, err)
 	t.Cleanup(func() {
 		require.NoError(t, manager.Close(nil))
@@ -274,7 +327,7 @@ func TestRouteRuleCountStableAcrossUpdates(t *testing.T) {
 
 	// Simulate 5 network map updates with the same route rule
 	for i := 0; i < 5; i++ {
-		rule, err := manager.AddRouteFiltering(
+		rule, err := manager.AddFilterRule(
 			[]byte("policy-1"),
 			sources,
 			destination,
@@ -304,7 +357,7 @@ func TestDeleteRouteRuleAfterIdempotentAdd(t *testing.T) {
 	destination := fw.Network{Prefix: netip.MustParsePrefix("192.168.1.0/24")}
 
 	// Add same rule twice
-	rule1, err := manager.AddRouteFiltering(
+	rule1, err := manager.AddFilterRule(
 		[]byte("policy-1"),
 		sources,
 		destination,
@@ -315,7 +368,7 @@ func TestDeleteRouteRuleAfterIdempotentAdd(t *testing.T) {
 	)
 	require.NoError(t, err)
 
-	rule2, err := manager.AddRouteFiltering(
+	rule2, err := manager.AddFilterRule(
 		[]byte("policy-1"),
 		sources,
 		destination,
@@ -329,7 +382,7 @@ func TestDeleteRouteRuleAfterIdempotentAdd(t *testing.T) {
 	require.Equal(t, rule1.ID(), rule2.ID(), "Should return same rule ID")
 
 	// Delete using first reference
-	err = manager.DeleteRouteRule(rule1)
+	err = manager.DeleteFilterRule(rule1)
 	require.NoError(t, err)
 
 	// Verify traffic no longer passes
@@ -364,7 +417,7 @@ func setupTestManager(t *testing.T) *Manager {
 		},
 	}
 
-	manager, err := Create(ifaceMock, false, flowLogger, iface.DefaultMTU)
+	manager, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 	require.NoError(t, err)
 	require.NoError(t, manager.EnableRouting())
 

client/firewall/uspfilter/filter_test.go

@@ -78,18 +78,19 @@ func TestManagerCreate(t *testing.T) {
 		SetFilterFunc: func(device.PacketFilter) error { return nil },
 	}
 
-	m, err := Create(ifaceMock, false, flowLogger, nbiface.DefaultMTU)
+	m, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
 	if err != nil {
 		t.Errorf("failed to create Manager: %v", err)
 		return
 	}
+	t.Cleanup(func() { require.NoError(t, m.Close(nil)) })
 
 	if m == nil {
 		t.Error("Manager is nil")
 	}
 }
 
-func TestManagerAddPeerFiltering(t *testing.T) {
+func TestManagerAddFilterRule(t *testing.T) {
 	isSetFilterCalled := false
 	ifaceMock := &IFaceMock{
 		SetFilterFunc: func(device.PacketFilter) error {
@@ -98,18 +99,19 @@ func TestManagerAddPeerFiltering(t *testing.T) {
 		},
 	}
 
-	m, err := Create(ifaceMock, false, flowLogger, nbiface.DefaultMTU)
+	m, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
 	if err != nil {
 		t.Errorf("failed to create Manager: %v", err)
 		return
 	}
+	t.Cleanup(func() { require.NoError(t, m.Close(nil)) })
 
 	ip := net.ParseIP("192.168.1.1")
 	proto := fw.ProtocolTCP
 	port := &fw.Port{Values: []uint16{80}}
 	action := fw.ActionDrop
 
-	rule, err := m.AddPeerFiltering(nil, ip, proto, nil, port, action, "")
+	rule, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, nil, port, action)
 	if err != nil {
 		t.Errorf("failed to add filtering: %v", err)
 		return
@@ -131,74 +133,47 @@ func TestManagerDeleteRule(t *testing.T) {
 		SetFilterFunc: func(device.PacketFilter) error { return nil },
 	}
 
-	m, err := Create(ifaceMock, false, flowLogger, nbiface.DefaultMTU)
+	m, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
 	if err != nil {
 		t.Errorf("failed to create Manager: %v", err)
 		return
 	}
+	t.Cleanup(func() { require.NoError(t, m.Close(nil)) })
 
 	ip := netip.MustParseAddr("192.168.1.1")
 	proto := fw.ProtocolTCP
 	port := &fw.Port{Values: []uint16{80}}
 	action := fw.ActionDrop
 
-	rule2, err := m.AddPeerFiltering(nil, ip.AsSlice(), proto, nil, port, action, "")
+	rule2, err := m.AddFilterRule(nil, pfx(ip.AsSlice()), fw.Network{}, proto, nil, port, action)
 	if err != nil {
 		t.Errorf("failed to add filtering: %v", err)
 		return
 	}
 
-	// Check rules exist in appropriate maps
+	peerRule, ok := rule2.(*PeerRule)
-	for _, r := range rule2 {
+	require.True(t, ok, "rule should be a peer rule")
-		peerRule, ok := r.(*PeerRule)
+
-		if !ok {
+	inMap := func() bool {
-			t.Errorf("rule should be a PeerRule")
+		if peerRule.action == fw.ActionDrop {
-			continue
+			return findRuleByID(m.incomingDenyRules, ip, rule2.ID())
-		}
-		// Check if rule exists in deny or allow maps based on action
-		var found bool
-		if peerRule.drop {
-			_, found = m.incomingDenyRules[ip][r.ID()]
-		} else {
-			_, found = m.incomingRules[ip][r.ID()]
-		}
-		if !found {
-			t.Errorf("rule2 is not in the expected rules map")
 		}
+		return findRuleByID(m.incomingAcceptRules, ip, rule2.ID())
 	}
 
-	for _, r := range rule2 {
+	require.True(t, inMap(), "rule2 should be in the expected rules list")
-		err = m.DeletePeerRule(r)
-		if err != nil {
-			t.Errorf("failed to delete rule: %v", err)
-			return
-		}
-	}
 
-	// Check rules are removed from appropriate maps
+	require.NoError(t, m.DeleteFilterRule(rule2), "failed to delete rule")
-	for _, r := range rule2 {
+
-		peerRule, ok := r.(*PeerRule)
+	require.False(t, inMap(), "rule2 should be removed from the rules list")
-		if !ok {
-			t.Errorf("rule should be a PeerRule")
-			continue
-		}
-		// Check if rule is removed from deny or allow maps based on action
-		var found bool
-		if peerRule.drop {
-			_, found = m.incomingDenyRules[ip][r.ID()]
-		} else {
-			_, found = m.incomingRules[ip][r.ID()]
-		}
-		if found {
-			t.Errorf("rule2 should be removed from the rules map")
-		}
-	}
 }
 
 func TestSetUDPPacketHook(t *testing.T) {
-	manager, err := Create(&IFaceMock{
+	manager, err := Create(Config{
-		SetFilterFunc: func(device.PacketFilter) error { return nil },
+		IFace: &IFaceMock{
-	}, false, flowLogger, nbiface.DefaultMTU)
+			SetFilterFunc: func(device.PacketFilter) error { return nil },
+		},
+		FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
 	require.NoError(t, err)
 	t.Cleanup(func() { require.NoError(t, manager.Close(nil)) })
 
@@ -220,9 +195,11 @@ func TestSetUDPPacketHook(t *testing.T) {
 }
 
 func TestSetTCPPacketHook(t *testing.T) {
-	manager, err := Create(&IFaceMock{
+	manager, err := Create(Config{
-		SetFilterFunc: func(device.PacketFilter) error { return nil },
+		IFace: &IFaceMock{
-	}, false, flowLogger, nbiface.DefaultMTU)
+			SetFilterFunc: func(device.PacketFilter) error { return nil },
+		},
+		FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
 	require.NoError(t, err)
 	t.Cleanup(func() { require.NoError(t, manager.Close(nil)) })
 
@@ -250,7 +227,7 @@ func TestPeerRuleLifecycleDenyRules(t *testing.T) {
 		SetFilterFunc: func(device.PacketFilter) error { return nil },
 	}
 
-	m, err := Create(ifaceMock, false, flowLogger, nbiface.DefaultMTU)
+	m, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
 	require.NoError(t, err)
 	defer func() {
 		require.NoError(t, m.Close(nil))
@@ -260,36 +237,34 @@ func TestPeerRuleLifecycleDenyRules(t *testing.T) {
 	addr := netip.MustParseAddr("192.168.1.1")
 
 	// Add multiple deny rules for different ports
-	rule1, err := m.AddPeerFiltering(nil, ip, fw.ProtocolTCP, nil,
+	rule1, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{22}}, fw.ActionDrop)
-		&fw.Port{Values: []uint16{22}}, fw.ActionDrop, "")
 	require.NoError(t, err)
 
-	rule2, err := m.AddPeerFiltering(nil, ip, fw.ProtocolTCP, nil,
+	rule2, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80}}, fw.ActionDrop)
-		&fw.Port{Values: []uint16{80}}, fw.ActionDrop, "")
 	require.NoError(t, err)
 
 	m.mutex.RLock()
-	denyCount := len(m.incomingDenyRules[addr])
+	denyCount := countRulesForAddr(m.incomingDenyRules, addr)
 	m.mutex.RUnlock()
 	require.Equal(t, 2, denyCount, "Should have exactly 2 deny rules")
 
 	// Delete the first deny rule
-	err = m.DeletePeerRule(rule1[0])
+	err = m.DeleteFilterRule(rule1)
 	require.NoError(t, err)
 
 	m.mutex.RLock()
-	denyCount = len(m.incomingDenyRules[addr])
+	denyCount = countRulesForAddr(m.incomingDenyRules, addr)
 	m.mutex.RUnlock()
 	require.Equal(t, 1, denyCount, "Should have 1 deny rule after deleting first")
 
 	// Delete the second deny rule
-	err = m.DeletePeerRule(rule2[0])
+	err = m.DeleteFilterRule(rule2)
 	require.NoError(t, err)
 
 	m.mutex.RLock()
-	_, exists := m.incomingDenyRules[addr]
+	exists := countRulesForAddr(m.incomingDenyRules, addr) > 0
 	m.mutex.RUnlock()
-	require.False(t, exists, "Deny rules IP entry should be cleaned up when empty")
+	require.False(t, exists, "Deny rules should be cleaned up when empty")
 }
 
 // TestPeerRuleAddAndDeleteDontLeak verifies that repeatedly adding and deleting
@@ -299,7 +274,7 @@ func TestPeerRuleAddAndDeleteDontLeak(t *testing.T) {
 		SetFilterFunc: func(device.PacketFilter) error { return nil },
 	}
 
-	m, err := Create(ifaceMock, false, flowLogger, nbiface.DefaultMTU)
+	m, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
 	require.NoError(t, err)
 	defer func() {
 		require.NoError(t, m.Close(nil))
@@ -311,27 +286,21 @@ func TestPeerRuleAddAndDeleteDontLeak(t *testing.T) {
 	// Simulate 10 network map updates: add rule, delete old, add new
 	for i := 0; i < 10; i++ {
 		// Add a deny rule
-		rules, err := m.AddPeerFiltering(nil, ip, fw.ProtocolTCP, nil,
+		rules, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{22}}, fw.ActionDrop)
-			&fw.Port{Values: []uint16{22}}, fw.ActionDrop, "")
 		require.NoError(t, err)
 
 		// Add an allow rule
-		allowRules, err := m.AddPeerFiltering(nil, ip, fw.ProtocolTCP, nil,
+		allowRules, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80}}, fw.ActionAccept)
-			&fw.Port{Values: []uint16{80}}, fw.ActionAccept, "")
 		require.NoError(t, err)
 
 		// Delete them (simulating ACL manager cleanup)
-		for _, r := range rules {
+		require.NoError(t, m.DeleteFilterRule(rules))
-			require.NoError(t, m.DeletePeerRule(r))
+		require.NoError(t, m.DeleteFilterRule(allowRules))
-		}
-		for _, r := range allowRules {
-			require.NoError(t, m.DeletePeerRule(r))
-		}
 	}
 
 	m.mutex.RLock()
-	denyCount := len(m.incomingDenyRules[addr])
+	denyCount := countRulesForAddr(m.incomingDenyRules, addr)
-	allowCount := len(m.incomingRules[addr])
+	allowCount := countRulesForAddr(m.incomingAcceptRules, addr)
 	m.mutex.RUnlock()
 
 	require.Equal(t, 0, denyCount, "No deny rules should remain after cleanup")
@@ -345,7 +314,7 @@ func TestMixedAllowDenyRulesSameIP(t *testing.T) {
 		SetFilterFunc: func(device.PacketFilter) error { return nil },
 	}
 
-	m, err := Create(ifaceMock, false, flowLogger, nbiface.DefaultMTU)
+	m, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
 	require.NoError(t, err)
 	defer func() {
 		require.NoError(t, m.Close(nil))
@@ -354,41 +323,39 @@ func TestMixedAllowDenyRulesSameIP(t *testing.T) {
 	ip := net.ParseIP("192.168.1.1")
 
 	// Add allow rule for port 80
-	allowRule, err := m.AddPeerFiltering(nil, ip, fw.ProtocolTCP, nil,
+	allowRule, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80}}, fw.ActionAccept)
-		&fw.Port{Values: []uint16{80}}, fw.ActionAccept, "")
 	require.NoError(t, err)
 
 	// Add deny rule for port 22
-	denyRule, err := m.AddPeerFiltering(nil, ip, fw.ProtocolTCP, nil,
+	denyRule, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{22}}, fw.ActionDrop)
-		&fw.Port{Values: []uint16{22}}, fw.ActionDrop, "")
 	require.NoError(t, err)
 
 	addr := netip.MustParseAddr("192.168.1.1")
 	m.mutex.RLock()
-	allowCount := len(m.incomingRules[addr])
+	allowCount := countRulesForAddr(m.incomingAcceptRules, addr)
-	denyCount := len(m.incomingDenyRules[addr])
+	denyCount := countRulesForAddr(m.incomingDenyRules, addr)
 	m.mutex.RUnlock()
 
 	require.Equal(t, 1, allowCount, "Should have 1 allow rule")
 	require.Equal(t, 1, denyCount, "Should have 1 deny rule")
 
 	// Delete allow rule should not affect deny rule
-	err = m.DeletePeerRule(allowRule[0])
+	err = m.DeleteFilterRule(allowRule)
 	require.NoError(t, err)
 
 	m.mutex.RLock()
-	denyCountAfter := len(m.incomingDenyRules[addr])
+	denyCountAfter := countRulesForAddr(m.incomingDenyRules, addr)
 	m.mutex.RUnlock()
 
 	require.Equal(t, 1, denyCountAfter, "Deny rule should still exist after deleting allow rule")
 
 	// Delete deny rule
-	err = m.DeletePeerRule(denyRule[0])
+	err = m.DeleteFilterRule(denyRule)
 	require.NoError(t, err)
 
 	m.mutex.RLock()
-	_, denyExists := m.incomingDenyRules[addr]
+	denyExists := countRulesForAddr(m.incomingDenyRules, addr) > 0
-	_, allowExists := m.incomingRules[addr]
+	allowExists := countRulesForAddr(m.incomingAcceptRules, addr) > 0
 	m.mutex.RUnlock()
 
 	require.False(t, denyExists, "Deny rules should be empty")
@@ -400,7 +367,7 @@ func TestManagerReset(t *testing.T) {
 		SetFilterFunc: func(device.PacketFilter) error { return nil },
 	}
 
-	m, err := Create(ifaceMock, false, flowLogger, nbiface.DefaultMTU)
+	m, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
 	if err != nil {
 		t.Errorf("failed to create Manager: %v", err)
 		return
@@ -411,7 +378,7 @@ func TestManagerReset(t *testing.T) {
 	port := &fw.Port{Values: []uint16{80}}
 	action := fw.ActionDrop
 
-	_, err = m.AddPeerFiltering(nil, ip, proto, nil, port, action, "")
+	_, err = m.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, nil, port, action)
 	if err != nil {
 		t.Errorf("failed to add filtering: %v", err)
 		return
@@ -423,7 +390,7 @@ func TestManagerReset(t *testing.T) {
 		return
 	}
 
-	if len(m.outgoingRules) != 0 || len(m.incomingRules) != 0 || len(m.incomingDenyRules) != 0 {
+	if len(m.incomingAcceptRules) != 0 || len(m.incomingDenyRules) != 0 {
 		t.Errorf("rules are not empty")
 	}
 }
@@ -439,7 +406,7 @@ func TestNotMatchByIP(t *testing.T) {
 		},
 	}
 
-	m, err := Create(ifaceMock, false, flowLogger, nbiface.DefaultMTU)
+	m, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
 	if err != nil {
 		t.Errorf("failed to create Manager: %v", err)
 		return
@@ -449,7 +416,7 @@ func TestNotMatchByIP(t *testing.T) {
 	proto := fw.ProtocolUDP
 	action := fw.ActionAccept
 
-	_, err = m.AddPeerFiltering(nil, ip, proto, nil, nil, action, "")
+	_, err = m.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, nil, nil, action)
 	if err != nil {
 		t.Errorf("failed to add filtering: %v", err)
 		return
@@ -502,7 +469,7 @@ func TestRemovePacketHook(t *testing.T) {
 	}
 
 	// creating manager instance
-	manager, err := Create(iface, false, flowLogger, nbiface.DefaultMTU)
+	manager, err := Create(Config{IFace: iface, FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
 	if err != nil {
 		t.Fatalf("Failed to create Manager: %s", err)
 	}
@@ -519,9 +486,11 @@ func TestRemovePacketHook(t *testing.T) {
 }
 
 func TestProcessOutgoingHooks(t *testing.T) {
-	manager, err := Create(&IFaceMock{
+	manager, err := Create(Config{
-		SetFilterFunc: func(device.PacketFilter) error { return nil },
+		IFace: &IFaceMock{
-	}, false, flowLogger, nbiface.DefaultMTU)
+			SetFilterFunc: func(device.PacketFilter) error { return nil },
+		},
+		FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
 	require.NoError(t, err)
 
 	manager.udpTracker.Close()
@@ -606,7 +575,7 @@ func TestUSPFilterCreatePerformance(t *testing.T) {
 			ifaceMock := &IFaceMock{
 				SetFilterFunc: func(device.PacketFilter) error { return nil },
 			}
-			manager, err := Create(ifaceMock, false, flowLogger, nbiface.DefaultMTU)
+			manager, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
 			require.NoError(t, err)
 			time.Sleep(time.Second)
 
@@ -621,7 +590,7 @@ func TestUSPFilterCreatePerformance(t *testing.T) {
 			start := time.Now()
 			for i := 0; i < testMax; i++ {
 				port := &fw.Port{Values: []uint16{uint16(1000 + i)}}
-				_, err = manager.AddPeerFiltering(nil, ip, "tcp", nil, port, fw.ActionAccept, "")
+				_, err = manager.AddFilterRule(nil, pfx(ip), fw.Network{}, "tcp", nil, port, fw.ActionAccept)
 
 				require.NoError(t, err, "failed to add rule")
 			}
@@ -631,9 +600,11 @@ func TestUSPFilterCreatePerformance(t *testing.T) {
 }
 
 func TestStatefulFirewall_UDPTracking(t *testing.T) {
-	manager, err := Create(&IFaceMock{
+	manager, err := Create(Config{
-		SetFilterFunc: func(device.PacketFilter) error { return nil },
+		IFace: &IFaceMock{
-	}, false, flowLogger, nbiface.DefaultMTU)
+			SetFilterFunc: func(device.PacketFilter) error { return nil },
+		},
+		FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
 	require.NoError(t, err)
 
 	manager.udpTracker.Close() // Close the existing tracker
@@ -845,7 +816,7 @@ func TestUpdateSetMerge(t *testing.T) {
 		SetFilterFunc: func(device.PacketFilter) error { return nil },
 	}
 
-	manager, err := Create(ifaceMock, false, flowLogger, nbiface.DefaultMTU)
+	manager, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
 	require.NoError(t, err)
 	t.Cleanup(func() {
 		require.NoError(t, manager.Close(nil))
@@ -858,7 +829,7 @@ func TestUpdateSetMerge(t *testing.T) {
 		netip.MustParsePrefix("192.168.1.0/24"),
 	}
 
