Add tests

# Conflicts:
#	shared/relay/client/manager.go

client/android/client.go

@@ -247,6 +247,9 @@ func (c *Client) DebugBundle(platformFiles PlatformFiles, anonymize bool) (strin
 		deps.SyncResponse = resp
 
 		if e := cc.Engine(); e != nil {
+			deps.RefreshStatus = func() {
+				e.RunHealthProbes(context.Background(), true)
+			}
 			if cm := e.GetClientMetrics(); cm != nil {
 				deps.ClientMetrics = cm
 			}

client/internal/peer/worker_relay.go

@@ -54,19 +54,15 @@ func (w *WorkerRelay) OnNewOffer(remoteOfferAnswer *OfferAnswer) {
 	w.relaySupportedOnRemotePeer.Store(true)
 
 	// the relayManager will return with error in case if the connection has lost with relay server
-	currentRelayAddress, _, err := w.relayManager.RelayInstanceAddress()
+	_, _, err := w.relayManager.RelayInstanceAddress()
 	if err != nil {
 		w.log.Errorf("failed to handle new offer: %s", err)
 		return
 	}
 
-	srv := w.preferredRelayServer(currentRelayAddress, remoteOfferAnswer.RelaySrvAddress)
-	var serverIP netip.Addr
-	if srv == remoteOfferAnswer.RelaySrvAddress {
-		serverIP = remoteOfferAnswer.RelaySrvIP
-	}
-
-	relayedConn, err := w.relayManager.OpenConn(w.peerCtx, srv, w.config.Key, serverIP)
+	preferForeign := !w.isController
+	remoteRelayServer := relayClient.RelayServer{Addr: remoteOfferAnswer.RelaySrvAddress, IP: remoteOfferAnswer.RelaySrvIP}
+	relayedConn, err := w.relayManager.OpenConn(w.peerCtx, remoteRelayServer, w.config.Key, preferForeign)
 	if err != nil {
 		if errors.Is(err, relayClient.ErrConnAlreadyExists) {
 			w.log.Debugf("handled offer by reusing existing relay connection")
@@ -80,14 +76,13 @@ func (w *WorkerRelay) OnNewOffer(remoteOfferAnswer *OfferAnswer) {
 	w.relayedConn = relayedConn
 	w.relayLock.Unlock()
 
-	err = w.relayManager.AddCloseListener(srv, w.onRelayClientDisconnected)
-	if err != nil {
-		log.Errorf("failed to add close listener: %s", err)
+	if err := w.relayManager.AddCloseListener(relayedConn.RemoteAddr().String(), w.onRelayClientDisconnected); err != nil {
+		w.log.Errorf("failed to add close listener: %s", err)
 		_ = relayedConn.Close()
 		return
 	}
 
-	w.log.Debugf("peer conn opened via Relay: %s", srv)
+	w.log.Debugf("peer conn opened via Relay: %s", relayedConn.RemoteAddr())
 	go w.conn.onRelayConnectionIsReady(RelayConnInfo{
 		relayedConn:     relayedConn,
 		rosenpassPubKey: remoteOfferAnswer.RosenpassPubKey,
@@ -126,13 +121,6 @@ func (w *WorkerRelay) isRelaySupported(answer *OfferAnswer) bool {
 	return answer.RelaySrvAddress != ""
 }
 
-func (w *WorkerRelay) preferredRelayServer(myRelayAddress, remoteRelayAddress string) string {
-	if w.isController {
-		return myRelayAddress
-	}
-	return remoteRelayAddress
-}
-
 func (w *WorkerRelay) onRelayClientDisconnected() {
 	go w.conn.onRelayDisconnected()
 }

client/ios/NetBirdSDK/client.go

@@ -233,6 +233,9 @@ func (c *Client) DebugBundle(anonymize bool) (string, error) {
 		deps.SyncResponse = resp
 
 		if e := cc.Engine(); e != nil {
+			deps.RefreshStatus = func() {
+				e.RunHealthProbes(context.Background(), true)
+			}
 			if cm := e.GetClientMetrics(); cm != nil {
 				deps.ClientMetrics = cm
 			}

go.mod

@@ -113,7 +113,7 @@ require (
 	github.com/ti-mo/conntrack v0.5.1
 	github.com/ti-mo/netfilter v0.5.2
 	github.com/vmihailenco/msgpack/v5 v5.4.1
-	github.com/wailsapp/wails/v3 v3.0.0-alpha2.111
+	github.com/wailsapp/wails/v3 v3.0.0-alpha2.117
 	github.com/yusufpapurcu/wmi v1.2.4
 	github.com/zcalusic/sysinfo v1.1.3
 	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.67.0
@@ -303,7 +303,6 @@ require (
 	github.com/tklauser/numcpus v0.10.0 // indirect
 	github.com/vishvananda/netns v0.0.5 // indirect
 	github.com/vmihailenco/tagparser/v2 v2.0.0 // indirect
-	github.com/wailsapp/wails/webview2 v1.0.27 // indirect
 	github.com/wlynxg/anet v0.0.5 // indirect
 	github.com/x448/float16 v0.8.4 // indirect
 	github.com/zeebo/blake3 v0.2.3 // indirect

go.sum

@@ -660,10 +660,8 @@ github.com/vmihailenco/msgpack/v5 v5.4.1 h1:cQriyiUvjTwOHg8QZaPihLWeRAAVoCpE00IU
 github.com/vmihailenco/msgpack/v5 v5.4.1/go.mod h1:GaZTsDaehaPpQVyxrf5mtQlH+pc21PIudVV/E3rRQok=
 github.com/vmihailenco/tagparser/v2 v2.0.0 h1:y09buUbR+b5aycVFQs/g70pqKVZNBmxwAhO7/IwNM9g=
 github.com/vmihailenco/tagparser/v2 v2.0.0/go.mod h1:Wri+At7QHww0WTrCBeu4J6bNtoV6mEfg5OIWRZA9qds=
-github.com/wailsapp/wails/v3 v3.0.0-alpha2.111 h1:MKx1nOnhnDuEGrRBmtxLOJq1NERwailu2cI4BvzWhi4=
-github.com/wailsapp/wails/v3 v3.0.0-alpha2.111/go.mod h1:wrdvmyeCsB/K3YqJDoH8E3MwcN8NXAMnEFaDTW46w60=
-github.com/wailsapp/wails/webview2 v1.0.27 h1:wjgAi/I8BBZ7kUGU8um3XF3ILEfzr96Q2Q1G4GPjMns=
-github.com/wailsapp/wails/webview2 v1.0.27/go.mod h1:zdM4jcO1IaC61RiJL5F1BzgoqBHFIdacz8gPr5exr0o=
+github.com/wailsapp/wails/v3 v3.0.0-alpha2.117 h1:udyjqPG3AIgkod5QDR/WblCkpV8R86BFPSrsWxSyt5Y=
+github.com/wailsapp/wails/v3 v3.0.0-alpha2.117/go.mod h1:74WH2FScMsgucZvHHvv7eOefDXCm/CjuIxqhhZgPhKg=
 github.com/wlynxg/anet v0.0.5 h1:J3VJGi1gvo0JwZ/P1/Yc/8p63SoW98B5dHkYDmpgvvU=
 github.com/wlynxg/anet v0.0.5/go.mod h1:eay5PRQr7fIVAMbTbchTnO9gG65Hg/uYGdc7mguHxoA=
 github.com/x448/float16 v0.8.4 h1:qLwI1I70+NjRFUR3zs1JPUCgaCXSh3SW62uAKT1mSBM=

management/internals/modules/agentnetwork/labelgen/labelgen.go

@@ -3,10 +3,9 @@ package labelgen
 
 import (
 	"fmt"
+	"math/rand"
 	"sort"
 	"sync"
-
-	"github.com/netbirdio/netbird/management/server/util"
 )
 
 // pickAttempts caps the random retries before falling back to the
@@ -41,15 +40,16 @@ func uniqueWords() []string {
 // PickUnique selects a label not already in `taken`. It tries up to
 // pickAttempts random picks; on exhaustion it scans the deduplicated
 // wordlist for any remaining free entry, and if none is left appends
-// `-<fallbackSuffix>` to a random word and returns.
-func PickUnique(taken map[string]struct{}, fallbackSuffix string) string {
+// `-<fallbackSuffix>` to a deterministic word and returns. The caller
+// is responsible for seeding rng (math/rand).
+func PickUnique(rng *rand.Rand, taken map[string]struct{}, fallbackSuffix string) string {
 	pool := uniqueWords()
 	if len(pool) == 0 {
 		return fallbackSuffix
 	}
 
 	for i := 0; i < pickAttempts; i++ {
-		w := pool[util.RandIntn(len(pool))]
+		w := pool[rng.Intn(len(pool))]
 		if _, ok := taken[w]; !ok {
 			return w
 		}
@@ -61,6 +61,6 @@ func PickUnique(taken map[string]struct{}, fallbackSuffix string) string {
 		}
 	}
 
-	w := pool[util.RandIntn(len(pool))]
+	w := pool[rng.Intn(len(pool))]
 	return fmt.Sprintf("%s-%s", w, fallbackSuffix)
 }

management/internals/modules/agentnetwork/labelgen/labelgen_test.go

@@ -1,7 +1,7 @@
 package labelgen
 
 import (
-	"slices"
+	"math/rand"
 	"strings"
 	"testing"
 
@@ -9,12 +9,19 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-// TestPickUnique_ReturnsWordFromPool confirms a pick against an empty
-// taken set is always drawn verbatim from the wordlist.
-func TestPickUnique_ReturnsWordFromPool(t *testing.T) {
-	got := PickUnique(map[string]struct{}{}, "abcd")
+// TestPickUnique_DeterministicWithSeededRng locks the property the
+// caller relies on: same seed + same taken set → same pick. Without
+// that, the bootstrap flow can't reproduce a label across retries.
+func TestPickUnique_DeterministicWithSeededRng(t *testing.T) {
+	taken := map[string]struct{}{}
 
-	assert.True(t, slices.Contains(uniqueWords(), got), "Pick %q must be drawn from the wordlist", got)
+	rngA := rand.New(rand.NewSource(42))
+	rngB := rand.New(rand.NewSource(42))
+
+	a := PickUnique(rngA, taken, "abcd")
+	b := PickUnique(rngB, taken, "abcd")
+
+	assert.Equal(t, a, b, "Same seed and taken set must produce identical pick")
 }
 
 // TestPickUnique_AvoidsTakenWordsWhenMostAreReserved seeds taken with
@@ -39,7 +46,8 @@ func TestPickUnique_AvoidsTakenWordsWhenMostAreReserved(t *testing.T) {
 		taken[w] = struct{}{}
 	}
 
-	got := PickUnique(taken, "abcd")
+	rng := rand.New(rand.NewSource(7))
+	got := PickUnique(rng, taken, "abcd")
 
 	_, isFree := free[got]
 	assert.True(t, isFree, "PickUnique must return one of the free words; got %q", got)
@@ -57,7 +65,8 @@ func TestPickUnique_FallsBackWhenAllReserved(t *testing.T) {
 		taken[w] = struct{}{}
 	}
 
-	got := PickUnique(taken, "abcd")
+	rng := rand.New(rand.NewSource(99))
+	got := PickUnique(rng, taken, "abcd")
 
 	assert.True(t, strings.HasSuffix(got, "-abcd"), "Exhausted pool must produce <word>-<suffix>; got %q", got)
 

management/internals/modules/agentnetwork/manager.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"math/rand"
 	"slices"
 	"strings"
 	"sync"
@@ -122,6 +123,11 @@ type managerImpl struct {
 	// accountID, then by synthesised service ID.
 	reconcileMu    sync.Mutex
 	reconcileCache map[string]map[string]*proto.ProxyMapping
+
+	// labelRngMu guards labelRng. PickUnique consumes math/rand.Source
+	// state; concurrent provider creates would otherwise race.
+	labelRngMu sync.Mutex
+	labelRng   *rand.Rand
 }
 
 // NewManager constructs the persistent Agent Network manager. The
@@ -141,6 +147,7 @@ func NewManager(
 		permissionsManager: permissionsManager,
 		proxyController:    proxyController,
 		reconcileCache:     make(map[string]map[string]*proto.ProxyMapping),
+		labelRng:           rand.New(rand.NewSource(time.Now().UnixNano())),
 	}
 }
 
@@ -646,7 +653,9 @@ func (m *managerImpl) bootstrapSettingsIfNeeded(ctx context.Context, accountID,
 		suffix = suffix[:4]
 	}
 
-	subdomain := labelgen.PickUnique(taken, suffix)
+	m.labelRngMu.Lock()
+	subdomain := labelgen.PickUnique(m.labelRng, taken, suffix)
+	m.labelRngMu.Unlock()
 
 	now := time.Now().UTC()
 	settings := &types.Settings{

management/server/account.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"math/rand"
 	"net"
 	"net/netip"
 	"os"
@@ -62,7 +63,7 @@ const (
 type userLoggedInOnce bool
 
 func cacheEntryExpiration() time.Duration {
-	r := util.RandIntn(int(nbcache.DefaultIDPCacheExpirationMax.Milliseconds()-nbcache.DefaultIDPCacheExpirationMin.Milliseconds())) + int(nbcache.DefaultIDPCacheExpirationMin.Milliseconds())
+	r := rand.Intn(int(nbcache.DefaultIDPCacheExpirationMax.Milliseconds()-nbcache.DefaultIDPCacheExpirationMin.Milliseconds())) + int(nbcache.DefaultIDPCacheExpirationMin.Milliseconds())
 	return time.Duration(r) * time.Millisecond
 }
 
@@ -2454,7 +2455,8 @@ func (am *DefaultAccountManager) ensureIPv6Subnet(ctx context.Context, transacti
 		return transaction.UpdateAccountNetworkV6(ctx, accountID, network.NetV6)
 	}
 	if network.NetV6.IP == nil {
-		network.NetV6 = types.AllocateIPv6Subnet()
+		r := rand.New(rand.NewSource(time.Now().UnixNano()))
+		network.NetV6 = types.AllocateIPv6Subnet(r)
 
 		// Sync settings to match the allocated subnet so SaveAccountSettings persists it.
 		ones, _ := network.NetV6.Mask.Size()

management/server/group_ipv6_test.go

@@ -2,6 +2,7 @@ package server
 
 import (
 	"context"
+	"math/rand"
 	"testing"
 	"time"
 
@@ -27,7 +28,7 @@ func TestGroupIPv6Assignment(t *testing.T) {
 	require.NoError(t, err)
 
 	// Allocate IPv6 subnet for the account
-	account.Network.NetV6 = types.AllocateIPv6Subnet()
+	account.Network.NetV6 = types.AllocateIPv6Subnet(rand.New(rand.NewSource(time.Now().UnixNano())))
 	require.NoError(t, am.Store.SaveAccount(ctx, account))
 
 	// Create setup key

management/server/idp/util.go

@@ -2,12 +2,11 @@ package idp
 
 import (
 	"encoding/json"
+	"math/rand"
 	"net/url"
 	"os"
 	"strings"
 	"time"
-
-	"github.com/netbirdio/netbird/management/server/util"
 )
 
 var (
@@ -34,32 +33,31 @@ func GeneratePassword(passwordLength, minSpecialChar, minNum, minUpperCase int)
 
 	//Set special character
 	for i := 0; i < minSpecialChar; i++ {
-		random := util.RandIntn(len(specialCharSet))
+		random := rand.Intn(len(specialCharSet))
 		password.WriteString(string(specialCharSet[random]))
 	}
 
 	//Set numeric
 	for i := 0; i < minNum; i++ {
-		random := util.RandIntn(len(numberSet))
+		random := rand.Intn(len(numberSet))
 		password.WriteString(string(numberSet[random]))
 	}
 
