add support for site-to-site routes via networks

* fix: dns/host_darwin.go was missing if err != nil before throwing error

.github/workflows/docs-ack.yml

@@ -16,19 +16,29 @@ jobs:
     steps:
       - name: Read PR body
         id: body
+        shell: bash
         run: |
-          BODY=$(jq -r '.pull_request.body // ""' "$GITHUB_EVENT_PATH")
-          echo "body<<EOF" >> $GITHUB_OUTPUT
-          echo "$BODY" >> $GITHUB_OUTPUT
-          echo "EOF" >> $GITHUB_OUTPUT
+          set -euo pipefail
+          BODY_B64=$(jq -r '.pull_request.body // "" | @base64' "$GITHUB_EVENT_PATH")
+          {
+            echo "body_b64=$BODY_B64"
+          } >> "$GITHUB_OUTPUT"
 
       - name: Validate checkbox selection
         id: validate
+        shell: bash
+        env:
+          BODY_B64: ${{ steps.body.outputs.body_b64 }}
         run: |
-          body='${{ steps.body.outputs.body }}'
+          set -euo pipefail
+          if ! body="$(printf '%s' "$BODY_B64" | base64 -d)"; then
+            echo "::error::Failed to decode PR body from base64. Data may be corrupted or missing."
+            exit 1
+          fi
+
+          added_checked=$(printf '%s' "$body" | grep -Ei '^[[:space:]]*-\s*\[x\]\s*I added/updated documentation' | wc -l | tr -d '[:space:]' || true)
+          noneed_checked=$(printf '%s' "$body" | grep -Ei '^[[:space:]]*-\s*\[x\]\s*Documentation is \*\*not needed\*\*' | wc -l | tr -d '[:space:]' || true)
 
-          added_checked=$(printf "%s" "$body" | grep -E '^- \[x\] I added/updated documentation' -i | wc -l | tr -d ' ')
-          noneed_checked=$(printf "%s" "$body" | grep -E '^- \[x\] Documentation is \*\*not needed\*\*' -i | wc -l | tr -d ' ')
 
           if [ "$added_checked" -eq 1 ] && [ "$noneed_checked" -eq 1 ]; then
             echo "::error::Choose exactly one: either 'docs added' OR 'not needed'."
@@ -41,30 +51,35 @@ jobs:
           fi
 
           if [ "$added_checked" -eq 1 ]; then
-            echo "mode=added" >> $GITHUB_OUTPUT
+            echo "mode=added" >> "$GITHUB_OUTPUT"
           else
-            echo "mode=noneed" >> $GITHUB_OUTPUT
+            echo "mode=noneed" >> "$GITHUB_OUTPUT"
           fi
 
       - name: Extract docs PR URL (when 'docs added')
         if: steps.validate.outputs.mode == 'added'
         id: extract
+        shell: bash
+        env:
+          BODY_B64: ${{ steps.body.outputs.body_b64 }}
         run: |
-          body='${{ steps.body.outputs.body }}'
+          set -euo pipefail
+          body="$(printf '%s' "$BODY_B64" | base64 -d)"
 
           # Strictly require HTTPS and that it's a PR in netbirdio/docs
-          # Examples accepted:
-          #   https://github.com/netbirdio/docs/pull/1234
-          url=$(printf "%s" "$body" | grep -Eo 'https://github\.com/netbirdio/docs/pull/[0-9]+' | head -n1 || true)
+          # e.g., https://github.com/netbirdio/docs/pull/1234
+          url="$(printf '%s' "$body" | grep -Eo 'https://github\.com/netbirdio/docs/pull/[0-9]+' | head -n1 || true)"
 
-          if [ -z "$url" ]; then
+          if [ -z "${url:-}" ]; then
             echo "::error::You checked 'docs added' but didn't include a valid HTTPS PR link to netbirdio/docs (e.g., https://github.com/netbirdio/docs/pull/1234)."
             exit 1
           fi
 
-          pr_number=$(echo "$url" | sed -E 's#.*/pull/([0-9]+)$#\1#')
-          echo "url=$url" >> $GITHUB_OUTPUT
-          echo "pr_number=$pr_number" >> $GITHUB_OUTPUT
+          pr_number="$(printf '%s' "$url" | sed -E 's#.*/pull/([0-9]+)$#\1#')"
+          {
+            echo "url=$url"
+            echo "pr_number=$pr_number"
+          } >> "$GITHUB_OUTPUT"
 
       - name: Verify docs PR exists (and is open or merged)
         if: steps.validate.outputs.mode == 'added'

.github/workflows/golang-test-freebsd.yml

@@ -25,8 +25,7 @@ jobs:
           release: "14.2"
           prepare: |
             pkg install -y curl pkgconf xorg
-            LATEST_VERSION=$(curl -s https://go.dev/VERSION?m=text|head -n 1)
-            GO_TARBALL="$LATEST_VERSION.freebsd-amd64.tar.gz"
+            GO_TARBALL="go1.23.12.freebsd-amd64.tar.gz"
             GO_URL="https://go.dev/dl/$GO_TARBALL"
             curl -vLO "$GO_URL"
             tar -C /usr/local -vxzf "$GO_TARBALL"            

.github/workflows/golangci-lint.yml

@@ -19,7 +19,7 @@ jobs:
       - name: codespell
         uses: codespell-project/actions-codespell@v2
         with:
-          ignore_words_list: erro,clienta,hastable,iif,groupd,testin,groupe
+          ignore_words_list: erro,clienta,hastable,iif,groupd,testin,groupe,cros
           skip: go.mod,go.sum
   golangci:
     strategy:

.github/workflows/test-infrastructure-files.yml

@@ -83,6 +83,15 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
 
+      - name: Setup MySQL privileges
+        if: matrix.store == 'mysql'
+        run: |
+          sleep 10
+          mysql -h 127.0.0.1 -u root -pmysqlroot -e "
+            GRANT SYSTEM_VARIABLES_ADMIN ON *.* TO 'netbird'@'%';
+            FLUSH PRIVILEGES;
+          "
+
       - name: cp setup.env
         run: cp infrastructure_files/tests/setup.env infrastructure_files/
 

.github/workflows/wasm-build-validation.yml

@@ -0,0 +1,67 @@
+name: Wasm
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}-${{ github.head_ref || github.actor_id }}
+  cancel-in-progress: true
+
+jobs:
+  js_lint:
+    name: "JS / Lint"
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+      - name: Install Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: "1.23.x"
+      - name: Install dependencies
+        run: sudo apt update && sudo apt install -y -q libgtk-3-dev libayatana-appindicator3-dev libgl1-mesa-dev xorg-dev libpcap-dev
+      - name: Install golangci-lint
+        uses: golangci/golangci-lint-action@d6238b002a20823d52840fda27e2d4891c5952dc
+        with:
+          version: latest
+          install-mode: binary
+          skip-cache: true
+          skip-pkg-cache: true
+          skip-build-cache: true
+      - name: Run golangci-lint for WASM
+        run: |
+          GOOS=js GOARCH=wasm golangci-lint run --timeout=12m --out-format colored-line-number ./client/...
+        continue-on-error: true
+
+  js_build:
+    name: "JS / Build"
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+      - name: Install Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: "1.23.x"
+      - name: Build Wasm client
+        run: GOOS=js GOARCH=wasm go build -o netbird.wasm ./client/wasm/cmd
+        env:
+          CGO_ENABLED: 0
+      - name: Check Wasm build size
+        run: |
+          echo "Wasm build size:"
+          ls -lh netbird.wasm
+
+          SIZE=$(stat -c%s netbird.wasm)
+          SIZE_MB=$((SIZE / 1024 / 1024))
+
+          echo "Size: ${SIZE} bytes (${SIZE_MB} MB)"
+
+          if [ ${SIZE} -gt 52428800 ]; then
+            echo "Wasm binary size (${SIZE_MB}MB) exceeds 50MB limit!"
+            exit 1
+          fi
+

.goreleaser.yaml

@@ -2,6 +2,18 @@ version: 2
 
 project_name: netbird
 builds:
+  - id: netbird-wasm
+    dir: client/wasm/cmd
+    binary: netbird.wasm
+    env: [GOOS=js, GOARCH=wasm, CGO_ENABLED=0]
+    goos:
+      - js
+    goarch:
+      - wasm
+    ldflags:
+      - -s -w -X github.com/netbirdio/netbird/version.version={{.Version}} -X main.commit={{.Commit}} -X main.date={{.CommitDate}} -X main.builtBy=goreleaser
+    mod_timestamp: "{{ .CommitTimestamp }}"
+
   - id: netbird
     dir: client
     binary: netbird
@@ -115,6 +127,13 @@ archives:
   - builds:
       - netbird
       - netbird-static
+  - id: netbird-wasm
+    builds:
+      - netbird-wasm
+    name_template: "{{ .ProjectName }}_wasm_{{ .Version }}"
+    format: tar.gz
+    files:
+      - none*
 
 nfpms:
   - maintainer: Netbird <dev@netbird.io>

client/cmd/debug.go

@@ -33,7 +33,7 @@ var (
 var debugCmd = &cobra.Command{
 	Use:   "debug",
 	Short: "Debugging commands",
-	Long:  "Provides commands for debugging and logging control within the NetBird daemon.",
+	Long:  "Commands for debugging and logging within the NetBird daemon.",
 }
 
 var debugBundleCmd = &cobra.Command{

client/cmd/debug_js.go

@@ -0,0 +1,8 @@
+package cmd
+
+import "context"
+
+// SetupDebugHandler is a no-op for WASM
+func SetupDebugHandler(context.Context, interface{}, interface{}, interface{}, string) {
+	// Debug handler not needed for WASM
+}

client/cmd/down.go

@@ -14,7 +14,8 @@ import (
 
 var downCmd = &cobra.Command{
 	Use:   "down",
-	Short: "down netbird connections",
+	Short: "Disconnect from the NetBird network",
+	Long:  "Disconnect the NetBird client from the network and management service. This will terminate all active connections with the remote peers.",
 	RunE: func(cmd *cobra.Command, args []string) error {
 		SetFlagsFromEnvVars(rootCmd)
 

client/cmd/login.go

@@ -31,7 +31,8 @@ func init() {
 
 var loginCmd = &cobra.Command{
 	Use:   "login",
-	Short: "login to the NetBird Management Service (first run)",
+	Short: "Log in to the NetBird network",
+	Long:  "Log in to the NetBird network using a setup key or SSO",
 	RunE: func(cmd *cobra.Command, args []string) error {
 		if err := setEnvAndFlags(cmd); err != nil {
 			return fmt.Errorf("set env and flags: %v", err)

client/cmd/logout.go

@@ -14,7 +14,8 @@ import (
 var logoutCmd = &cobra.Command{
 	Use:     "deregister",
 	Aliases: []string{"logout"},
-	Short:   "deregister from the NetBird Management Service and delete peer",
+	Short:   "Deregister from the NetBird management service and delete this peer",
+	Long:    "This command will deregister the current peer from the NetBird management service and all associated configuration. Use with caution as this will remove the peer from the network.",
 	RunE: func(cmd *cobra.Command, args []string) error {
 		SetFlagsFromEnvVars(rootCmd)
 

client/cmd/networks.go

@@ -15,7 +15,7 @@ var appendFlag bool
 var networksCMD = &cobra.Command{
 	Use:     "networks",
 	Aliases: []string{"routes"},
-	Short:   "Manage networks",
+	Short:   "Manage connections to NetBird Networks and Resources",
 	Long:    `Commands to list, select, or deselect networks. Replaces the "routes" command.`,
 }
 

client/cmd/profile.go

@@ -16,13 +16,13 @@ import (
 
 var profileCmd = &cobra.Command{
 	Use:   "profile",
-	Short: "manage NetBird profiles",
-	Long:  `Manage NetBird profiles, allowing you to list, switch, and remove profiles.`,
+	Short: "Manage NetBird client profiles",
+	Long:  `Commands to list, add, remove, and switch profiles. Profiles allow you to maintain different accounts in one client app.`,
 }
 
 var profileListCmd = &cobra.Command{
 	Use:     "list",
-	Short:   "list all profiles",
+	Short:   "List all profiles",
 	Long:    `List all available profiles in the NetBird client.`,
 	Aliases: []string{"ls"},
 	RunE:    listProfilesFunc,
@@ -30,7 +30,7 @@ var profileListCmd = &cobra.Command{
 
 var profileAddCmd = &cobra.Command{
 	Use:   "add <profile_name>",
-	Short: "add a new profile",
+	Short: "Add a new profile",
 	Long:  `Add a new profile to the NetBird client. The profile name must be unique.`,
 	Args:  cobra.ExactArgs(1),
 	RunE:  addProfileFunc,
@@ -38,16 +38,16 @@ var profileAddCmd = &cobra.Command{
 