-	rule, err := manager.AddRouteFiltering(
+	rule, err := manager.AddFilterRule(
 		nil,
 		[]netip.Prefix{netip.MustParsePrefix("0.0.0.0/0")},
 		fw.Network{Set: set},
@@ -931,7 +902,7 @@ func TestUpdateSetDeduplication(t *testing.T) {
 		SetFilterFunc: func(device.PacketFilter) error { return nil },
 	}
 
-	manager, err := Create(ifaceMock, false, flowLogger, nbiface.DefaultMTU)
+	manager, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
 	require.NoError(t, err)
 	t.Cleanup(func() {
 		require.NoError(t, manager.Close(nil))
@@ -939,7 +910,7 @@ func TestUpdateSetDeduplication(t *testing.T) {
 
 	set := fw.NewDomainSet(domain.List{"example.org"})
 
-	rule, err := manager.AddRouteFiltering(
+	rule, err := manager.AddFilterRule(
 		nil,
 		[]netip.Prefix{netip.MustParsePrefix("0.0.0.0/0")},
 		fw.Network{Set: set},
@@ -1051,7 +1022,7 @@ func TestMSSClamping(t *testing.T) {
 		},
 	}
 
-	manager, err := Create(ifaceMock, false, flowLogger, 1280)
+	manager, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: 1280})
 	require.NoError(t, err)
 	defer func() {
 		require.NoError(t, manager.Close(nil))
@@ -1243,7 +1214,7 @@ func TestShouldForward(t *testing.T) {
 		return wgaddr.Address{IP: wgIP, Network: netip.PrefixFrom(wgIP, 24)}
 	}
 
-	manager, err := Create(ifaceMock, false, flowLogger, nbiface.DefaultMTU)
+	manager, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
 	require.NoError(t, err)
 	defer func() {
 		require.NoError(t, manager.Close(nil))
@@ -1358,7 +1329,7 @@ func TestShouldForward(t *testing.T) {
 
 	// Re-create manager to pick up the new address with IPv6
 	require.NoError(t, manager.Close(nil))
-	manager, err = Create(ifaceMock, false, flowLogger, nbiface.DefaultMTU)
+	manager, err = Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
 	require.NoError(t, err)
 
 	v6Cases := []struct {

client/firewall/uspfilter/forwarder/forwarder.go

@@ -12,6 +12,7 @@ import (
 	"time"
 
 	log "github.com/sirupsen/logrus"
+	wgdevice "golang.zx2c4.com/wireguard/device"
 	"gvisor.dev/gvisor/pkg/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
@@ -22,9 +23,9 @@ import (
 	"gvisor.dev/gvisor/pkg/tcpip/transport/tcp"
 	"gvisor.dev/gvisor/pkg/tcpip/transport/udp"
 
-	"github.com/netbirdio/netbird/client/firewall/uspfilter/common"
 	"github.com/netbirdio/netbird/client/firewall/uspfilter/conntrack"
 	nblog "github.com/netbirdio/netbird/client/firewall/uspfilter/log"
+	"github.com/netbirdio/netbird/client/iface/wgaddr"
 	nftypes "github.com/netbirdio/netbird/client/internal/netflow/types"
 )
 
@@ -40,6 +41,12 @@ const (
 	envForceTCPRACK = "NB_FORCE_TCP_RACK"
 )
 
+// IFace provides the WireGuard device and overlay addresses the forwarder needs.
+type IFace interface {
+	GetWGDevice() *wgdevice.Device
+	Address() wgaddr.Address
+}
+
 type Forwarder struct {
 	logger     *nblog.Logger
 	flowLogger nftypes.FlowLogger
@@ -58,7 +65,7 @@ type Forwarder struct {
 	pingSemaphore      chan struct{}
 }
 
-func New(iface common.IFaceMapper, logger *nblog.Logger, flowLogger nftypes.FlowLogger, netstack bool, mtu uint16) (*Forwarder, error) {
+func New(iface IFace, logger *nblog.Logger, flowLogger nftypes.FlowLogger, netstack bool, mtu uint16) (*Forwarder, error) {
 	s := stack.New(stack.Options{
 		NetworkProtocols: []stack.NetworkProtocolFactory{
 			ipv4.NewProtocol,

client/firewall/uspfilter/fragment_test.go

@@ -39,7 +39,7 @@ func newFragmentTestManager(tb testing.TB) *Manager {
 		},
 	}
 
-	m, err := Create(ifaceMock, false, flowLogger, nbiface.DefaultMTU)
+	m, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
 	require.NoError(tb, err)
 	require.NoError(tb, m.UpdateLocalIPs())
 	tb.Cleanup(func() { require.NoError(tb, m.Close(nil)) })
@@ -175,8 +175,8 @@ func normalUDPPacket(tb testing.TB, dstPort uint16, payloadLen int) []byte {
 
 func allowUDP(tb testing.TB, m *Manager, dstPort uint16) {
 	tb.Helper()
-	_, err := m.AddPeerFiltering(nil, net.ParseIP(fragTestSrc), fw.ProtocolUDP, nil,
+	_, err := m.AddFilterRule(nil, pfx(net.ParseIP(fragTestSrc)), fw.Network{}, fw.ProtocolUDP, nil,
-		&fw.Port{Values: []uint16{dstPort}}, fw.ActionAccept, "")
+		&fw.Port{Values: []uint16{dstPort}}, fw.ActionAccept)
 	require.NoError(tb, err)
 }
 
@@ -228,8 +228,8 @@ func TestFragment_DeniedFirstDropsTrailing(t *testing.T) {
 // the overlap lands on real header bytes (the flags at byte 13).
 func TestFragment_OverlappingHeaderDropped(t *testing.T) {
 	m := newFragmentTestManager(t)
-	_, err := m.AddPeerFiltering(nil, net.ParseIP(fragTestSrc), fw.ProtocolTCP, nil,
+	_, err := m.AddFilterRule(nil, pfx(net.ParseIP(fragTestSrc)), fw.Network{}, fw.ProtocolTCP, nil,
-		&fw.Port{Values: []uint16{8080}}, fw.ActionAccept, "")
+		&fw.Port{Values: []uint16{8080}}, fw.ActionAccept)
 	require.NoError(t, err)
 
 	// First fragment: TCP header (20) + 12 data = 32 bytes -> headerEnd = 4 octets.
@@ -290,8 +290,8 @@ func TestFragment_TinyFirstDropped(t *testing.T) {
 // trailing fragments inherit the verdict.
 func TestFragment_TCPFirstFragment(t *testing.T) {
 	m := newFragmentTestManager(t)
-	_, err := m.AddPeerFiltering(nil, net.ParseIP(fragTestSrc), fw.ProtocolTCP, nil,
+	_, err := m.AddFilterRule(nil, pfx(net.ParseIP(fragTestSrc)), fw.Network{}, fw.ProtocolTCP, nil,
-		&fw.Port{Values: []uint16{8080}}, fw.ActionAccept, "")
+		&fw.Port{Values: []uint16{8080}}, fw.ActionAccept)
 	require.NoError(t, err)
 
 	// TCP header (20) + 12 data = 32 bytes -> headerEnd = 4 octets.
@@ -308,8 +308,8 @@ func TestFragment_TCPFirstFragment(t *testing.T) {
 // bytes would satisfy a UDP header but falls short of the 20-byte TCP header.
 func TestFragment_TCPTinyFirstDropped(t *testing.T) {
 	m := newFragmentTestManager(t)
-	_, err := m.AddPeerFiltering(nil, net.ParseIP(fragTestSrc), fw.ProtocolTCP, nil,
+	_, err := m.AddFilterRule(nil, pfx(net.ParseIP(fragTestSrc)), fw.Network{}, fw.ProtocolTCP, nil,
-		&fw.Port{Values: []uint16{8080}}, fw.ActionAccept, "")
+		&fw.Port{Values: []uint16{8080}}, fw.ActionAccept)
 	require.NoError(t, err)
 
 	tiny := trailingFragmentTo(t, fragTestDst, layers.IPProtocolTCP, 0x7777, 0, true, 12)
@@ -353,7 +353,7 @@ func TestFragment_RouteACL(t *testing.T) {
 	m.routingEnabled.Store(true)
 	m.nativeRouter.Store(false)
 
-	_, err := m.AddRouteFiltering(
+	_, err := m.AddFilterRule(
 		[]byte("rt-1"),
 		[]netip.Prefix{netip.MustParsePrefix("100.10.0.0/16")},
 		fw.Network{Prefix: netip.MustParsePrefix("198.51.100.0/24")},
@@ -511,8 +511,8 @@ func TestFragmentV6_TrailingWithoutFirstDropped(t *testing.T) {
 // through.
 func TestFragmentV6_AllowedFirstPassesTrailing(t *testing.T) {
 	m := newFragmentTestManager(t)
-	_, err := m.AddPeerFiltering(nil, net.ParseIP(fragTestSrcV6), fw.ProtocolUDP, nil,
+	_, err := m.AddFilterRule(nil, pfx(net.ParseIP(fragTestSrcV6)), fw.Network{}, fw.ProtocolUDP, nil,
-		&fw.Port{Values: []uint16{8080}}, fw.ActionAccept, "")
+		&fw.Port{Values: []uint16{8080}}, fw.ActionAccept)
 	require.NoError(t, err)
 
 	// First fragment: UDP header (8) + 32 data = 40 octets -> headerEnd = 5.
@@ -531,8 +531,8 @@ func TestFragmentV6_AllowedFirstPassesTrailing(t *testing.T) {
 // exhaust the verdict table.
 func TestFragmentV6_AtomicNotCached(t *testing.T) {
 	m := newFragmentTestManager(t)
-	_, err := m.AddPeerFiltering(nil, net.ParseIP(fragTestSrcV6), fw.ProtocolUDP, nil,
+	_, err := m.AddFilterRule(nil, pfx(net.ParseIP(fragTestSrcV6)), fw.Network{}, fw.ProtocolUDP, nil,
-		&fw.Port{Values: []uint16{8080}}, fw.ActionAccept, "")
+		&fw.Port{Values: []uint16{8080}}, fw.ActionAccept)
 	require.NoError(t, err)
 
 	atomic := fragmentUDPv6(t, 0xA70301C, 8080, 16, false)

client/firewall/uspfilter/interface_allower_windows.go

@@ -9,7 +9,6 @@ import (
 	log "github.com/sirupsen/logrus"
 
 	nberrors "github.com/netbirdio/netbird/client/errors"
-	"github.com/netbirdio/netbird/client/internal/statemanager"
 )
 
 type action string
@@ -20,35 +19,20 @@ const (
 	firewallRuleName        = "Netbird"
 )
 
-// Close cleans up the firewall manager by removing all rules and closing trackers
+// WindowsInterfaceAllower opens the NetBird interface in the Windows firewall
-func (m *Manager) Close(*statemanager.Manager) error {
+// via netsh advfirewall rules. It implements InterfaceAllower for the userspace
-	m.mutex.Lock()
+// firewall on Windows.
-	defer m.mutex.Unlock()
+type WindowsInterfaceAllower struct {
-
+	iface Iface
-	m.resetState()
-
-	if !isWindowsFirewallReachable() {
-		return nil
-	}
-
-	var merr *multierror.Error
-	if isFirewallRuleActive(firewallRuleName) {
-		if err := manageFirewallRule(firewallRuleName, deleteRule); err != nil {
-			merr = multierror.Append(merr, fmt.Errorf("remove windows firewall rule: %w", err))
-		}
-	}
-
-	if isFirewallRuleActive(firewallRuleName + "-v6") {
-		if err := manageFirewallRule(firewallRuleName+"-v6", deleteRule); err != nil {
-			merr = multierror.Append(merr, fmt.Errorf("remove windows v6 firewall rule: %w", err))
-		}
-	}
-
-	return nberrors.FormatErrorOrNil(merr)
 }
 
-// AllowNetbird allows netbird interface traffic
+// NewWindowsInterfaceAllower builds the Windows netsh-based interface allower.
-func (m *Manager) AllowNetbird() error {
+func NewWindowsInterfaceAllower(iface Iface) *WindowsInterfaceAllower {
+	return &WindowsInterfaceAllower{iface: iface}
+}
+
+// Apply adds inbound-allow netsh rules for the interface's addresses.
+func (a *WindowsInterfaceAllower) Apply() error {
 	if !isWindowsFirewallReachable() {
 		return nil
 	}
@@ -60,13 +44,13 @@ func (m *Manager) AllowNetbird() error {
 			"enable=yes",
 			"action=allow",
 			"profile=any",
-			"localip="+m.wgIface.Address().IP.String(),
+			"localip="+a.iface.Address().IP.String(),
 		); err != nil {
 			return err
 		}
 	}
 
-	if v6 := m.wgIface.Address().IPv6; v6.IsValid() && !isFirewallRuleActive(firewallRuleName+"-v6") {
+	if v6 := a.iface.Address().IPv6; v6.IsValid() && !isFirewallRuleActive(firewallRuleName+"-v6") {
 		if err := manageFirewallRule(firewallRuleName+"-v6",
 			addRule,
 			"dir=in",
@@ -82,8 +66,27 @@ func (m *Manager) AllowNetbird() error {
 	return nil
 }
 
-func manageFirewallRule(ruleName string, action action, extraArgs ...string) error {
+// Close removes the netsh rules added by Apply.
+func (a *WindowsInterfaceAllower) Close() error {
+	if !isWindowsFirewallReachable() {
+		return nil
+	}
 
+	var merr *multierror.Error
+	if isFirewallRuleActive(firewallRuleName) {
+		if err := manageFirewallRule(firewallRuleName, deleteRule); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("remove windows firewall rule: %w", err))
+		}
+	}
+	if isFirewallRuleActive(firewallRuleName + "-v6") {
+		if err := manageFirewallRule(firewallRuleName+"-v6", deleteRule); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("remove windows v6 firewall rule: %w", err))
+		}
+	}
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+func manageFirewallRule(ruleName string, action action, extraArgs ...string) error {
 	args := []string{"advfirewall", "firewall", string(action), "rule", "name=" + ruleName}
 	if action == addRule {
 		args = append(args, extraArgs...)

client/firewall/uspfilter/localip.go

@@ -7,8 +7,6 @@ import (
 	"sync/atomic"
 
 	log "github.com/sirupsen/logrus"
-
-	"github.com/netbirdio/netbird/client/firewall/uspfilter/common"
 )
 
 // localIPSnapshot is an immutable snapshot of local IP addresses, swapped
@@ -60,7 +58,7 @@ func processInterface(iface net.Interface, ips map[netip.Addr]struct{}, addresse
 }
 
 // UpdateLocalIPs rebuilds the local IP snapshot and swaps it in atomically.
-func (m *localIPManager) UpdateLocalIPs(iface common.IFaceMapper) (err error) {
+func (m *localIPManager) UpdateLocalIPs(iface Iface) (err error) {
 	defer func() {
 		if r := recover(); r != nil {
 			err = fmt.Errorf("panic: %v", r)

client/firewall/uspfilter/nat.go

@@ -487,19 +487,13 @@ func incrementalUpdate(oldChecksum uint16, oldBytes, newBytes []byte) uint16 {
 }
 
 // AddDNATRule adds outbound DNAT rule for forwarding external traffic to NetBird network.
-func (m *Manager) AddDNATRule(rule firewall.ForwardRule) (firewall.Rule, error) {
+func (m *Manager) AddDNATRule(firewall.ForwardRule) (firewall.Rule, error) {
-	if m.nativeFirewall == nil {
+	return nil, errNotSupported
-		return nil, errNatNotSupported
-	}
-	return m.nativeFirewall.AddDNATRule(rule)
 }
 
 // DeleteDNATRule deletes outbound DNAT rule.
-func (m *Manager) DeleteDNATRule(rule firewall.Rule) error {
+func (m *Manager) DeleteDNATRule(firewall.Rule) error {
-	if m.nativeFirewall == nil {
+	return errNotSupported
-		return errNatNotSupported
-	}
-	return m.nativeFirewall.DeleteDNATRule(rule)
 }
 
 // addPortRedirection adds a port redirection rule.
@@ -521,7 +515,6 @@ func (m *Manager) addPortRedirection(targetIP netip.Addr, protocol gopacket.Laye
 }
 
 // AddInboundDNAT adds an inbound DNAT rule redirecting traffic from NetBird peers to local services.
-// TODO: also delegate to nativeFirewall when available for kernel WG mode
 func (m *Manager) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
 	var layerType gopacket.LayerType
 	switch protocol {
@@ -567,20 +560,16 @@ func (m *Manager) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Prot
 	return m.removePortRedirection(localAddr, layerType, originalPort, translatedPort)
 }
 
-// AddOutputDNAT delegates to the native firewall if available.
+// AddOutputDNAT is not supported by the userspace firewall: it backs kernel DNS
-func (m *Manager) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+// redirection, but userspace DNS is served in-process on the gVisor netstack, so
-	if m.nativeFirewall == nil {
+// this should never be called.
-		return fmt.Errorf("output DNAT not supported without native firewall")
+func (m *Manager) AddOutputDNAT(netip.Addr, firewall.Protocol, uint16, uint16) error {
-	}
+	return errNotSupported
-	return m.nativeFirewall.AddOutputDNAT(localAddr, protocol, originalPort, translatedPort)
 }
 
-// RemoveOutputDNAT delegates to the native firewall if available.
+// RemoveOutputDNAT is a no-op for the userspace firewall (see AddOutputDNAT).
-func (m *Manager) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+func (m *Manager) RemoveOutputDNAT(netip.Addr, firewall.Protocol, uint16, uint16) error {
-	if m.nativeFirewall == nil {
+	return nil
-		return nil
-	}
-	return m.nativeFirewall.RemoveOutputDNAT(localAddr, protocol, originalPort, translatedPort)
 }
 
 // translateInboundPortDNAT applies port-specific DNAT translation to inbound packets.

client/firewall/uspfilter/nat_bench_test.go

@@ -64,9 +64,11 @@ func BenchmarkDNATTranslation(b *testing.B) {
 
 	for _, sc := range scenarios {
 		b.Run(sc.name, func(b *testing.B) {
-			manager, err := Create(&IFaceMock{
+			manager, err := Create(Config{
-				SetFilterFunc: func(device.PacketFilter) error { return nil },
+				IFace: &IFaceMock{
-			}, false, flowLogger, iface.DefaultMTU)
+					SetFilterFunc: func(device.PacketFilter) error { return nil },
+				},
+				FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 			require.NoError(b, err)
 			defer func() {
 				require.NoError(b, manager.Close(nil))
@@ -124,9 +126,11 @@ func BenchmarkDNATTranslation(b *testing.B) {
 
 // BenchmarkDNATConcurrency tests DNAT performance under concurrent load
 func BenchmarkDNATConcurrency(b *testing.B) {
-	manager, err := Create(&IFaceMock{
+	manager, err := Create(Config{
-		SetFilterFunc: func(device.PacketFilter) error { return nil },
+		IFace: &IFaceMock{
-	}, false, flowLogger, iface.DefaultMTU)
+			SetFilterFunc: func(device.PacketFilter) error { return nil },
+		},
+		FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 	require.NoError(b, err)
 	defer func() {
 		require.NoError(b, manager.Close(nil))
@@ -196,9 +200,11 @@ func BenchmarkDNATScaling(b *testing.B) {
 
 	for _, count := range mappingCounts {
 		b.Run(fmt.Sprintf("mappings_%d", count), func(b *testing.B) {
-			manager, err := Create(&IFaceMock{
+			manager, err := Create(Config{
-				SetFilterFunc: func(device.PacketFilter) error { return nil },
+				IFace: &IFaceMock{
-			}, false, flowLogger, iface.DefaultMTU)
+					SetFilterFunc: func(device.PacketFilter) error { return nil },
+				},
+				FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 			require.NoError(b, err)
 			defer func() {
 				require.NoError(b, manager.Close(nil))
@@ -308,9 +314,11 @@ func BenchmarkChecksumUpdate(b *testing.B) {
 