 	//Set uppercase
 	for i := 0; i < minUpperCase; i++ {
-		random := util.RandIntn(len(upperCharSet))
+		random := rand.Intn(len(upperCharSet))
 		password.WriteString(string(upperCharSet[random]))
 	}
 
 	remainingLength := passwordLength - minSpecialChar - minNum - minUpperCase
 	for i := 0; i < remainingLength; i++ {
-		random := util.RandIntn(len(allCharSet))
+		random := rand.Intn(len(allCharSet))
 		password.WriteString(string(allCharSet[random]))
 	}
 	inRune := []rune(password.String())
-	for i := len(inRune) - 1; i > 0; i-- {
-		j := util.RandIntn(i + 1)
+	rand.Shuffle(len(inRune), func(i, j int) {
 		inRune[i], inRune[j] = inRune[j], inRune[i]
-	}
+	})
 	return string(inRune)
 }
 

management/server/types/network.go

@@ -1,13 +1,14 @@
 package types
 
 import (
-	"crypto/rand"
 	"encoding/binary"
 	"fmt"
+	"math/rand"
 	"net"
 	"net/netip"
 	"slices"
 	"sync"
+	"time"
 
 	"github.com/c-robinson/iplib"
 	"github.com/rs/xid"
@@ -136,12 +137,14 @@ func NewNetwork() *Network {
 	n := iplib.NewNet4(net.ParseIP("100.64.0.0"), NetSize)
 	sub, _ := n.Subnet(SubnetSize)
 
-	intn := util.RandIntn(len(sub))
+	s := rand.NewSource(time.Now().UnixNano())
+	r := rand.New(s)
+	intn := r.Intn(len(sub))
 
 	return &Network{
 		Identifier: xid.New().String(),
 		Net:        sub[intn].IPNet,
-		NetV6:      AllocateIPv6Subnet(),
+		NetV6:      AllocateIPv6Subnet(r),
 		Dns:        "",
 		Serial:     0,
 	}
@@ -151,13 +154,18 @@ func NewNetwork() *Network {
 // The format follows RFC 4193 section 3.1: fd + 40-bit Global ID + 16-bit Subnet ID.
 // The Global ID and Subnet ID are randomized (simplified from the SHA-1 algorithm
 // in section 3.2.2), giving 2^56 possible /64 subnets across all accounts.
-func AllocateIPv6Subnet() net.IPNet {
+func AllocateIPv6Subnet(r *rand.Rand) net.IPNet {
 	ip := make(net.IP, 16)
 	ip[0] = 0xfd
-	// Bytes 1-5: 40-bit random Global ID, bytes 6-7: 16-bit random Subnet ID
-	if _, err := rand.Read(ip[1:8]); err != nil {
-		panic(err)
-	}
+	// Bytes 1-5: 40-bit random Global ID
+	ip[1] = byte(r.Intn(256))
+	ip[2] = byte(r.Intn(256))
+	ip[3] = byte(r.Intn(256))
+	ip[4] = byte(r.Intn(256))
+	ip[5] = byte(r.Intn(256))
+	// Bytes 6-7: 16-bit random Subnet ID
+	ip[6] = byte(r.Intn(256))
+	ip[7] = byte(r.Intn(256))
 
 	return net.IPNet{
 		IP:   ip,
@@ -209,10 +217,11 @@ func AllocatePeerIP(prefix netip.Prefix, takenIps []netip.Addr) (netip.Addr, err
 		taken[binary.BigEndian.Uint32(ab[:])] = struct{}{}
 	}
 
+	rng := rand.New(rand.NewSource(time.Now().UnixNano()))
 	maxAttempts := (int(totalIPs) - len(taken)) / 100
 
 	for i := 0; i < maxAttempts; i++ {
-		offset := uint32(util.RandIntn(int(totalIPs-2))) + 1
+		offset := uint32(rng.Intn(int(totalIPs-2))) + 1
 		candidate := baseIP + offset
 		if _, exists := taken[candidate]; !exists {
 			return uint32ToIP(candidate), nil
@@ -236,7 +245,8 @@ func AllocateRandomPeerIP(prefix netip.Prefix) (netip.Addr, error) {
 	hostBits := 32 - prefix.Bits()
 	totalIPs := uint32(1 << hostBits)
 
-	offset := uint32(util.RandIntn(int(totalIPs-2))) + 1
+	rng := rand.New(rand.NewSource(time.Now().UnixNano()))
+	offset := uint32(rng.Intn(int(totalIPs-2))) + 1
 
 	candidate := baseIP + offset
 	return uint32ToIP(candidate), nil
@@ -252,26 +262,23 @@ func AllocateRandomPeerIPv6(prefix netip.Prefix) (netip.Addr, error) {
 
 	ip := prefix.Addr().As16()
 
+	rng := rand.New(rand.NewSource(time.Now().UnixNano()))
+
 	// Determine which byte the host bits start in
 	firstHostByte := ones / 8
 	// If the prefix doesn't end on a byte boundary, handle the partial byte
 	partialBits := ones % 8
 
-	var rnd [16]byte
-	if _, err := rand.Read(rnd[firstHostByte:]); err != nil {
-		return netip.Addr{}, err
-	}
-
 	if partialBits > 0 {
 		// Keep the network bits in the partial byte, randomize the rest
 		hostMask := byte(0xff >> partialBits)
-		ip[firstHostByte] = (ip[firstHostByte] & ^hostMask) | (rnd[firstHostByte] & hostMask)
+		ip[firstHostByte] = (ip[firstHostByte] & ^hostMask) | (byte(rng.Intn(256)) & hostMask)
 		firstHostByte++
 	}
 
 	// Randomize remaining full host bytes
 	for i := firstHostByte; i < 16; i++ {
-		ip[i] = rnd[i]
+		ip[i] = byte(rng.Intn(256))
 	}
 
 	// Avoid all-zeros and all-ones host parts by checking only host bits.

management/server/util/util.go

@@ -1,20 +1,5 @@
 package util
 
-import (
-	"crypto/rand"
-	"math/big"
-)
-
-// RandIntn returns a uniformly distributed int in [0, n) sourced from
-// crypto/rand. It panics if n <= 0 or the platform randomness source fails.
-func RandIntn(n int) int {
-	v, err := rand.Int(rand.Reader, big.NewInt(int64(n)))
-	if err != nil {
-		panic(err)
-	}
-	return int(v.Int64())
-}
-
 // Difference returns the elements in `a` that aren't in `b`.
 func Difference(a, b []string) []string {
 	mb := make(map[string]struct{}, len(b))

proxy/cmd/proxy/cmd/root.go

@@ -18,6 +18,7 @@ import (
 	"github.com/netbirdio/netbird/client/embed"
 	"github.com/netbirdio/netbird/proxy"
 	nbacme "github.com/netbirdio/netbird/proxy/internal/acme"
+	"github.com/netbirdio/netbird/trustedproxy"
 	"github.com/netbirdio/netbird/util"
 )
 
@@ -209,7 +210,7 @@ func runServer(cmd *cobra.Command, args []string) error {
 		return fmt.Errorf("invalid domain value %q: %w", proxyDomain, err)
 	}
 
-	parsedTrustedProxies, err := proxy.ParseTrustedProxies(trustedProxies)
+	parsedTrustedProxies, err := trustedproxy.Parse(trustedProxies)
 	if err != nil {
 		return fmt.Errorf("invalid --trusted-proxies: %w", err)
 	}

proxy/internal/accesslog/logger.go

@@ -16,6 +16,7 @@ import (
 	"github.com/netbirdio/netbird/proxy/auth"
 	"github.com/netbirdio/netbird/proxy/internal/types"
 	"github.com/netbirdio/netbird/shared/management/proto"
+	"github.com/netbirdio/netbird/trustedproxy"
 )
 
 const (
@@ -66,7 +67,7 @@ type denyBucket struct {
 type Logger struct {
 	client         gRPCClient
 	logger         *log.Logger
-	trustedProxies []netip.Prefix
+	trustedProxies *trustedproxy.List
 
 	usageMux    sync.Mutex
 	domainUsage map[string]*domainUsage
@@ -82,7 +83,7 @@ type Logger struct {
 // NewLogger creates a new access log Logger. The trustedProxies parameter
 // configures which upstream proxy IP ranges are trusted for extracting
 // the real client IP from X-Forwarded-For headers.
-func NewLogger(client gRPCClient, logger *log.Logger, trustedProxies []netip.Prefix) *Logger {
+func NewLogger(client gRPCClient, logger *log.Logger, trustedProxies *trustedproxy.List) *Logger {
 	if logger == nil {
 		logger = log.StandardLogger()
 	}

proxy/internal/accesslog/requestip.go

@@ -4,13 +4,13 @@ import (
 	"net/http"
 	"net/netip"
 
-	"github.com/netbirdio/netbird/proxy/internal/proxy"
+	"github.com/netbirdio/netbird/trustedproxy"
 )
 
 // extractSourceIP resolves the real client IP from the request using trusted
 // proxy configuration. When trustedProxies is non-empty and the direct
 // connection is from a trusted source, it walks X-Forwarded-For right-to-left
 // skipping trusted IPs. Otherwise it returns RemoteAddr directly.
-func extractSourceIP(r *http.Request, trustedProxies []netip.Prefix) netip.Addr {
-	return proxy.ResolveClientIP(r.RemoteAddr, r.Header.Get("X-Forwarded-For"), trustedProxies)
+func extractSourceIP(r *http.Request, trustedProxies *trustedproxy.List) netip.Addr {
+	return trustedProxies.ResolveClientIP(r.RemoteAddr, r.Header.Get("X-Forwarded-For"))
 }

proxy/internal/llm/bedrock_model.go

@@ -0,0 +1,38 @@
+package llm
+
+import (
+	"regexp"
+	"strings"
+)
+
+// bedrockRegionPrefixes are the cross-region inference-profile prefixes that
+// front a Bedrock model id (e.g. "eu.anthropic.claude-...").
+var bedrockRegionPrefixes = []string{"us.", "eu.", "apac.", "global."}
+
+// bedrockVersionSuffix matches the trailing "-vN[:N]" or "-YYYYMMDD-vN[:N]"
+// version/throughput suffix of a Bedrock model id.
+var bedrockVersionSuffix = regexp.MustCompile(`-(\d{8}-)?v\d+(:\d+)?$`)
+
+// NormalizeBedrockModel strips an ARN wrapper, a cross-region inference-profile
+// prefix, and the version/throughput suffix from a Bedrock model id so it
+// matches the catalog/pricing key, e.g.
+// "eu.anthropic.claude-sonnet-4-5-20250929-v1:0" -> "anthropic.claude-sonnet-4-5"
+// and the inference-profile ARN's last segment likewise. It is the single
+// source of truth shared by the request parser (which normalizes the request
+// model from the URL path) and the router (which normalizes the operator's
+// registered Bedrock model ids so both sides compare equal).
+func NormalizeBedrockModel(modelID string) string {
+	m := modelID
+	if strings.HasPrefix(m, "arn:") {
+		if i := strings.LastIndex(m, "/"); i >= 0 {
+			m = m[i+1:]
+		}
+	}
+	for _, p := range bedrockRegionPrefixes {
+		if strings.HasPrefix(m, p) {
+			m = m[len(p):]
+			break
+		}
+	}
+	return bedrockVersionSuffix.ReplaceAllString(m, "")
+}

proxy/internal/llm/bedrock_model_test.go

@@ -0,0 +1,23 @@
+package llm
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestNormalizeBedrockModel(t *testing.T) {
+	cases := map[string]string{
+		"eu.anthropic.claude-sonnet-4-5-20250929-v1:0": "anthropic.claude-sonnet-4-5",
+		"us.anthropic.claude-haiku-4-5":                "anthropic.claude-haiku-4-5",
+		"us.anthropic.claude-opus-4-8-20250101-v1:0":   "anthropic.claude-opus-4-8",
+		"anthropic.claude-sonnet-4-5-20250929-v1:0":    "anthropic.claude-sonnet-4-5",
+		"meta.llama3-3-70b-instruct-v1:0":              "meta.llama3-3-70b-instruct",
+		"amazon.nova-pro-v1:0":                         "amazon.nova-pro",
+		// Inference-profile ARN — model id lives in the last path segment.
+		"arn:aws:bedrock:eu-central-1:123456789012:inference-profile/eu.anthropic.claude-sonnet-4-5-20250929-v1:0": "anthropic.claude-sonnet-4-5",
+	}
+	for in, want := range cases {
+		require.Equal(t, want, NormalizeBedrockModel(in), "normalize %q", in)
+	}
+}

proxy/internal/middleware/builtin/llm_router/bedrock_route_test.go

@@ -0,0 +1,30 @@
+package llm_router
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// TestRouteClaimsModel_BedrockNormalizesCandidate guards the fix for the native
+// Bedrock routing gap: the request model reaches the router already normalized
+// (the parser strips the region/inference-profile prefix and version suffix),
+// so a provider registered with the raw inference-profile id must still match.
+func TestRouteClaimsModel_BedrockNormalizesCandidate(t *testing.T) {
+	route := ProviderRoute{Bedrock: true, Models: []string{"us.anthropic.claude-haiku-4-5"}}
+	assert.True(t, routeClaimsModel(route, "anthropic.claude-haiku-4-5"),
+		"raw region-prefixed Bedrock model must match the normalized request model")
+	assert.False(t, routeClaimsModel(route, "anthropic.claude-opus-4-8"),
+		"a model outside the provider's list must not match")
+
+	// A provider registered with the already-normalized id also matches.
+	normalized := ProviderRoute{Bedrock: true, Models: []string{"anthropic.claude-haiku-4-5"}}
+	assert.True(t, routeClaimsModel(normalized, "anthropic.claude-haiku-4-5"),
+		"normalized Bedrock model must match")
+
+	// Non-Bedrock routes keep exact matching (no prefix stripping).
+	openai := ProviderRoute{Models: []string{"gpt-4o"}}
+	assert.True(t, routeClaimsModel(openai, "gpt-4o"), "exact model must match")
+	assert.False(t, routeClaimsModel(openai, "us.gpt-4o"),
+		"non-Bedrock routes must not strip a us. prefix")
+}

proxy/internal/middleware/builtin/llm_router/middleware.go

@@ -23,6 +23,7 @@ import (
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/google"
 
+	"github.com/netbirdio/netbird/proxy/internal/llm"
 	"github.com/netbirdio/netbird/proxy/internal/middleware"
 )
 