 var profileRemoveCmd = &cobra.Command{
 	Use:   "remove <profile_name>",
-	Short: "remove a profile",
-	Long:  `Remove a profile from the NetBird client. The profile must not be active.`,
+	Short: "Remove a profile",
+	Long:  `Remove a profile from the NetBird client. The profile must not be inactive.`,
 	Args:  cobra.ExactArgs(1),
 	RunE:  removeProfileFunc,
 }
 
 var profileSelectCmd = &cobra.Command{
 	Use:   "select <profile_name>",
-	Short: "select a profile",
-	Long:  `Select a profile to be the active profile in the NetBird client. The profile must exist.`,
+	Short: "Select a profile",
+	Long:  `Make the specified profile active. This will switch the client to use the selected profile's configuration.`,
 	Args:  cobra.ExactArgs(1),
 	RunE:  selectProfileFunc,
 }

client/cmd/root.go

@@ -39,6 +39,7 @@ const (
 	extraIFaceBlackListFlag  = "extra-iface-blacklist"
 	dnsRouteIntervalFlag     = "dns-router-interval"
 	enableLazyConnectionFlag = "enable-lazy-connection"
+	mtuFlag                  = "mtu"
 )
 
 var (
@@ -72,7 +73,9 @@ var (
 	anonymizeFlag           bool
 	dnsRouteInterval        time.Duration
 	lazyConnEnabled         bool
+	mtu                     uint16
 	profilesDisabled        bool
+	updateSettingsDisabled  bool
 
 	rootCmd = &cobra.Command{
 		Use:          "netbird",

client/cmd/root_test.go

@@ -54,6 +54,7 @@ func TestSetFlagsFromEnvVars(t *testing.T) {
 	cmd.PersistentFlags().StringVar(&interfaceName, interfaceNameFlag, iface.WgInterfaceDefault, "WireGuard interface name")
 	cmd.PersistentFlags().BoolVar(&rosenpassEnabled, enableRosenpassFlag, false, "Enable Rosenpass feature Rosenpass.")
 	cmd.PersistentFlags().Uint16Var(&wireguardPort, wireguardPortFlag, iface.DefaultWgPort, "WireGuard interface listening port")
+	cmd.PersistentFlags().Uint16Var(&mtu, mtuFlag, iface.DefaultMTU, "Set MTU (Maximum Transmission Unit) for the WireGuard interface")
 
 	t.Setenv("NB_EXTERNAL_IP_MAP", "abc,dec")
 	t.Setenv("NB_INTERFACE_NAME", "test-name")

client/cmd/service.go

@@ -19,7 +19,7 @@ import (
 
 var serviceCmd = &cobra.Command{
 	Use:   "service",
-	Short: "manages NetBird service",
+	Short: "Manage the NetBird daemon service",
 }
 
 var (
@@ -42,7 +42,8 @@ func init() {
 	}
 
 	serviceCmd.AddCommand(runCmd, startCmd, stopCmd, restartCmd, svcStatusCmd, installCmd, uninstallCmd, reconfigureCmd)
-	serviceCmd.PersistentFlags().BoolVar(&profilesDisabled, "disable-profiles", false, "Disables profiles feature. If enabled, the client will not be able to change or edit any profile.")
+	serviceCmd.PersistentFlags().BoolVar(&profilesDisabled, "disable-profiles", false, "Disables profiles feature. If enabled, the client will not be able to change or edit any profile. To persist this setting, use: netbird service install --disable-profiles")
+	serviceCmd.PersistentFlags().BoolVar(&updateSettingsDisabled, "disable-update-settings", false, "Disables update settings feature. If enabled, the client will not be able to change or edit any settings. To persist this setting, use: netbird service install --disable-update-settings")
 
 	rootCmd.PersistentFlags().StringVarP(&serviceName, "service", "s", defaultServiceName, "Netbird system service name")
 	serviceEnvDesc := `Sets extra environment variables for the service. ` +

client/cmd/service_controller.go

@@ -61,7 +61,7 @@ func (p *program) Start(svc service.Service) error {
 			}
 		}
 
-		serverInstance := server.New(p.ctx, util.FindFirstLogPath(logFiles), configPath, profilesDisabled)
+		serverInstance := server.New(p.ctx, util.FindFirstLogPath(logFiles), configPath, profilesDisabled, updateSettingsDisabled)
 		if err := serverInstance.Start(); err != nil {
 			log.Fatalf("failed to start daemon: %v", err)
 		}

client/cmd/service_installer.go

@@ -49,6 +49,14 @@ func buildServiceArguments() []string {
 		args = append(args, "--log-file", logFile)
 	}
 
+	if profilesDisabled {
+		args = append(args, "--disable-profiles")
+	}
+
+	if updateSettingsDisabled {
+		args = append(args, "--disable-update-settings")
+	}
+
 	return args
 }
 
@@ -99,7 +107,7 @@ func createServiceConfigForInstall() (*service.Config, error) {
 
 var installCmd = &cobra.Command{
 	Use:   "install",
-	Short: "installs NetBird service",
+	Short: "Install NetBird service",
 	RunE: func(cmd *cobra.Command, args []string) error {
 		if err := setupServiceCommand(cmd); err != nil {
 			return err

client/cmd/ssh.go

@@ -40,7 +40,7 @@ var sshCmd = &cobra.Command{
 
 		return nil
 	},
-	Short: "connect to a remote SSH server",
+	Short: "Connect to a remote SSH server",
 	RunE: func(cmd *cobra.Command, args []string) error {
 		SetFlagsFromEnvVars(rootCmd)
 		SetFlagsFromEnvVars(cmd)

client/cmd/status.go

@@ -32,7 +32,8 @@ var (
 
 var statusCmd = &cobra.Command{
 	Use:   "status",
-	Short: "status of the Netbird Service",
+	Short: "Display NetBird client status",
+	Long:  "Display the current status of the NetBird client, including connection status, peer information, and network details.",
 	RunE:  statusFunc,
 }
 

client/cmd/testutil_test.go

@@ -10,7 +10,9 @@ import (
 	"github.com/stretchr/testify/require"
 	"go.opentelemetry.io/otel"
 
+	"github.com/netbirdio/netbird/management/internals/server/config"
 	"github.com/netbirdio/netbird/management/server/activity"
+	"github.com/netbirdio/netbird/management/server/groups"
 	"github.com/netbirdio/netbird/management/server/integrations/port_forwarding"
 	"github.com/netbirdio/netbird/management/server/permissions"
 	"github.com/netbirdio/netbird/management/server/settings"
@@ -26,15 +28,15 @@ import (
 
 	clientProto "github.com/netbirdio/netbird/client/proto"
 	client "github.com/netbirdio/netbird/client/server"
-	mgmtProto "github.com/netbirdio/netbird/shared/management/proto"
 	mgmt "github.com/netbirdio/netbird/management/server"
+	mgmtProto "github.com/netbirdio/netbird/shared/management/proto"
 	sigProto "github.com/netbirdio/netbird/shared/signal/proto"
 	sig "github.com/netbirdio/netbird/signal/server"
 )
 
 func startTestingServices(t *testing.T) string {
 	t.Helper()
-	config := &types.Config{}
+	config := &config.Config{}
 	_, err := util.ReadJson("../testdata/management.json", config)
 	if err != nil {
 		t.Fatal(err)
@@ -69,7 +71,7 @@ func startSignal(t *testing.T) (*grpc.Server, net.Listener) {
 	return s, lis
 }
 
-func startManagement(t *testing.T, config *types.Config, testFile string) (*grpc.Server, net.Listener) {
+func startManagement(t *testing.T, config *config.Config, testFile string) (*grpc.Server, net.Listener) {
 	t.Helper()
 
 	lis, err := net.Listen("tcp", ":0")
@@ -97,6 +99,7 @@ func startManagement(t *testing.T, config *types.Config, testFile string) (*grpc
 
 	settingsMockManager := settings.NewMockManager(ctrl)
 	permissionsManagerMock := permissions.NewMockManager(ctrl)
+	groupsManager := groups.NewManagerMock()
 
 	settingsMockManager.EXPECT().
 		GetSettings(gomock.Any(), gomock.Any(), gomock.Any()).
@@ -108,7 +111,7 @@ func startManagement(t *testing.T, config *types.Config, testFile string) (*grpc
 		t.Fatal(err)
 	}
 
-	secretsManager := mgmt.NewTimeBasedAuthSecretsManager(peersUpdateManager, config.TURNConfig, config.Relay, settingsMockManager)
+	secretsManager := mgmt.NewTimeBasedAuthSecretsManager(peersUpdateManager, config.TURNConfig, config.Relay, settingsMockManager, groupsManager)
 	mgmtServer, err := mgmt.NewServer(context.Background(), config, accountManager, settingsMockManager, peersUpdateManager, secretsManager, nil, nil, nil, &mgmt.MockIntegratedValidator{})
 	if err != nil {
 		t.Fatal(err)
@@ -134,7 +137,7 @@ func startClientDaemon(
 	s := grpc.NewServer()
 
 	server := client.New(ctx,
-		"", "", false)
+		"", "", false, false)
 	if err := server.Start(); err != nil {
 		t.Fatal(err)
 	}

client/cmd/up.go

@@ -53,7 +53,8 @@ var (
 
 	upCmd = &cobra.Command{
 		Use:   "up",
-		Short: "install, login and start NetBird client",
+		Short: "Connect to the NetBird network",
+		Long:  "Connect to the NetBird network using the provided setup key or SSO auth. This command will bring up the WireGuard interface, connect to the management server, and establish peer-to-peer connections with other peers in the network if required.",
 		RunE:  upFunc,
 	}
 )
@@ -62,6 +63,7 @@ func init() {
 	upCmd.PersistentFlags().BoolVarP(&foregroundMode, "foreground-mode", "F", false, "start service in foreground")
 	upCmd.PersistentFlags().StringVar(&interfaceName, interfaceNameFlag, iface.WgInterfaceDefault, "WireGuard interface name")
 	upCmd.PersistentFlags().Uint16Var(&wireguardPort, wireguardPortFlag, iface.DefaultWgPort, "WireGuard interface listening port")
+	upCmd.PersistentFlags().Uint16Var(&mtu, mtuFlag, iface.DefaultMTU, "Set MTU (Maximum Transmission Unit) for the WireGuard interface")
 	upCmd.PersistentFlags().BoolVarP(&networkMonitor, networkMonitorFlag, "N", networkMonitor,
 		`Manage network monitoring. Defaults to true on Windows and macOS, false on Linux and FreeBSD. `+
 			`E.g. --network-monitor=false to disable or --network-monitor=true to enable.`,
@@ -356,6 +358,11 @@ func setupSetConfigReq(customDNSAddressConverted []byte, cmd *cobra.Command, pro
 		req.WireguardPort = &p
 	}
 
+	if cmd.Flag(mtuFlag).Changed {
+		m := int64(mtu)
+		req.Mtu = &m
+	}
+
 	if cmd.Flag(networkMonitorFlag).Changed {
 		req.NetworkMonitor = &networkMonitor
 	}
@@ -435,6 +442,13 @@ func setupConfig(customDNSAddressConverted []byte, cmd *cobra.Command, configFil
 		ic.WireguardPort = &p
 	}
 
+	if cmd.Flag(mtuFlag).Changed {
+		if err := iface.ValidateMTU(mtu); err != nil {
+			return nil, err
+		}
+		ic.MTU = &mtu
+	}
+
 	if cmd.Flag(networkMonitorFlag).Changed {
 		ic.NetworkMonitor = &networkMonitor
 	}
@@ -532,6 +546,14 @@ func setupLoginRequest(providedSetupKey string, customDNSAddressConverted []byte
 		loginRequest.WireguardPort = &wp
 	}
 
+	if cmd.Flag(mtuFlag).Changed {
+		if err := iface.ValidateMTU(mtu); err != nil {
+			return nil, err
+		}
+		m := int64(mtu)
+		loginRequest.Mtu = &m
+	}
+
 	if cmd.Flag(networkMonitorFlag).Changed {
 		loginRequest.NetworkMonitor = &networkMonitor
 	}

client/cmd/version.go

@@ -9,7 +9,7 @@ import (
 var (
 	versionCmd = &cobra.Command{
 		Use:   "version",
-		Short: "prints NetBird version",
+		Short: "Print the NetBird's client application version",
 		Run: func(cmd *cobra.Command, args []string) {
 			cmd.SetOut(cmd.OutOrStdout())
 			cmd.Println(version.NetbirdVersion())

client/embed/embed.go

@@ -23,23 +23,27 @@ import (
 
 var ErrClientAlreadyStarted = errors.New("client already started")
 var ErrClientNotStarted = errors.New("client not started")
+var ErrConfigNotInitialized = errors.New("config not initialized")
 
-// Client manages a netbird embedded client instance
+// Client manages a netbird embedded client instance.
 type Client struct {
 	deviceName string
 	config     *profilemanager.Config
 	mu         sync.Mutex
 	cancel     context.CancelFunc
 	setupKey   string
+	jwtToken   string
 	connect    *internal.ConnectClient
 }
 