 // BenchmarkDNATMemoryAllocations checks for memory allocations in DNAT operations
 func BenchmarkDNATMemoryAllocations(b *testing.B) {
-	manager, err := Create(&IFaceMock{
+	manager, err := Create(Config{
-		SetFilterFunc: func(device.PacketFilter) error { return nil },
+		IFace: &IFaceMock{
-	}, false, flowLogger, iface.DefaultMTU)
+			SetFilterFunc: func(device.PacketFilter) error { return nil },
+		},
+		FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 	require.NoError(b, err)
 	defer func() {
 		require.NoError(b, manager.Close(nil))
@@ -481,9 +489,11 @@ func BenchmarkPortDNAT(b *testing.B) {
 
 	for _, sc := range scenarios {
 		b.Run(sc.name, func(b *testing.B) {
-			manager, err := Create(&IFaceMock{
+			manager, err := Create(Config{
-				SetFilterFunc: func(device.PacketFilter) error { return nil },
+				IFace: &IFaceMock{
-			}, false, flowLogger, iface.DefaultMTU)
+					SetFilterFunc: func(device.PacketFilter) error { return nil },
+				},
+				FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 			require.NoError(b, err)
 			defer func() {
 				require.NoError(b, manager.Close(nil))

client/firewall/uspfilter/nat_stateful_test.go

@@ -13,9 +13,11 @@ import (
 
 // TestPortDNATBasic tests basic port DNAT functionality
 func TestPortDNATBasic(t *testing.T) {
-	manager, err := Create(&IFaceMock{
+	manager, err := Create(Config{
-		SetFilterFunc: func(device.PacketFilter) error { return nil },
+		IFace: &IFaceMock{
-	}, false, flowLogger, iface.DefaultMTU)
+			SetFilterFunc: func(device.PacketFilter) error { return nil },
+		},
+		FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 	require.NoError(t, err)
 	defer func() {
 		require.NoError(t, manager.Close(nil))
@@ -49,9 +51,11 @@ func TestPortDNATBasic(t *testing.T) {
 
 // TestPortDNATMultipleRules tests multiple port DNAT rules
 func TestPortDNATMultipleRules(t *testing.T) {
-	manager, err := Create(&IFaceMock{
+	manager, err := Create(Config{
-		SetFilterFunc: func(device.PacketFilter) error { return nil },
+		IFace: &IFaceMock{
-	}, false, flowLogger, iface.DefaultMTU)
+			SetFilterFunc: func(device.PacketFilter) error { return nil },
+		},
+		FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 	require.NoError(t, err)
 	defer func() {
 		require.NoError(t, manager.Close(nil))

client/firewall/uspfilter/nat_test.go

@@ -15,9 +15,11 @@ import (
 
 // TestDNATTranslationCorrectness verifies DNAT translation works correctly
 func TestDNATTranslationCorrectness(t *testing.T) {
-	manager, err := Create(&IFaceMock{
+	manager, err := Create(Config{
-		SetFilterFunc: func(device.PacketFilter) error { return nil },
+		IFace: &IFaceMock{
-	}, false, flowLogger, iface.DefaultMTU)
+			SetFilterFunc: func(device.PacketFilter) error { return nil },
+		},
+		FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 	require.NoError(t, err)
 	defer func() {
 		require.NoError(t, manager.Close(nil))
@@ -104,9 +106,11 @@ func parsePacket(t testing.TB, packetData []byte) *decoder {
 
 // TestDNATMappingManagement tests adding/removing DNAT mappings
 func TestDNATMappingManagement(t *testing.T) {
-	manager, err := Create(&IFaceMock{
+	manager, err := Create(Config{
-		SetFilterFunc: func(device.PacketFilter) error { return nil },
+		IFace: &IFaceMock{
-	}, false, flowLogger, iface.DefaultMTU)
+			SetFilterFunc: func(device.PacketFilter) error { return nil },
+		},
+		FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 	require.NoError(t, err)
 	defer func() {
 		require.NoError(t, manager.Close(nil))
@@ -152,9 +156,11 @@ func TestDNATMappingManagement(t *testing.T) {
 }
 
 func TestInboundPortDNAT(t *testing.T) {
-	manager, err := Create(&IFaceMock{
+	manager, err := Create(Config{
-		SetFilterFunc: func(device.PacketFilter) error { return nil },
+		IFace: &IFaceMock{
-	}, false, flowLogger, iface.DefaultMTU)
+			SetFilterFunc: func(device.PacketFilter) error { return nil },
+		},
+		FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 	require.NoError(t, err)
 	defer func() {
 		require.NoError(t, manager.Close(nil))
@@ -202,9 +208,11 @@ func TestInboundPortDNAT(t *testing.T) {
 }
 
 func TestInboundPortDNATNegative(t *testing.T) {
-	manager, err := Create(&IFaceMock{
+	manager, err := Create(Config{
-		SetFilterFunc: func(device.PacketFilter) error { return nil },
+		IFace: &IFaceMock{
-	}, false, flowLogger, iface.DefaultMTU)
+			SetFilterFunc: func(device.PacketFilter) error { return nil },
+		},
+		FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 	require.NoError(t, err)
 	defer func() {
 		require.NoError(t, manager.Close(nil))

client/firewall/uspfilter/peer_acl_bench_test.go

@@ -0,0 +1,333 @@
+//go:build uspbench
+
+package uspfilter
+
+import (
+	"fmt"
+	"io"
+	"math/rand"
+	"net"
+	"net/netip"
+	"runtime"
+	"testing"
+
+	"github.com/google/gopacket"
+	"github.com/google/gopacket/layers"
+	log "github.com/sirupsen/logrus"
+	"github.com/stretchr/testify/require"
+
+	fw "github.com/netbirdio/netbird/client/firewall/manager"
+	"github.com/netbirdio/netbird/client/iface"
+	"github.com/netbirdio/netbird/client/iface/device"
+	"github.com/netbirdio/netbird/client/iface/wgaddr"
+)
+
+// BenchmarkPeerACLMatch measures the per-packet cost of the peer ACL
+// matcher (peerACLsBlock) across realistic shapes: M distinct policy
+// rules, each with K source peers in its set.
+//
+// With the reverse-source index, miss cost is independent of M and
+// hit cost grows only with the number of rules touching a single
+// srcIP, not with total rule count.
+func BenchmarkPeerACLMatch(b *testing.B) {
+	shapes := []struct{ M, K int }{
+		{1, 100}, {10, 100}, {50, 100}, {100, 100}, {100, 1000},
+	}
+	families := []struct {
+		name string
+		v6   bool
+	}{{"v4", false}, {"v6", true}}
+
+	for _, fam := range families {
+		for _, s := range shapes {
+			b.Run(fmt.Sprintf("%s/M=%d/K=%d/hit", fam.name, s.M, s.K), func(b *testing.B) {
+				runPeerACLBench(b, s.M, s.K, true, fam.v6)
+			})
+			b.Run(fmt.Sprintf("%s/M=%d/K=%d/miss", fam.name, s.M, s.K), func(b *testing.B) {
+				runPeerACLBench(b, s.M, s.K, false, fam.v6)
+			})
+		}
+	}
+}
+
+func runPeerACLBench(b *testing.B, m, k int, hit, v6 bool) {
+	log.SetOutput(io.Discard) // keep manager logs out of the benchmark output
+
+	// Miss packets are dropped, so they always traverse the full peer
+	// ACL matcher (every bucket) without short-circuiting and without
+	// touching conntrack. Disable conntrack for the miss case so it
+	// measures the matcher, not established-state lookups. The hit case
+	// keeps conntrack on: an accepted packet reaches trackInbound, which
+	// needs the trackers conntrack creates.
+	if !hit {
+		b.Setenv("NB_DISABLE_CONNTRACK", "1")
+	}
+
+	bits := 32
+	genPkt := generatePacket
+	addrs := uniqueAddrs
+	if v6 {
+		bits = 128
+		genPkt = generatePacket6
+		addrs = uniqueAddrs6
+	}
+
+	// dstIP must be a local IP so filterInbound takes the local-traffic
+	// path (handleLocalTraffic → peerACLsBlock) we are measuring; an
+	// address the manager doesn't own would be treated as routed and
+	// short-circuit before the peer matcher.
+	dstIP := addrs(1, 2)[0]
+	mockAddr := wgaddr.Address{IP: dstIP, Network: netip.PrefixFrom(dstIP, bits)}
+	if v6 {
+		// The local-IP manager needs a valid v4 address too; expose the v6
+		// dst as the interface's IPv6 so IsLocalIP recognizes it.
+		mockAddr = wgaddr.Address{
+			IP:      netip.MustParseAddr("100.64.0.1"),
+			Network: netip.MustParsePrefix("100.64.0.0/16"),
+			IPv6:    dstIP,
+			IPv6Net: netip.PrefixFrom(dstIP, bits),
+		}
+	}
+	manager, err := Create(Config{
+		IFace: &IFaceMock{
+			SetFilterFunc: func(device.PacketFilter) error { return nil },
+			AddressFunc:   func() wgaddr.Address { return mockAddr },
+		},
+		FlowLogger: flowLogger, MTU: iface.DefaultMTU})
+	require.NoError(b, err)
+	b.Cleanup(func() { require.NoError(b, manager.Close(nil)) })
+
+	// Generate M policies × K source peers, all distinct.
+	all := addrs(m*k, 1)
+	for i := 0; i < m; i++ {
+		sources := make([]netip.Prefix, k)
+		for j, a := range all[i*k : (i+1)*k] {
+			sources[j] = netip.PrefixFrom(a, bits)
+		}
+		_, err := manager.AddFilterRule(
+			nil, sources, fw.Network{}, fw.ProtocolTCP, nil,
+			&fw.Port{Values: []uint16{uint16(80 + i)}},
+			fw.ActionAccept)
+		require.NoError(b, err)
+	}
+
+	// Hit: cycle through real sources, picking the matching policy's port.
+	// Miss: a source from a disjoint range, port 80 (matches no policy).
+	var pktFn func(i int) []byte
+	if hit {
+		pktFn = func(i int) []byte {
+			policy := i % m
+			src := all[policy*k+(i%k)]
+			return genPkt(b, src.AsSlice(), dstIP.AsSlice(),
+				uint16(1024+i%60000), uint16(80+policy), layers.IPProtocolTCP)
+		}
+	} else {
+		miss := addrs(4096, 99)
+		pktFn = func(i int) []byte {
+			return genPkt(b, miss[i%len(miss)].AsSlice(), dstIP.AsSlice(),
+				uint16(1024+i%60000), 80, layers.IPProtocolTCP)
+		}
+	}
+
+	// Pre-build a pool to avoid allocations dominating the measurement.
+	pool := make([][]byte, 1024)
+	for i := range pool {
+		pool[i] = pktFn(i)
+	}
+
+	// Confirm the matcher is actually exercised: a hit packet must be
+	// allowed and a miss packet dropped. Without this the benchmark
+	// could silently time the routed early-return instead.
+	require.Equal(b, !hit, manager.filterInbound(pool[0], 0),
+		"benchmark must reach the peer ACL matcher")
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		manager.filterInbound(pool[i%len(pool)], 0)
+	}
+}
+
+// BenchmarkPeerACLIndexMemory reports the resident memory cost of
+// the source-keyed index across realistic deployment shapes. Two
+// dimensions matter: (M, K), the number of policies × peers-per-policy,
+// and overlap, the fraction of peers shared between policies.
+//
+// The output uses ReportMetric("bytes/rule") so the cost can be
+// compared across shapes directly. Total bytes = bytes/rule * M.
+func BenchmarkPeerACLIndexMemory(b *testing.B) {
+	cases := []struct {
+		name        string
+		M, K        int
+		overlapFrac float64 // 0 = disjoint per-policy sources, 1 = all share the same pool
+	}{
+		{"M=10/K=100/disjoint", 10, 100, 0},
+		{"M=100/K=100/disjoint", 100, 100, 0},
+		{"M=100/K=1000/disjoint", 100, 1000, 0},
+		{"M=100/K=1000/overlap=0.5", 100, 1000, 0.5},
+		{"M=100/K=1000/overlap=1.0", 100, 1000, 1.0},
+		{"M=1000/K=100/overlap=1.0", 1000, 100, 1.0},
+	}
+
+	for _, c := range cases {
+		b.Run(c.name, func(b *testing.B) {
+			b.ReportAllocs()
+			for i := 0; i < b.N; i++ {
+				mgr, err := Create(Config{
+					IFace: &IFaceMock{
+						SetFilterFunc: func(device.PacketFilter) error { return nil },
+					},
+					FlowLogger: flowLogger, MTU: iface.DefaultMTU})
+				require.NoError(b, err)
+
+				populateIndexedRules(b, mgr, c.M, c.K, c.overlapFrac)
+
+				runtime.GC()
+				var ms runtime.MemStats
+				runtime.ReadMemStats(&ms)
+				before := ms.HeapAlloc
+
+				// Drop the manager's external roots so we can isolate
+				// the index cost. We hold the manager itself live; the
+				// index is what we measure on the second pass.
+				mgr.incomingAcceptIndex.reset()
+				mgr.incomingDenyIndex.reset()
+				mgr.incomingAcceptRules = mgr.incomingAcceptRules[:0]
+				mgr.incomingDenyRules = mgr.incomingDenyRules[:0]
+				runtime.GC()
+				runtime.ReadMemStats(&ms)
+				after := ms.HeapAlloc
+
+				delta := int64(before) - int64(after)
+				if delta < 0 {
+					delta = 0
+				}
+				b.ReportMetric(float64(delta)/float64(c.M), "bytes/rule")
+				b.ReportMetric(float64(delta), "bytes/total")
+
+				require.NoError(b, mgr.Close(nil))
+			}
+		})
+	}
+}
+
+func populateIndexedRules(b *testing.B, mgr *Manager, m, k int, overlapFrac float64) {
+	b.Helper()
+	pool := uniqueAddrs(k+m*k, 1) // big enough universe
+	sharedLen := int(float64(k) * overlapFrac)
+	if sharedLen > k {
+		sharedLen = k
+	}
+	shared := pool[:sharedLen]
+	uniquePool := pool[sharedLen:]
+
+	for i := 0; i < m; i++ {
+		sources := make([]netip.Prefix, 0, k)
+		for _, a := range shared {
+			sources = append(sources, netip.PrefixFrom(a, 32))
+		}
+		// each policy gets (k-sharedLen) addresses unique to it from the unique pool
+		unique := uniquePool[i*(k-sharedLen) : (i+1)*(k-sharedLen)]
+		for _, a := range unique {
+			sources = append(sources, netip.PrefixFrom(a, 32))
+		}
+		_, err := mgr.AddFilterRule(
+			nil, sources, fw.Network{}, fw.ProtocolTCP, nil,
+			&fw.Port{Values: []uint16{uint16(80 + i)}},
+			fw.ActionAccept)
+		require.NoError(b, err)
+	}
+}
+
+// uniqueAddrs returns n distinct addrs. Seeds 1, 2 are used for
+// policy sources / dst; seed 99 puts misses in 10/8.
+func uniqueAddrs(n int, seed int64) []netip.Addr {
+	out := make([]netip.Addr, 0, n)
+	seen := make(map[netip.Addr]struct{}, n)
+	r := rand.New(rand.NewSource(seed))
+	miss := seed == 99
+	for len(out) < n {
+		var b [4]byte
+		if miss {
+			b[0] = 10
+			b[1] = byte(r.Intn(256))
+		} else {
+			b[0] = 100
+			b[1] = byte(64 + r.Intn(63))
+		}
+		b[2] = byte(r.Intn(256))
+		b[3] = byte(1 + r.Intn(254))
+		a := netip.AddrFrom4(b)
+		if _, ok := seen[a]; ok {
+			continue
+		}
+		seen[a] = struct{}{}
+		out = append(out, a)
+	}
+	return out
+}
+
+// uniqueAddrs6 mirrors uniqueAddrs for IPv6: sources come from the ULA
+// range fd00::/8, the miss set (seed 99) from 2001:db8::/32 so it is
+// disjoint from any source.
+func uniqueAddrs6(n int, seed int64) []netip.Addr {
+	out := make([]netip.Addr, 0, n)
+	seen := make(map[netip.Addr]struct{}, n)
+	r := rand.New(rand.NewSource(seed))
+	miss := seed == 99
+	for len(out) < n {
+		var b [16]byte
+		if miss {
+			b[0], b[1], b[2], b[3] = 0x20, 0x01, 0x0d, 0xb8
+		} else {
+			b[0] = 0xfd
+		}
+		for x := 8; x < 16; x++ {
+			b[x] = byte(r.Intn(256))
+		}
+		a := netip.AddrFrom16(b)
+		if _, ok := seen[a]; ok {
+			continue
+		}
+		seen[a] = struct{}{}
+		out = append(out, a)
+	}
+	return out
+}
+
+// generatePacket6 builds an IPv6 TCP/UDP packet, mirroring
+// generatePacket for the v4 case.
+func generatePacket6(b *testing.B, srcIP, dstIP net.IP, srcPort, dstPort uint16, protocol layers.IPProtocol) []byte {
+	b.Helper()
+
+	ipv6 := &layers.IPv6{
+		Version:    6,
+		HopLimit:   64,
+		NextHeader: protocol,
+		SrcIP:      srcIP,
+		DstIP:      dstIP,
+	}
+
+	var transportLayer gopacket.SerializableLayer
+	switch protocol {
+	case layers.IPProtocolTCP:
+		tcp := &layers.TCP{
+			SrcPort: layers.TCPPort(srcPort),
+			DstPort: layers.TCPPort(dstPort),
+			SYN:     true,
+		}
+		require.NoError(b, tcp.SetNetworkLayerForChecksum(ipv6))
+		transportLayer = tcp
+	case layers.IPProtocolUDP:
+		udp := &layers.UDP{
+			SrcPort: layers.UDPPort(srcPort),
+			DstPort: layers.UDPPort(dstPort),
+		}
+		require.NoError(b, udp.SetNetworkLayerForChecksum(ipv6))
+		transportLayer = udp
+	}
+
+	buf := gopacket.NewSerializeBuffer()
+	opts := gopacket.SerializeOptions{ComputeChecksums: true, FixLengths: true}
+	require.NoError(b, gopacket.SerializeLayers(buf, opts, ipv6, transportLayer, gopacket.Payload("test")))
+	return buf.Bytes()
+}