@@ -555,6 +556,14 @@ func routeClaimsModel(route ProviderRoute, model string) bool {
 		if candidate == model {
 			return true
 		}
+		// Bedrock request models reach the router already normalized (the parser
+		// strips the region / inference-profile prefix and version suffix), but
+		// the operator may register the raw inference-profile id (e.g.
+		// "us.anthropic.claude-haiku-4-5"). Normalize the candidate so both sides
+		// compare equal; otherwise a native Bedrock request denies as not-routable.
+		if route.Bedrock && llm.NormalizeBedrockModel(candidate) == model {
+			return true
+		}
 	}
 	return false
 }

proxy/internal/proxy/reverseproxy.go

@@ -22,6 +22,7 @@ import (
 	"github.com/netbirdio/netbird/proxy/internal/roundtrip"
 	"github.com/netbirdio/netbird/proxy/internal/types"
 	"github.com/netbirdio/netbird/proxy/web"
+	"github.com/netbirdio/netbird/trustedproxy"
 )
 
 type ReverseProxy struct {
@@ -29,10 +30,10 @@ type ReverseProxy struct {
 	// forwardedProto overrides the X-Forwarded-Proto header value.
 	// Valid values: "auto" (detect from TLS), "http", "https".
 	forwardedProto string
-	// trustedProxies is a list of IP prefixes for trusted upstream proxies.
-	// When the direct connection comes from a trusted proxy, forwarding
-	// headers are preserved and appended to instead of being stripped.
-	trustedProxies []netip.Prefix
+	// trustedProxies is the set of trusted upstream proxies. When the direct
+	// connection comes from a trusted proxy, forwarding headers are preserved
+	// and appended to instead of being stripped.
+	trustedProxies *trustedproxy.List
 	mappingsMux    sync.RWMutex
 	mappings       map[string]Mapping
 	logger         *log.Logger
@@ -63,7 +64,7 @@ func WithMiddlewareManager(m *middleware.Manager) Option {
 // between requested URLs and targets.
 // The internal mappings can be modified using the AddMapping
 // and RemoveMapping functions.
-func NewReverseProxy(transport http.RoundTripper, forwardedProto string, trustedProxies []netip.Prefix, logger *log.Logger, opts ...Option) *ReverseProxy {
+func NewReverseProxy(transport http.RoundTripper, forwardedProto string, trustedProxies *trustedproxy.List, logger *log.Logger, opts ...Option) *ReverseProxy {
 	if logger == nil {
 		logger = log.StandardLogger()
 	}
@@ -527,7 +528,7 @@ func (p *ReverseProxy) isSelfTargetLoop(r *http.Request, target *url.URL) bool {
 	if !types.IsOverlayOrigin(r.Context()) {
 		return false
 	}
-	srcIP := extractHostIP(r.RemoteAddr)
+	srcIP := trustedproxy.ExtractHostIP(r.RemoteAddr)
 	if !srcIP.IsValid() {
 		return false
 	}
@@ -578,9 +579,9 @@ func (p *ReverseProxy) rewriteFunc(target *url.URL, matchedPath string, passHost
 
 		stampNetBirdIdentity(r)
 
-		clientIP := extractHostIP(r.In.RemoteAddr)
+		clientIP := trustedproxy.ExtractHostIP(r.In.RemoteAddr)
 
-		if isTrustedAddr(clientIP, p.trustedProxies) {
+		if p.trustedProxies.Contains(clientIP) {
 			p.setTrustedForwardingHeaders(r, clientIP)
 		} else {
 			p.setUntrustedForwardingHeaders(r, clientIP)
@@ -664,7 +665,7 @@ func (p *ReverseProxy) setTrustedForwardingHeaders(r *httputil.ProxyRequest, cli
 	if realIP := r.In.Header.Get("X-Real-IP"); realIP != "" {
 		r.Out.Header.Set("X-Real-IP", realIP)
 	} else {
-		resolved := ResolveClientIP(r.In.RemoteAddr, r.In.Header.Get("X-Forwarded-For"), p.trustedProxies)
+		resolved := p.trustedProxies.ResolveClientIP(r.In.RemoteAddr, r.In.Header.Get("X-Forwarded-For"))
 		r.Out.Header.Set("X-Real-IP", resolved.String())
 	}
 

proxy/internal/proxy/reverseproxy_test.go

@@ -23,6 +23,7 @@ import (
 	"github.com/netbirdio/netbird/proxy/internal/roundtrip"
 	"github.com/netbirdio/netbird/proxy/internal/types"
 	"github.com/netbirdio/netbird/proxy/web"
+	"github.com/netbirdio/netbird/trustedproxy"
 )
 
 func TestRewriteFunc_HostRewriting(t *testing.T) {
@@ -302,7 +303,7 @@ func TestExtractHostIP(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			assert.Equal(t, tt.expected, extractHostIP(tt.remoteAddr))
+			assert.Equal(t, tt.expected, trustedproxy.ExtractHostIP(tt.remoteAddr))
 		})
 	}
 }
@@ -330,7 +331,7 @@ func TestExtractForwardedPort(t *testing.T) {
 
 func TestRewriteFunc_TrustedProxy(t *testing.T) {
 	target, _ := url.Parse("http://backend.internal:8080")
-	trusted := []netip.Prefix{netip.MustParsePrefix("10.0.0.0/8")}
+	trusted := trustedproxy.FromPrefixes([]netip.Prefix{netip.MustParsePrefix("10.0.0.0/8")})
 
 	t.Run("appends to X-Forwarded-For", func(t *testing.T) {
 		p := &ReverseProxy{forwardedProto: "auto", trustedProxies: trusted}

proxy/internal/proxy/trustedproxy.go

@@ -1,81 +0,0 @@
-package proxy
-
-import (
-	"net/netip"
-	"strings"
-)
-
-// IsTrustedProxy checks if the given IP string falls within any of the trusted prefixes.
-func IsTrustedProxy(ipStr string, trusted []netip.Prefix) bool {
-	addr, err := netip.ParseAddr(ipStr)
-	if err != nil || len(trusted) == 0 {
-		return false
-	}
-	return isTrustedAddr(addr.Unmap(), trusted)
-}
-
-// ResolveClientIP extracts the real client IP from X-Forwarded-For using the trusted proxy list.
-// It walks the XFF chain right-to-left, skipping IPs that match trusted prefixes.
-// The first untrusted IP is the real client.
-//
-// If the trusted list is empty or remoteAddr is not trusted, it returns the
-// remoteAddr IP directly (ignoring any forwarding headers).
-func ResolveClientIP(remoteAddr, xff string, trusted []netip.Prefix) netip.Addr {
-	remoteIP := extractHostIP(remoteAddr)
-
-	if len(trusted) == 0 || !isTrustedAddr(remoteIP, trusted) {
-		return remoteIP
-	}
-
-	if xff == "" {
-		return remoteIP
-	}
-
-	parts := strings.Split(xff, ",")
-	for i := len(parts) - 1; i >= 0; i-- {
-		ip := strings.TrimSpace(parts[i])
-		if ip == "" {
-			continue
-		}
-		addr, err := netip.ParseAddr(ip)
-		if err != nil {
-			continue
-		}
-		addr = addr.Unmap()
-		if !isTrustedAddr(addr, trusted) {
-			return addr
-		}
-	}
-
-	// All IPs in XFF are trusted; return the leftmost as best guess.
-	if first := strings.TrimSpace(parts[0]); first != "" {
-		if addr, err := netip.ParseAddr(first); err == nil {
-			return addr.Unmap()
-		}
-	}
-	return remoteIP
-}
-
-// extractHostIP parses the IP from a host:port string and returns it unmapped.
-func extractHostIP(hostPort string) netip.Addr {
-	if ap, err := netip.ParseAddrPort(hostPort); err == nil {
-		return ap.Addr().Unmap()
-	}
-	if addr, err := netip.ParseAddr(hostPort); err == nil {
-		return addr.Unmap()
-	}
-	return netip.Addr{}
-}
-
-// isTrustedAddr checks if the given address falls within any of the trusted prefixes.
-func isTrustedAddr(addr netip.Addr, trusted []netip.Prefix) bool {
-	if !addr.IsValid() {
-		return false
-	}
-	for _, prefix := range trusted {
-		if prefix.Contains(addr) {
-			return true
-		}
-	}
-	return false
-}

proxy/internal/proxy/trustedproxy_test.go

@@ -1,129 +0,0 @@
-package proxy
-
-import (
-	"net/netip"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-)
-
-func TestIsTrustedProxy(t *testing.T) {
-	trusted := []netip.Prefix{
-		netip.MustParsePrefix("10.0.0.0/8"),
-		netip.MustParsePrefix("192.168.1.0/24"),
-		netip.MustParsePrefix("fd00::/8"),
-	}
-
-	tests := []struct {
-		name    string
-		ip      string
-		trusted []netip.Prefix
-		want    bool
-	}{
-		{"empty trusted list", "10.0.0.1", nil, false},
-		{"IP within /8 prefix", "10.1.2.3", trusted, true},
-		{"IP within /24 prefix", "192.168.1.100", trusted, true},
-		{"IP outside all prefixes", "203.0.113.50", trusted, false},
-		{"boundary IP just outside prefix", "192.168.2.1", trusted, false},
-		{"unparsable IP", "not-an-ip", trusted, false},
-		{"IPv6 in trusted range", "fd00::1", trusted, true},
-		{"IPv6 outside range", "2001:db8::1", trusted, false},
-		{"empty string", "", trusted, false},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			assert.Equal(t, tt.want, IsTrustedProxy(tt.ip, tt.trusted))
-		})
-	}
-}
-
-func TestResolveClientIP(t *testing.T) {
-	trusted := []netip.Prefix{
-		netip.MustParsePrefix("10.0.0.0/8"),
-		netip.MustParsePrefix("172.16.0.0/12"),
-	}
-
-	tests := []struct {
-		name       string
-		remoteAddr string
-		xff        string
-		trusted    []netip.Prefix
-		want       netip.Addr
-	}{
-		{
-			name:       "empty trusted list returns RemoteAddr",
-			remoteAddr: "203.0.113.50:9999",
-			xff:        "1.2.3.4",
-			trusted:    nil,
-			want:       netip.MustParseAddr("203.0.113.50"),
-		},
-		{
-			name:       "untrusted RemoteAddr ignores XFF",
-			remoteAddr: "203.0.113.50:9999",
-			xff:        "1.2.3.4, 10.0.0.1",
-			trusted:    trusted,
-			want:       netip.MustParseAddr("203.0.113.50"),
-		},
-		{
-			name:       "trusted RemoteAddr with single client in XFF",
-			remoteAddr: "10.0.0.1:5000",
-			xff:        "203.0.113.50",
-			trusted:    trusted,
-			want:       netip.MustParseAddr("203.0.113.50"),
-		},
-		{
-			name:       "trusted RemoteAddr walks past trusted entries in XFF",
-			remoteAddr: "10.0.0.1:5000",
-			xff:        "203.0.113.50, 10.0.0.2, 172.16.0.5",
-			trusted:    trusted,
-			want:       netip.MustParseAddr("203.0.113.50"),
-		},
-		{
-			name:       "trusted RemoteAddr with empty XFF falls back to RemoteAddr",
-			remoteAddr: "10.0.0.1:5000",
-			xff:        "",
-			trusted:    trusted,
-			want:       netip.MustParseAddr("10.0.0.1"),
-		},
-		{
-			name:       "all XFF IPs trusted returns leftmost",
-			remoteAddr: "10.0.0.1:5000",
-			xff:        "10.0.0.2, 172.16.0.1, 10.0.0.3",
-			trusted:    trusted,
-			want:       netip.MustParseAddr("10.0.0.2"),
-		},
-		{
-			name:       "XFF with whitespace",
-			remoteAddr: "10.0.0.1:5000",
-			xff:        " 203.0.113.50 , 10.0.0.2 ",
-			trusted:    trusted,
-			want:       netip.MustParseAddr("203.0.113.50"),
-		},
-		{
-			name:       "XFF with empty segments",
-			remoteAddr: "10.0.0.1:5000",
-			xff:        "203.0.113.50,,10.0.0.2",
-			trusted:    trusted,
-			want:       netip.MustParseAddr("203.0.113.50"),
-		},
-		{
-			name:       "multi-hop with mixed trust",
-			remoteAddr: "10.0.0.1:5000",
-			xff:        "8.8.8.8, 203.0.113.50, 172.16.0.1",
-			trusted:    trusted,
-			want:       netip.MustParseAddr("203.0.113.50"),
-		},
-		{
-			name:       "RemoteAddr without port",
-			remoteAddr: "10.0.0.1",
-			xff:        "203.0.113.50",
-			trusted:    trusted,
-			want:       netip.MustParseAddr("203.0.113.50"),
-		},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			assert.Equal(t, tt.want, ResolveClientIP(tt.remoteAddr, tt.xff, tt.trusted))
-		})
-	}
-}

proxy/lifecycle.go

@@ -2,13 +2,13 @@ package proxy
 
 import (
 	"context"
-	"net/netip"
 	"time"
 
 	log "github.com/sirupsen/logrus"
 
 	"github.com/netbirdio/netbird/client/embed"
 	"github.com/netbirdio/netbird/proxy/internal/acme"
+	"github.com/netbirdio/netbird/trustedproxy"
 )
 
 // Config bundles every knob the proxy reads at construction time. It mirrors
@@ -83,9 +83,9 @@ type Config struct {
 	// ForwardedProto overrides the X-Forwarded-Proto value sent to
 	// backends. Valid values: "auto", "http", "https".
 	ForwardedProto string
-	// TrustedProxies is a list of IP prefixes for trusted upstream
-	// proxies that may set forwarding headers.
-	TrustedProxies []netip.Prefix
+	// TrustedProxies is the set of trusted upstream proxies that may set
+	// forwarding headers.
+	TrustedProxies *trustedproxy.List
 	// WireguardPort is the UDP port for the embedded NetBird tunnel.
 	// Zero asks the OS for a random port.
 	WireguardPort uint16

proxy/proxyprotocol_test.go

@@ -10,12 +10,14 @@ import (
 	log "github.com/sirupsen/logrus"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+
+	"github.com/netbirdio/netbird/trustedproxy"
 )
 
 func TestWrapProxyProtocol_OverridesRemoteAddr(t *testing.T) {
 	srv := &Server{
 		Logger:         log.StandardLogger(),
-		TrustedProxies: []netip.Prefix{netip.MustParsePrefix("127.0.0.1/32")},
+		TrustedProxies: trustedproxy.FromPrefixes([]netip.Prefix{netip.MustParsePrefix("127.0.0.1/32")}),
 		ProxyProtocol:  true,
 	}
 
@@ -66,7 +68,7 @@ func TestWrapProxyProtocol_OverridesRemoteAddr(t *testing.T) {
 func TestProxyProtocolPolicy_TrustedRequires(t *testing.T) {
 	srv := &Server{
 		Logger:         log.StandardLogger(),
-		TrustedProxies: []netip.Prefix{netip.MustParsePrefix("10.0.0.0/8")},
+		TrustedProxies: trustedproxy.FromPrefixes([]netip.Prefix{netip.MustParsePrefix("10.0.0.0/8")}),
 	}
 
 	opts := proxyproto.ConnPolicyOptions{
@@ -80,7 +82,7 @@ func TestProxyProtocolPolicy_TrustedRequires(t *testing.T) {
 func TestProxyProtocolPolicy_UntrustedIgnores(t *testing.T) {
 	srv := &Server{
 		Logger:         log.StandardLogger(),
-		TrustedProxies: []netip.Prefix{netip.MustParsePrefix("10.0.0.0/8")},
+		TrustedProxies: trustedproxy.FromPrefixes([]netip.Prefix{netip.MustParsePrefix("10.0.0.0/8")}),
 	}
 
 	opts := proxyproto.ConnPolicyOptions{
@@ -94,7 +96,7 @@ func TestProxyProtocolPolicy_UntrustedIgnores(t *testing.T) {
 func TestProxyProtocolPolicy_InvalidIPRejects(t *testing.T) {
 	srv := &Server{
 		Logger:         log.StandardLogger(),
-		TrustedProxies: []netip.Prefix{netip.MustParsePrefix("10.0.0.0/8")},
+		TrustedProxies: trustedproxy.FromPrefixes([]netip.Prefix{netip.MustParsePrefix("10.0.0.0/8")}),
 	}
 
 	opts := proxyproto.ConnPolicyOptions{

proxy/server.go

@@ -67,6 +67,7 @@ import (
 	"github.com/netbirdio/netbird/proxy/web"
 	"github.com/netbirdio/netbird/shared/management/domain"
 	"github.com/netbirdio/netbird/shared/management/proto"
+	"github.com/netbirdio/netbird/trustedproxy"
 	"github.com/netbirdio/netbird/util/embeddedroots"
 )
 