-// Options configures a new Client
+// Options configures a new Client.
 type Options struct {
 	// DeviceName is this peer's name in the network
 	DeviceName string
 	// SetupKey is used for authentication
 	SetupKey string
+	// JWTToken is used for JWT-based authentication
+	JWTToken string
 	// ManagementURL overrides the default management server URL
 	ManagementURL string
 	// PreSharedKey is the pre-shared key for the WireGuard interface
@@ -58,8 +62,15 @@ type Options struct {
 	DisableClientRoutes bool
 }
 
-// New creates a new netbird embedded client
+// New creates a new netbird embedded client.
 func New(opts Options) (*Client, error) {
+	if opts.SetupKey == "" && opts.JWTToken == "" {
+		return nil, fmt.Errorf("either SetupKey or JWTToken must be provided")
+	}
+	if opts.SetupKey != "" && opts.JWTToken != "" {
+		return nil, fmt.Errorf("cannot specify both SetupKey and JWTToken")
+	}
+
 	if opts.LogOutput != nil {
 		logrus.SetOutput(opts.LogOutput)
 	}
@@ -110,6 +121,7 @@ func New(opts Options) (*Client, error) {
 	return &Client{
 		deviceName: opts.DeviceName,
 		setupKey:   opts.SetupKey,
+		jwtToken:   opts.JWTToken,
 		config:     config,
 	}, nil
 }
@@ -126,7 +138,7 @@ func (c *Client) Start(startCtx context.Context) error {
 	ctx := internal.CtxInitState(context.Background())
 	// nolint:staticcheck
 	ctx = context.WithValue(ctx, system.DeviceNameCtxKey, c.deviceName)
-	if err := internal.Login(ctx, c.config, c.setupKey, ""); err != nil {
+	if err := internal.Login(ctx, c.config, c.setupKey, c.jwtToken); err != nil {
 		return fmt.Errorf("login: %w", err)
 	}
 
@@ -187,6 +199,16 @@ func (c *Client) Stop(ctx context.Context) error {
 	}
 }
 
+// GetConfig returns a copy of the internal client config.
+func (c *Client) GetConfig() (profilemanager.Config, error) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.config == nil {
+		return profilemanager.Config{}, ErrConfigNotInitialized
+	}
+	return *c.config, nil
+}
+
 // Dial dials a network address in the netbird network.
 // Not applicable if the userspace networking mode is disabled.
 func (c *Client) Dial(ctx context.Context, network, address string) (net.Conn, error) {
@@ -211,7 +233,7 @@ func (c *Client) Dial(ctx context.Context, network, address string) (net.Conn, e
 	return nsnet.DialContext(ctx, network, address)
 }
 
-// ListenTCP listens on the given address in the netbird network
+// ListenTCP listens on the given address in the netbird network.
 // Not applicable if the userspace networking mode is disabled.
 func (c *Client) ListenTCP(address string) (net.Listener, error) {
 	nsnet, addr, err := c.getNet()
@@ -232,7 +254,7 @@ func (c *Client) ListenTCP(address string) (net.Listener, error) {
 	return nsnet.ListenTCP(tcpAddr)
 }
 
-// ListenUDP listens on the given address in the netbird network
+// ListenUDP listens on the given address in the netbird network.
 // Not applicable if the userspace networking mode is disabled.
 func (c *Client) ListenUDP(address string) (net.PacketConn, error) {
 	nsnet, addr, err := c.getNet()

client/firewall/iptables/acl_linux.go

@@ -85,7 +85,7 @@ func (m *aclManager) AddPeerFiltering(
 ) ([]firewall.Rule, error) {
 	chain := chainNameInputRules
 
-	ipsetName = transformIPsetName(ipsetName, sPort, dPort)
+	ipsetName = transformIPsetName(ipsetName, sPort, dPort, action)
 	specs := filterRuleSpecs(ip, string(protocol), sPort, dPort, action, ipsetName)
 
 	mangleSpecs := slices.Clone(specs)
@@ -135,7 +135,14 @@ func (m *aclManager) AddPeerFiltering(
 		return nil, fmt.Errorf("rule already exists")
 	}
 
-	if err := m.iptablesClient.Append(tableFilter, chain, specs...); err != nil {
+	// Insert DROP rules at the beginning, append ACCEPT rules at the end
+	if action == firewall.ActionDrop {
+		// Insert at the beginning of the chain (position 1)
+		err = m.iptablesClient.Insert(tableFilter, chain, 1, specs...)
+	} else {
+		err = m.iptablesClient.Append(tableFilter, chain, specs...)
+	}
+	if err != nil {
 		return nil, err
 	}
 
@@ -388,17 +395,25 @@ func actionToStr(action firewall.Action) string {
 	return "DROP"
 }
 
-func transformIPsetName(ipsetName string, sPort, dPort *firewall.Port) string {
-	switch {
-	case ipsetName == "":
+func transformIPsetName(ipsetName string, sPort, dPort *firewall.Port, action firewall.Action) string {
+	if ipsetName == "" {
 		return ""
+	}
+
+	// Include action in the ipset name to prevent squashing rules with different actions
+	actionSuffix := ""
+	if action == firewall.ActionDrop {
+		actionSuffix = "-drop"
+	}
+
+	switch {
 	case sPort != nil && dPort != nil:
-		return ipsetName + "-sport-dport"
+		return ipsetName + "-sport-dport" + actionSuffix
 	case sPort != nil:
-		return ipsetName + "-sport"
+		return ipsetName + "-sport" + actionSuffix
 	case dPort != nil:
-		return ipsetName + "-dport"
+		return ipsetName + "-dport" + actionSuffix
 	default:
-		return ipsetName
+		return ipsetName + actionSuffix
 	}
 }

client/firewall/iptables/manager_linux_test.go

@@ -3,6 +3,7 @@ package iptables
 import (
 	"fmt"
 	"net/netip"
+	"strings"
 	"testing"
 	"time"
 
@@ -15,7 +16,7 @@ import (
 
 var ifaceMock = &iFaceMock{
 	NameFunc: func() string {
-		return "lo"
+		return "wg-test"
 	},
 	AddressFunc: func() wgaddr.Address {
 		return wgaddr.Address{
@@ -109,10 +110,84 @@ func TestIptablesManager(t *testing.T) {
 	})
 }
 
+func TestIptablesManagerDenyRules(t *testing.T) {
+	ipv4Client, err := iptables.NewWithProtocol(iptables.ProtocolIPv4)
+	require.NoError(t, err)
+
+	manager, err := Create(ifaceMock)
+	require.NoError(t, err)
+	require.NoError(t, manager.Init(nil))
+
+	defer func() {
+		err := manager.Close(nil)
+		require.NoError(t, err)
+	}()
+
+	t.Run("add deny rule", func(t *testing.T) {
+		ip := netip.MustParseAddr("10.20.0.3")
+		port := &fw.Port{Values: []uint16{22}}
+
+		rule, err := manager.AddPeerFiltering(nil, ip.AsSlice(), "tcp", nil, port, fw.ActionDrop, "deny-ssh")
+		require.NoError(t, err, "failed to add deny rule")
+		require.NotEmpty(t, rule, "deny rule should not be empty")
+
+		// Verify the rule was added by checking iptables
+		for _, r := range rule {
+			rr := r.(*Rule)
+			checkRuleSpecs(t, ipv4Client, rr.chain, true, rr.specs...)
+		}
+	})
+
+	t.Run("deny rule precedence test", func(t *testing.T) {
+		ip := netip.MustParseAddr("10.20.0.4")
+		port := &fw.Port{Values: []uint16{80}}
+
+		// Add accept rule first
+		_, err := manager.AddPeerFiltering(nil, ip.AsSlice(), "tcp", nil, port, fw.ActionAccept, "accept-http")
+		require.NoError(t, err, "failed to add accept rule")
+
+		// Add deny rule second for same IP/port - this should take precedence
+		_, err = manager.AddPeerFiltering(nil, ip.AsSlice(), "tcp", nil, port, fw.ActionDrop, "deny-http")
+		require.NoError(t, err, "failed to add deny rule")
+
+		// Inspect the actual iptables rules to verify deny rule comes before accept rule
+		rules, err := ipv4Client.List("filter", chainNameInputRules)
+		require.NoError(t, err, "failed to list iptables rules")
+
+		// Debug: print all rules
+		t.Logf("All iptables rules in chain %s:", chainNameInputRules)
+		for i, rule := range rules {
+			t.Logf("  [%d] %s", i, rule)
+		}
+
+		var denyRuleIndex, acceptRuleIndex int = -1, -1
+		for i, rule := range rules {
+			if strings.Contains(rule, "DROP") {
+				t.Logf("Found DROP rule at index %d: %s", i, rule)
+				if strings.Contains(rule, "deny-http") && strings.Contains(rule, "80") {
+					denyRuleIndex = i
+				}
+			}
+			if strings.Contains(rule, "ACCEPT") {
+				t.Logf("Found ACCEPT rule at index %d: %s", i, rule)
+				if strings.Contains(rule, "accept-http") && strings.Contains(rule, "80") {
+					acceptRuleIndex = i
+				}
+			}
+		}
+
+		require.NotEqual(t, -1, denyRuleIndex, "deny rule should exist in iptables")
+		require.NotEqual(t, -1, acceptRuleIndex, "accept rule should exist in iptables")
+		require.Less(t, denyRuleIndex, acceptRuleIndex,
+			"deny rule should come before accept rule in iptables chain (deny at index %d, accept at index %d)",
+			denyRuleIndex, acceptRuleIndex)
+	})
+}
+
 func TestIptablesManagerIPSet(t *testing.T) {
 	mock := &iFaceMock{
 		NameFunc: func() string {
-			return "lo"
+			return "wg-test"
 		},
 		AddressFunc: func() wgaddr.Address {
 			return wgaddr.Address{
@@ -176,7 +251,7 @@ func checkRuleSpecs(t *testing.T, ipv4Client *iptables.IPTables, chainName strin
 func TestIptablesCreatePerformance(t *testing.T) {
 	mock := &iFaceMock{
 		NameFunc: func() string {
-			return "lo"
+			return "wg-test"
 		},
 		AddressFunc: func() wgaddr.Address {
 			return wgaddr.Address{

client/firewall/nftables/acl_linux.go

@@ -341,30 +341,38 @@ func (m *AclManager) addIOFiltering(
 	userData := []byte(ruleId)
 
 	chain := m.chainInputRules
-	nftRule := m.rConn.AddRule(&nftables.Rule{
+	rule := &nftables.Rule{
 		Table:    m.workTable,
 		Chain:    chain,
 		Exprs:    mainExpressions,
 		UserData: userData,
-	})
+	}
+
+	// Insert DROP rules at the beginning, append ACCEPT rules at the end
+	var nftRule *nftables.Rule
+	if action == firewall.ActionDrop {
+		nftRule = m.rConn.InsertRule(rule)
+	} else {
+		nftRule = m.rConn.AddRule(rule)
+	}
 
 	if err := m.rConn.Flush(); err != nil {
 		return nil, fmt.Errorf(flushError, err)
 	}
 
-	rule := &Rule{
+	ruleStruct := &Rule{
 		nftRule:    nftRule,
 		mangleRule: m.createPreroutingRule(expressions, userData),
 		nftSet:     ipset,
 		ruleID:     ruleId,
 		ip:         ip,
 	}
-	m.rules[ruleId] = rule
+	m.rules[ruleId] = ruleStruct
 	if ipset != nil {
 		m.ipsetStore.AddReferenceToIpset(ipset.Name)
 	}
 
-	return rule, nil
+	return ruleStruct, nil
 }
 
 func (m *AclManager) createPreroutingRule(expressions []expr.Any, userData []byte) *nftables.Rule {

client/firewall/nftables/manager_linux_test.go

@@ -2,6 +2,7 @@ package nftables
 
 import (
 	"bytes"
+	"encoding/binary"
 	"fmt"
 	"net/netip"
 	"os/exec"
@@ -20,7 +21,7 @@ import (
 
 var ifaceMock = &iFaceMock{
 	NameFunc: func() string {
-		return "lo"
+		return "wg-test"
 	},
 	AddressFunc: func() wgaddr.Address {
 		return wgaddr.Address{
@@ -103,9 +104,8 @@ func TestNftablesManager(t *testing.T) {
 			Kind: expr.VerdictAccept,
 		},
 	}
-	compareExprsIgnoringCounters(t, rules[0].Exprs, expectedExprs1)
-
-	expectedExprs2 := []expr.Any{
+	// Since DROP rules are inserted at position 0, the DROP rule comes first
+	expectedDropExprs := []expr.Any{
 		&expr.Payload{
 			DestRegister: 1,
 			Base:         expr.PayloadBaseNetworkHeader,
@@ -141,7 +141,12 @@ func TestNftablesManager(t *testing.T) {
 		},
 		&expr.Verdict{Kind: expr.VerdictDrop},
 	}
-	require.ElementsMatch(t, rules[1].Exprs, expectedExprs2, "expected the same expressions")
+
+	// Compare DROP rule at position 0 (inserted first due to InsertRule)
+	compareExprsIgnoringCounters(t, rules[0].Exprs, expectedDropExprs)
+
+	// Compare connection tracking rule at position 1 (pushed down by DROP rule insertion)
+	compareExprsIgnoringCounters(t, rules[1].Exprs, expectedExprs1)
 
 	for _, r := range rule {
 		err = manager.DeletePeerRule(r)
@@ -160,10 +165,90 @@ func TestNftablesManager(t *testing.T) {
 	require.NoError(t, err, "failed to reset")
 }
 