client/firewall/uspfilter/peer_acl_dedup_test.go

@@ -0,0 +1,150 @@
+package uspfilter
+
+import (
+	"net"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	fw "github.com/netbirdio/netbird/client/firewall/manager"
+	nbiface "github.com/netbirdio/netbird/client/iface"
+	"github.com/netbirdio/netbird/client/iface/device"
+)
+
+func newTestManager(t *testing.T) *Manager {
+	t.Helper()
+	ifaceMock := &IFaceMock{
+		SetFilterFunc: func(device.PacketFilter) error { return nil },
+	}
+	m, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
+	require.NoError(t, err, "create manager")
+	t.Cleanup(func() { require.NoError(t, m.Close(nil)) })
+	return m
+}
+
+// TestAddPeerFiltering_DeduplicatesIdenticalRules verifies that adding
+// the same peer rule twice does not create two backing rules. The acl
+// manager keys its own cache, but the firewall backend must be
+// idempotent on its own so a double-apply cannot leak rules, matching
+// the route path and the kernel backends.
+func TestAddPeerFiltering_DeduplicatesIdenticalRules(t *testing.T) {
+	m := newTestManager(t)
+
+	ip := net.ParseIP("192.168.1.1")
+	proto := fw.ProtocolTCP
+	port := &fw.Port{Values: []uint16{80}}
+	action := fw.ActionDrop
+
+	first, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, nil, port, action)
+	require.NoError(t, err, "first add")
+
+	second, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, nil, port, action)
+	require.NoError(t, err, "second add")
+
+	assert.Equal(t, first.ID(), second.ID(), "duplicate add should return the same rule id")
+	assert.Len(t, m.incomingDenyRules, 1, "duplicate add must not create a second backing rule")
+}
+
+// TestDeletePeerFiltering_NoRefcountSingleDeleteRemoves locks the
+// backend's owner accounting for the same-owner case: a content key
+// installed twice by the same owner registers one owner claim, so the
+// first DeleteFilterRule removes the rule. Owner counting only kicks
+// in for distinct management rule IDs (see the peer owner tests); the
+// acl manager keys its tracking per (policy, content) and deletes once
+// per key, so adds and deletes stay balanced.
+func TestDeletePeerFiltering_NoRefcountSingleDeleteRemoves(t *testing.T) {
+	m := newTestManager(t)
+
+	ip := net.ParseIP("192.168.1.1")
+	proto := fw.ProtocolTCP
+	port := &fw.Port{Values: []uint16{80}}
+	action := fw.ActionDrop
+
+	first, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, nil, port, action)
+	require.NoError(t, err, "first add")
+
+	second, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, nil, port, action)
+	require.NoError(t, err, "second add")
+	require.Equal(t, first.ID(), second.ID(), "dedup to one rule")
+	require.Len(t, m.incomingDenyRules, 1, "still one backing rule after duplicate add")
+
+	require.NoError(t, m.DeleteFilterRule(first), "delete once")
+	assert.Empty(t, m.incomingDenyRules, "single delete removes the backing rule (no refcount)")
+	assert.NotContains(t, m.peerRulesMap, first.ID(), "dedup map entry cleared")
+}
+
+// TestAddPeerFiltering_DeterministicID verifies the peer rule id is a
+// content hash, not a random UUID: identical inputs produce the same id
+// across independent managers. A random id breaks caller-side dedup.
+func TestAddPeerFiltering_DeterministicID(t *testing.T) {
+	ip := net.ParseIP("10.0.0.5")
+	proto := fw.ProtocolUDP
+	port := &fw.Port{Values: []uint16{53}}
+	action := fw.ActionAccept
+
+	m1 := newTestManager(t)
+	r1, err := m1.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, nil, port, action)
+	require.NoError(t, err)
+
+	m2 := newTestManager(t)
+	r2, err := m2.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, nil, port, action)
+	require.NoError(t, err)
+
+	assert.Equal(t, r1.ID(), r2.ID(), "same inputs must produce the same rule id")
+}
+
+// TestAddPeerFiltering_DistinctRulesNotDeduped verifies that rules
+// differing only by port are kept separate.
+func TestAddPeerFiltering_DistinctRulesNotDeduped(t *testing.T) {
+	m := newTestManager(t)
+
+	ip := net.ParseIP("192.168.1.1")
+	proto := fw.ProtocolTCP
+	action := fw.ActionAccept
+
+	r80, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, nil, &fw.Port{Values: []uint16{80}}, action)
+	require.NoError(t, err)
+
+	r443, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, nil, &fw.Port{Values: []uint16{443}}, action)
+	require.NoError(t, err)
+
+	assert.NotEqual(t, r80.ID(), r443.ID(), "different ports must produce different rule ids")
+	assert.Len(t, m.incomingAcceptRules, 2, "distinct rules must both be stored")
+}
+
+// TestAddPeerFiltering_SourceVsDestPortNotDeduped verifies that a rule
+// matching on source port and one matching on destination port for the
+// same selector do not collide: the port lands in a different slot, so
+// the content key must differ.
+func TestAddPeerFiltering_SourceVsDestPortNotDeduped(t *testing.T) {
+	m := newTestManager(t)
+
+	ip := net.ParseIP("192.168.1.1")
+	proto := fw.ProtocolTCP
+	port := &fw.Port{Values: []uint16{80}}
+	action := fw.ActionAccept
+
+	dPortRule, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, nil, port, action)
+	require.NoError(t, err)
+
+	sPortRule, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, port, nil, action)
+	require.NoError(t, err)
+
+	assert.NotEqual(t, dPortRule.ID(), sPortRule.ID(), "source-port and dest-port matches must produce different rule ids")
+}
+
+// TestAddFilterRule_EmptySourcesRejected verifies that an empty source
+// list is rejected rather than treated as "match any". "Match any" must
+// be an explicit /0, so a zeroed list can never silently widen a rule to
+// every source.
+func TestAddFilterRule_EmptySourcesRejected(t *testing.T) {
+	m := newTestManager(t)
+
+	proto := fw.ProtocolTCP
+	port := &fw.Port{Values: []uint16{80}}
+
+	_, err := m.AddFilterRule(nil, nil, fw.Network{}, proto, nil, port, fw.ActionAccept)
+	require.ErrorIs(t, err, fw.ErrNoSources, "empty sources must be rejected")
+	assert.Empty(t, m.incomingAcceptRules, "no rule should be stored for empty sources")
+}

client/firewall/uspfilter/peer_acl_ipv6_test.go

@@ -0,0 +1,105 @@
+package uspfilter
+
+import (
+	"net"
+	"net/netip"
+	"testing"
+
+	"github.com/google/gopacket"
+	"github.com/google/gopacket/layers"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	fw "github.com/netbirdio/netbird/client/firewall/manager"
+	nbiface "github.com/netbirdio/netbird/client/iface"
+	"github.com/netbirdio/netbird/client/iface/device"
+	"github.com/netbirdio/netbird/client/iface/wgaddr"
+)
+
+func newV6TestManager(t *testing.T, localV6 string) *Manager {
+	t.Helper()
+	ifaceMock := &IFaceMock{
+		SetFilterFunc: func(device.PacketFilter) error { return nil },
+		AddressFunc: func() wgaddr.Address {
+			return wgaddr.Address{
+				IP:      netip.MustParseAddr("100.10.0.100"),
+				Network: netip.MustParsePrefix("100.10.0.0/16"),
+				IPv6:    netip.MustParseAddr(localV6),
+				IPv6Net: netip.MustParsePrefix("fd00::/64"),
+			}
+		},
+	}
+	m, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: nbiface.DefaultMTU})
+	require.NoError(t, err, "create manager")
+	t.Cleanup(func() { require.NoError(t, m.Close(nil)) })
+	return m
+}
+
+func v6UDPPacket(t *testing.T, src, dst string, dstPort uint16) []byte {
+	t.Helper()
+	ip6 := &layers.IPv6{
+		Version:    6,
+		HopLimit:   64,
+		NextHeader: layers.IPProtocolUDP,
+		SrcIP:      net.ParseIP(src),
+		DstIP:      net.ParseIP(dst),
+	}
+	udp := &layers.UDP{SrcPort: 51334, DstPort: layers.UDPPort(dstPort)}
+	require.NoError(t, udp.SetNetworkLayerForChecksum(ip6))
+
+	buf := gopacket.NewSerializeBuffer()
+	opts := gopacket.SerializeOptions{ComputeChecksums: true, FixLengths: true}
+	require.NoError(t, gopacket.SerializeLayers(buf, opts, ip6, udp, gopacket.Payload("test")))
+	return buf.Bytes()
+}
+
+// TestPeerACL_IPv6HostRule verifies the source index resolves /128 v6
+// rules: a matching v6 source is accepted, a non-matching one is
+// denied by the default. This is the end-to-end proof that the index
+// is not v4-only.
+func TestPeerACL_IPv6HostRule(t *testing.T) {
+	m := newV6TestManager(t, "fd00::100")
+
+	src := net.ParseIP("fd00::1")
+	_, err := m.AddFilterRule(nil, pfx(src), fw.Network{}, fw.ProtocolUDP, nil, &fw.Port{Values: []uint16{53}}, fw.ActionAccept)
+	require.NoError(t, err, "add v6 accept rule")
+
+	require.False(t, m.filterInbound(v6UDPPacket(t, "fd00::1", "fd00::100", 53), 0),
+		"v6 packet from the allowed /128 source must be accepted")
+	require.True(t, m.filterInbound(v6UDPPacket(t, "fd00::2", "fd00::100", 53), 0),
+		"v6 packet from an unlisted source must be denied by default")
+}
+
+// TestPeerACL_IPv6IndexBuckets verifies that v6 sources land in the
+// right index bucket: a /128 in bySource keyed by its address, and
+// coarser prefixes (including ::/0) in the nonHost slice.
+func TestPeerACL_IPv6IndexBuckets(t *testing.T) {
+	m := newV6TestManager(t, "fd00::100")
+	port := &fw.Port{Values: []uint16{53}}
+
+	host := netip.MustParseAddr("fd00::1")
+	_, err := m.AddFilterRule(nil, []netip.Prefix{netip.PrefixFrom(host, 128)}, fw.Network{}, fw.ProtocolUDP, nil, port, fw.ActionAccept)
+	require.NoError(t, err)
+	assert.Contains(t, m.incomingAcceptIndex.bySource, host, "/128 v6 source must be indexed by address")
+
+	_, err = m.AddFilterRule(nil, []netip.Prefix{netip.MustParsePrefix("fd00:dead::/64")}, fw.Network{}, fw.ProtocolUDP, nil, port, fw.ActionAccept)
+	require.NoError(t, err)
+	require.Len(t, m.incomingAcceptIndex.nonHost, 1, "coarser v6 prefix must land in nonHost")
+
+	_, err = m.AddFilterRule(nil, []netip.Prefix{netip.MustParsePrefix("::/0")}, fw.Network{}, fw.ProtocolUDP, nil, port, fw.ActionAccept)
+	require.NoError(t, err)
+	require.Len(t, m.incomingAcceptIndex.nonHost, 2, "::/0 source must also land in nonHost")
+}
+
+// TestPeerACL_IPv4MappedSourceNormalized verifies a v4-mapped v6
+// source prefix is normalized to v4 so a plain v4 packet matches it.
+func TestPeerACL_IPv4MappedSourceNormalized(t *testing.T) {
+	m := newTestManager(t)
+
+	mapped := netip.MustParseAddr("::ffff:192.168.1.1")
+	_, err := m.AddFilterRule(nil, []netip.Prefix{netip.PrefixFrom(mapped, mapped.BitLen())}, fw.Network{}, fw.ProtocolUDP, nil, &fw.Port{Values: []uint16{53}}, fw.ActionAccept)
+	require.NoError(t, err)
+
+	v4 := netip.MustParseAddr("192.168.1.1")
+	assert.Contains(t, m.incomingAcceptIndex.bySource, v4, "v4-mapped v6 source must be indexed as plain v4")
+}

client/firewall/uspfilter/peer_family_scope_test.go

@@ -0,0 +1,104 @@
+package uspfilter
+
+import (
+	"net"
+	"net/netip"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	fw "github.com/netbirdio/netbird/client/firewall/manager"
+)
+
+// peerACLCheck decodes the packet and runs it through the peer ACLs,
+// returning the attributed management rule id and the drop verdict.
+func peerACLCheck(t *testing.T, m *Manager, packet []byte) ([]byte, bool) {
+	t.Helper()
+	d := m.decoders.Get().(*decoder)
+	defer m.decoders.Put(d)
+	require.NoError(t, d.decodePacket(packet))
+	src, _ := m.extractIPs(d)
+	return m.peerACLsBlock(src, d, packet)
+}
+
+// TestPeerACL_MultiValuePortMatchesEachListedPort guards the multi-value
+// port path: a rule listing several discrete destination ports must
+// match a packet to each listed port and drop one that is not listed.
+// Management currently splits a multi-port policy into one rule per port
+// (and the wire format carries a single port), so this list shape is not
+// emitted today; the test locks correct matching in case that changes.
+func TestPeerACL_MultiValuePortMatchesEachListedPort(t *testing.T) {
+	m := newTestManager(t)
+
+	src := net.ParseIP("192.168.1.1")
+	ports := &fw.Port{Values: []uint16{80, 443}}
+	_, err := m.AddFilterRule(nil, pfx(src), fw.Network{}, fw.ProtocolTCP, nil, ports, fw.ActionAccept)
+	require.NoError(t, err, "add multi-value port rule")
+
+	for _, p := range []uint16{80, 443} {
+		_, blocked := peerACLCheck(t, m, createTestPacket(t, "192.168.1.1", "10.0.0.2", fw.ProtocolTCP, 12345, p))
+		assert.False(t, blocked, "packet to listed port %d must match the rule", p)
+	}
+
+	_, blocked := peerACLCheck(t, m, createTestPacket(t, "192.168.1.1", "10.0.0.2", fw.ProtocolTCP, 12345, 8080))
+	assert.True(t, blocked, "packet to a port not in the list must not match the rule")
+}
+
+// TestPeerACL_MatchAnyIsFamilyScoped verifies that a /0 source matches
+// only packets of its own family: 0.0.0.0/0 must not match IPv6 packets
+// and ::/0 must not match IPv4 packets, matching kernel backend
+// semantics.
+func TestPeerACL_MatchAnyIsFamilyScoped(t *testing.T) {
+	m := newTestManager(t)
+
+	v4Packet := createTestPacket(t, "10.0.0.1", "10.0.0.2", fw.ProtocolUDP, 12345, 53)
+	v6Packet := v6UDPPacket(t, "fd00::1", "fd00::100", 53)
+
+	v4Any := []netip.Prefix{netip.PrefixFrom(netip.IPv4Unspecified(), 0)}
+	rule, err := m.AddFilterRule(nil, v4Any, fw.Network{}, fw.ProtocolALL, nil, nil, fw.ActionAccept)
+	require.NoError(t, err, "add v4 /0 rule")
+
+	_, blocked := peerACLCheck(t, m, v4Packet)
+	assert.False(t, blocked, "0.0.0.0/0 must match IPv4 packets")
+	_, blocked = peerACLCheck(t, m, v6Packet)
+	assert.True(t, blocked, "0.0.0.0/0 must not match IPv6 packets")
+
+	require.NoError(t, m.DeleteFilterRule(rule))
+
+	v6Any := []netip.Prefix{netip.PrefixFrom(netip.IPv6Unspecified(), 0)}
+	_, err = m.AddFilterRule(nil, v6Any, fw.Network{}, fw.ProtocolALL, nil, nil, fw.ActionAccept)
+	require.NoError(t, err, "add v6 /0 rule")
+
+	_, blocked = peerACLCheck(t, m, v6Packet)
+	assert.False(t, blocked, "::/0 must match IPv6 packets")
+	_, blocked = peerACLCheck(t, m, v4Packet)
+	assert.True(t, blocked, "::/0 must not match IPv4 packets")
+}
+
+// TestRouteACL_MixedFamilyZeroSourcesStayFamilySafe verifies the route
+// path keeps per-prefix family matching when a single rule carries both
+// 0.0.0.0/0 and ::/0 sources, as blockInvalidRouted does.
+func TestRouteACL_MixedFamilyZeroSourcesStayFamilySafe(t *testing.T) {
+	m := newTestManager(t)
+
+	sources := []netip.Prefix{
+		netip.PrefixFrom(netip.IPv4Unspecified(), 0),
+		netip.PrefixFrom(netip.IPv6Unspecified(), 0),
+	}
+
+	_, err := m.AddFilterRule(nil, sources, fw.Network{Prefix: netip.MustParsePrefix("10.0.0.0/24")},
+		fw.ProtocolALL, nil, nil, fw.ActionAccept)
+	require.NoError(t, err)
+	_, err = m.AddFilterRule(nil, sources, fw.Network{Prefix: netip.MustParsePrefix("fd00:1::/64")},
+		fw.ProtocolALL, nil, nil, fw.ActionAccept)
+	require.NoError(t, err)
+
+	v4Src := netip.MustParseAddr("192.168.1.1")
+	v6Src := netip.MustParseAddr("fd00::1")
+
+	_, pass := m.routeACLsPass(v4Src, netip.MustParseAddr("10.0.0.5"), 255, 0, 0)
+	assert.True(t, pass, "v4 source must match the v4 destination rule via 0.0.0.0/0")
+	_, pass = m.routeACLsPass(v6Src, netip.MustParseAddr("fd00:1::5"), 255, 0, 0)
+	assert.True(t, pass, "v6 source must match the v6 destination rule via ::/0")
+}

client/firewall/uspfilter/peer_index.go

@@ -0,0 +1,140 @@
+package uspfilter
+
+import (
+	"net/netip"
+	"slices"
+
+	"github.com/google/gopacket"
+	"github.com/google/gopacket/layers"
+
+	firewall "github.com/netbirdio/netbird/client/firewall/manager"
+)
+
+// peerRuleIndex is the source-side dispatcher consulted on the packet
+// hot path. It splits rules into two buckets by the shape of their
+// source list:
+//
+//   - bySource: every source is a host prefix (/32 for v4, /128 for
+//     v6). Keyed by the concrete source address, so a hit guarantees
+//     the source filter passes and the matcher goes straight to
+//     proto/port checks. This is the common case for peer ACLs.
+//   - nonHost: any source list with a prefix coarser than a host,
+//     including a /0 "match any". Walked linearly with a per-rule
+//     Contains() check. Expected small or empty for typical peer ACLs.
+//
+// Maintained incrementally by add/remove, never rebuilt.
+type peerRuleIndex struct {
+	bySource map[netip.Addr][]*PeerRule
+	nonHost  []*PeerRule
+}
+
+func (i *peerRuleIndex) add(r *PeerRule) {
+	if hasNonHostSource(r) {
+		i.nonHost = append(i.nonHost, r)
+		return
+	}
+	if i.bySource == nil {
+		i.bySource = make(map[netip.Addr][]*PeerRule)
+	}
+	for a := range r.sourceAddrs {
+		i.bySource[a] = append(i.bySource[a], r)
+	}
+}
+
+func (i *peerRuleIndex) remove(r *PeerRule) {
+	if hasNonHostSource(r) {
+		i.nonHost = slices.DeleteFunc(i.nonHost, eqRule(r))
+		return
+	}
+	if i.bySource == nil {
+		return
+	}
+	for a := range r.sourceAddrs {
+		entries := slices.DeleteFunc(i.bySource[a], eqRule(r))
+		if len(entries) == 0 {
+			delete(i.bySource, a)
+		} else {
+			i.bySource[a] = entries
+		}
+	}
+}
+
+func (i *peerRuleIndex) reset() {
+	i.bySource = nil
+	i.nonHost = i.nonHost[:0]
+}
+
+// match returns the first rule matching src and the decoded packet.
+// Host rules are found by direct map lookup; nonHost rules run a
+// per-rule source Contains() check. Containment is family-scoped, so
+// a /0 source matches every address of its own family only (0.0.0.0/0
+// never matches v6 sources and ::/0 never matches v4). Within either
+// bucket the matcher runs the proto/port filter.
+func (i *peerRuleIndex) match(src netip.Addr, d *decoder) ([]byte, bool, bool) {
+	payloadLayer := d.decoded[1]
+
+	for _, rule := range i.bySource[src] {
+		if id, drop, ok := matchProto(rule, d, payloadLayer); ok {
+			return id, drop, true
+		}
+	}
+	for _, rule := range i.nonHost {
+		if !prefixesContain(rule.sources, src) {
+			continue
+		}
+		if id, drop, ok := matchProto(rule, d, payloadLayer); ok {
+			return id, drop, true
+		}
+	}
+	return nil, false, false
+}
+
+func eqRule(target *PeerRule) func(*PeerRule) bool {
+	return func(p *PeerRule) bool { return p == target }
+}
+
+// hasNonHostSource reports whether the rule has any source prefix
+// that is not a single host address. Called only at add/remove time,
+// not on the packet path.
+func hasNonHostSource(r *PeerRule) bool {
+	for _, p := range r.sources {
+		if p.Bits() != p.Addr().BitLen() {
+			return true
+		}
+	}
+	return false
+}
+
+// matchProto applies the proto/port half of a rule against the
+// decoded packet. Source matching is the caller's responsibility.
+func matchProto(rule *PeerRule, d *decoder, payloadLayer gopacket.LayerType) ([]byte, bool, bool) {
+	drop := rule.action == firewall.ActionDrop
+	if rule.protoLayer == layerTypeAll {
+		return rule.mgmtId, drop, true
+	}
+	if !protoLayerMatches(rule.protoLayer, payloadLayer) {
+		return nil, false, false
+	}
+	switch payloadLayer {
+	case layers.LayerTypeTCP:
+		if portsMatch(rule.srcPort, uint16(d.tcp.SrcPort)) && portsMatch(rule.dstPort, uint16(d.tcp.DstPort)) {
+			return rule.mgmtId, drop, true
+		}
+	case layers.LayerTypeUDP:
+		if portsMatch(rule.srcPort, uint16(d.udp.SrcPort)) && portsMatch(rule.dstPort, uint16(d.udp.DstPort)) {
+			return rule.mgmtId, drop, true
+		}
+	case layers.LayerTypeICMPv4, layers.LayerTypeICMPv6:
+		return rule.mgmtId, drop, true
+	}
+	return nil, false, false
+}
+
+func prefixesContain(sources []netip.Prefix, src netip.Addr) bool {
+	for _, p := range sources {
+		if p.Contains(src) {
+			return true
+		}
+	}
+	return false
+}

client/firewall/uspfilter/rule.go

@@ -10,24 +10,43 @@ import (
 
 // PeerRule to handle management of rules
 type PeerRule struct {
-	id         string
+	id     firewall.RuleID
-	mgmtId     []byte
+	mgmtId []byte
-	ip         netip.Addr
+	// sources is the canonical list of source prefixes this rule
-	ipLayer    gopacket.LayerType
+	// matches against.
-	matchByIP  bool
+	sources []netip.Prefix
-	protoLayer gopacket.LayerType
+	// sourceAddrs is a fast-path membership set for host-prefix
-	sPort      *firewall.Port
+	// sources (/32 v4, /128 v6). Populated alongside sources;
-	dPort      *firewall.Port
+	// consulted before falling back to prefix scan.
-	drop bool
+	sourceAddrs map[netip.Addr]struct{}
+	protoLayer  gopacket.LayerType
+	srcPort     *firewall.Port
+	dstPort     *firewall.Port
+	action      firewall.Action
+}
+
+// matchesSource reports whether the given source address is covered
+// by this rule's source list. Prefix containment is family-scoped, so
+// a /0 source matches every address of its own family only.
+func (r *PeerRule) matchesSource(src netip.Addr) bool {
+	if _, ok := r.sourceAddrs[src]; ok {
+		return true
+	}
+	for _, p := range r.sources {
+		if p.Contains(src) {
+			return true
+		}
+	}
+	return false
 }
 