@@ -79,19 +80,19 @@ type portRouter struct {
 
 type Server struct {
 	ctx               context.Context
-	mgmtClient    proto.ProxyServiceClient
-	proxy         *proxy.ReverseProxy
-	netbird       *roundtrip.NetBird
-	acme          *acme.Manager
+	mgmtClient        proto.ProxyServiceClient
+	proxy             *proxy.ReverseProxy
+	netbird           *roundtrip.NetBird
+	acme              *acme.Manager
 	staticCertWatcher *certwatch.Watcher
-	auth          *auth.Middleware
-	http          *http.Server
-	https         *http.Server
-	debug         *http.Server
-	healthServer  *health.Server
-	healthChecker *health.Checker
-	meter         *proxymetrics.Metrics
-	accessLog     *accesslog.Logger
+	auth              *auth.Middleware
+	http              *http.Server
+	https             *http.Server
+	debug             *http.Server
+	healthServer      *health.Server
+	healthChecker     *health.Checker
+	meter             *proxymetrics.Metrics
+	accessLog         *accesslog.Logger
 	// middlewareManager drives per-target middleware dispatch. Always
 	// constructed during boot; an empty registry produces empty chains and
 	// the reverse-proxy stays on the no-capture fast path.
@@ -99,16 +100,16 @@ type Server struct {
 	// middlewareRegistry is the source of registered middleware factories.
 	// Concrete middlewares register themselves through init().
 	middlewareRegistry *middleware.Registry
-	mainRouter    *nbtcp.Router
-	mainPort      uint16
-	udpMu         sync.Mutex
-	udpRelays     map[types.ServiceID]*udprelay.Relay
-	udpRelayWg    sync.WaitGroup
-	portMu        sync.RWMutex
-	portRouters   map[uint16]*portRouter
-	svcPorts      map[types.ServiceID][]uint16
-	lastMappings  map[types.ServiceID]*proto.ProxyMapping
-	portRouterWg  sync.WaitGroup
+	mainRouter         *nbtcp.Router
+	mainPort           uint16
+	udpMu              sync.Mutex
+	udpRelays          map[types.ServiceID]*udprelay.Relay
+	udpRelayWg         sync.WaitGroup
+	portMu             sync.RWMutex
+	portRouters        map[uint16]*portRouter
+	svcPorts           map[types.ServiceID][]uint16
+	lastMappings       map[types.ServiceID]*proto.ProxyMapping
+	portRouterWg       sync.WaitGroup
 
 	// hijackTracker tracks hijacked connections (e.g. WebSocket upgrades)
 	// so they can be closed during graceful shutdown, since http.Server.Shutdown
@@ -192,10 +193,10 @@ type Server struct {
 	// ForwardedProto overrides the X-Forwarded-Proto value sent to backends.
 	// Valid values: "auto" (detect from TLS), "http", "https".
 	ForwardedProto string
-	// TrustedProxies is a list of IP prefixes for trusted upstream proxies.
-	// When set, forwarding headers from these sources are preserved and
-	// appended to instead of being stripped.
-	TrustedProxies []netip.Prefix
+	// TrustedProxies is the set of trusted upstream proxies. When set,
+	// forwarding headers from these sources are preserved and appended to
+	// instead of being stripped.
+	TrustedProxies *trustedproxy.List
 	// WireguardPort is the port for the NetBird tunnel interface. Use 0
 	// for a random OS-assigned port. A fixed port only works with
 	// single-account deployments; multiple accounts will fail to bind
@@ -718,7 +719,7 @@ func (s *Server) wrapProxyProtocol(ln net.Listener) net.Listener {
 		Listener:          ln,
 		ReadHeaderTimeout: proxyProtoHeaderTimeout,
 	}
-	if len(s.TrustedProxies) > 0 {
+	if !s.TrustedProxies.Empty() {
 		ppListener.ConnPolicy = s.proxyProtocolPolicy
 	} else {
 		s.Logger.Warn("PROXY protocol enabled without trusted proxies; any source may send PROXY headers")
@@ -742,10 +743,8 @@ func (s *Server) proxyProtocolPolicy(opts proxyproto.ConnPolicyOptions) (proxypr
 	addr = addr.Unmap()
 
 	// called per accept
-	for _, prefix := range s.TrustedProxies {
-		if prefix.Contains(addr) {
-			return proxyproto.REQUIRE, nil
-		}
+	if s.TrustedProxies.Contains(addr) {
+		return proxyproto.REQUIRE, nil
 	}
 	return proxyproto.IGNORE, nil
 }

proxy/trustedproxy.go

@@ -1,43 +0,0 @@
-package proxy
-
-import (
-	"fmt"
-	"net/netip"
-	"strings"
-)
-
-// ParseTrustedProxies parses a comma-separated list of CIDR prefixes or bare IPs
-// into a slice of netip.Prefix values suitable for trusted proxy configuration.
-// Bare IPs are converted to single-host prefixes (/32 or /128).
-func ParseTrustedProxies(raw string) ([]netip.Prefix, error) {
-	if raw == "" {
-		return nil, nil
-	}
-
-	parts := strings.Split(raw, ",")
-	prefixes := make([]netip.Prefix, 0, len(parts))
-	for _, part := range parts {
-		part = strings.TrimSpace(part)
-		if part == "" {
-			continue
-		}
-
-		prefix, err := netip.ParsePrefix(part)
-		if err == nil {
-			prefixes = append(prefixes, prefix)
-			continue
-		}
-
-		addr, addrErr := netip.ParseAddr(part)
-		if addrErr != nil {
-			return nil, fmt.Errorf("parse trusted proxy %q: not a valid CIDR or IP: %w", part, addrErr)
-		}
-
-		bits := 32
-		if addr.Is6() {
-			bits = 128
-		}
-		prefixes = append(prefixes, netip.PrefixFrom(addr, bits))
-	}
-	return prefixes, nil
-}

proxy/trustedproxy_test.go

@@ -1,90 +0,0 @@
-package proxy
-
-import (
-	"net/netip"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-func TestParseTrustedProxies(t *testing.T) {
-	tests := []struct {
-		name    string
-		raw     string
-		want    []netip.Prefix
-		wantErr bool
-	}{
-		{
-			name: "empty string returns nil",
-			raw:  "",
-			want: nil,
-		},
-		{
-			name: "single CIDR",
-			raw:  "10.0.0.0/8",
-			want: []netip.Prefix{netip.MustParsePrefix("10.0.0.0/8")},
-		},
-		{
-			name: "single bare IPv4",
-			raw:  "1.2.3.4",
-			want: []netip.Prefix{netip.MustParsePrefix("1.2.3.4/32")},
-		},
-		{
-			name: "single bare IPv6",
-			raw:  "::1",
-			want: []netip.Prefix{netip.MustParsePrefix("::1/128")},
-		},
-		{
-			name: "comma-separated CIDRs",
-			raw:  "10.0.0.0/8, 192.168.1.0/24",
-			want: []netip.Prefix{
-				netip.MustParsePrefix("10.0.0.0/8"),
-				netip.MustParsePrefix("192.168.1.0/24"),
-			},
-		},
-		{
-			name: "mixed CIDRs and bare IPs",
-			raw:  "10.0.0.0/8, 1.2.3.4, fd00::/8",
-			want: []netip.Prefix{
-				netip.MustParsePrefix("10.0.0.0/8"),
-				netip.MustParsePrefix("1.2.3.4/32"),
-				netip.MustParsePrefix("fd00::/8"),
-			},
-		},
-		{
-			name: "whitespace around entries",
-			raw:  "  10.0.0.0/8 , 192.168.0.0/16  ",
-			want: []netip.Prefix{
-				netip.MustParsePrefix("10.0.0.0/8"),
-				netip.MustParsePrefix("192.168.0.0/16"),
-			},
-		},
-		{
-			name: "trailing comma produces no extra entry",
-			raw:  "10.0.0.0/8,",
-			want: []netip.Prefix{netip.MustParsePrefix("10.0.0.0/8")},
-		},
-		{
-			name:    "invalid entry",
-			raw:     "not-an-ip",
-			wantErr: true,
-		},
-		{
-			name:    "partially invalid",
-			raw:     "10.0.0.0/8, garbage",
-			wantErr: true,
-		},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			got, err := ParseTrustedProxies(tt.raw)
-			if tt.wantErr {
-				require.Error(t, err)
-				return
-			}
-			require.NoError(t, err)
-			assert.Equal(t, tt.want, got)
-		})
-	}
-}

relay/cmd/root.go

@@ -24,6 +24,7 @@ import (
 	"github.com/netbirdio/netbird/shared/metrics"
 	"github.com/netbirdio/netbird/shared/relay/auth"
 	"github.com/netbirdio/netbird/stun"
+	"github.com/netbirdio/netbird/trustedproxy"
 	"github.com/netbirdio/netbird/util"
 )
 
@@ -45,6 +46,9 @@ type Config struct {
 	LogLevel                 string
 	LogFile                  string
 	HealthcheckListenAddress string
+	// TrustedProxies is a comma-separated list of upstream proxy CIDRs/IPs whose
+	// X-Real-Ip/X-Real-Port headers are trusted. Empty means never trust these headers.
+	TrustedProxies string
 	// STUN server configuration
 	EnableSTUN   bool
 	STUNPorts    []int
@@ -116,6 +120,7 @@ func init() {
 	rootCmd.PersistentFlags().StringVar(&cobraConfig.LogLevel, "log-level", "info", "log level")
 	rootCmd.PersistentFlags().StringVar(&cobraConfig.LogFile, "log-file", "console", "log file")
 	rootCmd.PersistentFlags().StringVarP(&cobraConfig.HealthcheckListenAddress, "health-listen-address", "H", ":9000", "listen address of healthcheck server")
+	rootCmd.PersistentFlags().StringVar(&cobraConfig.TrustedProxies, "trusted-proxies", "", "comma-separated list of upstream proxy CIDRs or IPs whose X-Real-Ip/X-Real-Port headers are trusted; leave empty to always use the direct connection address")
 	rootCmd.PersistentFlags().BoolVar(&cobraConfig.EnableSTUN, "enable-stun", false, "enable embedded STUN server")
 	rootCmd.PersistentFlags().IntSliceVar(&cobraConfig.STUNPorts, "stun-ports", []int{3478}, "ports for the embedded STUN server (can be specified multiple times or comma-separated)")
 	rootCmd.PersistentFlags().StringVar(&cobraConfig.STUNLogLevel, "stun-log-level", "info", "log level for STUN server (panic, fatal, error, warn, info, debug, trace)")
@@ -155,8 +160,15 @@ func execute(cmd *cobra.Command, args []string) error {
 		return fmt.Errorf("setup metrics: %v", err)
 	}
 
+	trustedProxies, err := trustedproxy.Parse(cobraConfig.TrustedProxies)
+	if err != nil {
+		log.Debugf("failed to parse trusted proxies: %s", err)
+		return fmt.Errorf("failed to parse trusted proxies: %s", err)
+	}
+
 	srvListenerCfg := server.ListenerConfig{
-		Address: cobraConfig.ListenAddress,
+		Address:        cobraConfig.ListenAddress,
+		TrustedProxies: trustedProxies,
 	}
 
 	tlsConfig, tlsSupport, err := handleTLSConfig(cobraConfig)

relay/server/listener/ws/listener.go

@@ -15,6 +15,7 @@ import (
 	"github.com/netbirdio/netbird/relay/protocol"
 	relaylistener "github.com/netbirdio/netbird/relay/server/listener"
 	"github.com/netbirdio/netbird/shared/relay"
+	"github.com/netbirdio/netbird/trustedproxy"
 )
 
 const (
@@ -27,6 +28,9 @@ type Listener struct {
 	Address string
 	// TLSConfig is the TLS configuration for the server.
 	TLSConfig *tls.Config
+	// TrustedProxies is the set of upstream proxies whose X-Real-Ip/X-Real-Port
+	// headers are trusted. Headers from any other immediate peer are ignored.
+	TrustedProxies *trustedproxy.List
 
 	server   *http.Server
 	acceptFn func(conn relaylistener.Conn)
@@ -75,7 +79,7 @@ func (l *Listener) Shutdown(ctx context.Context) error {
 }
 
 func (l *Listener) onAccept(w http.ResponseWriter, r *http.Request) {
-	connRemoteAddr := remoteAddr(r)
+	connRemoteAddr := remoteAddr(r, l.TrustedProxies)
 
 	acceptOptions := &websocket.AcceptOptions{
 		OriginPatterns: []string{"*"},
@@ -102,9 +106,17 @@ func (l *Listener) onAccept(w http.ResponseWriter, r *http.Request) {
 	l.acceptFn(conn)
 }
 
-func remoteAddr(r *http.Request) string {
-	if r.Header.Get("X-Real-Ip") == "" || r.Header.Get("X-Real-Port") == "" {
+func remoteAddr(r *http.Request, trustedProxies *trustedproxy.List) string {
+	realIP := r.Header.Get("X-Real-Ip")
+	realPort := r.Header.Get("X-Real-Port")
+	if realIP == "" || realPort == "" {
 		return r.RemoteAddr
 	}
-	return net.JoinHostPort(r.Header.Get("X-Real-Ip"), r.Header.Get("X-Real-Port"))
+
+	if !trustedProxies.IsTrusted(r.RemoteAddr) {
+		log.Debugf("ignoring X-Real-Ip header from untrusted peer %s", r.RemoteAddr)
+		return r.RemoteAddr
+	}
+
+	return net.JoinHostPort(realIP, realPort)
 }

relay/server/server.go

@@ -15,14 +15,17 @@ import (
 	"github.com/netbirdio/netbird/relay/server/listener/quic"
 	"github.com/netbirdio/netbird/relay/server/listener/ws"
 	quictls "github.com/netbirdio/netbird/shared/relay/tls"
+	"github.com/netbirdio/netbird/trustedproxy"
 )
 
 // ListenerConfig is the configuration for the listener.
 // Address: the address to bind the listener to. It could be an address behind a reverse proxy.
 // TLSConfig: the TLS configuration for the listener.
+// TrustedProxies: upstream proxy prefixes whose forwarding headers (X-Real-Ip/X-Real-Port) are trusted.
 type ListenerConfig struct {
-	Address   string
-	TLSConfig *tls.Config
+	Address        string
+	TLSConfig      *tls.Config
+	TrustedProxies *trustedproxy.List
 }
 