+func TestNftablesManagerRuleOrder(t *testing.T) {
+	// This test verifies rule insertion order in nftables peer ACLs
+	// We add accept rule first, then deny rule to test ordering behavior
+	manager, err := Create(ifaceMock)
+	require.NoError(t, err)
+	require.NoError(t, manager.Init(nil))
+
+	defer func() {
+		err = manager.Close(nil)
+		require.NoError(t, err)
+	}()
+
+	ip := netip.MustParseAddr("100.96.0.2").Unmap()
+	testClient := &nftables.Conn{}
+
+	// Add accept rule first
+	_, err = manager.AddPeerFiltering(nil, ip.AsSlice(), fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80}}, fw.ActionAccept, "accept-http")
+	require.NoError(t, err, "failed to add accept rule")
+
+	// Add deny rule second for the same traffic
+	_, err = manager.AddPeerFiltering(nil, ip.AsSlice(), fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80}}, fw.ActionDrop, "deny-http")
+	require.NoError(t, err, "failed to add deny rule")
+
+	err = manager.Flush()
+	require.NoError(t, err, "failed to flush")
+
+	rules, err := testClient.GetRules(manager.aclManager.workTable, manager.aclManager.chainInputRules)
+	require.NoError(t, err, "failed to get rules")
+
+	t.Logf("Found %d rules in nftables chain", len(rules))
+
+	// Find the accept and deny rules and verify deny comes before accept
+	var acceptRuleIndex, denyRuleIndex int = -1, -1
+	for i, rule := range rules {
+		hasAcceptHTTPSet := false
+		hasDenyHTTPSet := false
+		hasPort80 := false
+		var action string
+
+		for _, e := range rule.Exprs {
+			// Check for set lookup
+			if lookup, ok := e.(*expr.Lookup); ok {
+				if lookup.SetName == "accept-http" {
+					hasAcceptHTTPSet = true
+				} else if lookup.SetName == "deny-http" {
+					hasDenyHTTPSet = true
+				}
+			}
+			// Check for port 80
+			if cmp, ok := e.(*expr.Cmp); ok {
+				if cmp.Op == expr.CmpOpEq && len(cmp.Data) == 2 && binary.BigEndian.Uint16(cmp.Data) == 80 {
+					hasPort80 = true
+				}
+			}
+			// Check for verdict
+			if verdict, ok := e.(*expr.Verdict); ok {
+				if verdict.Kind == expr.VerdictAccept {
+					action = "ACCEPT"
+				} else if verdict.Kind == expr.VerdictDrop {
+					action = "DROP"
+				}
+			}
+		}
+
+		if hasAcceptHTTPSet && hasPort80 && action == "ACCEPT" {
+			t.Logf("Rule [%d]: accept-http set + Port 80 + ACCEPT", i)
+			acceptRuleIndex = i
+		} else if hasDenyHTTPSet && hasPort80 && action == "DROP" {
+			t.Logf("Rule [%d]: deny-http set + Port 80 + DROP", i)
+			denyRuleIndex = i
+		}
+	}
+
+	require.NotEqual(t, -1, acceptRuleIndex, "accept rule should exist in nftables")
+	require.NotEqual(t, -1, denyRuleIndex, "deny rule should exist in nftables")
+	require.Less(t, denyRuleIndex, acceptRuleIndex,
+		"deny rule should come before accept rule in nftables chain (deny at index %d, accept at index %d)",
+		denyRuleIndex, acceptRuleIndex)
+}
+
 func TestNFtablesCreatePerformance(t *testing.T) {
 	mock := &iFaceMock{
 		NameFunc: func() string {
-			return "lo"
+			return "wg-test"
 		},
 		AddressFunc: func() wgaddr.Address {
 			return wgaddr.Address{

client/firewall/uspfilter/allow_netbird.go

@@ -18,6 +18,7 @@ func (m *Manager) Close(stateManager *statemanager.Manager) error {
 	defer m.mutex.Unlock()
 
 	m.outgoingRules = make(map[netip.Addr]RuleSet)
+	m.incomingDenyRules = make(map[netip.Addr]RuleSet)
 	m.incomingRules = make(map[netip.Addr]RuleSet)
 
 	if m.udpTracker != nil {

client/firewall/uspfilter/allow_netbird_windows.go

@@ -27,6 +27,7 @@ func (m *Manager) Close(*statemanager.Manager) error {
 	defer m.mutex.Unlock()
 
 	m.outgoingRules = make(map[netip.Addr]RuleSet)
+	m.incomingDenyRules = make(map[netip.Addr]RuleSet)
 	m.incomingRules = make(map[netip.Addr]RuleSet)
 
 	if m.udpTracker != nil {

client/firewall/uspfilter/filter.go

@@ -70,14 +70,13 @@ func (r RouteRules) Sort() {
 
 // Manager userspace firewall manager
 type Manager struct {
-	// outgoingRules is used for hooks only
-	outgoingRules map[netip.Addr]RuleSet
-	// incomingRules is used for filtering and hooks
-	incomingRules  map[netip.Addr]RuleSet
-	routeRules     RouteRules
-	decoders       sync.Pool
-	wgIface        common.IFaceMapper
-	nativeFirewall firewall.Manager
+	outgoingRules     map[netip.Addr]RuleSet
+	incomingDenyRules map[netip.Addr]RuleSet
+	incomingRules     map[netip.Addr]RuleSet
+	routeRules        RouteRules
+	decoders          sync.Pool
+	wgIface           common.IFaceMapper
+	nativeFirewall    firewall.Manager
 
 	mutex sync.RWMutex
 
@@ -186,6 +185,7 @@ func create(iface common.IFaceMapper, nativeFirewall firewall.Manager, disableSe
 		},
 		nativeFirewall:      nativeFirewall,
 		outgoingRules:       make(map[netip.Addr]RuleSet),
+		incomingDenyRules:   make(map[netip.Addr]RuleSet),
 		incomingRules:       make(map[netip.Addr]RuleSet),
 		wgIface:             iface,
 		localipmanager:      newLocalIPManager(),
@@ -417,10 +417,17 @@ func (m *Manager) AddPeerFiltering(
 	}
 
 	m.mutex.Lock()
-	if _, ok := m.incomingRules[r.ip]; !ok {
-		m.incomingRules[r.ip] = make(RuleSet)
+	var targetMap map[netip.Addr]RuleSet
+	if r.drop {
+		targetMap = m.incomingDenyRules
+	} else {
+		targetMap = m.incomingRules
 	}
-	m.incomingRules[r.ip][r.id] = r
+
+	if _, ok := targetMap[r.ip]; !ok {
+		targetMap[r.ip] = make(RuleSet)
+	}
+	targetMap[r.ip][r.id] = r
 	m.mutex.Unlock()
 	return []firewall.Rule{&r}, nil
 }
@@ -507,10 +514,24 @@ func (m *Manager) DeletePeerRule(rule firewall.Rule) error {
 		return fmt.Errorf("delete rule: invalid rule type: %T", rule)
 	}
 
-	if _, ok := m.incomingRules[r.ip][r.id]; !ok {
+	var sourceMap map[netip.Addr]RuleSet
+	if r.drop {
+		sourceMap = m.incomingDenyRules
+	} else {
+		sourceMap = m.incomingRules
+	}
+
+	if ruleset, ok := sourceMap[r.ip]; ok {
+		if _, exists := ruleset[r.id]; !exists {
+			return fmt.Errorf("delete rule: no rule with such id: %v", r.id)
+		}
+		delete(ruleset, r.id)
+		if len(ruleset) == 0 {
+			delete(sourceMap, r.ip)
+		}
+	} else {
 		return fmt.Errorf("delete rule: no rule with such id: %v", r.id)
 	}
-	delete(m.incomingRules[r.ip], r.id)
 
 	return nil
 }
@@ -572,7 +593,7 @@ func (m *Manager) UpdateSet(set firewall.Set, prefixes []netip.Prefix) error {
 	return nil
 }
 
-// FilterOutBound filters outgoing packets
+// FilterOutbound filters outgoing packets
 func (m *Manager) FilterOutbound(packetData []byte, size int) bool {
 	return m.filterOutbound(packetData, size)
 }
@@ -761,7 +782,7 @@ func (m *Manager) filterInbound(packetData []byte, size int) bool {
 // handleLocalTraffic handles local traffic.
 // If it returns true, the packet should be dropped.
 func (m *Manager) handleLocalTraffic(d *decoder, srcIP, dstIP netip.Addr, packetData []byte, size int) bool {
-	ruleID, blocked := m.peerACLsBlock(srcIP, packetData, m.incomingRules, d)
+	ruleID, blocked := m.peerACLsBlock(srcIP, d, packetData)
 	if blocked {
 		_, pnum := getProtocolFromPacket(d)
 		srcPort, dstPort := getPortsFromPacket(d)
@@ -971,26 +992,28 @@ func (m *Manager) isSpecialICMP(d *decoder) bool {
 		icmpType == layers.ICMPv4TypeTimeExceeded
 }
 
-func (m *Manager) peerACLsBlock(srcIP netip.Addr, packetData []byte, rules map[netip.Addr]RuleSet, d *decoder) ([]byte, bool) {
+func (m *Manager) peerACLsBlock(srcIP netip.Addr, d *decoder, packetData []byte) ([]byte, bool) {
 	m.mutex.RLock()
 	defer m.mutex.RUnlock()
+
 	if m.isSpecialICMP(d) {
 		return nil, false
 	}
 
-	if mgmtId, filter, ok := validateRule(srcIP, packetData, rules[srcIP], d); ok {
+	if mgmtId, filter, ok := validateRule(srcIP, packetData, m.incomingDenyRules[srcIP], d); ok {
 		return mgmtId, filter
 	}
 
-	if mgmtId, filter, ok := validateRule(srcIP, packetData, rules[netip.IPv4Unspecified()], d); ok {
+	if mgmtId, filter, ok := validateRule(srcIP, packetData, m.incomingRules[srcIP], d); ok {
+		return mgmtId, filter
+	}
+	if mgmtId, filter, ok := validateRule(srcIP, packetData, m.incomingRules[netip.IPv4Unspecified()], d); ok {
+		return mgmtId, filter
+	}
+	if mgmtId, filter, ok := validateRule(srcIP, packetData, m.incomingRules[netip.IPv6Unspecified()], d); ok {
 		return mgmtId, filter
 	}
 
-	if mgmtId, filter, ok := validateRule(srcIP, packetData, rules[netip.IPv6Unspecified()], d); ok {
-		return mgmtId, filter
-	}
-
-	// Default policy: DROP ALL
 	return nil, true
 }
 
@@ -1013,6 +1036,7 @@ func portsMatch(rulePort *firewall.Port, packetPort uint16) bool {
 
 func validateRule(ip netip.Addr, packetData []byte, rules map[string]PeerRule, d *decoder) ([]byte, bool, bool) {
 	payloadLayer := d.decoded[1]
+
 	for _, rule := range rules {
 		if rule.matchByIP && ip.Compare(rule.ip) != 0 {
 			continue
@@ -1045,6 +1069,7 @@ func validateRule(ip netip.Addr, packetData []byte, rules map[string]PeerRule, d
 			return rule.mgmtId, rule.drop, true
 		}
 	}
+
 	return nil, false, false
 }
 
@@ -1116,6 +1141,7 @@ func (m *Manager) AddUDPPacketHook(in bool, ip netip.Addr, dPort uint16, hook fu
 
 	m.mutex.Lock()
 	if in {
+		// Incoming UDP hooks are stored in allow rules map
 		if _, ok := m.incomingRules[r.ip]; !ok {
 			m.incomingRules[r.ip] = make(map[string]PeerRule)
 		}
@@ -1136,6 +1162,7 @@ func (m *Manager) RemovePacketHook(hookID string) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
+	// Check incoming hooks (stored in allow rules)
 	for _, arr := range m.incomingRules {
 		for _, r := range arr {
 			if r.id == hookID {
@@ -1144,6 +1171,7 @@ func (m *Manager) RemovePacketHook(hookID string) error {
 			}
 		}
 	}
+	// Check outgoing hooks
 	for _, arr := range m.outgoingRules {
 		for _, r := range arr {
 			if r.id == hookID {

client/firewall/uspfilter/filter_filter_test.go

@@ -458,6 +458,31 @@ func TestPeerACLFiltering(t *testing.T) {
 			ruleAction:      fw.ActionDrop,
 			shouldBeBlocked: true,
 		},
+		{
+			name:            "Peer ACL - Drop rule should override accept all rule",
+			srcIP:           "100.10.0.1",
+			dstIP:           "100.10.0.100",
+			proto:           fw.ProtocolTCP,
+			srcPort:         12345,
+			dstPort:         22,
+			ruleIP:          "100.10.0.1",
+			ruleProto:       fw.ProtocolTCP,
+			ruleDstPort:     &fw.Port{Values: []uint16{22}},
+			ruleAction:      fw.ActionDrop,
+			shouldBeBlocked: true,
+		},
+		{
+			name:            "Peer ACL - Drop all traffic from specific IP",
+			srcIP:           "100.10.0.99",
+			dstIP:           "100.10.0.100",
+			proto:           fw.ProtocolTCP,
+			srcPort:         12345,
+			dstPort:         80,
+			ruleIP:          "100.10.0.99",
+			ruleProto:       fw.ProtocolALL,
+			ruleAction:      fw.ActionDrop,
+			shouldBeBlocked: true,
+		},
 	}
 
 	t.Run("Implicit DROP (no rules)", func(t *testing.T) {
@@ -468,13 +493,11 @@ func TestPeerACLFiltering(t *testing.T) {
 