 // ID returns the rule id
-func (r *PeerRule) ID() string {
+func (r *PeerRule) ID() firewall.RuleID {
 	return r.id
 }
 
 type RouteRule struct {
-	id           string
+	id           firewall.RuleID
 	mgmtId       []byte
 	sources      []netip.Prefix
 	dstSet       firewall.Set
@@ -39,6 +58,6 @@ type RouteRule struct {
 }
 
 // ID returns the rule id
-func (r *RouteRule) ID() string {
+func (r *RouteRule) ID() firewall.RuleID {
 	return r.id
 }

client/firewall/uspfilter/testhelpers_test.go

@@ -0,0 +1,50 @@
+package uspfilter
+
+import (
+	"net"
+	"net/netip"
+
+	firewall "github.com/netbirdio/netbird/client/firewall/manager"
+)
+
+// countRulesForAddr reports how many rules in the given slice match
+// the supplied source address.
+func countRulesForAddr(rules peerRules, src netip.Addr) int {
+	n := 0
+	for _, r := range rules {
+		if r.matchesSource(src) {
+			n++
+		}
+	}
+	return n
+}
+
+// findRuleByID returns true if the rules slice contains a rule with
+// the given id whose source set covers src.
+func findRuleByID(rules peerRules, src netip.Addr, id firewall.RuleID) bool {
+	for _, r := range rules {
+		if r.id == id && r.matchesSource(src) {
+			return true
+		}
+	}
+	return false
+}
+
+// pfx converts a single net.IP into the []netip.Prefix form
+// AddFilterRule expects. A nil or unspecified address becomes a /0
+// ("match any") prefix in the matching family; any other address
+// becomes its /32 (or /128) host prefix.
+func pfx(ip net.IP) []netip.Prefix {
+	if ip == nil {
+		return []netip.Prefix{netip.PrefixFrom(netip.IPv4Unspecified(), 0)}
+	}
+	if ip.IsUnspecified() {
+		if ip.To4() != nil {
+			return []netip.Prefix{netip.PrefixFrom(netip.IPv4Unspecified(), 0)}
+		}
+		return []netip.Prefix{netip.PrefixFrom(netip.IPv6Unspecified(), 0)}
+	}
+	a, _ := netip.AddrFromSlice(ip)
+	a = a.Unmap()
+	return []netip.Prefix{netip.PrefixFrom(a, a.BitLen())}
+}

client/firewall/uspfilter/tracer.go

@@ -285,6 +285,14 @@ func (m *Manager) TracePacket(packetData []byte, direction fw.RuleDirection) *Pa
 	trace.SourceIP = srcIP
 	trace.DestinationIP = dstIP
 
+	// A fragment or otherwise truncated packet has no transport layer.
+	// The inbound datapath drops these via isValidPacket; the tracer must
+	// guard explicitly since every downstream stage reads d.decoded[1].
+	if len(d.decoded) < 2 {
+		trace.AddResult(StageReceived, "Packet has no transport layer (fragment or unsupported protocol)", false)
+		return trace
+	}
+
 	// Determine protocol and ports
 	switch d.decoded[1] {
 	case layers.LayerTypeTCP:

client/firewall/uspfilter/tracer_test.go

@@ -45,7 +45,7 @@ func TestTracePacket(t *testing.T) {
 			},
 		}
 
-		m, err := Create(ifaceMock, false, flowLogger, iface.DefaultMTU)
+		m, err := Create(Config{IFace: ifaceMock, FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 		require.NoError(t, err)
 
 		if !statefulMode {
@@ -97,7 +97,7 @@ func TestTracePacket(t *testing.T) {
 				proto := fw.ProtocolTCP
 				port := &fw.Port{Values: []uint16{80}}
 				action := fw.ActionAccept
-				_, err := m.AddPeerFiltering(nil, ip, proto, nil, port, action, "")
+				_, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, nil, port, action)
 				require.NoError(t, err)
 			},
 			packetBuilder: func() *PacketBuilder {
@@ -121,7 +121,7 @@ func TestTracePacket(t *testing.T) {
 				proto := fw.ProtocolTCP
 				port := &fw.Port{Values: []uint16{80}}
 				action := fw.ActionDrop
-				_, err := m.AddPeerFiltering(nil, ip, proto, nil, port, action, "")
+				_, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, nil, port, action)
 				require.NoError(t, err)
 			},
 			packetBuilder: func() *PacketBuilder {
@@ -150,7 +150,7 @@ func TestTracePacket(t *testing.T) {
 				proto := fw.ProtocolTCP
 				port := &fw.Port{Values: []uint16{80}}
 				action := fw.ActionAccept
-				_, err := m.AddPeerFiltering(nil, ip, proto, nil, port, action, "")
+				_, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, nil, port, action)
 				require.NoError(t, err)
 			},
 			packetBuilder: func() *PacketBuilder {
@@ -178,7 +178,7 @@ func TestTracePacket(t *testing.T) {
 				proto := fw.ProtocolTCP
 				port := &fw.Port{Values: []uint16{80}}
 				action := fw.ActionAccept
-				_, err := m.AddPeerFiltering(nil, ip, proto, nil, port, action, "")
+				_, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, nil, port, action)
 				require.NoError(t, err)
 			},
 			packetBuilder: func() *PacketBuilder {
@@ -205,7 +205,7 @@ func TestTracePacket(t *testing.T) {
 
 				src := netip.PrefixFrom(netip.AddrFrom4([4]byte{1, 1, 1, 1}), 32)
 				dst := netip.PrefixFrom(netip.AddrFrom4([4]byte{192, 168, 17, 2}), 32)
-				_, err := m.AddRouteFiltering(nil, []netip.Prefix{src}, fw.Network{Prefix: dst}, fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80}}, fw.ActionAccept)
+				_, err := m.AddFilterRule(nil, []netip.Prefix{src}, fw.Network{Prefix: dst}, fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80}}, fw.ActionAccept)
 				require.NoError(t, err)
 			},
 			packetBuilder: func() *PacketBuilder {
@@ -231,7 +231,7 @@ func TestTracePacket(t *testing.T) {
 
 				src := netip.PrefixFrom(netip.AddrFrom4([4]byte{1, 1, 1, 1}), 32)
 				dst := netip.PrefixFrom(netip.AddrFrom4([4]byte{192, 168, 17, 2}), 32)
-				_, err := m.AddRouteFiltering(nil, []netip.Prefix{src}, fw.Network{Prefix: dst}, fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80}}, fw.ActionDrop)
+				_, err := m.AddFilterRule(nil, []netip.Prefix{src}, fw.Network{Prefix: dst}, fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80}}, fw.ActionDrop)
 				require.NoError(t, err)
 			},
 			packetBuilder: func() *PacketBuilder {
@@ -332,7 +332,7 @@ func TestTracePacket(t *testing.T) {
 				ip := net.ParseIP("1.1.1.1")
 				proto := fw.ProtocolICMP
 				action := fw.ActionAccept
-				_, err := m.AddPeerFiltering(nil, ip, proto, nil, nil, action, "")
+				_, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, nil, nil, action)
 				require.NoError(t, err)
 			},
 			packetBuilder: func() *PacketBuilder {
@@ -355,7 +355,7 @@ func TestTracePacket(t *testing.T) {
 				ip := net.ParseIP("1.1.1.1")
 				proto := fw.ProtocolICMP
 				action := fw.ActionDrop
-				_, err := m.AddPeerFiltering(nil, ip, proto, nil, nil, action, "")
+				_, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, nil, nil, action)
 				require.NoError(t, err)
 			},
 			packetBuilder: func() *PacketBuilder {
@@ -379,7 +379,7 @@ func TestTracePacket(t *testing.T) {
 				proto := fw.ProtocolUDP
 				port := &fw.Port{Values: []uint16{53}}
 				action := fw.ActionAccept
-				_, err := m.AddPeerFiltering(nil, ip, proto, nil, port, action, "")
+				_, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, nil, port, action)
 				require.NoError(t, err)
 			},
 			packetBuilder: func() *PacketBuilder {
@@ -423,7 +423,7 @@ func TestTracePacket(t *testing.T) {
 				proto := fw.ProtocolTCP
 				port := &fw.Port{Values: []uint16{80}}
 				action := fw.ActionDrop
-				_, err := m.AddPeerFiltering(nil, ip, proto, nil, port, action, "")
+				_, err := m.AddFilterRule(nil, pfx(ip), fw.Network{}, proto, nil, port, action)
 				require.NoError(t, err)
 			},
 			packetBuilder: func() *PacketBuilder {

client/internal/acl/dispatch_test.go

@@ -0,0 +1,190 @@
+package acl
+
+import (
+	"net/netip"
+	"sync"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.uber.org/mock/gomock"
+
+	"github.com/netbirdio/netbird/client/firewall"
+	fwmgr "github.com/netbirdio/netbird/client/firewall/manager"
+	"github.com/netbirdio/netbird/client/iface"
+	"github.com/netbirdio/netbird/client/iface/wgaddr"
+	"github.com/netbirdio/netbird/client/internal/acl/mocks"
+	mgmProto "github.com/netbirdio/netbird/shared/management/proto"
+)
+
+// TestNetworkZeroPrefixIsRoute guards the route-vs-peer dispatch
+// invariant: the backends classify a rule as a peer rule purely by the
+// absence of a destination (neither prefix nor set). A default route
+// (0.0.0.0/0 or ::/0) is a valid prefix and must therefore classify as
+// a route, not collapse into the peer path.
+func TestNetworkZeroPrefixIsRoute(t *testing.T) {
+	for _, p := range []string{"0.0.0.0/0", "::/0", "10.0.0.0/8"} {
+		n := fwmgr.Network{Prefix: netip.MustParsePrefix(p)}
+		assert.True(t, n.IsPrefix(), "%s must report IsPrefix", p)
+		assert.True(t, n.IsPrefix() || n.IsSet(), "%s must classify as a route", p)
+	}
+
+	// A zero-value Network is the only peer-rule shape.
+	var empty fwmgr.Network
+	assert.False(t, empty.IsPrefix(), "zero Network must not be a prefix")
+	assert.False(t, empty.IsSet(), "zero Network must not be a set")
+}
+
+// TestDetermineDestinationAlwaysRoute verifies determineDestination
+// never yields an empty Network for a valid route rule: every branch
+// (static prefix, default route, dynamic with/without domains, with and
+// without a local resolver) produces a destination that classifies as a
+// route. If this regresses, a route rule would be dispatched down the
+// peer path, which matches on source only.
+func TestDetermineDestinationAlwaysRoute(t *testing.T) {
+	v4 := []netip.Prefix{netip.MustParsePrefix("10.0.0.0/24")}
+	v6 := []netip.Prefix{netip.MustParsePrefix("2001:db8::/48")}
+
+	cases := []struct {
+		name     string
+		rule     *mgmProto.RouteFirewallRule
+		resolver bool
+		sources  []netip.Prefix
+	}{
+		{"static prefix", &mgmProto.RouteFirewallRule{Destination: "192.168.0.0/16"}, false, v4},
+		{"static default route", &mgmProto.RouteFirewallRule{Destination: "0.0.0.0/0"}, false, v4},
+		{"dynamic with domains + resolver", &mgmProto.RouteFirewallRule{IsDynamic: true, Domains: []string{"example.com"}}, true, v4},
+		{"dynamic no domains + resolver (v4)", &mgmProto.RouteFirewallRule{IsDynamic: true}, true, v4},
+		{"dynamic no domains + resolver (v6)", &mgmProto.RouteFirewallRule{IsDynamic: true}, true, v6},
+		{"dynamic + no local resolver (v4)", &mgmProto.RouteFirewallRule{IsDynamic: true}, false, v4},
+		{"dynamic + no local resolver (v6)", &mgmProto.RouteFirewallRule{IsDynamic: true}, false, v6},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			dest, err := determineDestination(tc.rule, tc.resolver, tc.sources)
+			require.NoError(t, err)
+			assert.True(t, dest.IsPrefix() || dest.IsSet(),
+				"destination must classify as a route, got empty Network")
+		})
+	}
+}
+
+// countingFirewall wraps a real firewall.Manager and counts filter-rule
+// add/delete calls so a test can assert how many backing rules the acl
+// manager actually creates and tears down.
+type countingFirewall struct {
+	fwmgr.Manager
+	mu       sync.Mutex
+	addCalls int
+	dels     int
+	ruleIDs  map[fwmgr.RuleID]struct{}
+}
+
+// distinctRules returns the number of distinct backing rules the
+// backend produced. Because the backend dedups identical content,
+// repeated AddFilterRule calls for the same rule resolve to one id.
+func (f *countingFirewall) distinctRules() int {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	return len(f.ruleIDs)
+}
+
+func (f *countingFirewall) AddFilterRule(id []byte, sources []netip.Prefix, destination fwmgr.Network, proto fwmgr.Protocol, sPort, dPort *fwmgr.Port, action fwmgr.Action) (fwmgr.Rule, error) {
+	rule, err := f.Manager.AddFilterRule(id, sources, destination, proto, sPort, dPort, action)
+	if err == nil {
+		f.mu.Lock()
+		f.addCalls++
+		if f.ruleIDs == nil {
+			f.ruleIDs = make(map[fwmgr.RuleID]struct{})
+		}
+		if rule != nil {
+			f.ruleIDs[rule.ID()] = struct{}{}
+		}
+		f.mu.Unlock()
+	}
+	return rule, err
+}
+
+func (f *countingFirewall) DeleteFilterRule(r fwmgr.Rule) error {
+	err := f.Manager.DeleteFilterRule(r)
+	if err == nil {
+		f.mu.Lock()
+		f.dels++
+		delete(f.ruleIDs, r.ID())
+		f.mu.Unlock()
+	}
+	return err
+}
+
+func newCountingACL(t *testing.T) (*DefaultManager, *countingFirewall, func()) {
+	t.Helper()
+	t.Setenv("NB_WG_KERNEL_DISABLED", "true")
+	t.Setenv(firewall.EnvForceUserspaceFirewall, "true")
+
+	ctrl := gomock.NewController(t)
+	ifaceMock := mocks.NewMockIFaceMapper(ctrl)
+	ifaceMock.EXPECT().IsUserspaceBind().Return(true).AnyTimes()
+	ifaceMock.EXPECT().SetFilter(gomock.Any())
+	network := netip.MustParsePrefix("172.0.0.1/32")
+	ifaceMock.EXPECT().Name().Return("lo").AnyTimes()
+	ifaceMock.EXPECT().Address().Return(wgaddr.Address{IP: network.Addr(), Network: network}).AnyTimes()
+	ifaceMock.EXPECT().GetWGDevice().Return(nil).AnyTimes()
+
+	realFW, err := firewall.NewFirewall(ifaceMock, nil, flowLogger, false, iface.DefaultMTU)
+	require.NoError(t, err)
+
+	fw := &countingFirewall{Manager: realFW}
+	cleanup := func() {
+		require.NoError(t, realFW.Close(nil))
+		ctrl.Finish()
+	}
+	return NewDefaultManager(fw), fw, cleanup
+}
+
+// TestDuplicateContentPoliciesShareOneRule verifies the dedup contract
+// the backends rely on: two policies that authorize an identical flow
+// (same selector and sources) collapse to a single backing firewall
+// rule, and that rule survives until BOTH policies are gone. This is
+// why the backend can dedup on add without refcounting on delete: the
+// acl manager's pair key matches the backend's content key, so add and
+// delete stay balanced per content key across full-state reapplies.
+func TestDuplicateContentPoliciesShareOneRule(t *testing.T) {
+	acl, fw, cleanup := newCountingACL(t)
+	defer cleanup()
+
+	ruleA := &mgmProto.FirewallRule{
+		PolicyID:  []byte("policy-A"),
+		PeerIP:    "10.0.0.1", //nolint:staticcheck
+		Direction: mgmProto.RuleDirection_IN,
+		Action:    mgmProto.RuleAction_ACCEPT,
+		Protocol:  mgmProto.RuleProtocol_TCP,
+		Port:      "443",
+	}
+	ruleB := &mgmProto.FirewallRule{
+		PolicyID:  []byte("policy-B"),
+		PeerIP:    "10.0.0.1", //nolint:staticcheck
+		Direction: mgmProto.RuleDirection_IN,
+		Action:    mgmProto.RuleAction_ACCEPT,
+		Protocol:  mgmProto.RuleProtocol_TCP,
+		Port:      "443",
+	}
+
+	// Both policies present: identical content collapses to one rule.
+	acl.ApplyFiltering(&mgmProto.NetworkMap{FirewallRules: []*mgmProto.FirewallRule{ruleA, ruleB}, FirewallRulesIsEmpty: false}, false)
+	assert.Equal(t, 1, fw.distinctRules(), "identical-content policies must produce one backing rule")
+	assert.Equal(t, 1, len(acl.peerRulesPairs), "one content key, one pair")
+
+	// Drop policy A only: the shared rule is still authorized by B, so
+	// nothing is deleted.
+	acl.ApplyFiltering(&mgmProto.NetworkMap{FirewallRules: []*mgmProto.FirewallRule{ruleB}, FirewallRulesIsEmpty: false}, false)
+	assert.Equal(t, 1, fw.distinctRules(), "no new backing rule on reapply")
+	assert.Equal(t, 0, fw.dels, "rule must survive while any policy still authorizes it")
+	assert.Equal(t, 1, len(acl.peerRulesPairs))
+
+	// Drop policy B too: now the content key has no authorizer and the
+	// single backing rule is removed exactly once.
+	acl.ApplyFiltering(&mgmProto.NetworkMap{FirewallRules: nil, FirewallRulesIsEmpty: true}, false)
+	assert.Equal(t, 1, fw.dels, "rule removed once when last policy is gone")
+	assert.Equal(t, 0, len(acl.peerRulesPairs))
+}