 // Server is the main entry point for the relay server.
@@ -62,8 +65,9 @@ func NewServer(config Config) (*Server, error) {
 // Listen starts the relay server.
 func (r *Server) Listen(cfg ListenerConfig) error {
 	wSListener := &ws.Listener{
-		Address:   cfg.Address,
-		TLSConfig: cfg.TLSConfig,
+		Address:        cfg.Address,
+		TLSConfig:      cfg.TLSConfig,
+		TrustedProxies: cfg.TrustedProxies,
 	}
 
 	r.listenerMux.Lock()

shared/relay/client/fallback_opener.go

@@ -0,0 +1,176 @@
+package client
+
+import (
+	"context"
+	"errors"
+	"net"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+)
+
+const (
+	raceTotalTimeout  = 40 * time.Second
+	raceFallbackDelay = 10 * time.Second
+)
+
+type raceAttempt struct {
+	conn net.Conn
+	err  error
+}
+
+type raceOutcome struct {
+	conn net.Conn
+	err  error
+	done bool
+}
+
+type connRace struct {
+	opener            *FallbackOpener
+	peerKey           string
+	remoteRelayServer RelayServer
+	preferForeign     bool
+
+	raceCtx         context.Context
+	otherCtx        context.Context
+	cancelPreferred context.CancelFunc
+	cancelOther     context.CancelFunc
+	results         chan raceAttempt
+	fallbackTimer   *time.Timer
+
+	otherStarted bool
+	settled      int
+	lastErr      error
+}
+
+type FallbackOpener struct {
+	home         *Client
+	foreignStore *ForeignRelaysStore
+
+	fallbackDelay time.Duration
+	totalTimeout  time.Duration
+	// openFn performs a single attempt. It is overridable in tests; when nil the
+	// real home/foreign dispatch in open is used.
+	openFn func(ctx context.Context, peerKey string, remoteRelayServer RelayServer, foreign bool) raceAttempt
+}
+
+func NewFallbackOpener(home *Client, foreignStore *ForeignRelaysStore) *FallbackOpener {
+	return &FallbackOpener{
+		home:          home,
+		foreignStore:  foreignStore,
+		fallbackDelay: raceFallbackDelay,
+		totalTimeout:  raceTotalTimeout,
+	}
+}
+
+func (r *FallbackOpener) Run(ctx context.Context, peerKey string, remoteRelayServer RelayServer, preferForeign bool) (net.Conn, error) {
+	raceCtx, cancel := context.WithTimeout(ctx, r.totalTimeout)
+	defer cancel()
+
+	preferredCtx, cancelPreferred := context.WithCancel(raceCtx)
+	otherCtx, cancelOther := context.WithCancel(raceCtx)
+
+	race := &connRace{
+		opener:            r,
+		peerKey:           peerKey,
+		remoteRelayServer: remoteRelayServer,
+		preferForeign:     preferForeign,
+		raceCtx:           raceCtx,
+		otherCtx:          otherCtx,
+		cancelPreferred:   cancelPreferred,
+		cancelOther:       cancelOther,
+		results:           make(chan raceAttempt, 2),
+		fallbackTimer:     time.NewTimer(r.fallbackDelay),
+	}
+	defer race.fallbackTimer.Stop()
+
+	go func() {
+		race.results <- r.open(preferredCtx, peerKey, remoteRelayServer, preferForeign)
+	}()
+
+	for {
+		select {
+		case <-race.fallbackTimer.C:
+			race.startOther()
+		case res := <-race.results:
+			if o := race.handleResult(res); o.done {
+				return o.conn, o.err
+			}
+		case <-raceCtx.Done():
+			return race.onTimeout()
+		}
+	}
+}
+
+func (c *connRace) startOther() {
+	if c.otherStarted {
+		return
+	}
+	c.otherStarted = true
+	c.fallbackTimer.Stop()
+	go func() {
+		c.results <- c.opener.open(c.otherCtx, c.peerKey, c.remoteRelayServer, !c.preferForeign)
+	}()
+}
+
+func (c *connRace) handleResult(res raceAttempt) raceOutcome {
+	if (res.err == nil && res.conn != nil) || errors.Is(res.err, ErrConnAlreadyExists) {
+		c.settled++
+		c.stop()
+		return raceOutcome{conn: res.conn, err: res.err, done: true}
+	}
+
+	c.lastErr = res.err
+	c.settled++
+	if !c.otherStarted {
+		c.startOther()
+		return raceOutcome{}
+	}
+	if c.settled == 2 {
+		c.cancelPreferred()
+		c.cancelOther()
+		return raceOutcome{err: c.lastErr, done: true}
+	}
+	return raceOutcome{}
+}
+
+func (c *connRace) onTimeout() (net.Conn, error) {
+	c.stop()
+	if c.lastErr != nil {
+		return nil, c.lastErr
+	}
+	return nil, c.raceCtx.Err()
+}
+
+func (c *connRace) stop() {
+	c.cancelPreferred()
+	c.cancelOther()
+	go c.opener.drainLoser(c.results, c.settled, c.otherStarted)
+}
+
+func (r *FallbackOpener) open(ctx context.Context, peerKey string, remoteRelayServer RelayServer, foreign bool) raceAttempt {
+	if r.openFn != nil {
+		return r.openFn(ctx, peerKey, remoteRelayServer, foreign)
+	}
+	if foreign {
+		conn, err := r.foreignStore.OpenConn(ctx, peerKey, remoteRelayServer)
+		return raceAttempt{conn: conn, err: err}
+	}
+	conn, err := r.home.OpenConn(ctx, peerKey)
+	return raceAttempt{conn: conn, err: err}
+}
+
+func (r *FallbackOpener) drainLoser(results chan raceAttempt, settled int, otherStarted bool) {
+	started := 1
+	if otherStarted {
+		started = 2
+	}
+	for i := settled; i < started; i++ {
+		res := <-results
+		if res.conn != nil {
+			if err := res.conn.Close(); err != nil {
+				log.Debugf("failed to close losing relay connection: %v", err)
+			}
+		}
+	}
+}

shared/relay/client/fallback_opener_test.go

@@ -0,0 +1,450 @@
+package client
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// The FallbackOpener race is driven by a single goroutine (Run's select loop)
+// with worker goroutines that communicate only through the buffered results
+// channel and the two cancel contexts. These tests exercise that state machine
+// in isolation via an injected openFn, so no relay server or network is needed.
+// Timing is scaled down through the fallbackDelay/totalTimeout fields.
+
+// raceFakeConn tracks whether Close was called. Only Close is exercised by the
+// race logic (drainLoser closes losers; Run returns the winner untouched).
+type raceFakeConn struct {
+	net.Conn
+	label  string
+	closed atomic.Bool
+}
+
+func (c *raceFakeConn) Close() error {
+	c.closed.Store(true)
+	return nil
+}
+
+// raceAttemptScript describes how a single scripted attempt behaves.
+type raceAttemptScript struct {
+	delay time.Duration
+	conn  *raceFakeConn // non-nil => the attempt succeeds and returns this conn
+	err   error         // returned when conn is nil
+	// ignoreCtx makes the attempt complete after delay even if its context is
+	// cancelled. It models an OpenConn that produced a real connection right as
+	// the race cancelled it - exactly the case drainLoser must clean up.
+	ignoreCtx bool
+}
+
+// fakeOpener replaces FallbackOpener.open. Scripts are keyed by the foreign
+// flag, so which script is "preferred" depends on the preferForeign argument
+// passed to Run.
+type fakeOpener struct {
+	mu      sync.Mutex
+	scripts map[bool]raceAttemptScript
+	calls   []bool // foreign flag of each open() invocation, in order
+}
+
+func (f *fakeOpener) open(ctx context.Context, _ string, _ RelayServer, foreign bool) raceAttempt {
+	f.mu.Lock()
+	f.calls = append(f.calls, foreign)
+	s, ok := f.scripts[foreign]
+	f.mu.Unlock()
+	if !ok {
+		return raceAttempt{err: fmt.Errorf("no script for foreign=%v", foreign)}
+	}
+
+	if s.delay > 0 {
+		timer := time.NewTimer(s.delay)
+		defer timer.Stop()
+		if s.ignoreCtx {
+			<-timer.C
+		} else {
+			select {
+			case <-timer.C:
+			case <-ctx.Done():
+				return raceAttempt{err: ctx.Err()}
+			}
+		}
+	}
+
+	if s.conn != nil {
+		return raceAttempt{conn: s.conn}
+	}
+	return raceAttempt{err: s.err}
+}
+
+func (f *fakeOpener) callCount() int {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	return len(f.calls)
+}
+
+func (f *fakeOpener) firstCallForeign(t *testing.T) bool {
+	t.Helper()
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	require.NotEmpty(t, f.calls, "expected at least one open attempt")
+	return f.calls[0]
+}
+
+func newTestOpener(f *fakeOpener, fallbackDelay, totalTimeout time.Duration) *FallbackOpener {
+	o := NewFallbackOpener(nil, nil)
+	o.openFn = f.open
+	o.fallbackDelay = fallbackDelay
+	o.totalTimeout = totalTimeout
+	return o
+}
+
+const (
+	// controller prefers the home relay, i.e. preferForeign == false.
+	preferHome    = false
+	preferForeign = true
+)
+
+var errAttempt = errors.New("attempt failed")
+
+// The preferred attempt wins before the fallback timer fires, so the other
+// attempt is never started.
+func TestFallbackOpener_PreferredWinsImmediately(t *testing.T) {
+	homeConn := &raceFakeConn{label: "home"}
+	foreignConn := &raceFakeConn{label: "foreign"}
+	f := &fakeOpener{scripts: map[bool]raceAttemptScript{
+		false: {conn: homeConn},                            // preferred (home): instant success
+		true:  {delay: 5 * time.Second, conn: foreignConn}, // would never finish in time
+	}}
+	o := newTestOpener(f, 40*time.Millisecond, 2*time.Second)
+
+	conn, err := o.Run(context.Background(), "peer", RelayServer{Addr: "srv"}, preferHome)
+
+	require.NoError(t, err)
+	require.Same(t, homeConn, conn)
+	assert.Equal(t, 1, f.callCount(), "other attempt must not start when preferred wins first")
+	assert.False(t, f.firstCallForeign(t), "home must be tried first when preferring home")
+	assert.False(t, foreignConn.closed.Load())
+}
+
+// preferForeign flips which relay is tried first.
+func TestFallbackOpener_PreferForeignRoutesForeignFirst(t *testing.T) {
+	foreignConn := &raceFakeConn{label: "foreign"}
+	f := &fakeOpener{scripts: map[bool]raceAttemptScript{
+		true:  {conn: foreignConn}, // preferred (foreign): instant success
+		false: {delay: 5 * time.Second, conn: &raceFakeConn{}},
+	}}
+	o := newTestOpener(f, 40*time.Millisecond, 2*time.Second)
+
+	conn, err := o.Run(context.Background(), "peer", RelayServer{Addr: "srv"}, preferForeign)
+
+	require.NoError(t, err)
+	require.Same(t, foreignConn, conn)
+	assert.Equal(t, 1, f.callCount())
+	assert.True(t, f.firstCallForeign(t), "foreign must be tried first when preferring foreign")
+}
+
+// ErrConnAlreadyExists counts as success: Run returns it and does not start the
+// other attempt.
+func TestFallbackOpener_ErrConnAlreadyExistsIsSuccess(t *testing.T) {
+	f := &fakeOpener{scripts: map[bool]raceAttemptScript{
+		false: {err: ErrConnAlreadyExists},
+		true:  {delay: 5 * time.Second, conn: &raceFakeConn{}},
+	}}
+	o := newTestOpener(f, 40*time.Millisecond, 2*time.Second)
+
+	conn, err := o.Run(context.Background(), "peer", RelayServer{Addr: "srv"}, preferHome)
+
+	require.ErrorIs(t, err, ErrConnAlreadyExists)
+	assert.Nil(t, conn)
+	assert.Equal(t, 1, f.callCount(), "other attempt must not start on ErrConnAlreadyExists")
+}
+
+// A preferred failure starts the other attempt immediately, without waiting for
+// the fallback timer.
+func TestFallbackOpener_PreferredFailsStartsOtherBeforeTimer(t *testing.T) {
+	foreignConn := &raceFakeConn{label: "foreign"}
+	f := &fakeOpener{scripts: map[bool]raceAttemptScript{
+		false: {err: errAttempt}, // preferred fails instantly
+		true:  {delay: 5 * time.Millisecond, conn: foreignConn},
+	}}
+	fallbackDelay := 500 * time.Millisecond
+	o := newTestOpener(f, fallbackDelay, 2*time.Second)
+
+	start := time.Now()
+	conn, err := o.Run(context.Background(), "peer", RelayServer{Addr: "srv"}, preferHome)
+	elapsed := time.Since(start)
+
+	require.NoError(t, err)
+	require.Same(t, foreignConn, conn)
+	assert.Equal(t, 2, f.callCount())
+	assert.Less(t, elapsed, fallbackDelay/2, "fallback must not wait for the timer after a preferred failure")
+}
+
+// When the preferred attempt is slow, the fallback timer starts the other
+// attempt and its success wins.
+func TestFallbackOpener_TimerStartsOtherWhenPreferredSlow(t *testing.T) {
+	foreignConn := &raceFakeConn{label: "foreign"}
+	f := &fakeOpener{scripts: map[bool]raceAttemptScript{
+		false: {delay: 5 * time.Second}, // preferred hangs until cancelled
+		true:  {delay: 5 * time.Millisecond, conn: foreignConn},
+	}}
+	fallbackDelay := 40 * time.Millisecond
+	o := newTestOpener(f, fallbackDelay, 2*time.Second)
+
+	start := time.Now()
+	conn, err := o.Run(context.Background(), "peer", RelayServer{Addr: "srv"}, preferHome)
+	elapsed := time.Since(start)
+
+	require.NoError(t, err)
+	require.Same(t, foreignConn, conn)
+	assert.Equal(t, 2, f.callCount())
+	assert.GreaterOrEqual(t, elapsed, fallbackDelay, "other must not start before the fallback timer fires")
+}
+
+// Both attempts fail: Run returns the last error and tries both relays.
+func TestFallbackOpener_BothFail(t *testing.T) {
+	errOther := errors.New("other failed")
+	f := &fakeOpener{scripts: map[bool]raceAttemptScript{
+		false: {err: errAttempt},
+		true:  {err: errOther},
+	}}
+	o := newTestOpener(f, 40*time.Millisecond, 2*time.Second)
+
+	conn, err := o.Run(context.Background(), "peer", RelayServer{Addr: "srv"}, preferHome)
+
+	require.Error(t, err)
+	assert.Nil(t, conn)
+	assert.ErrorIs(t, err, errOther, "the most recent error should be surfaced")
+	assert.Equal(t, 2, f.callCount())
+}
+
+// When both attempts succeed, drainLoser must close the losing connection so it
+// is not leaked. Here the preferred attempt wins and the foreign loser - which
+// produced a real conn despite being cancelled - is closed.
+func TestFallbackOpener_DoubleSuccessClosesLoser(t *testing.T) {
+	homeConn := &raceFakeConn{label: "home"}
+	foreignConn := &raceFakeConn{label: "foreign"}
+	f := &fakeOpener{scripts: map[bool]raceAttemptScript{
+		false: {delay: 30 * time.Millisecond, conn: homeConn},                     // preferred wins
+		true:  {delay: 80 * time.Millisecond, conn: foreignConn, ignoreCtx: true}, // loser yields a conn after cancel
+	}}
+	o := newTestOpener(f, 15*time.Millisecond, 2*time.Second)
+
+	conn, err := o.Run(context.Background(), "peer", RelayServer{Addr: "srv"}, preferHome)
+
+	require.NoError(t, err)
+	require.Same(t, homeConn, conn)
+	assert.Equal(t, 2, f.callCount())
+	assert.False(t, homeConn.closed.Load(), "the winning connection must not be closed")
+	require.Eventually(t, foreignConn.closed.Load, time.Second, 5*time.Millisecond,
+		"the losing connection must be closed by drainLoser")
+}
+
+// Winner selection is purely by result arrival order, not by preference: when
+// the non-preferred attempt returns first it wins even though home was
+// preferred. This is the mechanism behind the split-relay concern - two peers
+// racing independently have no shared tie-break, so under adversarial timing
+// they can settle on different relays. Documented here as current behavior.
+func TestFallbackOpener_FasterOtherWinsDespitePreference(t *testing.T) {
+	homeConn := &raceFakeConn{label: "home"}
+	foreignConn := &raceFakeConn{label: "foreign"}
+	f := &fakeOpener{scripts: map[bool]raceAttemptScript{
+		false: {delay: 60 * time.Millisecond, conn: homeConn, ignoreCtx: true}, // preferred but slower
+		true:  {delay: 5 * time.Millisecond, conn: foreignConn},                // other is faster
+	}}
+	o := newTestOpener(f, 15*time.Millisecond, 2*time.Second)
+
+	conn, err := o.Run(context.Background(), "peer", RelayServer{Addr: "srv"}, preferHome)
+
+	require.NoError(t, err)
+	require.Same(t, foreignConn, conn, "the first successful attempt wins regardless of preference")
+	require.Eventually(t, homeConn.closed.Load, time.Second, 5*time.Millisecond,
+		"the slower preferred attempt becomes the loser and is closed")
+}
+
+// The whole race is bounded by totalTimeout. With no attempt succeeding or
+// failing, Run returns the deadline error.
+func TestFallbackOpener_TotalTimeout(t *testing.T) {
+	f := &fakeOpener{scripts: map[bool]raceAttemptScript{
+		false: {delay: 5 * time.Second},
+		true:  {delay: 5 * time.Second},
+	}}
+	o := newTestOpener(f, 20*time.Millisecond, 80*time.Millisecond)
+
+	conn, err := o.Run(context.Background(), "peer", RelayServer{Addr: "srv"}, preferHome)
+
+	require.Error(t, err)
+	assert.Nil(t, conn)
+	assert.ErrorIs(t, err, context.DeadlineExceeded)
+}
+
+// Cancelling the caller's context aborts the race promptly with the cancel
+// error, even before the fallback timer would fire.
+func TestFallbackOpener_ParentContextCanceled(t *testing.T) {
+	f := &fakeOpener{scripts: map[bool]raceAttemptScript{
+		false: {delay: 5 * time.Second},
+		true:  {delay: 5 * time.Second},
+	}}
+	// fallbackDelay large so the timer never fires; only the parent cancel ends the race.
+	o := newTestOpener(f, 5*time.Second, 5*time.Second)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	go func() {
+		time.Sleep(20 * time.Millisecond)
+		cancel()
+	}()
+
+	start := time.Now()
+	conn, err := o.Run(ctx, "peer", RelayServer{Addr: "srv"}, preferHome)
+
+	require.Error(t, err)
+	assert.Nil(t, conn)
+	assert.ErrorIs(t, err, context.Canceled)
+	assert.Less(t, time.Since(start), time.Second, "must return shortly after the parent context is cancelled")
+	assert.Equal(t, 1, f.callCount(), "the other attempt must not start")
+}
+
+// rendezvous models the relay-level requirement that a relayed connection is
+// established only once BOTH peers subscribe to the same relay server. arrive
+// records a peer's presence on a relay and returns a channel that closes when
+// the second peer arrives, so an attempt can only complete after a real
+// rendezvous - the same coupling the production code depends on.
+type rendezvous struct {
+	mu       sync.Mutex
+	arrivals map[string]int
+	gates    map[string]chan struct{}
+}
+
+func newRendezvous() *rendezvous {
+	return &rendezvous{arrivals: map[string]int{}, gates: map[string]chan struct{}{}}
+}
+
+func (r *rendezvous) arrive(relay string) <-chan struct{} {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	g, ok := r.gates[relay]
+	if !ok {
+		g = make(chan struct{})
+		r.gates[relay] = g
+	}
+	r.arrivals[relay]++
+	if r.arrivals[relay] == 2 {
+		close(g)
+	}
+	return g
+}
+
+// splitPeer is one peer's view of the two relays. relayFor maps the foreign
+// flag to a relay name; postDelay is how long after the rendezvous that peer's
+// OpenConn takes to return (its per-relay subscribe latency). Different values
+// per peer model the asymmetric timing that triggers finding #1.
+type splitPeer struct {
+	rv        *rendezvous
+	relayFor  map[bool]string
+	postDelay map[string]time.Duration
+}
+
+func (p *splitPeer) open(ctx context.Context, _ string, _ RelayServer, foreign bool) raceAttempt {
+	relay := p.relayFor[foreign]
+
+	select {
+	case <-p.rv.arrive(relay):
+	case <-ctx.Done():
+		return raceAttempt{err: ctx.Err()}
+	}
+
+	timer := time.NewTimer(p.postDelay[relay])
+	defer timer.Stop()
+	select {
+	case <-timer.C:
+	case <-ctx.Done():
+		return raceAttempt{err: ctx.Err()}
+	}
+	return raceAttempt{conn: &raceFakeConn{label: relay}}
+}
+
+// TestFallbackOpener_SplitRelaySelection reproduces finding #1: the two peers
+// run FallbackOpener.Run independently with no shared tie-break, so the winner
+// is chosen purely by local result-arrival order. Under an adversarial - but
+// self-consistent - timing profile they settle on DIFFERENT relays.
+//
+// Both peers prefer relayA (the controller's home). The split needs each peer's
+// preferred relayA to be slow enough that both start their fallback (so both
+// relays actually rendezvous), and then each peer's fast path to be a different
+// relay:
+//   - peerA: relayA slow (abandoned), relayB fast  -> peerA wins relayB
+//   - peerB: relayA fast (wins),      relayB slow  -> peerB wins relayA
+//
+// Each winner then cancels its attempt on the relay the OTHER peer actually
+// kept, leaving two half-open relayed connections that were both reported as
+// successful. When a deterministic cross-peer tie-break is added to fix this,
+// invert the assertion below to require convergence.
+func TestFallbackOpener_SplitRelaySelection(t *testing.T) {
+	const (
+		relayA = "relayA" // controller's home relay; both peers prefer it
+		relayB = "relayB" // non-controller's home relay
+	)
+	rv := newRendezvous()
+
+	peerA := &splitPeer{
+		rv:       rv,
+		relayFor: map[bool]string{false: relayA, true: relayB}, // home=relayA
+		postDelay: map[string]time.Duration{
+			relayA: 500 * time.Millisecond, // preferred but slow -> abandoned
+			relayB: 10 * time.Millisecond,  // fallback is fast -> peerA wins relayB
+		},
+	}
+	peerB := &splitPeer{
+		rv:       rv,
+		relayFor: map[bool]string{false: relayB, true: relayA}, // home=relayB
+		postDelay: map[string]time.Duration{
+			relayA: 80 * time.Millisecond,  // preferred, wins - but only after starting fallback
+			relayB: 500 * time.Millisecond, // fallback (home) is slow -> abandoned
+		},
+	}
+
+	fallbackDelay := 30 * time.Millisecond
+	newPeerOpener := func(p *splitPeer) *FallbackOpener {
+		o := NewFallbackOpener(nil, nil)
+		o.openFn = p.open
+		o.fallbackDelay = fallbackDelay
+		o.totalTimeout = 5 * time.Second
+		return o
+	}
+	oA := newPeerOpener(peerA)
+	oB := newPeerOpener(peerB)
+
+	type result struct {
+		conn net.Conn
+		err  error
+	}
+	var ra, rb result
+	var wg sync.WaitGroup
+	wg.Add(2)
+	go func() {
+		defer wg.Done()
+		ra.conn, ra.err = oA.Run(context.Background(), "peerB", RelayServer{Addr: relayB}, preferHome)
+	}()
+	go func() {
+		defer wg.Done()
+		rb.conn, rb.err = oB.Run(context.Background(), "peerA", RelayServer{Addr: relayA}, preferForeign)
+	}()
+	wg.Wait()
+
+	require.NoError(t, ra.err)
+	require.NoError(t, rb.err)
+	aRelay := ra.conn.(*raceFakeConn).label
+	bRelay := rb.conn.(*raceFakeConn).label
+	t.Logf("peerA settled on %s, peerB settled on %s", aRelay, bRelay)
+
+	assert.Equal(t, aRelay, bRelay,
+		"peers selected different relays with no cross-peer tie-break")
+	assert.Equal(t, relayB, aRelay, "peerA abandoned its slow preferred relay and won the fallback")
+	assert.Equal(t, relayA, bRelay, "peerB won its preferred relay after starting the fallback")
+}