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
-
 			if tc.ruleAction == fw.ActionDrop {
-				// add general accept rule to test drop rule
-				// TODO: this only works because 0.0.0.0 is tested last, we need to implement order
+				// add general accept rule for the same IP to test drop rule precedence
 				rules, err := manager.AddPeerFiltering(
 					nil,
-					net.ParseIP("0.0.0.0"),
+					net.ParseIP(tc.ruleIP),
 					fw.ProtocolALL,
 					nil,
 					nil,

client/firewall/uspfilter/filter_test.go

@@ -136,9 +136,22 @@ func TestManagerDeleteRule(t *testing.T) {
 		return
 	}
 
+	// Check rules exist in appropriate maps
 	for _, r := range rule2 {
-		if _, ok := m.incomingRules[ip][r.ID()]; !ok {
-			t.Errorf("rule2 is not in the incomingRules")
+		peerRule, ok := r.(*PeerRule)
+		if !ok {
+			t.Errorf("rule should be a PeerRule")
+			continue
+		}
+		// Check if rule exists in deny or allow maps based on action
+		var found bool
+		if peerRule.drop {
+			_, found = m.incomingDenyRules[ip][r.ID()]
+		} else {
+			_, found = m.incomingRules[ip][r.ID()]
+		}
+		if !found {
+			t.Errorf("rule2 is not in the expected rules map")
 		}
 	}
 
@@ -150,9 +163,22 @@ func TestManagerDeleteRule(t *testing.T) {
 		}
 	}
 
+	// Check rules are removed from appropriate maps
 	for _, r := range rule2 {
-		if _, ok := m.incomingRules[ip][r.ID()]; ok {
-			t.Errorf("rule2 is not in the incomingRules")
+		peerRule, ok := r.(*PeerRule)
+		if !ok {
+			t.Errorf("rule should be a PeerRule")
+			continue
+		}
+		// Check if rule is removed from deny or allow maps based on action
+		var found bool
+		if peerRule.drop {
+			_, found = m.incomingDenyRules[ip][r.ID()]
+		} else {
+			_, found = m.incomingRules[ip][r.ID()]
+		}
+		if found {
+			t.Errorf("rule2 should be removed from the rules map")
 		}
 	}
 }
@@ -196,16 +222,17 @@ func TestAddUDPPacketHook(t *testing.T) {
 
 			var addedRule PeerRule
 			if tt.in {
+				// Incoming UDP hooks are stored in allow rules map
 				if len(manager.incomingRules[tt.ip]) != 1 {
-					t.Errorf("expected 1 incoming rule, got %d", len(manager.incomingRules))
+					t.Errorf("expected 1 incoming rule, got %d", len(manager.incomingRules[tt.ip]))
 					return
 				}
 				for _, rule := range manager.incomingRules[tt.ip] {
 					addedRule = rule
 				}
 			} else {
-				if len(manager.outgoingRules) != 1 {
-					t.Errorf("expected 1 outgoing rule, got %d", len(manager.outgoingRules))
+				if len(manager.outgoingRules[tt.ip]) != 1 {
+					t.Errorf("expected 1 outgoing rule, got %d", len(manager.outgoingRules[tt.ip]))
 					return
 				}
 				for _, rule := range manager.outgoingRules[tt.ip] {
@@ -261,8 +288,8 @@ func TestManagerReset(t *testing.T) {
 		return
 	}
 
-	if len(m.outgoingRules) != 0 || len(m.incomingRules) != 0 {
-		t.Errorf("rules is not empty")
+	if len(m.outgoingRules) != 0 || len(m.incomingRules) != 0 || len(m.incomingDenyRules) != 0 {
+		t.Errorf("rules are not empty")
 	}
 }
 

client/firewall/uspfilter/tracer.go

@@ -314,7 +314,7 @@ func (m *Manager) buildConntrackStateMessage(d *decoder) string {
 func (m *Manager) handleLocalDelivery(trace *PacketTrace, packetData []byte, d *decoder, srcIP, dstIP netip.Addr) bool {
 	trace.AddResult(StageRouting, "Packet destined for local delivery", true)
 
-	ruleId, blocked := m.peerACLsBlock(srcIP, packetData, m.incomingRules, d)
+	ruleId, blocked := m.peerACLsBlock(srcIP, d, packetData)
 
 	strRuleId := "<no id>"
 	if ruleId != nil {

client/iface/bind/ice_bind.go

@@ -1,3 +1,5 @@
+//go:build !js
+
 package bind
 
 import (
@@ -56,10 +58,11 @@ type ICEBind struct {
 	muUDPMux         sync.Mutex
 	udpMux           *UniversalUDPMuxDefault
 	address          wgaddr.Address
+	mtu              uint16
 	activityRecorder *ActivityRecorder
 }
 
-func NewICEBind(transportNet transport.Net, filterFn FilterFn, address wgaddr.Address) *ICEBind {
+func NewICEBind(transportNet transport.Net, filterFn FilterFn, address wgaddr.Address, mtu uint16) *ICEBind {
 	b, _ := wgConn.NewStdNetBind().(*wgConn.StdNetBind)
 	ib := &ICEBind{
 		StdNetBind:       b,
@@ -69,6 +72,7 @@ func NewICEBind(transportNet transport.Net, filterFn FilterFn, address wgaddr.Ad
 		endpoints:        make(map[netip.Addr]net.Conn),
 		closedChan:       make(chan struct{}),
 		closed:           true,
+		mtu:              mtu,
 		address:          address,
 		activityRecorder: NewActivityRecorder(),
 	}
@@ -80,6 +84,10 @@ func NewICEBind(transportNet transport.Net, filterFn FilterFn, address wgaddr.Ad
 	return ib
 }
 
+func (s *ICEBind) MTU() uint16 {
+	return s.mtu
+}
+
 func (s *ICEBind) Open(uport uint16) ([]wgConn.ReceiveFunc, uint16, error) {
 	s.closed = false
 	s.closedChanMu.Lock()
@@ -158,6 +166,7 @@ func (s *ICEBind) createIPv4ReceiverFn(pc *ipv4.PacketConn, conn *net.UDPConn, r
 			Net:       s.transportNet,
 			FilterFn:  s.filterFn,
 			WGAddress: s.address,
+			MTU:       s.mtu,
 		},
 	)
 	return func(bufs [][]byte, sizes []int, eps []wgConn.Endpoint) (n int, err error) {

client/iface/bind/ice_bind_common.go

@@ -0,0 +1,69 @@
+//go:build js
+
+package bind
+
+import (
+	"net"
+	"net/netip"
+	"sync"
+
+	"github.com/pion/transport/v3"
+
+	"github.com/netbirdio/netbird/client/iface/wgaddr"
+)
+
+// RecvMessage represents a received message
+type RecvMessage struct {
+	Endpoint *Endpoint
+	Buffer   []byte
+}
+
+// ICEBind is a bind implementation that uses ICE candidates for connectivity
+type ICEBind struct {
+	address          wgaddr.Address
+	filterFn         FilterFn
+	endpoints        map[netip.Addr]net.Conn
+	endpointsMu      sync.Mutex
+	udpMux           *UniversalUDPMuxDefault
+	muUDPMux         sync.Mutex
+	transportNet     transport.Net
+	receiverCreated  bool
+	activityRecorder *ActivityRecorder
+	RecvChan         chan RecvMessage
+	closed           bool // Flag to signal that bind is closed
+	closedMu         sync.Mutex
+	mtu              uint16
+}
+
+// NewICEBind creates a new ICEBind instance
+func NewICEBind(transportNet transport.Net, filterFn FilterFn, address wgaddr.Address, mtu uint16) *ICEBind {
+	return &ICEBind{
+		address:          address,
+		transportNet:     transportNet,
+		filterFn:         filterFn,
+		endpoints:        make(map[netip.Addr]net.Conn),
+		RecvChan:         make(chan RecvMessage, 100),
+		activityRecorder: NewActivityRecorder(),
+		mtu:              mtu,
+	}
+}
+
+// SetFilter updates the filter function
+func (s *ICEBind) SetFilter(filter FilterFn) {
+	s.filterFn = filter
+}
+
+// GetAddress returns the bind address
+func (s *ICEBind) GetAddress() wgaddr.Address {
+	return s.address
+}
+
+// ActivityRecorder returns the activity recorder
+func (s *ICEBind) ActivityRecorder() *ActivityRecorder {
+	return s.activityRecorder
+}
+
+// MTU returns the maximum transmission unit
+func (s *ICEBind) MTU() uint16 {
+	return s.mtu
+}

client/iface/bind/ice_bind_js.go

@@ -0,0 +1,141 @@
+//go:build js
+
+package bind
+
+import (
+	"net"
+	"net/netip"
+
+	log "github.com/sirupsen/logrus"
+	"golang.zx2c4.com/wireguard/conn"
+)
+
+// GetICEMux returns a dummy UDP mux for WASM since browsers don't support UDP.
+func (s *ICEBind) GetICEMux() (*UniversalUDPMuxDefault, error) {
+	return nil, nil
+}
+
+// Open creates a receive function for handling relay packets in WASM.
+func (s *ICEBind) Open(uport uint16) ([]conn.ReceiveFunc, uint16, error) {
+	log.Debugf("Open: creating receive function for port %d", uport)
+
+	s.closedMu.Lock()
+	s.closed = false
+	s.closedMu.Unlock()
+
+	if !s.receiverCreated {
+		s.receiverCreated = true
+		log.Debugf("Open: first call, setting receiverCreated=true")
+	}
+
+	receiveFn := func(bufs [][]byte, sizes []int, eps []conn.Endpoint) (int, error) {
+		s.closedMu.Lock()
+		if s.closed {
+			s.closedMu.Unlock()
+			return 0, net.ErrClosed
+		}
+		s.closedMu.Unlock()
+
+		msg, ok := <-s.RecvChan
+		if !ok {
+			return 0, net.ErrClosed
+		}
+
+		copy(bufs[0], msg.Buffer)
+		sizes[0] = len(msg.Buffer)
+		eps[0] = conn.Endpoint(msg.Endpoint)
+		return 1, nil
+	}
+
+	log.Debugf("Open: receive function created, returning port %d", uport)
+	return []conn.ReceiveFunc{receiveFn}, uport, nil
+}
+
+// SetMark is not applicable in WASM/browser environment.
+func (s *ICEBind) SetMark(_ uint32) error {
+	return nil
+}
+
+// Send forwards packets through the relay connection for WASM.
+func (s *ICEBind) Send(bufs [][]byte, ep conn.Endpoint) error {
+	if ep == nil {
+		return nil
+	}
+
+	fakeIP := ep.DstIP()
+
+	s.endpointsMu.Lock()
+	relayConn, ok := s.endpoints[fakeIP]
+	s.endpointsMu.Unlock()
+
+	if !ok {
+		return nil
+	}
+
+	for _, buf := range bufs {
+		if _, err := relayConn.Write(buf); err != nil {
+			log.Errorf("Send: failed to write to relay: %v", err)
+			return err
+		}
+	}
+
+	return nil
+}
+
+// SetEndpoint stores a relay endpoint for a fake IP.
+func (s *ICEBind) SetEndpoint(fakeIP netip.Addr, conn net.Conn) {
+	s.endpointsMu.Lock()
+	defer s.endpointsMu.Unlock()
+
+	if oldConn, exists := s.endpoints[fakeIP]; exists {
+		if oldConn != conn {
+			log.Debugf("SetEndpoint: replacing existing connection for %s", fakeIP)
+			if err := oldConn.Close(); err != nil {
+				log.Debugf("SetEndpoint: error closing old connection: %v", err)
+			}
+			s.endpoints[fakeIP] = conn
+		} else {
+			log.Tracef("SetEndpoint: same connection already set for %s, skipping", fakeIP)
+		}
+	} else {
+		log.Debugf("SetEndpoint: setting new relay connection for fake IP %s", fakeIP)
+		s.endpoints[fakeIP] = conn
+	}
+}
+
+// RemoveEndpoint removes a relay endpoint.
+func (s *ICEBind) RemoveEndpoint(fakeIP netip.Addr) {
+	s.endpointsMu.Lock()
+	defer s.endpointsMu.Unlock()
+	delete(s.endpoints, fakeIP)
+}
+
+// BatchSize returns the batch size for WASM.
+func (s *ICEBind) BatchSize() int {
+	return 1
+}
+
+// ParseEndpoint parses an endpoint string.
+func (s *ICEBind) ParseEndpoint(s2 string) (conn.Endpoint, error) {
+	addrPort, err := netip.ParseAddrPort(s2)
+	if err != nil {
+		log.Errorf("ParseEndpoint: failed to parse %s: %v", s2, err)
+		return nil, err
+	}
+	ep := &Endpoint{AddrPort: addrPort}
+	return ep, nil
+}
+
+// Close closes the ICEBind.
+func (s *ICEBind) Close() error {
+	log.Debugf("Close: closing ICEBind (receiverCreated=%v)", s.receiverCreated)
+
+	s.closedMu.Lock()
+	s.closed = true
+	s.closedMu.Unlock()
+
+	s.receiverCreated = false
+
+	log.Debugf("Close: returning from Close")
+	return nil
+}

client/iface/bind/udp_mux_ios.go

@@ -4,4 +4,4 @@ package bind
 
 func (m *UDPMuxDefault) notifyAddressRemoval(addr string) {
 	// iOS doesn't support nbnet hooks, so this is a no-op
-}
+}

client/iface/bind/udp_mux_universal.go

@@ -18,6 +18,7 @@ import (
 	"github.com/pion/stun/v2"
 	"github.com/pion/transport/v3"
 