client/internal/acl/grouping_test.go

@@ -0,0 +1,318 @@
+package acl
+
+import (
+	"errors"
+	"net/netip"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.uber.org/mock/gomock"
+
+	"github.com/netbirdio/netbird/client/firewall"
+	fwmgr "github.com/netbirdio/netbird/client/firewall/manager"
+	"github.com/netbirdio/netbird/client/iface"
+	"github.com/netbirdio/netbird/client/iface/wgaddr"
+	"github.com/netbirdio/netbird/client/internal/acl/mocks"
+	mgmProto "github.com/netbirdio/netbird/shared/management/proto"
+	"github.com/netbirdio/netbird/shared/netiputil"
+)
+
+// TestGroupPeerRulesPolicyIDSeparates verifies that two FirewallRules
+// with identical selectors but different PolicyIDs do NOT get merged
+// into one group, so each policy's sources merge under its own
+// attribution id. (Identical-content groups may still dedup to one
+// backing rule at the backend; see TestDuplicateContentPoliciesShareOneRule.)
+func TestGroupPeerRulesPolicyIDSeparates(t *testing.T) {
+	rules := []*mgmProto.FirewallRule{
+		{
+			PolicyID:  []byte("policy-A"),
+			PeerIP:    "10.0.0.1",
+			Direction: mgmProto.RuleDirection_IN,
+			Action:    mgmProto.RuleAction_ACCEPT,
+			Protocol:  mgmProto.RuleProtocol_TCP,
+			Port:      "443",
+		},
+		{
+			PolicyID:  []byte("policy-B"),
+			PeerIP:    "10.0.0.1",
+			Direction: mgmProto.RuleDirection_IN,
+			Action:    mgmProto.RuleAction_ACCEPT,
+			Protocol:  mgmProto.RuleProtocol_TCP,
+			Port:      "443",
+		},
+	}
+
+	groups, denyErr, err := groupPeerRules(rules)
+	require.NoError(t, denyErr)
+	require.NoError(t, err)
+	require.Len(t, groups, 2, "rules with different PolicyIDs must produce separate groups")
+}
+
+// TestGroupPeerRulesFamilySeparates verifies that v4 and v6 rules
+// belonging to the same policy don't merge.
+func TestGroupPeerRulesFamilySeparates(t *testing.T) {
+	rules := []*mgmProto.FirewallRule{
+		{
+			PolicyID:  []byte("policy-A"),
+			PeerIP:    "10.0.0.1",
+			Direction: mgmProto.RuleDirection_IN,
+			Action:    mgmProto.RuleAction_ACCEPT,
+			Protocol:  mgmProto.RuleProtocol_TCP,
+			Port:      "443",
+		},
+		{
+			PolicyID:  []byte("policy-A"),
+			PeerIP:    "2001:db8::1",
+			Direction: mgmProto.RuleDirection_IN,
+			Action:    mgmProto.RuleAction_ACCEPT,
+			Protocol:  mgmProto.RuleProtocol_TCP,
+			Port:      "443",
+		},
+	}
+
+	groups, denyErr, err := groupPeerRules(rules)
+	require.NoError(t, denyErr)
+	require.NoError(t, err)
+	require.Len(t, groups, 2, "rules of different families must produce separate groups")
+
+	var sawV4, sawV6 bool
+	for _, g := range groups {
+		require.Len(t, g.sources, 1)
+		if g.sources[0].Addr().Is4() {
+			sawV4 = true
+		}
+		if g.sources[0].Addr().Is6() {
+			sawV6 = true
+		}
+	}
+	assert.True(t, sawV4 && sawV6)
+}
+
+// TestGroupPeerRulesSplitsMixedFamilySingleRule verifies that a single
+// FirewallRule carrying both v4 and v6 source prefixes is split into one
+// group per family. Each backend keys a rule to a single family, so a
+// group whose sources span families would mismatch the other family's
+// sources. mgmt normally emits one rule per family; this guards against
+// a mixed-family rule slipping through.
+func TestGroupPeerRulesSplitsMixedFamilySingleRule(t *testing.T) {
+	srcs := [][]byte{
+		netiputil.EncodeAddr(netip.MustParseAddr("10.0.0.1")),
+		netiputil.EncodeAddr(netip.MustParseAddr("2001:db8::1")),
+		netiputil.EncodeAddr(netip.MustParseAddr("10.0.0.2")),
+		netiputil.EncodeAddr(netip.MustParseAddr("2001:db8::2")),
+	}
+	rules := []*mgmProto.FirewallRule{
+		{
+			PolicyID:       []byte("policy-A"),
+			SourcePrefixes: srcs,
+			Direction:      mgmProto.RuleDirection_IN,
+			Action:         mgmProto.RuleAction_ACCEPT,
+			Protocol:       mgmProto.RuleProtocol_TCP,
+			Port:           "443",
+		},
+	}
+
+	groups, denyErr, err := groupPeerRules(rules)
+	require.NoError(t, denyErr)
+	require.NoError(t, err)
+	require.Len(t, groups, 2, "mixed-family sources in one rule must split into two groups")
+
+	for _, g := range groups {
+		require.Len(t, g.sources, 2)
+		v6 := prefixIsV6(g.sources[0])
+		for _, s := range g.sources {
+			assert.Equal(t, v6, prefixIsV6(s), "every source in a group must share one family")
+		}
+	}
+}
+
+// TestGroupPeerRulesMergesSameSelector verifies that rules sharing
+// every distinguishing field (policy, family, direction, action,
+// proto, port) collapse into a single multi-source group.
+func TestGroupPeerRulesMergesSameSelector(t *testing.T) {
+	mk := func(peerIP string) *mgmProto.FirewallRule {
+		return &mgmProto.FirewallRule{
+			PolicyID:  []byte("policy-A"),
+			PeerIP:    peerIP, //nolint:staticcheck
+			Direction: mgmProto.RuleDirection_IN,
+			Action:    mgmProto.RuleAction_ACCEPT,
+			Protocol:  mgmProto.RuleProtocol_TCP,
+			Port:      "443",
+		}
+	}
+	rules := []*mgmProto.FirewallRule{mk("10.0.0.1"), mk("10.0.0.2"), mk("10.0.0.3")}
+
+	groups, denyErr, err := groupPeerRules(rules)
+	require.NoError(t, denyErr)
+	require.NoError(t, err)
+	require.Len(t, groups, 1)
+	require.Len(t, groups[0].sources, 3)
+}
+
+// TestGroupPeerRulesPortSeparates verifies that PortInfo is part of the
+// selector key: rules differing only in port must not merge, and a
+// single port must not merge with a range. A regression dropping the
+// port from the key would collapse rules for different ports into one.
+func TestGroupPeerRulesPortSeparates(t *testing.T) {
+	mkPort := func(peerIP string, port uint32) *mgmProto.FirewallRule {
+		return &mgmProto.FirewallRule{
+			PolicyID:  []byte("policy-A"),
+			PeerIP:    peerIP, //nolint:staticcheck
+			Direction: mgmProto.RuleDirection_IN,
+			Action:    mgmProto.RuleAction_ACCEPT,
+			Protocol:  mgmProto.RuleProtocol_TCP,
+			PortInfo:  &mgmProto.PortInfo{PortSelection: &mgmProto.PortInfo_Port{Port: port}},
+		}
+	}
+
+	groups, denyErr, err := groupPeerRules([]*mgmProto.FirewallRule{
+		mkPort("10.0.0.1", 80), mkPort("10.0.0.2", 80), mkPort("10.0.0.3", 443),
+	})
+	require.NoError(t, denyErr)
+	require.NoError(t, err)
+	require.Len(t, groups, 2, "rules on different ports must not merge")
+
+	rangeRule := &mgmProto.FirewallRule{
+		PolicyID:  []byte("policy-A"),
+		PeerIP:    "10.0.0.4", //nolint:staticcheck
+		Direction: mgmProto.RuleDirection_IN,
+		Action:    mgmProto.RuleAction_ACCEPT,
+		Protocol:  mgmProto.RuleProtocol_TCP,
+		PortInfo:  &mgmProto.PortInfo{PortSelection: &mgmProto.PortInfo_Range_{Range: &mgmProto.PortInfo_Range{Start: 80, End: 90}}},
+	}
+	groups, denyErr, err = groupPeerRules([]*mgmProto.FirewallRule{mkPort("10.0.0.1", 80), rangeRule})
+	require.NoError(t, denyErr)
+	require.NoError(t, err)
+	require.Len(t, groups, 2, "a single port and a range must not merge")
+}
+
+// TestGroupPeerRulesUsesSourcePrefixesWhenPresent verifies that the
+// new sourcePrefixes wire field is consumed and produces a
+// multi-source group in one shot (no client-side merging needed).
+func TestGroupPeerRulesUsesSourcePrefixesWhenPresent(t *testing.T) {
+	srcs := [][]byte{
+		netiputil.EncodeAddr(netip.MustParseAddr("10.0.0.1")),
+		netiputil.EncodeAddr(netip.MustParseAddr("10.0.0.2")),
+		netiputil.EncodeAddr(netip.MustParseAddr("10.0.0.3")),
+	}
+	rules := []*mgmProto.FirewallRule{
+		{
+			PolicyID:       []byte("policy-A"),
+			SourcePrefixes: srcs,
+			Direction:      mgmProto.RuleDirection_IN,
+			Action:         mgmProto.RuleAction_ACCEPT,
+			Protocol:       mgmProto.RuleProtocol_TCP,
+			Port:           "443",
+		},
+	}
+
+	groups, denyErr, err := groupPeerRules(rules)
+	require.NoError(t, denyErr)
+	require.NoError(t, err)
+	require.Len(t, groups, 1)
+	require.Len(t, groups[0].sources, 3)
+}
+
+// TestGroupPeerRulesActionSeparates verifies the obvious: accept
+// and drop rules with the same selector don't merge.
+func TestGroupPeerRulesActionSeparates(t *testing.T) {
+	rules := []*mgmProto.FirewallRule{
+		{
+			PolicyID:  []byte("policy-A"),
+			PeerIP:    "10.0.0.1",
+			Direction: mgmProto.RuleDirection_IN,
+			Action:    mgmProto.RuleAction_ACCEPT,
+			Protocol:  mgmProto.RuleProtocol_TCP,
+			Port:      "443",
+		},
+		{
+			PolicyID:  []byte("policy-A"),
+			PeerIP:    "10.0.0.1",
+			Direction: mgmProto.RuleDirection_IN,
+			Action:    mgmProto.RuleAction_DROP,
+			Protocol:  mgmProto.RuleProtocol_TCP,
+			Port:      "443",
+		},
+	}
+
+	groups, denyErr, err := groupPeerRules(rules)
+	require.NoError(t, denyErr)
+	require.NoError(t, err)
+	require.Len(t, groups, 2)
+}
+
+// failingDeleteFirewall wraps a real firewall.Manager and forces the
+// next N DeleteFilterRule calls to fail. Used to verify that the acl
+// manager retains rules whose deletion was rejected by the backend,
+// so they get retried on the next ApplyFiltering pass instead of
+// becoming orphans.
+type failingDeleteFirewall struct {
+	fwmgr.Manager
+	failCount int
+}
+
+func (f *failingDeleteFirewall) DeleteFilterRule(r fwmgr.Rule) error {
+	if f.failCount > 0 {
+		f.failCount--
+		return errors.New("simulated delete failure")
+	}
+	return f.Manager.DeleteFilterRule(r)
+}
+
+// TestApplyFilteringRetainsRulesOnDeleteFailure verifies that a
+// transient DeleteFilterRule error doesn't make the acl manager
+// forget about a rule. The rule must remain in peerRulesPairs so the
+// next ApplyFiltering pass attempts the delete again.
+func TestApplyFilteringRetainsRulesOnDeleteFailure(t *testing.T) {
+	t.Setenv("NB_WG_KERNEL_DISABLED", "true")
+	t.Setenv(firewall.EnvForceUserspaceFirewall, "true")
+
+	ctrl := gomock.NewController(t)
+	defer ctrl.Finish()
+
+	ifaceMock := mocks.NewMockIFaceMapper(ctrl)
+	ifaceMock.EXPECT().IsUserspaceBind().Return(true).AnyTimes()
+	ifaceMock.EXPECT().SetFilter(gomock.Any())
+	network := netip.MustParsePrefix("172.0.0.1/32")
+	ifaceMock.EXPECT().Name().Return("lo").AnyTimes()
+	ifaceMock.EXPECT().Address().Return(wgaddr.Address{IP: network.Addr(), Network: network}).AnyTimes()
+	ifaceMock.EXPECT().GetWGDevice().Return(nil).AnyTimes()
+
+	realFW, err := firewall.NewFirewall(ifaceMock, nil, flowLogger, false, iface.DefaultMTU)
+	require.NoError(t, err)
+	defer func() { require.NoError(t, realFW.Close(nil)) }()
+
+	fw := &failingDeleteFirewall{Manager: realFW}
+	acl := NewDefaultManager(fw)
+
+	// First pass: install a rule.
+	netmap1 := &mgmProto.NetworkMap{
+		FirewallRules: []*mgmProto.FirewallRule{
+			{
+				PolicyID:  []byte("policy-A"),
+				PeerIP:    "10.0.0.1",
+				Direction: mgmProto.RuleDirection_IN,
+				Action:    mgmProto.RuleAction_DROP,
+				Protocol:  mgmProto.RuleProtocol_TCP,
+				Port:      "22",
+			},
+		},
+		FirewallRulesIsEmpty: false,
+	}
+	acl.ApplyFiltering(netmap1, false)
+	require.Equal(t, 1, len(acl.peerRulesPairs), "rule should be installed")
+
+	// Second pass: remove the rule from the map. The backend will
+	// fail the delete; the acl manager must retain the rule.
+	fw.failCount = 1
+	netmap2 := &mgmProto.NetworkMap{FirewallRules: nil, FirewallRulesIsEmpty: true}
+	acl.ApplyFiltering(netmap2, false)
+	require.Equal(t, 1, len(acl.peerRulesPairs),
+		"rule must be retained when DeleteFilterRule fails so it gets retried")
+
+	// Third pass: same map, backend no longer fails. The rule
+	// should now succeed in being removed.
+	acl.ApplyFiltering(netmap2, false)
+	require.Equal(t, 0, len(acl.peerRulesPairs), "retry should succeed")
+}

client/internal/acl/id/id.go

@@ -5,18 +5,18 @@ import (
 	"encoding/hex"
 	"fmt"
 	"net/netip"
+	"slices"
 	"strconv"
 
 	"github.com/netbirdio/netbird/client/firewall/manager"
 )
 
-type RuleID string
+// RuleID aliases manager.RuleID so existing nbid.RuleID references
+// keep working while the canonical type lives in the firewall package.
+type RuleID = manager.RuleID
 
-func (r RuleID) ID() string {
+// GenerateRuleID returns a deterministic content hash identifying a filter rule.
-	return string(r)
+func GenerateRuleID(
-}
-
-func GenerateRouteRuleKey(
 	sources []netip.Prefix,
 	destination manager.Network,
 	proto manager.Protocol,
@@ -24,6 +24,7 @@ func GenerateRouteRuleKey(
 	dPort *manager.Port,
 	action manager.Action,
 ) RuleID {
+	sources = slices.Clone(sources)
 	manager.SortPrefixes(sources)
 
 	h := sha256.New()

client/internal/acl/legacy_fallback_test.go

@@ -0,0 +1,75 @@
+package acl
+
+import (
+	"net/netip"
+	"sync"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.uber.org/mock/gomock"
+
+	"github.com/netbirdio/netbird/client/firewall"
+	fwmgr "github.com/netbirdio/netbird/client/firewall/manager"
+	"github.com/netbirdio/netbird/client/iface"
+	"github.com/netbirdio/netbird/client/iface/wgaddr"
+	"github.com/netbirdio/netbird/client/internal/acl/mocks"
+	mgmProto "github.com/netbirdio/netbird/shared/management/proto"
+)
+
+// sourcesRecordingFirewall wraps a real firewall.Manager and records
+// the source prefixes of every AddFilterRule call.
+type sourcesRecordingFirewall struct {
+	fwmgr.Manager
+	mu      sync.Mutex
+	sources [][]netip.Prefix
+}
+
+func (f *sourcesRecordingFirewall) AddFilterRule(id []byte, sources []netip.Prefix, destination fwmgr.Network, proto fwmgr.Protocol, sPort, dPort *fwmgr.Port, action fwmgr.Action) (fwmgr.Rule, error) {
+	f.mu.Lock()
+	f.sources = append(f.sources, sources)
+	f.mu.Unlock()
+	return f.Manager.AddFilterRule(id, sources, destination, proto, sPort, dPort, action)
+}
+
+// TestLegacyManagementFallbackUsesMatchAnySources verifies the
+// allow-all fallback for old management servers (empty FirewallRules
+// without the FirewallRulesIsEmpty flag) reaches the firewall as /0
+// match-any sources. The fallback rule carries PeerIP 0.0.0.0; if that
+// were converted to a host prefix (0.0.0.0/32) it would match nothing
+// and all peer traffic would be dropped.
+func TestLegacyManagementFallbackUsesMatchAnySources(t *testing.T) {
+	t.Setenv("NB_WG_KERNEL_DISABLED", "true")
+	t.Setenv(firewall.EnvForceUserspaceFirewall, "true")
+
+	ctrl := gomock.NewController(t)
+	defer ctrl.Finish()
+
+	ifaceMock := mocks.NewMockIFaceMapper(ctrl)
+	ifaceMock.EXPECT().IsUserspaceBind().Return(true).AnyTimes()
+	ifaceMock.EXPECT().SetFilter(gomock.Any())
+	network := netip.MustParsePrefix("172.0.0.1/32")
+	ifaceMock.EXPECT().Name().Return("lo").AnyTimes()
+	ifaceMock.EXPECT().Address().Return(wgaddr.Address{IP: network.Addr(), Network: network}).AnyTimes()
+	ifaceMock.EXPECT().GetWGDevice().Return(nil).AnyTimes()
+
+	realFW, err := firewall.NewFirewall(ifaceMock, nil, flowLogger, false, iface.DefaultMTU)
+	require.NoError(t, err)
+	defer func() { require.NoError(t, realFW.Close(nil)) }()
+
+	fw := &sourcesRecordingFirewall{Manager: realFW}
+	acl := NewDefaultManager(fw)
+
+	// Old management: no rules and no FirewallRulesIsEmpty flag.
+	acl.ApplyFiltering(&mgmProto.NetworkMap{FirewallRules: nil, FirewallRulesIsEmpty: false}, false)
+
+	fw.mu.Lock()
+	defer fw.mu.Unlock()
+	require.NotEmpty(t, fw.sources, "legacy fallback must install at least one allow-all rule")
+	for _, sources := range fw.sources {
+		require.NotEmpty(t, sources)
+		for _, p := range sources {
+			assert.Equal(t, 0, p.Bits(), "legacy fallback source %s must be a /0 match-any prefix", p)
+		}
+	}
+}

client/internal/acl/manager.go

@@ -1,8 +1,6 @@
 package acl
 
 import (
-	"crypto/md5"
-	"encoding/hex"
 	"errors"
 	"fmt"
 	"net/netip"
@@ -24,6 +22,10 @@ import (
 
 var ErrSourceRangesEmpty = errors.New("sources range is empty")
 
+// ErrNoRuleReturned is returned when the firewall backend reports success
+// from AddFilterRule but yields no rule to track.
+var ErrNoRuleReturned = errors.New("backend returned no rule")
+
 // Manager is a ACL rules manager
 type Manager interface {
 	ApplyFiltering(networkMap *mgmProto.NetworkMap, dnsRouteFeatureFlag bool)
@@ -32,19 +34,48 @@ type Manager interface {
 // DefaultManager uses firewall manager to handle
 type DefaultManager struct {
 	firewall           firewall.Manager
-	ipsetCounter       int
 	peerRulesPairs     map[id.RuleID][]firewall.Rule
-	routeRules         map[id.RuleID]struct{}
+	routeRules         map[id.RuleID]firewall.Rule
 	previousConfigHash uint64
 	hasAppliedConfig   bool
 	mutex              sync.Mutex
 }
 