shared/relay/client/foreign_relays_store.go

@@ -0,0 +1,155 @@
+package client
+
+import (
+	"context"
+	"net"
+	"sync"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+	"golang.org/x/sync/singleflight"
+
+	relayAuth "github.com/netbirdio/netbird/shared/relay/auth/hmac"
+)
+
+type foreignRelay struct {
+	client  *Client
+	created time.Time
+	inUse   int
+}
+
+type ForeignRelaysStore struct {
+	mu      sync.RWMutex
+	clients map[string]*foreignRelay
+
+	group singleflight.Group
+
+	ctx                  context.Context
+	tokenStore           *relayAuth.TokenStore
+	peerID               string
+	mtu                  uint16
+	transportFallback    *transportFallback
+	onDisconnect         func(string)
+	keepUnusedServerTime time.Duration
+}
+
+func NewForeignRelaysStore(ctx context.Context, tokenStore *relayAuth.TokenStore, peerID string, mtu uint16, transportFallback *transportFallback, onDisconnect func(string), keepUnusedServerTime time.Duration) *ForeignRelaysStore {
+	return &ForeignRelaysStore{
+		clients:              make(map[string]*foreignRelay),
+		ctx:                  ctx,
+		tokenStore:           tokenStore,
+		peerID:               peerID,
+		mtu:                  mtu,
+		transportFallback:    transportFallback,
+		onDisconnect:         onDisconnect,
+		keepUnusedServerTime: keepUnusedServerTime,
+	}
+}
+
+func (f *ForeignRelaysStore) OpenConn(ctx context.Context, peerKey string, remoteRelayServer RelayServer) (net.Conn, error) {
+	fr, err := f.acquire(remoteRelayServer)
+	if err != nil {
+		return nil, err
+	}
+	defer f.release(fr)
+
+	return fr.client.OpenConn(ctx, peerKey)
+}
+
+func (f *ForeignRelaysStore) acquire(remoteRelayServer RelayServer) (*foreignRelay, error) {
+	f.mu.Lock()
+	if fr, ok := f.clients[remoteRelayServer.Addr]; ok {
+		fr.inUse++
+		f.mu.Unlock()
+		return fr, nil
+	}
+	f.mu.Unlock()
+
+	v, err, _ := f.group.Do(remoteRelayServer.Addr, func() (any, error) {
+		f.mu.RLock()
+		fr, ok := f.clients[remoteRelayServer.Addr]
+		f.mu.RUnlock()
+		if ok {
+			return fr, nil
+		}
+
+		relayClient := NewClientWithServerIP(remoteRelayServer.Addr, remoteRelayServer.IP, f.tokenStore, f.peerID, f.mtu)
+		relayClient.SetTransportFallback(f.transportFallback)
+		if err := relayClient.Connect(f.ctx); err != nil {
+			return nil, err
+		}
+		relayClient.SetOnDisconnectListener(f.onDisconnect)
+
+		f.mu.Lock()
+		fr = &foreignRelay{client: relayClient, created: time.Now()}
+		f.clients[remoteRelayServer.Addr] = fr
+		f.mu.Unlock()
+		return fr, nil
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	fr := v.(*foreignRelay)
+	f.mu.Lock()
+	if cur, ok := f.clients[remoteRelayServer.Addr]; !ok || cur != fr {
+		f.mu.Unlock()
+		return f.acquire(remoteRelayServer)
+	}
+	fr.inUse++
+	f.mu.Unlock()
+	return fr, nil
+}
+
+func (f *ForeignRelaysStore) release(fr *foreignRelay) {
+	f.mu.Lock()
+	fr.inUse--
+	f.mu.Unlock()
+}
+
+func (f *ForeignRelaysStore) evict(serverAddress string) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if _, ok := f.clients[serverAddress]; ok {
+		delete(f.clients, serverAddress)
+		log.Debugf("evicted disconnected foreign relay client: %s", serverAddress)
+	}
+}
+
+func (f *ForeignRelaysStore) cleanupUnused() {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+
+	for addr, fr := range f.clients {
+		if time.Since(fr.created) <= f.keepUnusedServerTime {
+			continue
+		}
+		if fr.inUse > 0 {
+			continue
+		}
+		if fr.client.HasConns() {
+			continue
+		}
+		fr.client.SetOnDisconnectListener(nil)
+		go func() {
+			_ = fr.client.Close()
+		}()
+		log.Debugf("clean up unused relay server connection: %s", addr)
+		delete(f.clients, addr)
+	}
+}
+
+func (f *ForeignRelaysStore) states() []RelayConnState {
+	f.mu.RLock()
+	clients := make([]*Client, 0, len(f.clients))
+	for _, fr := range f.clients {
+		clients = append(clients, fr.client)
+	}
+	f.mu.RUnlock()
+
+	states := make([]RelayConnState, 0, len(clients))
+	for _, c := range clients {
+		states = append(states, relayConnState(c))
+	}
+	return states
+}

shared/relay/client/manager.go

@@ -22,27 +22,6 @@ var (
 	ErrRelayClientNotConnected = fmt.Errorf("relay client not connected")
 )
 
-// RelayTrack hold the relay clients for the foreign relay servers.
-// With the mutex can ensure we can open new connection in case the relay connection has been established with
-// the relay server.
-type RelayTrack struct {
-	sync.RWMutex
-	relayClient *Client
-	err         error
-	created     time.Time
-	// ready is closed once the dial started by openConnVia finishes (relayClient
-	// or err is set). Callers reusing a track wait on this instead of the track
-	// lock, so the dial never runs under rt.Lock.
-	ready chan struct{}
-}
-
-func NewRelayTrack() *RelayTrack {
-	return &RelayTrack{
-		created: time.Now(),
-		ready:   make(chan struct{}),
-	}
-}
-
 type OnServerCloseListener func()
 
 // ManagerOption configures a Manager at construction time.
@@ -59,6 +38,11 @@ type RelayConnState struct {
 	Err error
 }
 
+type RelayServer struct {
+	Addr string
+	IP   netip.Addr
+}
+
 // WithMaxBackoffInterval caps the exponential backoff between reconnect
 // attempts to the home relay. A non-positive value keeps the default.
 func WithMaxBackoffInterval(d time.Duration) ManagerOption {
@@ -83,8 +67,7 @@ type Manager struct {
 	relayClientMu  sync.RWMutex
 	reconnectGuard *Guard
 
-	relayClients      map[string]*RelayTrack
-	relayClientsMutex sync.RWMutex
+	foreign *ForeignRelaysStore
 
 	onDisconnectedListeners map[string]*list.List
 	onReconnectedListenerFn func()
@@ -120,7 +103,6 @@ func NewManager(ctx context.Context, serverURLs []string, peerID string, mtu uin
 			ConnectionTimeout: defaultConnectionTimeout,
 			TransportFallback: tf,
 		},
-		relayClients:            make(map[string]*RelayTrack),
 		onDisconnectedListeners: make(map[string]*list.List),
 		cleanupInterval:         relayCleanupInterval,
 		keepUnusedServerTime:    keepUnusedServerTime,
@@ -128,6 +110,7 @@ func NewManager(ctx context.Context, serverURLs []string, peerID string, mtu uin
 	for _, opt := range opts {
 		opt(m)
 	}
+	m.foreign = NewForeignRelaysStore(ctx, tokenStore, peerID, mtu, tf, m.onServerDisconnected, m.keepUnusedServerTime)
 	m.serverPicker.ServerURLs.Store(serverURLs)
 	m.reconnectGuard = NewGuard(m.serverPicker, m.maxBackoffInterval)
 	return m
@@ -159,40 +142,26 @@ func (m *Manager) Serve() error {
 	return err
 }
 
-// OpenConn opens a connection to the given peer key. If the peer is on the same relay server, the connection will be
-// established via the relay server. If the peer is on a different relay server, the manager will establish a new
-// connection to the relay server. It returns back with a net.Conn what represent the remote peer connection.
-//
-// serverIP, when valid and serverAddress is foreign, is used as a dial target if the FQDN-based dial fails.
-// Ignored for the local home-server path. TLS verification still uses the FQDN via SNI.
-func (m *Manager) OpenConn(ctx context.Context, serverAddress, peerKey string, serverIP netip.Addr) (net.Conn, error) {
+func (m *Manager) OpenConn(ctx context.Context, remoteRelayServer RelayServer, peerKey string, preferForeign bool) (net.Conn, error) {
 	m.relayClientMu.RLock()
-	defer m.relayClientMu.RUnlock()
+	relayClient := m.relayClient
+	m.relayClientMu.RUnlock()
 