+	"github.com/netbirdio/netbird/client/iface/bufsize"
 	"github.com/netbirdio/netbird/client/iface/wgaddr"
 )
 
@@ -44,6 +45,7 @@ type UniversalUDPMuxParams struct {
 	Net                   transport.Net
 	FilterFn              FilterFn
 	WGAddress             wgaddr.Address
+	MTU                   uint16
 }
 
 // NewUniversalUDPMuxDefault creates an implementation of UniversalUDPMux embedding UDPMux
@@ -84,7 +86,7 @@ func NewUniversalUDPMuxDefault(params UniversalUDPMuxParams) *UniversalUDPMuxDef
 // just ignore other packets printing an warning message.
 // It is a blocking method, consider running in a go routine.
 func (m *UniversalUDPMuxDefault) ReadFromConn(ctx context.Context) {
-	buf := make([]byte, 1500)
+	buf := make([]byte, m.params.MTU+bufsize.WGBufferOverhead)
 	for {
 		select {
 		case <-ctx.Done():

client/iface/bufsize/bufsize.go

@@ -0,0 +1,9 @@
+package bufsize
+
+const (
+	// WGBufferOverhead represents the additional buffer space needed beyond MTU
+	// for WireGuard packet encapsulation (WG header + UDP + IP + safety margin)
+	// Original hardcoded buffers were 1500, default MTU is 1280, so overhead = 220
+	// TODO: Calculate this properly based on actual protocol overhead instead of using hardcoded difference
+	WGBufferOverhead = 220
+)

client/iface/configurer/name.go

@@ -1,4 +1,4 @@
-//go:build linux || windows || freebsd
+//go:build linux || windows || freebsd || js || wasip1
 
 package configurer
 

client/iface/configurer/uapi.go

@@ -1,4 +1,4 @@
-//go:build !windows
+//go:build !windows && !js
 
 package configurer
 

client/iface/configurer/uapi_js.go

@@ -0,0 +1,23 @@
+package configurer
+
+import (
+	"net"
+)
+
+type noopListener struct{}
+
+func (n *noopListener) Accept() (net.Conn, error) {
+	return nil, net.ErrClosed
+}
+
+func (n *noopListener) Close() error {
+	return nil
+}
+
+func (n *noopListener) Addr() net.Addr {
+	return nil
+}
+
+func openUAPI(deviceName string) (net.Listener, error) {
+	return &noopListener{}, nil
+}

client/iface/device.go

@@ -17,6 +17,7 @@ type WGTunDevice interface {
 	Up() (*bind.UniversalUDPMuxDefault, error)
 	UpdateAddr(address wgaddr.Address) error
 	WgAddress() wgaddr.Address
+	MTU() uint16
 	DeviceName() string
 	Close() error
 	FilteredDevice() *device.FilteredDevice

client/iface/device/device_android.go

@@ -21,7 +21,7 @@ type WGTunDevice struct {
 	address    wgaddr.Address
 	port       int
 	key        string
-	mtu        int
+	mtu        uint16
 	iceBind    *bind.ICEBind
 	tunAdapter TunAdapter
 	disableDNS bool
@@ -33,7 +33,7 @@ type WGTunDevice struct {
 	configurer     WGConfigurer
 }
 
-func NewTunDevice(address wgaddr.Address, port int, key string, mtu int, iceBind *bind.ICEBind, tunAdapter TunAdapter, disableDNS bool) *WGTunDevice {
+func NewTunDevice(address wgaddr.Address, port int, key string, mtu uint16, iceBind *bind.ICEBind, tunAdapter TunAdapter, disableDNS bool) *WGTunDevice {
 	return &WGTunDevice{
 		address:    address,
 		port:       port,
@@ -58,7 +58,7 @@ func (t *WGTunDevice) Create(routes []string, dns string, searchDomains []string
 		searchDomainsToString = ""
 	}
 
-	fd, err := t.tunAdapter.ConfigureInterface(t.address.String(), t.mtu, dns, searchDomainsToString, routesString)
+	fd, err := t.tunAdapter.ConfigureInterface(t.address.String(), int(t.mtu), dns, searchDomainsToString, routesString)
 	if err != nil {
 		log.Errorf("failed to create Android interface: %s", err)
 		return nil, err
@@ -137,6 +137,10 @@ func (t *WGTunDevice) WgAddress() wgaddr.Address {
 	return t.address
 }
 
+func (t *WGTunDevice) MTU() uint16 {
+	return t.mtu
+}
+
 func (t *WGTunDevice) FilteredDevice() *FilteredDevice {
 	return t.filteredDevice
 }

client/iface/device/device_darwin.go

@@ -21,7 +21,7 @@ type TunDevice struct {
 	address wgaddr.Address
 	port    int
 	key     string
-	mtu     int
+	mtu     uint16
 	iceBind *bind.ICEBind
 
 	device         *device.Device
@@ -30,7 +30,7 @@ type TunDevice struct {
 	configurer     WGConfigurer
 }
 
-func NewTunDevice(name string, address wgaddr.Address, port int, key string, mtu int, iceBind *bind.ICEBind) *TunDevice {
+func NewTunDevice(name string, address wgaddr.Address, port int, key string, mtu uint16, iceBind *bind.ICEBind) *TunDevice {
 	return &TunDevice{
 		name:    name,
 		address: address,
@@ -42,7 +42,7 @@ func NewTunDevice(name string, address wgaddr.Address, port int, key string, mtu
 }
 
 func (t *TunDevice) Create() (WGConfigurer, error) {
-	tunDevice, err := tun.CreateTUN(t.name, t.mtu)
+	tunDevice, err := tun.CreateTUN(t.name, int(t.mtu))
 	if err != nil {
 		return nil, fmt.Errorf("error creating tun device: %s", err)
 	}
@@ -111,6 +111,10 @@ func (t *TunDevice) WgAddress() wgaddr.Address {
 	return t.address
 }
 
+func (t *TunDevice) MTU() uint16 {
+	return t.mtu
+}
+
 func (t *TunDevice) DeviceName() string {
 	return t.name
 }

client/iface/device/device_ios.go

@@ -22,6 +22,7 @@ type TunDevice struct {
 	address wgaddr.Address
 	port    int
 	key     string
+	mtu     uint16
 	iceBind *bind.ICEBind
 	tunFd   int
 
@@ -31,12 +32,13 @@ type TunDevice struct {
 	configurer     WGConfigurer
 }
 
-func NewTunDevice(name string, address wgaddr.Address, port int, key string, iceBind *bind.ICEBind, tunFd int) *TunDevice {
+func NewTunDevice(name string, address wgaddr.Address, port int, key string, mtu uint16, iceBind *bind.ICEBind, tunFd int) *TunDevice {
 	return &TunDevice{
 		name:    name,
 		address: address,
 		port:    port,
 		key:     key,
+		mtu:     mtu,
 		iceBind: iceBind,
 		tunFd:   tunFd,
 	}
@@ -125,6 +127,10 @@ func (t *TunDevice) WgAddress() wgaddr.Address {
 	return t.address
 }
 
+func (t *TunDevice) MTU() uint16 {
+	return t.mtu
+}
+
 func (t *TunDevice) UpdateAddr(_ wgaddr.Address) error {
 	// todo implement
 	return nil

client/iface/device/device_kernel_unix.go

@@ -24,7 +24,7 @@ type TunKernelDevice struct {
 	address      wgaddr.Address
 	wgPort       int
 	key          string
-	mtu          int
+	mtu          uint16
 	ctx          context.Context
 	ctxCancel    context.CancelFunc
 	transportNet transport.Net
@@ -36,7 +36,7 @@ type TunKernelDevice struct {
 	filterFn bind.FilterFn
 }
 
-func NewKernelDevice(name string, address wgaddr.Address, wgPort int, key string, mtu int, transportNet transport.Net) *TunKernelDevice {
+func NewKernelDevice(name string, address wgaddr.Address, wgPort int, key string, mtu uint16, transportNet transport.Net) *TunKernelDevice {
 	ctx, cancel := context.WithCancel(context.Background())
 	return &TunKernelDevice{
 		ctx:          ctx,
@@ -66,7 +66,7 @@ func (t *TunKernelDevice) Create() (WGConfigurer, error) {
 	// TODO: do a MTU discovery
 	log.Debugf("setting MTU: %d interface: %s", t.mtu, t.name)
 
-	if err := link.setMTU(t.mtu); err != nil {
+	if err := link.setMTU(int(t.mtu)); err != nil {
 		return nil, fmt.Errorf("set mtu: %w", err)
 	}
 
@@ -96,7 +96,7 @@ func (t *TunKernelDevice) Up() (*bind.UniversalUDPMuxDefault, error) {
 		return nil, err
 	}
 
-	rawSock, err := sharedsock.Listen(t.wgPort, sharedsock.NewIncomingSTUNFilter())
+	rawSock, err := sharedsock.Listen(t.wgPort, sharedsock.NewIncomingSTUNFilter(), t.mtu)
 	if err != nil {
 		return nil, err
 	}
@@ -111,6 +111,7 @@ func (t *TunKernelDevice) Up() (*bind.UniversalUDPMuxDefault, error) {
 		Net:       t.transportNet,
 		FilterFn:  t.filterFn,
 		WGAddress: t.address,
+		MTU:       t.mtu,
 	}
 	mux := bind.NewUniversalUDPMuxDefault(bindParams)
 	go mux.ReadFromConn(t.ctx)
@@ -158,6 +159,10 @@ func (t *TunKernelDevice) WgAddress() wgaddr.Address {
 	return t.address
 }
 
+func (t *TunKernelDevice) MTU() uint16 {
+	return t.mtu
+}
+
 func (t *TunKernelDevice) DeviceName() string {
 	return t.name
 }

client/iface/device/device_netstack.go

@@ -1,6 +1,3 @@
-//go:build !android
-// +build !android
-
 package device
 
 import (
@@ -22,7 +19,7 @@ type TunNetstackDevice struct {
 	address       wgaddr.Address
 	port          int
 	key           string
-	mtu           int
+	mtu           uint16
 	listenAddress string
 	iceBind       *bind.ICEBind
 
@@ -35,7 +32,7 @@ type TunNetstackDevice struct {
 	net *netstack.Net
 }
 
-func NewNetstackDevice(name string, address wgaddr.Address, wgPort int, key string, mtu int, iceBind *bind.ICEBind, listenAddress string) *TunNetstackDevice {
+func NewNetstackDevice(name string, address wgaddr.Address, wgPort int, key string, mtu uint16, iceBind *bind.ICEBind, listenAddress string) *TunNetstackDevice {
 	return &TunNetstackDevice{
 		name:          name,
 		address:       address,
@@ -47,7 +44,7 @@ func NewNetstackDevice(name string, address wgaddr.Address, wgPort int, key stri
 	}
 }
 
-func (t *TunNetstackDevice) Create() (WGConfigurer, error) {
+func (t *TunNetstackDevice) create() (WGConfigurer, error) {
 	log.Info("create nbnetstack tun interface")
 