+// peerRuleGroup collapses a set of single-source FirewallRules sharing
+// the same selector into one multi-source rule to push to the backend.
+type peerRuleGroup struct {
+	direction mgmProto.RuleDirection
+	action    mgmProto.RuleAction
+	protocol  mgmProto.RuleProtocol
+	port      *mgmProto.PortInfo
+	// legacyPort is used only when PortInfo is empty (old management).
+	legacyPort string
+	policyID   []byte
+	sources    []netip.Prefix
+}
+
+// peerRuleKey is the comparable selector that decides which single-source
+// rules merge into one group. Rules with an equal key collapse into one
+// multi-source backend rule. PortInfo is flattened into its scalar fields
+// so the key compares by value; policyID keeps policies separate so two
+// policies authorizing different peers don't merge under one attribution.
+type peerRuleKey struct {
+	v6         bool
+	policyID   string
+	direction  mgmProto.RuleDirection
+	action     mgmProto.RuleAction
+	protocol   mgmProto.RuleProtocol
+	legacyPort string
+	port       uint16
+	rangeStart uint16
+	rangeEnd   uint16
+}
+
 func NewDefaultManager(fm firewall.Manager) *DefaultManager {
 	return &DefaultManager{
 		firewall:       fm,
 		peerRulesPairs: make(map[id.RuleID][]firewall.Rule),
-		routeRules:     make(map[id.RuleID]struct{}),
+		routeRules:     make(map[id.RuleID]firewall.Rule),
 	}
 }
 
@@ -88,11 +119,14 @@ func (d *DefaultManager) ApplyFiltering(networkMap *mgmProto.NetworkMap, dnsRout
 			time.Since(start), total)
 	}()
 
-	d.applyPeerACLs(networkMap)
+	peerErr := d.applyPeerACLs(networkMap)
+	if peerErr != nil {
+		log.Errorf("apply peer ACLs: %v", peerErr)
+	}
 
 	routeErr := d.applyRouteACLs(networkMap.RoutesFirewallRules, dnsRouteFeatureFlag)
 	if routeErr != nil {
-		log.Errorf("Failed to apply route ACLs: %v", routeErr)
+		log.Errorf("apply route ACLs: %v", routeErr)
 	}
 
 	flushErr := d.firewall.Flush()
@@ -104,7 +138,7 @@ func (d *DefaultManager) ApplyFiltering(networkMap *mgmProto.NetworkMap, dnsRout
 	// If applying or flushing failed, leave the previous hash untouched so the
 	// next (possibly identical) update is not skipped and gets a chance to
 	// reconcile the firewall state.
-	if err == nil && routeErr == nil && flushErr == nil {
+	if err == nil && peerErr == nil && routeErr == nil && flushErr == nil {
 		d.previousConfigHash = hash
 		d.hasAppliedConfig = true
 	} else {
@@ -135,7 +169,7 @@ func (d *DefaultManager) firewallConfigHash(networkMap *mgmProto.NetworkMap, dns
 	})
 }
 
-func (d *DefaultManager) applyPeerACLs(networkMap *mgmProto.NetworkMap) {
+func (d *DefaultManager) applyPeerACLs(networkMap *mgmProto.NetworkMap) error {
 	rules := networkMap.FirewallRules
 
 	// if we got empty rules list but management not set networkMap.FirewallRulesIsEmpty flag
@@ -158,59 +192,167 @@ func (d *DefaultManager) applyPeerACLs(networkMap *mgmProto.NetworkMap) {
 		)
 	}
 
-	newRulePairs := make(map[id.RuleID][]firewall.Rule)
+	// Group incoming single-source rules from management by their
-	ipsetByRuleSelectors := make(map[string]string)
+	// (direction, action, proto, port) selector and merge sources.
+	// One call to the firewall backend per merged rule.
+	// A deny we cannot decode would leave its traffic unblocked, so skip
+	// the whole pass and keep existing rules until the next sync.
+	groups, denyErr, err := groupPeerRules(rules)
+	if denyErr != nil {
+		return fmt.Errorf("decode deny rule sources: %w", denyErr)
+	}
 
-	// TODO: deny rules should be fatal: if a deny rule fails to apply, we must
+	newRulePairs := make(map[id.RuleID][]firewall.Rule)
-	// roll back all allow rules to avoid a fail-open where allowed traffic bypasses
-	// the missing deny. Currently we accumulate errors and continue.
 	var merr *multierror.Error
-	for _, r := range rules {
+	if err != nil {
-		// if this rule is member of rule selection with more than DefaultIPsCountForSet
+		merr = multierror.Append(merr, err)
-		// it's IP address can be used in the ipset for firewall manager which supports it
+	}
-		selector := d.getRuleGroupingSelector(r)
+
-		ipsetName, ok := ipsetByRuleSelectors[selector]
+	// Apply denies first. A deny that fails to install is a security
-		if !ok {
+	// failure (fail-open), so if any deny errors we roll back the
-			d.ipsetCounter++
+	// denies we already installed in this pass and bail out without
-			ipsetName = fmt.Sprintf("nb%07d", d.ipsetCounter)
+	// installing any accept. Pre-existing rules stay untouched until
-			ipsetByRuleSelectors[selector] = ipsetName
+	// the next successful pass clears them.
-		}
+	denies, accepts := splitDenyAccept(groups)
-		pairID, rulePair, err := d.protoRuleToFirewallRule(r, ipsetName)
+	if err := d.installPeerGroups(denies, newRulePairs, true); err != nil {
-		if err != nil {
+		return fmt.Errorf("install deny rules: %w", err)
-			merr = multierror.Append(merr, fmt.Errorf("apply firewall rule: %w", err))
+	}
+
+	if err := d.installPeerGroups(accepts, newRulePairs, false); err != nil {
+		merr = multierror.Append(merr, err)
+	}
+
+	// Tear down rules that disappeared from the networkmap. Any rule
+	// the backend refuses to delete stays in our tracking so it gets
+	// retried on the next ApplyFiltering. Otherwise a transient
+	// delete failure would leak the rule in the firewall until the
+	// process exits.
+	for pairID, rules := range d.peerRulesPairs {
+		if _, ok := newRulePairs[pairID]; ok {
 			continue
 		}
-		if len(rulePair) > 0 {
+		var remaining []firewall.Rule
-			d.peerRulesPairs[pairID] = rulePair
+		for _, rule := range rules {
-			newRulePairs[pairID] = rulePair
+			if err := d.firewall.DeleteFilterRule(rule); err != nil {
-		}
+				merr = multierror.Append(merr, fmt.Errorf("delete peer rule, will retry: %w", err))
-	}
+				remaining = append(remaining, rule)
-
-	if merr != nil {
-		log.Errorf("failed to apply %d peer ACL rule(s): %v", merr.Len(), nberrors.FormatErrorOrNil(merr))
-	}
-
-	for pairID, rules := range d.peerRulesPairs {
-		if _, ok := newRulePairs[pairID]; !ok {
-			for _, rule := range rules {
-				if err := d.firewall.DeletePeerRule(rule); err != nil {
-					log.Errorf("failed to delete peer firewall rule: %v", err)
-					continue
-				}
 			}
-			delete(d.peerRulesPairs, pairID)
+		}
+		if len(remaining) > 0 {
+			newRulePairs[pairID] = remaining
 		}
 	}
 	d.peerRulesPairs = newRulePairs
+
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+// installPeerGroups applies each group and records the resulting rule
+// pairs in newRulePairs. With atomic set (deny rules), a single failure
+// rolls back every rule installed in this call and returns, leaving the
+// firewall exactly as before: denies are fail-closed and must be applied
+// all-or-nothing. With atomic unset (accept rules), failures are
+// accumulated and the remaining groups still install, so one malformed
+// allow cannot drop every other legitimate allow in the pass.
+func (d *DefaultManager) installPeerGroups(groups []*peerRuleGroup, newRulePairs map[id.RuleID][]firewall.Rule, atomic bool) error {
+	var freshlyInstalled []id.RuleID
+	var merr *multierror.Error
+	for _, g := range groups {
+		pairID, rulePair, err := d.applyPeerGroup(g)
+		if err != nil {
+			if atomic {
+				d.rollbackInstalled(freshlyInstalled)
+				return fmt.Errorf("apply firewall rule: %w", err)
+			}
+			merr = multierror.Append(merr, fmt.Errorf("apply firewall rule: %w", err))
+			continue
+		}
+		if len(rulePair) == 0 {
+			continue
+		}
+		if _, existed := d.peerRulesPairs[pairID]; !existed {
+			freshlyInstalled = append(freshlyInstalled, pairID)
+		}
+		d.peerRulesPairs[pairID] = rulePair
+		newRulePairs[pairID] = rulePair
+	}
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+func (d *DefaultManager) rollbackInstalled(pairIDs []id.RuleID) {
+	var merr *multierror.Error
+	for _, pairID := range pairIDs {
+		// Keep any rule the backend refuses to delete tracked so it is
+		// retried on the next ApplyFiltering instead of leaking in the
+		// firewall with no tracking left to remove it.
+		var remaining []firewall.Rule
+		for _, rule := range d.peerRulesPairs[pairID] {
+			if err := d.firewall.DeleteFilterRule(rule); err != nil {
+				merr = multierror.Append(merr, fmt.Errorf("rule %s: %w", pairID, err))
+				remaining = append(remaining, rule)
+			}
+		}
+		if len(remaining) > 0 {
+			d.peerRulesPairs[pairID] = remaining
+		} else {
+			delete(d.peerRulesPairs, pairID)
+		}
+	}
+	if err := nberrors.FormatErrorOrNil(merr); err != nil {
+		log.Errorf("rollback peer rules: %v", err)
+	}
+}
+
+func (d *DefaultManager) applyPeerGroup(g *peerRuleGroup) (id.RuleID, []firewall.Rule, error) {
+	protocol, err := ConvertToFirewallProtocol(g.protocol)
+	if err != nil {
+		return "", nil, fmt.Errorf("skipping firewall rule: %w", err)
+	}
+	action, err := convertFirewallAction(g.action)
+	if err != nil {
+		return "", nil, fmt.Errorf("skipping firewall rule: %w", err)
+	}
+	port, err := resolveGroupPort(g)
+	if err != nil {
+		return "", nil, err
+	}
+
+	var fwRule firewall.Rule
+	switch g.direction {
+	case mgmProto.RuleDirection_IN:
+		fwRule, err = d.firewall.AddFilterRule(g.policyID, g.sources, firewall.Network{}, protocol, nil, port, action)
+	case mgmProto.RuleDirection_OUT:
+		if d.firewall.IsStateful() {
+			return "", nil, nil
+		}
+		if shouldSkipInvertedRule(protocol, port) {
+			return "", nil, nil
+		}
+		fwRule, err = d.firewall.AddFilterRule(g.policyID, g.sources, firewall.Network{}, protocol, port, nil, action)
+	default:
+		return "", nil, errors.New("invalid direction")
+	}
+
+	if err != nil {
+		return "", nil, fmt.Errorf("add firewall rule: %w", err)
+	}
+	if fwRule == nil {
+		return "", nil, fmt.Errorf("add firewall rule: %w", ErrNoRuleReturned)
+	}
+
+	// Derive the pair id from the backend rule, like the route path:
+	// the backend dedups identical content, so two policies authorizing
+	// the same flow resolve to the same id and a single backing rule.
+	return fwRule.ID(), []firewall.Rule{fwRule}, nil
 }
 
 func (d *DefaultManager) applyRouteACLs(rules []*mgmProto.RouteFirewallRule, dynamicResolver bool) error {
-	newRouteRules := make(map[id.RuleID]struct{}, len(rules))
+	newRouteRules := make(map[id.RuleID]firewall.Rule, len(rules))
 	var merr *multierror.Error
 
-	// Apply new rules - firewall manager will return existing rule ID if already present
+	// Apply new rules - firewall manager will return the existing rule if already present
 	for _, rule := range rules {
-		id, err := d.applyRouteACL(rule, dynamicResolver)
+		addedRule, err := d.applyRouteACL(rule, dynamicResolver)
 		if err != nil {
 			if errors.Is(err, ErrSourceRangesEmpty) {
 				log.Debugf("skipping empty sources rule with destination %s: %v", rule.Destination, err)
@@ -219,16 +361,18 @@ func (d *DefaultManager) applyRouteACLs(rules []*mgmProto.RouteFirewallRule, dyn
 			}
 			continue
 		}
-		newRouteRules[id] = struct{}{}
+		newRouteRules[addedRule.ID()] = addedRule
 	}
 
-	// Clean up old firewall rules
+	// Tear down old route rules; retain ones the backend refused so a
-	for id := range d.routeRules {
+	// transient failure doesn't leave orphaned rules in the firewall.
-		if _, exists := newRouteRules[id]; !exists {
+	for ruleID, rule := range d.routeRules {
-			if err := d.firewall.DeleteRouteRule(id); err != nil {
+		if _, exists := newRouteRules[ruleID]; exists {
-				merr = multierror.Append(merr, fmt.Errorf("delete route rule: %w", err))
+			continue
-			}
+		}
-			// implicitly deleted from the map
+		if err := d.firewall.DeleteFilterRule(rule); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("delete route rule, will retry: %w", err))
+			newRouteRules[ruleID] = rule
 		}
 	}
 
@@ -236,102 +380,202 @@ func (d *DefaultManager) applyRouteACLs(rules []*mgmProto.RouteFirewallRule, dyn
 	return nberrors.FormatErrorOrNil(merr)
 }
 
-func (d *DefaultManager) applyRouteACL(rule *mgmProto.RouteFirewallRule, dynamicResolver bool) (id.RuleID, error) {
+func (d *DefaultManager) applyRouteACL(rule *mgmProto.RouteFirewallRule, dynamicResolver bool) (firewall.Rule, error) {
 	if len(rule.SourceRanges) == 0 {
-		return "", ErrSourceRangesEmpty
+		return nil, ErrSourceRangesEmpty
 	}
 
 	var sources []netip.Prefix
 	for _, sourceRange := range rule.SourceRanges {
 		source, err := netip.ParsePrefix(sourceRange)
 		if err != nil {
-			return "", fmt.Errorf("parse source range: %w", err)
+			return nil, fmt.Errorf("parse source range: %w", err)
 		}
-		sources = append(sources, source)
+		sources = append(sources, firewall.UnmapPrefix(source))
 	}
 
 	destination, err := determineDestination(rule, dynamicResolver, sources)
 	if err != nil {
-		return "", fmt.Errorf("determine destination: %w", err)
+		return nil, fmt.Errorf("determine destination: %w", err)
 	}
 
-	protocol, err := convertToFirewallProtocol(rule.Protocol)
+	protocol, err := ConvertToFirewallProtocol(rule.Protocol)
 	if err != nil {
-		return "", fmt.Errorf("invalid protocol: %w", err)
+		return nil, fmt.Errorf("invalid protocol: %w", err)
 	}
 
 	action, err := convertFirewallAction(rule.Action)
 	if err != nil {
-		return "", fmt.Errorf("invalid action: %w", err)
+		return nil, fmt.Errorf("invalid action: %w", err)
 	}
 
 	dPorts := convertPortInfo(rule.PortInfo)
 
-	addedRule, err := d.firewall.AddRouteFiltering(rule.PolicyID, sources, destination, protocol, nil, dPorts, action)
+	addedRule, err := d.firewall.AddFilterRule(rule.PolicyID, sources, destination, protocol, nil, dPorts, action)
 	if err != nil {
-		return "", fmt.Errorf("add route rule: %w", err)
+		return nil, fmt.Errorf("add route rule: %w", err)
+	}
+	if addedRule == nil {
+		return nil, fmt.Errorf("add route rule: %w", ErrNoRuleReturned)
 	}
 
-	return id.RuleID(addedRule.ID()), nil
+	return addedRule, nil
 }
 
-func (d *DefaultManager) protoRuleToFirewallRule(
+// splitDenyAccept partitions groups by action so denies can be
-	r *mgmProto.FirewallRule,
+// applied before accepts. Order within each bucket is preserved.
-	ipsetName string,
+func splitDenyAccept(groups []*peerRuleGroup) (denies, accepts []*peerRuleGroup) {
-) (id.RuleID, []firewall.Rule, error) {
+	for _, g := range groups {
-	ip, err := extractRuleIP(r)
+		if g.action == mgmProto.RuleAction_DROP {
-	if err != nil {
+			denies = append(denies, g)
-		return "", nil, err
+		} else {
+			accepts = append(accepts, g)
+		}
+	}
+	return denies, accepts
+}
+
+// groupPeerRules merges single-source rules sharing a selector into
+// multi-source groups. It splits source-decode failures by action:
+// denyErr is non-nil when a deny rule could not be decoded, which is a
+// fail-open risk the caller must treat as fatal for the pass; err
+// carries the tolerable accept-rule failures the caller can log and
+// continue past.
+func groupPeerRules(rules []*mgmProto.FirewallRule) (groups []*peerRuleGroup, denyErr error, err error) {
+	var denyMerr, acceptMerr *multierror.Error
+	byKey := make(map[peerRuleKey]*peerRuleGroup)
+	order := make([]peerRuleKey, 0)
+
+	for _, r := range rules {
+		srcs, decErr := extractRuleSources(r)
+		if decErr != nil {
+			if r.Action == mgmProto.RuleAction_DROP {
+				denyMerr = multierror.Append(denyMerr, decErr)
+			} else {
+				acceptMerr = multierror.Append(acceptMerr, decErr)
+			}
+			continue
+		}
+		// A single FirewallRule normally carries one address family, but
+		// split by family defensively: each backend keys a rule to one
+		// family and would mismatch sources of the other, so a group's
+		// sources must never span families.
+		v4, v6 := splitPrefixesByFamily(srcs)
+		for _, sub := range []struct {
+			isV6    bool
+			sources []netip.Prefix
+		}{{false, v4}, {true, v6}} {
+			if len(sub.sources) == 0 {
+				continue
+			}
+			key := ruleGroupKey(r, sub.isV6)
+			g, ok := byKey[key]
+			if !ok {
+				g = &peerRuleGroup{
+					direction:  r.Direction,
+					action:     r.Action,
+					protocol:   r.Protocol,
+					port:       r.PortInfo,
+					legacyPort: r.Port,
+					policyID:   r.PolicyID,
+				}
+				byKey[key] = g
+				order = append(order, key)
+			}
+			g.sources = append(g.sources, sub.sources...)
+		}
 	}
 
-	protocol, err := convertToFirewallProtocol(r.Protocol)
+	out := make([]*peerRuleGroup, 0, len(order))
-	if err != nil {
+	for _, k := range order {
-		return "", nil, fmt.Errorf("skipping firewall rule: %s", err)
+		out = append(out, byKey[k])
+	}
+	return out, nberrors.FormatErrorOrNil(denyMerr), nberrors.FormatErrorOrNil(acceptMerr)
+}
+
+func prefixIsV6(p netip.Prefix) bool {
+	return p.Addr().Is6() && !p.Addr().Is4In6()
+}
+
+// splitPrefixesByFamily partitions prefixes into IPv4 and IPv6 groups.
+func splitPrefixesByFamily(prefixes []netip.Prefix) (v4, v6 []netip.Prefix) {
+	for _, p := range prefixes {
+		if prefixIsV6(p) {
+			v6 = append(v6, p)
+		} else {
+			v4 = append(v4, p)
+		}
+	}
+	return v4, v6
+}
+
+// ruleGroupKey builds the selector key for a rule. v6 must reflect the
+// rule's source family: mgmt emits one rule per family and mixing them
+// would break ICMP-variant selection in uspfilter.
+func ruleGroupKey(r *mgmProto.FirewallRule, v6 bool) peerRuleKey {
+	k := peerRuleKey{
+		v6:         v6,
+		policyID:   string(r.PolicyID),
+		direction:  r.Direction,
+		action:     r.Action,
+		protocol:   r.Protocol,
+		legacyPort: r.Port,
+	}
+	if pi := r.PortInfo; pi != nil {
+		k.port = uint16(pi.GetPort())
+		if rng := pi.GetRange(); rng != nil {
+			k.rangeStart = uint16(rng.GetStart())
+			k.rangeEnd = uint16(rng.GetEnd())
+		}
+	}
+	return k
+}
+
+// extractRuleSources returns all source prefixes the rule applies to.
+// New management populates sourcePrefixes; older management sets PeerIP.
+func extractRuleSources(r *mgmProto.FirewallRule) ([]netip.Prefix, error) {
+	if len(r.SourcePrefixes) > 0 {
+		out := make([]netip.Prefix, 0, len(r.SourcePrefixes))
+		for _, raw := range r.SourcePrefixes {
+			addr, err := netiputil.DecodeAddr(raw)
+			if err != nil {
+				return nil, fmt.Errorf("decode source prefix: %w", err)
+			}
+			out = append(out, netip.PrefixFrom(addr.Unmap(), addr.Unmap().BitLen()))
+		}
+		return out, nil
 	}
 