-	if m.relayClient == nil {
+	if relayClient == nil {
 		return nil, ErrRelayClientNotConnected
 	}
 
-	foreign, err := m.isForeignServer(serverAddress)
+	foreign, err := m.isForeignServer(relayClient, remoteRelayServer.Addr)
 	if err != nil {
 		return nil, err
 	}
 
-	var (
-		netConn net.Conn
-	)
 	if !foreign {
-		log.Debugf("open peer connection via permanent server: %s", peerKey)
-		netConn, err = m.relayClient.OpenConn(ctx, peerKey)
-	} else {
-		log.Debugf("open peer connection via foreign server: %s", serverAddress)
-		netConn, err = m.openConnVia(ctx, serverAddress, peerKey, serverIP)
-	}
-	if err != nil {
-		return nil, err
+		return relayClient.OpenConn(ctx, peerKey)
 	}
 
-	return netConn, err
+	opener := NewFallbackOpener(relayClient, m.foreign)
+	return opener.Run(ctx, peerKey, remoteRelayServer, preferForeign)
 }
 
 // Ready returns true if the home Relay client is connected to the relay server.
@@ -223,7 +192,7 @@ func (m *Manager) AddCloseListener(serverAddress string, onClosedListener OnServ
 		return ErrRelayClientNotConnected
 	}
 
-	foreign, err := m.isForeignServer(serverAddress)
+	foreign, err := m.isForeignServer(m.relayClient, serverAddress)
 	if err != nil {
 		return err
 	}
@@ -287,26 +256,7 @@ func (m *Manager) RelayStates() []RelayConnState {
 		states = append(states, st)
 	}
 
-	// Snapshot the tracks, then query each outside the map lock: a track can be
-	// held by an in-progress Connect, and blocking on it must not stall other
-	// relay operations.
-	m.relayClientsMutex.RLock()
-	tracks := make([]*RelayTrack, 0, len(m.relayClients))
-	for _, rt := range m.relayClients {
-		tracks = append(tracks, rt)
-	}
-	m.relayClientsMutex.RUnlock()
-
-	// Only connected foreign relays carry state; a failed connect is evicted
-	// immediately (openConnVia), so there is no error state to surface.
-	for _, rt := range tracks {
-		rt.RLock()
-		rc := rt.relayClient
-		rt.RUnlock()
-		if rc != nil {
-			states = append(states, relayConnState(rc))
-		}
-	}
+	states = append(states, m.foreign.states()...)
 
 	return states
 }
@@ -327,76 +277,6 @@ func (m *Manager) UpdateToken(token *relayAuth.Token) error {
 	return m.tokenStore.UpdateToken(token)
 }
 
-func (m *Manager) openConnVia(ctx context.Context, serverAddress, peerKey string, serverIP netip.Addr) (net.Conn, error) {
-	// check if already has a connection to the desired relay server
-	m.relayClientsMutex.RLock()
-	rt, ok := m.relayClients[serverAddress]
-	m.relayClientsMutex.RUnlock()
-	if ok {
-		return m.openConnOnTrack(ctx, rt, peerKey)
-	}
-
-	// if not, establish a new connection but check it again (because changed the lock type) before starting the
-	// connection
-	m.relayClientsMutex.Lock()
-	rt, ok = m.relayClients[serverAddress]
-	if ok {
-		m.relayClientsMutex.Unlock()
-		return m.openConnOnTrack(ctx, rt, peerKey)
-	}
-
-	// Publish the track and release the map lock BEFORE dialing, so the dial does
-	// not run under rt.Lock (which would block RelayStates and the cleanup loop
-	// for the full dial). Concurrent callers find this track and wait on rt.ready.
-	rt = NewRelayTrack()
-	m.relayClients[serverAddress] = rt
-	m.relayClientsMutex.Unlock()
-
-	relayClient := NewClientWithServerIP(serverAddress, serverIP, m.tokenStore, m.peerID, m.mtu)
-	relayClient.SetTransportFallback(m.transportFallback)
-	err := relayClient.Connect(m.ctx)
-	if err != nil {
-		rt.Lock()
-		rt.err = err
-		rt.Unlock()
-		close(rt.ready)
-		m.relayClientsMutex.Lock()
-		delete(m.relayClients, serverAddress)
-		m.relayClientsMutex.Unlock()
-		return nil, err
-	}
-	// if connection closed then delete the relay client from the list
-	relayClient.SetOnDisconnectListener(m.onServerDisconnected)
-	rt.Lock()
-	rt.relayClient = relayClient
-	rt.Unlock()
-	close(rt.ready)
-
-	return relayClient.OpenConn(ctx, peerKey)
-}
-
-// openConnOnTrack opens a peer connection through an existing relay track,
-// waiting for the dial started by another openConnVia call to finish. It waits
-// on rt.ready rather than the track lock, so it neither holds nor contends the
-// track lock across the dial.
-func (m *Manager) openConnOnTrack(ctx context.Context, rt *RelayTrack, peerKey string) (net.Conn, error) {
-	select {
-	case <-rt.ready:
-	case <-ctx.Done():
-		return nil, ctx.Err()
-	}
-
-	rt.RLock()
-	defer rt.RUnlock()
-	if rt.err != nil {
-		return nil, rt.err
-	}
-	if rt.relayClient == nil {
-		return nil, ErrRelayClientNotConnected
-	}
-	return rt.relayClient.OpenConn(ctx, peerKey)
-}
-
 func (m *Manager) onServerConnected() {
 	m.listenerLock.Lock()
 	defer m.listenerLock.Unlock()
@@ -422,21 +302,12 @@ func (m *Manager) onServerDisconnected(serverAddress string) {
 	m.relayClientMu.Unlock()
 
 	if !isHome {
-		m.evictForeignRelay(serverAddress)
+		m.foreign.evict(serverAddress)
 	}
 
 	m.notifyOnDisconnectListeners(serverAddress)
 }
 
-func (m *Manager) evictForeignRelay(serverAddress string) {
-	m.relayClientsMutex.Lock()
-	defer m.relayClientsMutex.Unlock()
-	if _, ok := m.relayClients[serverAddress]; ok {
-		delete(m.relayClients, serverAddress)
-		log.Debugf("evicted disconnected foreign relay client: %s", serverAddress)
-	}
-}
-
 func (m *Manager) listenGuardEvent(ctx context.Context) {
 	for {
 		select {
@@ -459,8 +330,8 @@ func (m *Manager) storeClient(client *Client) {
 	m.relayClient.SetOnDisconnectListener(m.onServerDisconnected)
 }
 
-func (m *Manager) isForeignServer(address string) (bool, error) {
-	rAddr, err := m.relayClient.ServerInstanceURL()
+func (m *Manager) isForeignServer(relayClient *Client, address string) (bool, error) {
+	rAddr, err := relayClient.ServerInstanceURL()
 	if err != nil {
 		return false, fmt.Errorf("relay client not connected")
 	}
@@ -475,50 +346,11 @@ func (m *Manager) startCleanupLoop() {
 		case <-m.ctx.Done():
 			return
 		case <-ticker.C:
-			m.cleanUpUnusedRelays()
+			m.foreign.cleanupUnused()
 		}
 	}
 }
 
-func (m *Manager) cleanUpUnusedRelays() {
-	m.relayClientsMutex.Lock()
-	defer m.relayClientsMutex.Unlock()
-
-	for addr, rt := range m.relayClients {
-		rt.Lock()
-		// if the connection failed to the server the relay client will be nil
-		// but the instance will be kept in the relayClients until the next locking
-		if rt.err != nil {
-			rt.Unlock()
-			continue
-		}
-
-		// dial still in progress (openConnVia publishes the track before Connect
-		// completes and no longer holds rt.Lock during it), nothing to clean up.
-		if rt.relayClient == nil {
-			rt.Unlock()
-			continue
-		}
-
-		if time.Since(rt.created) <= m.keepUnusedServerTime {
-			rt.Unlock()
-			continue
-		}
-
-		if rt.relayClient.HasConns() {
-			rt.Unlock()
-			continue
-		}
-		rt.relayClient.SetOnDisconnectListener(nil)
-		go func() {
-			_ = rt.relayClient.Close()
-		}()
-		log.Debugf("clean up unused relay server connection: %s", addr)
-		delete(m.relayClients, addr)
-		rt.Unlock()
-	}
-}
-
 func (m *Manager) addListener(serverAddress string, onClosedListener OnServerCloseListener) {
 	m.listenerLock.Lock()
 	defer m.listenerLock.Unlock()

shared/relay/client/manager_cleanup_test.go

@@ -2,17 +2,14 @@ package client
 
 import (
 	"context"
-	"net/netip"
 	"testing"
 	"time"
-
-	"github.com/stretchr/testify/require"
 )
 
 // TestCleanUpUnusedRelays_DoesNotBlockOnRealHangingDial drives a real, hanging foreign
-// relay dial and asserts cleanUpUnusedRelays does not stall behind it.
+// relay dial and asserts the foreign store cleanup does not stall behind it.
 func TestCleanUpUnusedRelays_DoesNotBlockOnRealHangingDial(t *testing.T) {
-	serverAddr := stallingRelayListener(t)
+	serverAddr, accepted := stallingRelayListener(t)
 
 	mCtx, mCancel := context.WithCancel(context.Background())
 	t.Cleanup(mCancel)
@@ -22,39 +19,32 @@ func TestCleanUpUnusedRelays_DoesNotBlockOnRealHangingDial(t *testing.T) {
 	dialDone := make(chan struct{})
 	go func() {
 		defer close(dialDone)
-		_, _ = m.openConnVia(mCtx, serverAddr, "peerKey", netip.Addr{})
+		_, _ = m.foreign.OpenConn(mCtx, "peerKey", RelayServer{Addr: serverAddr})
 	}()
 
-	// The track appears in the map once the dial is in flight.
-	require.Eventually(t, func() bool {
-		m.relayClientsMutex.RLock()
-		defer m.relayClientsMutex.RUnlock()
-		_, ok := m.relayClients[serverAddr]
-		return ok
-	}, 5*time.Second, 5*time.Millisecond, "relay dial did not start")
+	select {
+	case <-accepted:
+	case <-time.After(5 * time.Second):
+		t.Fatal("relay dial did not reach the listener")
+	}
 
 	cleanupDone := make(chan struct{})
 	go func() {
 		defer close(cleanupDone)
-		m.cleanUpUnusedRelays()
+		m.foreign.cleanupUnused()
 	}()
 
 	select {
 	case <-cleanupDone:
 	case <-time.After(2 * time.Second):
-		t.Fatal("cleanUpUnusedRelays blocked on an in-progress relay dial while holding the relay map lock")
+		t.Fatal("cleanupUnused blocked on an in-progress relay dial")
 	}
 
-	m.relayClientsMutex.RLock()
-	_, stillTracked := m.relayClients[serverAddr]
-	m.relayClientsMutex.RUnlock()
-	require.True(t, stillTracked, "an in-progress relay dial must not be evicted by cleanup")
-
 	// Release the hanging dial so the goroutine can exit cleanly.
 	mCancel()
 	select {
 	case <-dialDone:
 	case <-time.After(5 * time.Second):
-		t.Fatal("openConnVia did not return after context cancellation")
+		t.Fatal("foreign OpenConn did not return after context cancellation")
 	}
 }

shared/relay/client/manager_relaystates_test.go

@@ -3,7 +3,6 @@ package client
 import (
 	"context"
 	"net"
-	"net/netip"
 	"sync"
 	"testing"
 	"time"
@@ -13,13 +12,16 @@ import (
 
 // stallingRelayListener accepts TCP connections and holds them open without ever
 // responding, so a relay handshake dialed against it blocks until its context is
-// cancelled. It returns the "rel://host:port" URL to dial.
-func stallingRelayListener(t *testing.T) string {
+// cancelled. accepted is signalled once per incoming connection so a caller can
+// wait until a dial has actually reached the listener. It returns the
+// "rel://host:port" URL to dial.
+func stallingRelayListener(t *testing.T) (string, <-chan struct{}) {
 	t.Helper()
 
 	ln, err := net.Listen("tcp", "127.0.0.1:0")
 	require.NoError(t, err)
 
+	accepted := make(chan struct{}, 1)
 	var mu sync.Mutex
 	var conns []net.Conn
 	go func() {
@@ -31,6 +33,10 @@ func stallingRelayListener(t *testing.T) string {
 			mu.Lock()
 			conns = append(conns, c)
 			mu.Unlock()
+			select {
+			case accepted <- struct{}{}:
+			default:
+			}
 		}
 	}()
 	t.Cleanup(func() {
@@ -42,14 +48,14 @@ func stallingRelayListener(t *testing.T) string {
 		mu.Unlock()
 	})
 
-	return "rel://" + ln.Addr().String()
+	return "rel://" + ln.Addr().String(), accepted
 }
 
 // TestRelayStates_DoesNotBlockOnRealHangingDial is a regression test for
 // RelayStates() called by a "status -d command" hanging behind an in-progress
-// relay dial.
+// foreign relay dial.
 func TestRelayStates_DoesNotBlockOnRealHangingDial(t *testing.T) {
-	serverAddr := stallingRelayListener(t)
+	serverAddr, accepted := stallingRelayListener(t)
 
 	mCtx, mCancel := context.WithCancel(context.Background())
 	t.Cleanup(mCancel)
@@ -59,15 +65,14 @@ func TestRelayStates_DoesNotBlockOnRealHangingDial(t *testing.T) {
 	dialDone := make(chan struct{})
 	go func() {
 		defer close(dialDone)
-		_, _ = m.openConnVia(mCtx, serverAddr, "peerKey", netip.Addr{})
+		_, _ = m.foreign.OpenConn(mCtx, "peerKey", RelayServer{Addr: serverAddr})
 	}()
 
-	require.Eventually(t, func() bool {
-		m.relayClientsMutex.RLock()
-		defer m.relayClientsMutex.RUnlock()
-		_, ok := m.relayClients[serverAddr]
-		return ok
-	}, 5*time.Second, 5*time.Millisecond, "relay dial did not start")
+	select {
+	case <-accepted:
+	case <-time.After(5 * time.Second):
+		t.Fatal("relay dial did not reach the listener")
+	}
 
 	done := make(chan []RelayConnState, 1)
 	go func() {
@@ -86,6 +91,6 @@ func TestRelayStates_DoesNotBlockOnRealHangingDial(t *testing.T) {
 	select {
 	case <-dialDone:
 	case <-time.After(5 * time.Second):
-		t.Fatal("openConnVia did not return after context cancellation")
+		t.Fatal("foreign OpenConn did not return after context cancellation")
 	}
 }

shared/relay/client/manager_serverip_test.go

@@ -3,7 +3,6 @@ package client
 import (
 	"context"
 	"io"
-	"net/netip"
 	"testing"
 	"time"
 
@@ -85,7 +84,7 @@ func TestManager_ForeignRelayServerIP(t *testing.T) {
 	t.Run("no server IP, dial fails", func(t *testing.T) {
 		dialCtx, dialCancel := context.WithTimeout(ctx, 5*time.Second)
 		defer dialCancel()
-		_, err := mgrAlice.OpenConn(dialCtx, brokenFQDN, "bob", netip.Addr{})
+		_, err := mgrAlice.OpenConn(dialCtx, RelayServer{Addr: brokenFQDN}, "bob", true)
 		if err == nil {
 			t.Fatalf("expected OpenConn to fail without server IP, got success")
 		}
@@ -95,7 +94,7 @@ func TestManager_ForeignRelayServerIP(t *testing.T) {
 		// Bob waits for Alice's incoming peer connection on his side.
 		bobSideCh := make(chan error, 1)
 		go func() {
-			conn, err := mgrBob.OpenConn(ctx, bobRealAddr, "alice", netip.Addr{})
+			conn, err := mgrBob.OpenConn(ctx, RelayServer{Addr: bobRealAddr}, "alice", false)
 			if err != nil {
 				bobSideCh <- err
 				return
@@ -113,7 +112,7 @@ func TestManager_ForeignRelayServerIP(t *testing.T) {
 			bobSideCh <- nil
 		}()
 