 	// TODO: get from service listener runtime IP
@@ -57,7 +54,7 @@ func (t *TunNetstackDevice) Create() (WGConfigurer, error) {
 	}
 
 	log.Debugf("netstack using address: %s", t.address.IP)
-	t.nsTun = nbnetstack.NewNetStackTun(t.listenAddress, t.address.IP, dnsAddr, t.mtu)
+	t.nsTun = nbnetstack.NewNetStackTun(t.listenAddress, t.address.IP, dnsAddr, int(t.mtu))
 	log.Debugf("netstack using dns address: %s", dnsAddr)
 	tunIface, net, err := t.nsTun.Create()
 	if err != nil {
@@ -125,6 +122,10 @@ func (t *TunNetstackDevice) WgAddress() wgaddr.Address {
 	return t.address
 }
 
+func (t *TunNetstackDevice) MTU() uint16 {
+	return t.mtu
+}
+
 func (t *TunNetstackDevice) DeviceName() string {
 	return t.name
 }

client/iface/device/device_netstack_android.go

@@ -0,0 +1,7 @@
+//go:build android
+
+package device
+
+func (t *TunNetstackDevice) Create(routes []string, dns string, searchDomains []string) (WGConfigurer, error) {
+	return t.create()
+}

client/iface/device/device_netstack_generic.go

@@ -0,0 +1,7 @@
+//go:build !android
+
+package device
+
+func (t *TunNetstackDevice) Create() (WGConfigurer, error) {
+	return t.create()
+}

client/iface/device/device_usp_unix.go

@@ -20,7 +20,7 @@ type USPDevice struct {
 	address wgaddr.Address
 	port    int
 	key     string
-	mtu     int
+	mtu     uint16
 	iceBind *bind.ICEBind
 
 	device         *device.Device
@@ -29,7 +29,7 @@ type USPDevice struct {
 	configurer     WGConfigurer
 }
 
-func NewUSPDevice(name string, address wgaddr.Address, port int, key string, mtu int, iceBind *bind.ICEBind) *USPDevice {
+func NewUSPDevice(name string, address wgaddr.Address, port int, key string, mtu uint16, iceBind *bind.ICEBind) *USPDevice {
 	log.Infof("using userspace bind mode")
 
 	return &USPDevice{
@@ -44,9 +44,9 @@ func NewUSPDevice(name string, address wgaddr.Address, port int, key string, mtu
 
 func (t *USPDevice) Create() (WGConfigurer, error) {
 	log.Info("create tun interface")
-	tunIface, err := tun.CreateTUN(t.name, t.mtu)
+	tunIface, err := tun.CreateTUN(t.name, int(t.mtu))
 	if err != nil {
-		log.Debugf("failed to create tun interface (%s, %d): %s", t.name, t.mtu, err)
+		log.Debugf("failed to create tun interface (%s, %d): %s", t.name, int(t.mtu), err)
 		return nil, fmt.Errorf("error creating tun device: %s", err)
 	}
 	t.filteredDevice = newDeviceFilter(tunIface)
@@ -118,6 +118,10 @@ func (t *USPDevice) WgAddress() wgaddr.Address {
 	return t.address
 }
 
+func (t *USPDevice) MTU() uint16 {
+	return t.mtu
+}
+
 func (t *USPDevice) DeviceName() string {
 	return t.name
 }

client/iface/device/device_windows.go

@@ -23,7 +23,7 @@ type TunDevice struct {
 	address wgaddr.Address
 	port    int
 	key     string
-	mtu     int
+	mtu     uint16
 	iceBind *bind.ICEBind
 
 	device          *device.Device
@@ -33,7 +33,7 @@ type TunDevice struct {
 	configurer      WGConfigurer
 }
 
-func NewTunDevice(name string, address wgaddr.Address, port int, key string, mtu int, iceBind *bind.ICEBind) *TunDevice {
+func NewTunDevice(name string, address wgaddr.Address, port int, key string, mtu uint16, iceBind *bind.ICEBind) *TunDevice {
 	return &TunDevice{
 		name:    name,
 		address: address,
@@ -59,7 +59,7 @@ func (t *TunDevice) Create() (WGConfigurer, error) {
 		return nil, err
 	}
 	log.Info("create tun interface")
-	tunDevice, err := tun.CreateTUNWithRequestedGUID(t.name, &guid, t.mtu)
+	tunDevice, err := tun.CreateTUNWithRequestedGUID(t.name, &guid, int(t.mtu))
 	if err != nil {
 		return nil, fmt.Errorf("error creating tun device: %s", err)
 	}
@@ -144,6 +144,10 @@ func (t *TunDevice) WgAddress() wgaddr.Address {
 	return t.address
 }
 
+func (t *TunDevice) MTU() uint16 {
+	return t.mtu
+}
+
 func (t *TunDevice) DeviceName() string {
 	return t.name
 }

client/iface/device_android.go

@@ -15,6 +15,7 @@ type WGTunDevice interface {
 	Up() (*bind.UniversalUDPMuxDefault, error)
 	UpdateAddr(address wgaddr.Address) error
 	WgAddress() wgaddr.Address
+	MTU() uint16
 	DeviceName() string
 	Close() error
 	FilteredDevice() *device.FilteredDevice

client/iface/iface.go

@@ -26,6 +26,8 @@ import (
 
 const (
 	DefaultMTU         = 1280
+	MinMTU             = 576
+	MaxMTU             = 8192
 	DefaultWgPort      = 51820
 	WgInterfaceDefault = configurer.WgInterfaceDefault
 )
@@ -35,6 +37,17 @@ var (
 	ErrIfaceNotFound = fmt.Errorf("wireguard interface not found")
 )
 
+// ValidateMTU validates that MTU is within acceptable range
+func ValidateMTU(mtu uint16) error {
+	if mtu < MinMTU {
+		return fmt.Errorf("MTU %d below minimum (%d bytes)", mtu, MinMTU)
+	}
+	if mtu > MaxMTU {
+		return fmt.Errorf("MTU %d exceeds maximum supported size (%d bytes)", mtu, MaxMTU)
+	}
+	return nil
+}
+
 type wgProxyFactory interface {
 	GetProxy() wgproxy.Proxy
 	Free() error
@@ -45,7 +58,7 @@ type WGIFaceOpts struct {
 	Address      string
 	WGPort       int
 	WGPrivKey    string
-	MTU          int
+	MTU          uint16
 	MobileArgs   *device.MobileIFaceArguments
 	TransportNet transport.Net
 	FilterFn     bind.FilterFn
@@ -82,6 +95,10 @@ func (w *WGIface) Address() wgaddr.Address {
 	return w.tun.WgAddress()
 }
 
+func (w *WGIface) MTU() uint16 {
+	return w.tun.MTU()
+}
+
 // ToInterface returns the net.Interface for the Wireguard interface
 func (r *WGIface) ToInterface() *net.Interface {
 	name := r.tun.DeviceName()

client/iface/iface_destroy_js.go

@@ -0,0 +1,6 @@
+package iface
+
+// Destroy is a no-op on WASM
+func (w *WGIface) Destroy() error {
+	return nil
+}

client/iface/iface_new_android.go

@@ -3,6 +3,7 @@ package iface
 import (
 	"github.com/netbirdio/netbird/client/iface/bind"
 	"github.com/netbirdio/netbird/client/iface/device"
+	"github.com/netbirdio/netbird/client/iface/netstack"
 	"github.com/netbirdio/netbird/client/iface/wgaddr"
 	"github.com/netbirdio/netbird/client/iface/wgproxy"
 )
@@ -14,7 +15,16 @@ func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
 		return nil, err
 	}
 
-	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress)
+	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
+
+	if netstack.IsEnabled() {
+		wgIFace := &WGIface{
+			userspaceBind:  true,
+			tun:            device.NewNetstackDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind, netstack.ListenAddr()),
+			wgProxyFactory: wgproxy.NewUSPFactory(iceBind),
+		}
+		return wgIFace, nil
+	}
 
 	wgIFace := &WGIface{
 		userspaceBind:  true,

client/iface/iface_new_darwin.go

@@ -17,7 +17,7 @@ func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
 		return nil, err
 	}
 
-	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress)
+	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
 
 	var tun WGTunDevice
 	if netstack.IsEnabled() {

client/iface/iface_new_ios.go

@@ -16,10 +16,10 @@ func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
 		return nil, err
 	}
 
-	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress)
+	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
 
 	wgIFace := &WGIface{
-		tun:            device.NewTunDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, iceBind, opts.MobileArgs.TunFd),
+		tun:            device.NewTunDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind, opts.MobileArgs.TunFd),
 		userspaceBind:  true,
 		wgProxyFactory: wgproxy.NewUSPFactory(iceBind),
 	}

client/iface/iface_new_js.go

@@ -0,0 +1,27 @@
+package iface
+
+import (
+	"github.com/netbirdio/netbird/client/iface/bind"
+	"github.com/netbirdio/netbird/client/iface/device"
+	"github.com/netbirdio/netbird/client/iface/netstack"
+	"github.com/netbirdio/netbird/client/iface/wgaddr"
+	"github.com/netbirdio/netbird/client/iface/wgproxy"
+)
+
+// NewWGIFace creates a new WireGuard interface for WASM (always uses netstack mode)
+func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
+	wgAddress, err := wgaddr.ParseWGAddress(opts.Address)
+	if err != nil {
+		return nil, err
+	}
+
+	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
+
+	wgIface := &WGIface{
+		tun:            device.NewNetstackDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind, netstack.ListenAddr()),
+		userspaceBind:  true,
+		wgProxyFactory: wgproxy.NewUSPFactory(iceBind),
+	}
+
+	return wgIface, nil
+}

client/iface/iface_new_unix.go

@@ -22,7 +22,7 @@ func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
 	wgIFace := &WGIface{}
 
 	if netstack.IsEnabled() {
-		iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress)
+		iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
 		wgIFace.tun = device.NewNetstackDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind, netstack.ListenAddr())
 		wgIFace.userspaceBind = true
 		wgIFace.wgProxyFactory = wgproxy.NewUSPFactory(iceBind)
@@ -31,11 +31,11 @@ func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
 
 	if device.WireGuardModuleIsLoaded() {
 		wgIFace.tun = device.NewKernelDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, opts.TransportNet)
-		wgIFace.wgProxyFactory = wgproxy.NewKernelFactory(opts.WGPort)
+		wgIFace.wgProxyFactory = wgproxy.NewKernelFactory(opts.WGPort, opts.MTU)
 		return wgIFace, nil
 	}
 	if device.ModuleTunIsLoaded() {
-		iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress)
+		iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
 		wgIFace.tun = device.NewUSPDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind)
 		wgIFace.userspaceBind = true
 		wgIFace.wgProxyFactory = wgproxy.NewUSPFactory(iceBind)

client/iface/iface_new_windows.go

@@ -14,7 +14,7 @@ func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
 	if err != nil {
 		return nil, err
 	}
-	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress)
+	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
 
 	var tun WGTunDevice
 	if netstack.IsEnabled() {

client/iface/netstack/env.go

@@ -1,3 +1,5 @@
+//go:build !js
+
 package netstack
 
 import (

client/iface/netstack/env_js.go

@@ -0,0 +1,12 @@
+package netstack
+
+const EnvUseNetstackMode = "NB_USE_NETSTACK_MODE"
+
+// IsEnabled always returns true for js since it's the only mode available
+func IsEnabled() bool {
+	return true
+}
+
+func ListenAddr() string {
+	return ""
+}

client/iface/wgproxy/bind/proxy.go

@@ -12,6 +12,7 @@ import (
 	log "github.com/sirupsen/logrus"
 
 	"github.com/netbirdio/netbird/client/iface/bind"
+	"github.com/netbirdio/netbird/client/iface/bufsize"
 	"github.com/netbirdio/netbird/client/iface/wgproxy/listener"
 )
 
@@ -135,7 +136,7 @@ func (p *ProxyBind) proxyToLocal(ctx context.Context) {
 	}()
 
 	for {
-		buf := make([]byte, 1500)
+		buf := make([]byte, p.Bind.MTU()+bufsize.WGBufferOverhead)
 		n, err := p.remoteConn.Read(buf)
 		if err != nil {
 			if ctx.Err() != nil {

client/iface/wgproxy/ebpf/proxy.go

@@ -17,6 +17,7 @@ import (
 	log "github.com/sirupsen/logrus"
 
 	nberrors "github.com/netbirdio/netbird/client/errors"
+	"github.com/netbirdio/netbird/client/iface/bufsize"
 	"github.com/netbirdio/netbird/client/internal/ebpf"
 	ebpfMgr "github.com/netbirdio/netbird/client/internal/ebpf/manager"
 	nbnet "github.com/netbirdio/netbird/util/net"
@@ -29,6 +30,7 @@ const (
 // WGEBPFProxy definition for proxy with EBPF support
 type WGEBPFProxy struct {
 	localWGListenPort int
+	mtu               uint16
 
 	ebpfManager   ebpfMgr.Manager
 	turnConnStore map[uint16]net.Conn
@@ -43,10 +45,11 @@ type WGEBPFProxy struct {
 }
 