-	action, err := convertFirewallAction(r.Action)
+	peerIP := r.PeerIP //nolint:staticcheck // PeerIP is the legacy source field for old management servers
+	addr, err := netip.ParseAddr(peerIP)
 	if err != nil {
-		return "", nil, fmt.Errorf("skipping firewall rule: %s", err)
+		return nil, fmt.Errorf("parse peer IP %q: %w", peerIP, err)
 	}
+	addr = addr.Unmap()
+	// An unspecified PeerIP means "any peer" (legacy management
+	// allow-all fallback); only a /0 prefix matches any source in the
+	// backends, a full-length prefix would match nothing.
+	if addr.IsUnspecified() {
+		return []netip.Prefix{netip.PrefixFrom(addr, 0)}, nil
+	}
+	return []netip.Prefix{netip.PrefixFrom(addr, addr.BitLen())}, nil
+}
 
-	var port *firewall.Port
+func resolveGroupPort(g *peerRuleGroup) (*firewall.Port, error) {
-	if !portInfoEmpty(r.PortInfo) {
+	if !portInfoEmpty(g.port) {
-		port = convertPortInfo(r.PortInfo)
+		return convertPortInfo(g.port), nil
-	} else if r.Port != "" {
+	}
-		// old version of management, single port
+	if g.legacyPort != "" {
-		value, err := strconv.Atoi(r.Port)
+		value, err := strconv.ParseUint(g.legacyPort, 10, 16)
 		if err != nil {
-			return "", nil, fmt.Errorf("invalid port: %w", err)
+			return nil, fmt.Errorf("invalid port: %w", err)
 		}
-		port = &firewall.Port{
+		return &firewall.Port{
 			Values: []uint16{uint16(value)},
-		}
+		}, nil
 	}
-
+	// nolint:nilnil // a nil port legitimately means "no port restriction"
-	ruleID := d.getPeerRuleID(ip, protocol, int(r.Direction), port, action)
+	return nil, nil
-	if rulesPair, ok := d.peerRulesPairs[ruleID]; ok {
-		return ruleID, rulesPair, nil
-	}
-
-	var rules []firewall.Rule
-	switch r.Direction {
-	case mgmProto.RuleDirection_IN:
-		rules, err = d.addInRules(r.PolicyID, ip, protocol, port, action, ipsetName)
-	case mgmProto.RuleDirection_OUT:
-		if d.firewall.IsStateful() {
-			return "", nil, nil
-		}
-		// return traffic for outbound connections if firewall is stateless
-		rules, err = d.addOutRules(r.PolicyID, ip, protocol, port, action, ipsetName)
-	default:
-		return "", nil, fmt.Errorf("invalid direction, skipping firewall rule")
-	}
-
-	if err != nil {
-		return "", nil, err
-	}
-
-	return ruleID, rules, nil
 }
 
 func portInfoEmpty(portInfo *mgmProto.PortInfo) bool {
@@ -350,84 +594,9 @@ func portInfoEmpty(portInfo *mgmProto.PortInfo) bool {
 	}
 }
 
-func (d *DefaultManager) addInRules(
+// ConvertToFirewallProtocol maps a management rule protocol to the
-	id []byte,
+// firewall protocol type.
-	ip netip.Addr,
+func ConvertToFirewallProtocol(protocol mgmProto.RuleProtocol) (firewall.Protocol, error) {
-	protocol firewall.Protocol,
-	port *firewall.Port,
-	action firewall.Action,
-	ipsetName string,
-) ([]firewall.Rule, error) {
-	rule, err := d.firewall.AddPeerFiltering(id, ip.AsSlice(), protocol, nil, port, action, ipsetName)
-	if err != nil {
-		return nil, fmt.Errorf("add firewall rule: %w", err)
-	}
-
-	return rule, nil
-}
-
-func (d *DefaultManager) addOutRules(
-	id []byte,
-	ip netip.Addr,
-	protocol firewall.Protocol,
-	port *firewall.Port,
-	action firewall.Action,
-	ipsetName string,
-) ([]firewall.Rule, error) {
-	if shouldSkipInvertedRule(protocol, port) {
-		return nil, nil
-	}
-
-	rule, err := d.firewall.AddPeerFiltering(id, ip.AsSlice(), protocol, port, nil, action, ipsetName)
-	if err != nil {
-		return nil, fmt.Errorf("add firewall rule: %w", err)
-	}
-
-	return rule, nil
-}
-
-// getPeerRuleID returns unique ID for the rule based on its parameters.
-func (d *DefaultManager) getPeerRuleID(
-	ip netip.Addr,
-	proto firewall.Protocol,
-	direction int,
-	port *firewall.Port,
-	action firewall.Action,
-) id.RuleID {
-	idStr := ip.String() + string(proto) + strconv.Itoa(direction) + strconv.Itoa(int(action))
-	if port != nil {
-		idStr += port.String()
-	}
-
-	return id.RuleID(hex.EncodeToString(md5.New().Sum([]byte(idStr))))
-}
-
-// getRuleGroupingSelector takes all rule properties except IP address to build selector
-func (d *DefaultManager) getRuleGroupingSelector(rule *mgmProto.FirewallRule) string {
-	return fmt.Sprintf("%v:%v:%v:%s:%v", strconv.Itoa(int(rule.Direction)), rule.Action, rule.Protocol, rule.Port, rule.PortInfo)
-}
-
-// extractRuleIP extracts the peer IP from a firewall rule.
-// If sourcePrefixes is populated (new management), decode the first entry and use its address.
-// Otherwise fall back to the deprecated PeerIP string field (old management).
-func extractRuleIP(r *mgmProto.FirewallRule) (netip.Addr, error) {
-	if len(r.SourcePrefixes) > 0 {
-		addr, err := netiputil.DecodeAddr(r.SourcePrefixes[0])
-		if err != nil {
-			return netip.Addr{}, fmt.Errorf("decode source prefix: %w", err)
-		}
-		return addr.Unmap(), nil
-	}
-
-	//nolint:staticcheck // PeerIP used for backward compatibility with old management
-	addr, err := netip.ParseAddr(r.PeerIP)
-	if err != nil {
-		return netip.Addr{}, fmt.Errorf("invalid IP address, skipping firewall rule")
-	}
-	return addr.Unmap(), nil
-}
-
-func convertToFirewallProtocol(protocol mgmProto.RuleProtocol) (firewall.Protocol, error) {
 	switch protocol {
 	case mgmProto.RuleProtocol_TCP:
 		return firewall.ProtocolTCP, nil

client/internal/acl/manager_test.go

@@ -10,6 +10,7 @@ import (
 	"go.uber.org/mock/gomock"
 
 	"github.com/netbirdio/netbird/client/firewall"
+	fwmanager "github.com/netbirdio/netbird/client/firewall/manager"
 	"github.com/netbirdio/netbird/client/iface"
 	"github.com/netbirdio/netbird/client/iface/wgaddr"
 	"github.com/netbirdio/netbird/client/internal/acl/mocks"
@@ -77,9 +78,9 @@ func TestDefaultManager(t *testing.T) {
 	})
 
 	t.Run("add extra rules", func(t *testing.T) {
-		existedPairs := map[string]struct{}{}
+		existedPairs := map[fwmanager.RuleID]struct{}{}
 		for id := range acl.peerRulesPairs {
-			existedPairs[id.ID()] = struct{}{}
+			existedPairs[id] = struct{}{}
 		}
 
 		// remove first rule
@@ -106,7 +107,7 @@ func TestDefaultManager(t *testing.T) {
 		// check that old rule was removed
 		previousCount := 0
 		for id := range acl.peerRulesPairs {
-			if _, ok := existedPairs[id.ID()]; ok {
+			if _, ok := existedPairs[id]; ok {
 				previousCount++
 			}
 		}

client/internal/dns/server_test.go

@@ -423,7 +423,7 @@ func createWgInterfaceWithBind(t *testing.T) (*iface.WGIface, error) {
 		return nil, err
 	}
 
-	pf, err := uspfilter.Create(wgIface, false, flowLogger, iface.DefaultMTU)
+	pf, err := uspfilter.Create(uspfilter.Config{IFace: wgIface, FlowLogger: flowLogger, MTU: iface.DefaultMTU})
 	if err != nil {
 		t.Fatalf("failed to create uspfilter: %v", err)
 		return nil, err

client/internal/dnsfwd/manager.go

@@ -3,7 +3,6 @@ package dnsfwd
 import (
 	"context"
 	"fmt"
-	"net"
 	"net/netip"
 	"os"
 	"strconv"
@@ -160,12 +159,13 @@ func (m *Manager) allowDNSFirewall() error {
 		return nil
 	}
 
-	dnsRules, err := m.firewall.AddPeerFiltering(nil, net.IP{0, 0, 0, 0}, firewall.ProtocolUDP, nil, dport, firewall.ActionAccept, "")
+	anyV4 := []netip.Prefix{netip.PrefixFrom(netip.IPv4Unspecified(), 0)}
+	dnsRule, err := m.firewall.AddFilterRule(nil, anyV4, firewall.Network{}, firewall.ProtocolUDP, nil, dport, firewall.ActionAccept)
 	if err != nil {
 		return fmt.Errorf("add udp firewall rule: %w", err)
 	}
 
-	tcpRules, err := m.firewall.AddPeerFiltering(nil, net.IP{0, 0, 0, 0}, firewall.ProtocolTCP, nil, dport, firewall.ActionAccept, "")
+	tcpRule, err := m.firewall.AddFilterRule(nil, anyV4, firewall.Network{}, firewall.ProtocolTCP, nil, dport, firewall.ActionAccept)
 	if err != nil {
 		return fmt.Errorf("add tcp firewall rule: %w", err)
 	}
@@ -174,8 +174,12 @@ func (m *Manager) allowDNSFirewall() error {
 		return fmt.Errorf("flush: %w", err)
 	}
 
-	m.fwRules = dnsRules
+	if dnsRule != nil {
-	m.tcpRules = tcpRules
+		m.fwRules = []firewall.Rule{dnsRule}
+	}
+	if tcpRule != nil {
+		m.tcpRules = []firewall.Rule{tcpRule}
+	}
 
 	m.registerNetstackServices()
 
@@ -209,12 +213,12 @@ func (m *Manager) unregisterNetstackServices() {
 func (m *Manager) dropDNSFirewall() error {
 	var mErr *multierror.Error
 	for _, rule := range m.fwRules {
-		if err := m.firewall.DeletePeerRule(rule); err != nil {
+		if err := m.firewall.DeleteFilterRule(rule); err != nil {
 			mErr = multierror.Append(mErr, fmt.Errorf("failed to delete DNS router rules, err: %v", err))
 		}
 	}
 	for _, rule := range m.tcpRules {
-		if err := m.firewall.DeletePeerRule(rule); err != nil {
+		if err := m.firewall.DeleteFilterRule(rule); err != nil {
 			mErr = multierror.Append(mErr, fmt.Errorf("failed to delete DNS router rules, err: %v", err))
 		}
 	}

client/internal/engine.go

@@ -745,6 +745,11 @@ func (e *Engine) initFirewall() error {
 		return fmt.Errorf("set firewall: %w", err)
 	}
 
+	// TODO: the firewall backends dedup filter rules by content, so a
+	// management route ACL with identical content would collapse onto the
+	// untracked drop rules installed here, and a later management delete
+	// could remove them. Needs backend refcounting or per-consumer key
+	// namespacing.
 	if e.config.BlockLANAccess {
 		e.blockLanAccess()
 	}
@@ -757,14 +762,14 @@ func (e *Engine) initFirewall() error {
 	port := firewallManager.Port{Values: []uint16{uint16(rosenpassPort)}}
 
 	// IPv4-only: rosenpass peers connect via AllowedIps[0] which is always v4.
-	if _, err := e.firewall.AddPeerFiltering(
+	if _, err := e.firewall.AddFilterRule(
 		nil,
-		net.IP{0, 0, 0, 0},
+		[]netip.Prefix{netip.PrefixFrom(netip.IPv4Unspecified(), 0)},
+		firewallManager.Network{},
 		firewallManager.ProtocolUDP,
 		nil,
 		&port,
 		firewallManager.ActionAccept,
-		"",
 	); err != nil {
 		log.Errorf("failed to allow rosenpass interface traffic: %v", err)
 		return nil
@@ -814,7 +819,7 @@ func (e *Engine) blockLanAccess() {
 		if network.Addr().Is6() {
 			source = v6
 		}
-		if _, err := e.firewall.AddRouteFiltering(
+		if _, err := e.firewall.AddFilterRule(
 			nil,
 			[]netip.Prefix{source},
 			firewallManager.Network{Prefix: network},
@@ -2658,7 +2663,7 @@ func (e *Engine) updateForwardRules(rules []*mgmProto.ForwardingRule) ([]firewal
 	var merr *multierror.Error
 	forwardingRules := make([]firewallManager.ForwardRule, 0, len(rules))
 	for _, rule := range rules {
-		proto, err := convertToFirewallProtocol(rule.GetProtocol())
+		proto, err := acl.ConvertToFirewallProtocol(rule.GetProtocol())
 		if err != nil {
 			merr = multierror.Append(merr, fmt.Errorf("failed to convert protocol '%s': %w", rule.GetProtocol(), err))
 			continue

client/internal/ingressgw/manager.go

@@ -24,14 +24,14 @@ type RulePair struct {
 type Manager struct {
 	dnatFirewall DNATFirewall
 
-	rules   map[string]RulePair // keys is the ID of the ForwardRule
+	rules   map[firewall.RuleID]RulePair
 	rulesMu sync.Mutex
 }
 
 func NewManager(dnatFirewall DNATFirewall) *Manager {
 	return &Manager{
 		dnatFirewall: dnatFirewall,
-		rules:        make(map[string]RulePair),
+		rules:        make(map[firewall.RuleID]RulePair),
 	}
 }
 
@@ -41,7 +41,7 @@ func (h *Manager) Update(forwardRules []firewall.ForwardRule) error {
 
 	var mErr *multierror.Error
 
-	toDelete := make(map[string]RulePair, len(h.rules))
+	toDelete := make(map[firewall.RuleID]RulePair, len(h.rules))
 	for id, r := range h.rules {
 		toDelete[id] = r
 	}
@@ -59,6 +59,10 @@ func (h *Manager) Update(forwardRules []firewall.ForwardRule) error {
 			mErr = multierror.Append(mErr, fmt.Errorf("add forward rule '%s': %v", fwdRule.String(), err))
 			continue
 		}
+		if rule == nil {
+			mErr = multierror.Append(mErr, fmt.Errorf("add forward rule '%s': backend returned no rule", fwdRule.String()))
+			continue
+		}
 		log.Infof("forward rule has been added '%s'", fwdRule)
 		h.rules[id] = RulePair{
 			ForwardRule: fwdRule,
@@ -90,7 +94,7 @@ func (h *Manager) Close() error {
 		}
 	}
 
-	h.rules = make(map[string]RulePair)
+	h.rules = make(map[firewall.RuleID]RulePair)
 	return nberrors.FormatErrorOrNil(mErr)
 }
 

client/internal/ingressgw/manager_test.go

@@ -14,11 +14,11 @@ var (
 )
 
 type MocFwRule struct {
-	id string
+	id firewall.RuleID
 }
 
-func (m *MocFwRule) ID() string {
+func (m *MocFwRule) ID() firewall.RuleID {
-	return string(m.id)
+	return m.id
 }
 
 type MockDNATFirewall struct {

client/internal/message_convert.go

@@ -10,21 +10,6 @@ import (
 	mgmProto "github.com/netbirdio/netbird/shared/management/proto"
 )
 
-func convertToFirewallProtocol(protocol mgmProto.RuleProtocol) (firewallManager.Protocol, error) {
-	switch protocol {
-	case mgmProto.RuleProtocol_TCP:
-		return firewallManager.ProtocolTCP, nil
-	case mgmProto.RuleProtocol_UDP:
-		return firewallManager.ProtocolUDP, nil
-	case mgmProto.RuleProtocol_ICMP:
-		return firewallManager.ProtocolICMP, nil
-	case mgmProto.RuleProtocol_ALL:
-		return firewallManager.ProtocolALL, nil
-	default:
-		return "", fmt.Errorf("invalid protocol type: %s", protocol.String())
-	}
-}
-
 func convertPortInfo(portInfo *mgmProto.PortInfo) (*firewallManager.Port, error) {
 	if portInfo == nil {
 		return nil, errors.New("portInfo cannot be nil")

client/internal/routemanager/server/server.go

@@ -135,6 +135,14 @@ func (r *Router) CleanUp() {
 		}
 	}
 
+	// Give back the routing reference taken in UpdateRoutes, after the routes
+	// are gone as above. Without this the sysctls enabling it changed (IPv6
+	// forwarding and the accept_ra values that keep RA handling alive next to
+	// it) stay applied once the client stops.
+	if err := r.firewall.DisableRouting(); err != nil {
+		log.Errorf("Failed to disable routing: %v", err)
+	}
+
 	r.statusRecorder.CleanLocalPeerStateRoutes()
 }
 

client/internal/routemanager/server/server_test.go

@@ -0,0 +1,66 @@
+package server
+
+import (
+	"context"
+	"net/netip"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	firewall "github.com/netbirdio/netbird/client/firewall/manager"
+	"github.com/netbirdio/netbird/client/internal/peer"
+	"github.com/netbirdio/netbird/route"
+)
+
+// routingFirewall records the routing lifecycle calls the router makes. The
+// embedded interface covers the methods this test never reaches.
+type routingFirewall struct {
+	firewall.Manager
+
+	removed  []firewall.RouterPair
+	enabled  int
+	disabled int
+}
+
+func (f *routingFirewall) RemoveNatRule(pair firewall.RouterPair) error {
+	f.removed = append(f.removed, pair)
+	return nil
+}
+
+func (f *routingFirewall) EnableRouting() error {
+	f.enabled++
+	return nil
+}
+
+func (f *routingFirewall) DisableRouting() error {
+	f.disabled++
+	return nil
+}
+
+// TestRouterCleanUpReleasesRouting covers the shutdown path: the router holds a
+// routing reference for as long as it serves routes, and CleanUp has to give it
+// back. Without that the sysctls the reference enabled (IPv6 forwarding and the
+// accept_ra values that keep RA handling working alongside it) stay applied
+// after the client stops, leaving the host configured as a router.
+func TestRouterCleanUpReleasesRouting(t *testing.T) {
+	fw := &routingFirewall{}
+	r := &Router{
+		ctx:            context.Background(),
+		firewall:       fw,
+		statusRecorder: peer.NewRecorder("https://mgm"),
+		routes: map[route.ID]*route.Route{
+			"route-1": {
+				ID:          "route-1",
+				Network:     netip.MustParsePrefix("192.168.55.0/24"),
+				NetworkType: route.IPv4Network,
+				Masquerade:  true,
+			},
+		},
+	}
+
+	r.CleanUp()
+
+	require.Len(t, fw.removed, 1, "the route's NAT rule must be removed")
+	assert.Equal(t, 1, fw.disabled, "CleanUp must release the routing reference")
+}

client/ssh/server/test.go

@@ -1,9 +1,9 @@
 // This file is intentionally named test.go (not test_test.go) so the exported
 // StartTestServer helper is visible to the ssh/proxy and ssh/client external
 // test packages, not just this package's own tests. The //go:build !js tag
-// keeps its "testing" import — and the whole testing/flag/regexp transitive
+// keeps its "testing" import, along with the whole testing/flag/regexp
-// chain it drags in — out of the wasm client, which links ssh/server through
+// transitive chain it drags in, out of the wasm client, which links
-// the engine but never runs Go tests under GOOS=js.
+// ssh/server through the engine but never runs Go tests under GOOS=js.
 //go:build !js
 
 package server