-		aliceConn, err := mgrAlice.OpenConn(ctx, brokenFQDN, "bob", bobAdvertisedIP)
+		aliceConn, err := mgrAlice.OpenConn(ctx, RelayServer{Addr: brokenFQDN, IP: bobAdvertisedIP}, "bob", true)
 		if err != nil {
 			t.Fatalf("alice OpenConn with server IP: %s", err)
 		}

shared/relay/client/manager_test.go

@@ -3,7 +3,6 @@ package client
 import (
 	"context"
 	"fmt"
-	"net/netip"
 	"testing"
 	"time"
 
@@ -106,11 +105,11 @@ func TestForeignConn(t *testing.T) {
 	if err != nil {
 		t.Fatalf("failed to get relay address: %s", err)
 	}
-	connAliceToBob, err := clientAlice.OpenConn(ctx, bobsSrvAddr, "bob", netip.Addr{})
+	connAliceToBob, err := clientAlice.OpenConn(ctx, RelayServer{Addr: bobsSrvAddr}, "bob", true)
 	if err != nil {
 		t.Fatalf("failed to bind channel: %s", err)
 	}
-	connBobToAlice, err := clientBob.OpenConn(ctx, bobsSrvAddr, "alice", netip.Addr{})
+	connBobToAlice, err := clientBob.OpenConn(ctx, RelayServer{Addr: bobsSrvAddr}, "alice", false)
 	if err != nil {
 		t.Fatalf("failed to bind channel: %s", err)
 	}
@@ -210,7 +209,7 @@ func TestForeginConnClose(t *testing.T) {
 	if err != nil {
 		t.Fatalf("failed to serve manager: %s", err)
 	}
-	conn, err := mgr.OpenConn(ctx, toURL(srvCfg2)[0], "bob", netip.Addr{})
+	conn, err := mgr.OpenConn(ctx, RelayServer{Addr: toURL(srvCfg2)[0]}, "bob", true)
 	if err != nil {
 		t.Fatalf("failed to bind channel: %s", err)
 	}
@@ -302,7 +301,7 @@ func TestForeignAutoClose(t *testing.T) {
 	}
 
 	t.Log("open connection to another peer")
-	if _, err = mgr.OpenConn(ctx, foreignServerURL, "anotherpeer", netip.Addr{}); err == nil {
+	if _, err = mgr.OpenConn(ctx, RelayServer{Addr: foreignServerURL}, "anotherpeer", true); err == nil {
 		t.Fatalf("should have failed to open connection to another peer")
 	}
 
@@ -372,7 +371,7 @@ func TestAutoReconnect(t *testing.T) {
 	if err != nil {
 		t.Errorf("failed to get relay address: %s", err)
 	}
-	conn, err := clientAlice.OpenConn(ctx, ra, "bob", netip.Addr{})
+	conn, err := clientAlice.OpenConn(ctx, RelayServer{Addr: ra}, "bob", false)
 	if err != nil {
 		t.Errorf("failed to bind channel: %s", err)
 	}
@@ -392,7 +391,7 @@ func TestAutoReconnect(t *testing.T) {
 	}
 
 	log.Infof("reopent the connection")
-	_, err = clientAlice.OpenConn(ctx, ra, "bob", netip.Addr{})
+	_, err = clientAlice.OpenConn(ctx, RelayServer{Addr: ra}, "bob", false)
 	if err != nil {
 		t.Errorf("failed to open channel: %s", err)
 	}
@@ -454,7 +453,7 @@ func TestNotifierDoubleAdd(t *testing.T) {
 		t.Fatalf("failed to serve manager: %s", err)
 	}
 
-	conn1, err := clientAlice.OpenConn(ctx, clientAlice.ServerURLs()[0], "bob", netip.Addr{})
+	conn1, err := clientAlice.OpenConn(ctx, RelayServer{Addr: clientAlice.ServerURLs()[0]}, "bob", false)
 	if err != nil {
 		t.Fatalf("failed to bind channel: %s", err)
 	}

trustedproxy/trustedproxy.go

@@ -0,0 +1,132 @@
+package trustedproxy
+
+import (
+	"fmt"
+	"net/netip"
+	"strings"
+)
+
+// List holds a parsed set of trusted upstream proxy prefixes and answers trust
+// questions against it. The zero value (and a nil *List) is a valid, empty list
+// that never trusts any address, so callers can use it without a nil check.
+type List struct {
+	prefixes []netip.Prefix
+}
+
+// Parse parses a comma-separated list of CIDR prefixes or bare IPs into a List.
+// Bare IPs are converted to single-host prefixes (/32 or /128). An empty input
+// yields an empty List that trusts nothing.
+func Parse(raw string) (*List, error) {
+	if raw == "" {
+		return &List{}, nil
+	}
+
+	parts := strings.Split(raw, ",")
+	prefixes := make([]netip.Prefix, 0, len(parts))
+	for _, part := range parts {
+		part = strings.TrimSpace(part)
+		if part == "" {
+			continue
+		}
+
+		prefix, err := netip.ParsePrefix(part)
+		if err == nil {
+			prefixes = append(prefixes, prefix)
+			continue
+		}
+
+		addr, addrErr := netip.ParseAddr(part)
+		if addrErr != nil {
+			return nil, fmt.Errorf("parse trusted proxy %q: not a valid CIDR or IP: %w", part, addrErr)
+		}
+
+		bits := 32
+		if addr.Is6() {
+			bits = 128
+		}
+		prefixes = append(prefixes, netip.PrefixFrom(addr, bits))
+	}
+	return &List{prefixes: prefixes}, nil
+}
+
+// FromPrefixes wraps an already-parsed set of prefixes in a List.
+func FromPrefixes(prefixes []netip.Prefix) *List {
+	return &List{prefixes: prefixes}
+}
+
+// Empty reports whether the list contains no prefixes.
+func (l *List) Empty() bool {
+	return l == nil || len(l.prefixes) == 0
+}
+
+// IsTrusted reports whether the given host:port or bare IP falls within the list.
+func (l *List) IsTrusted(remoteAddr string) bool {
+	if l.Empty() {
+		return false
+	}
+	return l.Contains(ExtractHostIP(remoteAddr))
+}
+
+// Contains reports whether the given address falls within any trusted prefix.
+func (l *List) Contains(addr netip.Addr) bool {
+	if l.Empty() || !addr.IsValid() {
+		return false
+	}
+	for _, prefix := range l.prefixes {
+		if prefix.Contains(addr) {
+			return true
+		}
+	}
+	return false
+}
+
+// ResolveClientIP extracts the real client IP from X-Forwarded-For using the
+// list. It walks the XFF chain right-to-left, skipping IPs that match trusted
+// prefixes; the first untrusted IP is the real client. If the list is empty or
+// remoteAddr is not trusted, it returns the remoteAddr IP directly, ignoring any
+// forwarding headers.
+func (l *List) ResolveClientIP(remoteAddr, xff string) netip.Addr {
+	remoteIP := ExtractHostIP(remoteAddr)
+
+	if l.Empty() || !l.Contains(remoteIP) {
+		return remoteIP
+	}
+
+	if xff == "" {
+		return remoteIP
+	}
+
+	parts := strings.Split(xff, ",")
+	for i := len(parts) - 1; i >= 0; i-- {
+		ip := strings.TrimSpace(parts[i])
+		if ip == "" {
+			continue
+		}
+		addr, err := netip.ParseAddr(ip)
+		if err != nil {
+			continue
+		}
+		addr = addr.Unmap()
+		if !l.Contains(addr) {
+			return addr
+		}
+	}
+
+	if first := strings.TrimSpace(parts[0]); first != "" {
+		if addr, err := netip.ParseAddr(first); err == nil {
+			return addr.Unmap()
+		}
+	}
+	return remoteIP
+}
+
+// ExtractHostIP parses the IP from a host:port string and returns it unmapped.
+func ExtractHostIP(hostPort string) netip.Addr {
+	if ap, err := netip.ParseAddrPort(hostPort); err == nil {
+		return ap.Addr().Unmap()
+	}
+	if addr, err := netip.ParseAddr(hostPort); err == nil {
+		return addr.Unmap()
+	}
+	return netip.Addr{}
+}

trustedproxy/trustedproxy_test.go

@@ -0,0 +1,216 @@
+package trustedproxy
+
+import (
+	"net/netip"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestParse(t *testing.T) {
+	tests := []struct {
+		name    string
+		raw     string
+		want    []netip.Prefix
+		wantErr bool
+	}{
+		{
+			name: "empty string returns empty list",
+			raw:  "",
+			want: nil,
+		},
+		{
+			name: "single CIDR",
+			raw:  "10.0.0.0/8",
+			want: []netip.Prefix{netip.MustParsePrefix("10.0.0.0/8")},
+		},
+		{
+			name: "single bare IPv4",
+			raw:  "1.2.3.4",
+			want: []netip.Prefix{netip.MustParsePrefix("1.2.3.4/32")},
+		},
+		{
+			name: "single bare IPv6",
+			raw:  "::1",
+			want: []netip.Prefix{netip.MustParsePrefix("::1/128")},
+		},
+		{
+			name: "comma-separated CIDRs",
+			raw:  "10.0.0.0/8, 192.168.1.0/24",
+			want: []netip.Prefix{
+				netip.MustParsePrefix("10.0.0.0/8"),
+				netip.MustParsePrefix("192.168.1.0/24"),
+			},
+		},
+		{
+			name: "mixed CIDRs and bare IPs",
+			raw:  "10.0.0.0/8, 1.2.3.4, fd00::/8",
+			want: []netip.Prefix{
+				netip.MustParsePrefix("10.0.0.0/8"),
+				netip.MustParsePrefix("1.2.3.4/32"),
+				netip.MustParsePrefix("fd00::/8"),
+			},
+		},
+		{
+			name: "whitespace around entries",
+			raw:  "  10.0.0.0/8 , 192.168.0.0/16  ",
+			want: []netip.Prefix{
+				netip.MustParsePrefix("10.0.0.0/8"),
+				netip.MustParsePrefix("192.168.0.0/16"),
+			},
+		},
+		{
+			name: "trailing comma produces no extra entry",
+			raw:  "10.0.0.0/8,",
+			want: []netip.Prefix{netip.MustParsePrefix("10.0.0.0/8")},
+		},
+		{
+			name:    "invalid entry",
+			raw:     "not-an-ip",
+			wantErr: true,
+		},
+		{
+			name:    "partially invalid",
+			raw:     "10.0.0.0/8, garbage",
+			wantErr: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := Parse(tt.raw)
+			if tt.wantErr {
+				require.Error(t, err)
+				return
+			}
+			require.NoError(t, err)
+			assert.Equal(t, tt.want, got.prefixes)
+		})
+	}
+}
+
+func TestListIsTrusted(t *testing.T) {
+	list, err := Parse("10.0.0.0/8, 192.168.1.0/24, fd00::/8")
+	require.NoError(t, err)
+
+	tests := []struct {
+		name string
+		addr string
+		list *List
+		want bool
+	}{
+		{"nil list", "10.0.0.1", nil, false},
+		{"empty list", "10.0.0.1", &List{}, false},
+		{"IP within /8 prefix", "10.1.2.3", list, true},
+		{"IP within /24 prefix", "192.168.1.100", list, true},
+		{"IP outside all prefixes", "203.0.113.50", list, false},
+		{"boundary IP just outside prefix", "192.168.2.1", list, false},
+		{"unparsable IP", "not-an-ip", list, false},
+		{"IPv6 in trusted range", "fd00::1", list, true},
+		{"IPv6 outside range", "2001:db8::1", list, false},
+		{"empty string", "", list, false},
+		{"host:port within prefix", "10.1.2.3:9999", list, true},
+		{"host:port outside prefix", "203.0.113.50:9999", list, false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.want, tt.list.IsTrusted(tt.addr))
+		})
+	}
+}
+
+func TestListResolveClientIP(t *testing.T) {
+	trusted, err := Parse("10.0.0.0/8, 172.16.0.0/12")
+	require.NoError(t, err)
+
+	tests := []struct {
+		name       string
+		remoteAddr string
+		xff        string
+		list       *List
+		want       netip.Addr
+	}{
+		{
+			name:       "empty list returns RemoteAddr",
+			remoteAddr: "203.0.113.50:9999",
+			xff:        "1.2.3.4",
+			list:       &List{},
+			want:       netip.MustParseAddr("203.0.113.50"),
+		},
+		{
+			name:       "nil list returns RemoteAddr",
+			remoteAddr: "203.0.113.50:9999",
+			xff:        "1.2.3.4",
+			list:       nil,
+			want:       netip.MustParseAddr("203.0.113.50"),
+		},
+		{
+			name:       "untrusted RemoteAddr ignores XFF",
+			remoteAddr: "203.0.113.50:9999",
+			xff:        "1.2.3.4, 10.0.0.1",
+			list:       trusted,
+			want:       netip.MustParseAddr("203.0.113.50"),
+		},
+		{
+			name:       "trusted RemoteAddr with single client in XFF",
+			remoteAddr: "10.0.0.1:5000",
+			xff:        "203.0.113.50",
+			list:       trusted,
+			want:       netip.MustParseAddr("203.0.113.50"),
+		},
+		{
+			name:       "trusted RemoteAddr walks past trusted entries in XFF",
+			remoteAddr: "10.0.0.1:5000",
+			xff:        "203.0.113.50, 10.0.0.2, 172.16.0.5",
+			list:       trusted,
+			want:       netip.MustParseAddr("203.0.113.50"),
+		},
+		{
+			name:       "trusted RemoteAddr with empty XFF falls back to RemoteAddr",
+			remoteAddr: "10.0.0.1:5000",
+			xff:        "",
+			list:       trusted,
+			want:       netip.MustParseAddr("10.0.0.1"),
+		},
+		{
+			name:       "all XFF IPs trusted returns leftmost",
+			remoteAddr: "10.0.0.1:5000",
+			xff:        "10.0.0.2, 172.16.0.1, 10.0.0.3",
+			list:       trusted,
+			want:       netip.MustParseAddr("10.0.0.2"),
+		},
+		{
+			name:       "XFF with whitespace",
+			remoteAddr: "10.0.0.1:5000",
+			xff:        " 203.0.113.50 , 10.0.0.2 ",
+			list:       trusted,
+			want:       netip.MustParseAddr("203.0.113.50"),
+		},
+		{
+			name:       "XFF with empty segments",
+			remoteAddr: "10.0.0.1:5000",
+			xff:        "203.0.113.50,,10.0.0.2",
+			list:       trusted,
+			want:       netip.MustParseAddr("203.0.113.50"),
+		},
+		{
+			name:       "multi-hop with mixed trust",
+			remoteAddr: "10.0.0.1:5000",
+			xff:        "8.8.8.8, 203.0.113.50, 172.16.0.1",
+			list:       trusted,
+			want:       netip.MustParseAddr("203.0.113.50"),
+		},
+		{
+			name:       "RemoteAddr without port",
+			remoteAddr: "10.0.0.1",
+			xff:        "203.0.113.50",
+			list:       trusted,
+			want:       netip.MustParseAddr("203.0.113.50"),
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.want, tt.list.ResolveClientIP(tt.remoteAddr, tt.xff))
+		})
+	}
+}