 // NewWGEBPFProxy create new WGEBPFProxy instance
-func NewWGEBPFProxy(wgPort int) *WGEBPFProxy {
+func NewWGEBPFProxy(wgPort int, mtu uint16) *WGEBPFProxy {
 	log.Debugf("instantiate ebpf proxy")
 	wgProxy := &WGEBPFProxy{
 		localWGListenPort: wgPort,
+		mtu:               mtu,
 		ebpfManager:       ebpf.GetEbpfManagerInstance(),
 		turnConnStore:     make(map[uint16]net.Conn),
 	}
@@ -138,7 +141,7 @@ func (p *WGEBPFProxy) Free() error {
 // proxyToRemote read messages from local WireGuard interface and forward it to remote conn
 // From this go routine has only one instance.
 func (p *WGEBPFProxy) proxyToRemote() {
-	buf := make([]byte, 1500)
+	buf := make([]byte, p.mtu+bufsize.WGBufferOverhead)
 	for p.ctx.Err() == nil {
 		if err := p.readAndForwardPacket(buf); err != nil {
 			if p.ctx.Err() != nil {

client/iface/wgproxy/ebpf/proxy_test.go

@@ -7,7 +7,7 @@ import (
 )
 
 func TestWGEBPFProxy_connStore(t *testing.T) {
-	wgProxy := NewWGEBPFProxy(1)
+	wgProxy := NewWGEBPFProxy(1, 1280)
 
 	p, _ := wgProxy.storeTurnConn(nil)
 	if p != 1 {
@@ -27,7 +27,7 @@ func TestWGEBPFProxy_connStore(t *testing.T) {
 }
 
 func TestWGEBPFProxy_portCalculation_overflow(t *testing.T) {
-	wgProxy := NewWGEBPFProxy(1)
+	wgProxy := NewWGEBPFProxy(1, 1280)
 
 	_, _ = wgProxy.storeTurnConn(nil)
 	wgProxy.lastUsedPort = 65535
@@ -43,7 +43,7 @@ func TestWGEBPFProxy_portCalculation_overflow(t *testing.T) {
 }
 
 func TestWGEBPFProxy_portCalculation_maxConn(t *testing.T) {
-	wgProxy := NewWGEBPFProxy(1)
+	wgProxy := NewWGEBPFProxy(1, 1280)
 
 	for i := 0; i < 65535; i++ {
 		_, _ = wgProxy.storeTurnConn(nil)

client/iface/wgproxy/ebpf/wrapper.go

@@ -12,6 +12,7 @@ import (
 
 	log "github.com/sirupsen/logrus"
 
+	"github.com/netbirdio/netbird/client/iface/bufsize"
 	"github.com/netbirdio/netbird/client/iface/wgproxy/listener"
 )
 
@@ -103,7 +104,7 @@ func (e *ProxyWrapper) CloseConn() error {
 func (p *ProxyWrapper) proxyToLocal(ctx context.Context) {
 	defer p.WgeBPFProxy.removeTurnConn(uint16(p.wgEndpointAddr.Port))
 
-	buf := make([]byte, 1500)
+	buf := make([]byte, p.WgeBPFProxy.mtu+bufsize.WGBufferOverhead)
 	for {
 		n, err := p.readFromRemote(ctx, buf)
 		if err != nil {

client/iface/wgproxy/factory_kernel.go

@@ -11,16 +11,18 @@ import (
 
 type KernelFactory struct {
 	wgPort int
+	mtu    uint16
 
 	ebpfProxy *ebpf.WGEBPFProxy
 }
 
-func NewKernelFactory(wgPort int) *KernelFactory {
+func NewKernelFactory(wgPort int, mtu uint16) *KernelFactory {
 	f := &KernelFactory{
 		wgPort: wgPort,
+		mtu:    mtu,
 	}
 
-	ebpfProxy := ebpf.NewWGEBPFProxy(wgPort)
+	ebpfProxy := ebpf.NewWGEBPFProxy(wgPort, mtu)
 	if err := ebpfProxy.Listen(); err != nil {
 		log.Infof("WireGuard Proxy Factory will produce UDP proxy")
 		log.Warnf("failed to initialize ebpf proxy, fallback to user space proxy: %s", err)
@@ -33,7 +35,7 @@ func NewKernelFactory(wgPort int) *KernelFactory {
 
 func (w *KernelFactory) GetProxy() Proxy {
 	if w.ebpfProxy == nil {
-		return udpProxy.NewWGUDPProxy(w.wgPort)
+		return udpProxy.NewWGUDPProxy(w.wgPort, w.mtu)
 	}
 
 	return ebpf.NewProxyWrapper(w.ebpfProxy)

client/iface/wgproxy/factory_kernel_freebsd.go

@@ -9,19 +9,21 @@ import (
 // KernelFactory todo: check eBPF support on FreeBSD
 type KernelFactory struct {
 	wgPort int
+	mtu    uint16
 }
 
-func NewKernelFactory(wgPort int) *KernelFactory {
+func NewKernelFactory(wgPort int, mtu uint16) *KernelFactory {
 	log.Infof("WireGuard Proxy Factory will produce UDP proxy")
 	f := &KernelFactory{
 		wgPort: wgPort,
+		mtu:    mtu,
 	}
 
 	return f
 }
 
 func (w *KernelFactory) GetProxy() Proxy {
-	return udpProxy.NewWGUDPProxy(w.wgPort)
+	return udpProxy.NewWGUDPProxy(w.wgPort, w.mtu)
 }
 
 func (w *KernelFactory) Free() error {

client/iface/wgproxy/proxy_linux_test.go

@@ -16,7 +16,7 @@ func TestProxyCloseByRemoteConnEBPF(t *testing.T) {
 	}
 	ctx := context.Background()
 
-	ebpfProxy := ebpf.NewWGEBPFProxy(51831)
+	ebpfProxy := ebpf.NewWGEBPFProxy(51831, 1280)
 	if err := ebpfProxy.Listen(); err != nil {
 		t.Fatalf("failed to initialize ebpf proxy: %s", err)
 	}

client/iface/wgproxy/proxy_test.go

@@ -84,12 +84,12 @@ func TestProxyCloseByRemoteConn(t *testing.T) {
 	}{
 		{
 			name:  "userspace proxy",
-			proxy: udpProxy.NewWGUDPProxy(51830),
+			proxy: udpProxy.NewWGUDPProxy(51830, 1280),
 		},
 	}
 
 	if runtime.GOOS == "linux" && os.Getenv("GITHUB_ACTIONS") != "true" {
-		ebpfProxy := ebpf.NewWGEBPFProxy(51831)
+		ebpfProxy := ebpf.NewWGEBPFProxy(51831, 1280)
 		if err := ebpfProxy.Listen(); err != nil {
 			t.Fatalf("failed to initialize ebpf proxy: %s", err)
 		}

client/iface/wgproxy/udp/proxy.go

@@ -12,12 +12,14 @@ import (
 	log "github.com/sirupsen/logrus"
 
 	cerrors "github.com/netbirdio/netbird/client/errors"
+	"github.com/netbirdio/netbird/client/iface/bufsize"
 	"github.com/netbirdio/netbird/client/iface/wgproxy/listener"
 )
 
 // WGUDPProxy proxies
 type WGUDPProxy struct {
 	localWGListenPort int
+	mtu               uint16
 
 	remoteConn net.Conn
 	localConn  net.Conn
@@ -34,10 +36,11 @@ type WGUDPProxy struct {
 }
 
 // NewWGUDPProxy instantiate a UDP based WireGuard proxy. This is not a thread safe implementation
-func NewWGUDPProxy(wgPort int) *WGUDPProxy {
+func NewWGUDPProxy(wgPort int, mtu uint16) *WGUDPProxy {
 	log.Debugf("Initializing new user space proxy with port %d", wgPort)
 	p := &WGUDPProxy{
 		localWGListenPort: wgPort,
+		mtu:               mtu,
 		closeListener:     listener.NewCloseListener(),
 	}
 	return p
@@ -144,7 +147,7 @@ func (p *WGUDPProxy) proxyToRemote(ctx context.Context) {
 		}
 	}()
 
-	buf := make([]byte, 1500)
+	buf := make([]byte, p.mtu+bufsize.WGBufferOverhead)
 	for ctx.Err() == nil {
 		n, err := p.localConn.Read(buf)
 		if err != nil {
@@ -179,7 +182,7 @@ func (p *WGUDPProxy) proxyToLocal(ctx context.Context) {
 		}
 	}()
 
-	buf := make([]byte, 1500)
+	buf := make([]byte, p.mtu+bufsize.WGBufferOverhead)
 	for {
 		n, err := p.remoteConnRead(ctx, buf)
 		if err != nil {

client/internal/auth/device_flow_test.go

@@ -3,15 +3,17 @@ package auth
 import (
 	"context"
 	"fmt"
-	"github.com/golang-jwt/jwt"
-	"github.com/netbirdio/netbird/client/internal"
-	"github.com/stretchr/testify/require"
 	"io"
 	"net/http"
 	"net/url"
 	"strings"
 	"testing"
 	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+	"github.com/stretchr/testify/require"
+
+	"github.com/netbirdio/netbird/client/internal"
 )
 
 type mockHTTPClient struct {

client/internal/connect.go

@@ -18,6 +18,7 @@ import (
 	"google.golang.org/grpc/codes"
 	gstatus "google.golang.org/grpc/status"
 
+	"github.com/netbirdio/netbird/client/iface"
 	"github.com/netbirdio/netbird/client/iface/device"
 	"github.com/netbirdio/netbird/client/internal/dns"
 	"github.com/netbirdio/netbird/client/internal/listener"
@@ -244,7 +245,15 @@ func (c *ConnectClient) run(mobileDependency MobileDependency, runningChan chan
 		c.statusRecorder.MarkSignalConnected()
 
 		relayURLs, token := parseRelayInfo(loginResp)
-		relayManager := relayClient.NewManager(engineCtx, relayURLs, myPrivateKey.PublicKey().String())
+		peerConfig := loginResp.GetPeerConfig()
+
+		engineConfig, err := createEngineConfig(myPrivateKey, c.config, peerConfig)
+		if err != nil {
+			log.Error(err)
+			return wrapErr(err)
+		}
+
+		relayManager := relayClient.NewManager(engineCtx, relayURLs, myPrivateKey.PublicKey().String(), engineConfig.MTU)
 		c.statusRecorder.SetRelayMgr(relayManager)
 		if len(relayURLs) > 0 {
 			if token != nil {
@@ -259,14 +268,6 @@ func (c *ConnectClient) run(mobileDependency MobileDependency, runningChan chan
 			}
 		}
 
-		peerConfig := loginResp.GetPeerConfig()
-
-		engineConfig, err := createEngineConfig(myPrivateKey, c.config, peerConfig)
-		if err != nil {
-			log.Error(err)
-			return wrapErr(err)
-		}
-
 		checks := loginResp.GetChecks()
 
 		c.engineMutex.Lock()
@@ -444,6 +445,8 @@ func createEngineConfig(key wgtypes.Key, config *profilemanager.Config, peerConf
 		BlockInbound:        config.BlockInbound,
 
 		LazyConnectionEnabled: config.LazyConnectionEnabled,
+
+		MTU: selectMTU(config.MTU, peerConfig.Mtu),
 	}
 
 	if config.PreSharedKey != "" {
@@ -466,6 +469,20 @@ func createEngineConfig(key wgtypes.Key, config *profilemanager.Config, peerConf
 	return engineConf, nil
 }
 
+func selectMTU(localMTU uint16, peerMTU int32) uint16 {
+	var finalMTU uint16 = iface.DefaultMTU
+	if localMTU > 0 {
+		finalMTU = localMTU
+	} else if peerMTU > 0 {
+		finalMTU = uint16(peerMTU)
+	}
+
+	// Set global DNS MTU
+	dns.SetCurrentMTU(finalMTU)
+
+	return finalMTU
+}
+
 // connectToSignal creates Signal Service client and established a connection
 func connectToSignal(ctx context.Context, wtConfig *mgmProto.NetbirdConfig, ourPrivateKey wgtypes.Key) (*signal.GrpcClient, error) {
 	var sigTLSEnabled bool

client/internal/dns/file_parser_unix_test.go

@@ -176,4 +176,3 @@ nameserver 192.168.0.1
 		t.Errorf("unexpected resolv.conf content: %v", cfg)
 	}
 }
-

client/internal/dns/host_darwin.go

@@ -166,9 +166,10 @@ func (s *systemConfigurator) removeKeyFromSystemConfig(key string) error {
 
 func (s *systemConfigurator) addLocalDNS() error {
 	if !s.systemDNSSettings.ServerIP.IsValid() || len(s.systemDNSSettings.Domains) == 0 {
-		err := s.recordSystemDNSSettings(true)
-		log.Errorf("Unable to get system DNS configuration")
-		return err
+		if err := s.recordSystemDNSSettings(true); err != nil {
+			log.Errorf("Unable to get system DNS configuration")
+			return fmt.Errorf("recordSystemDNSSettings(): %w", err)
+		}
 	}
 	localKey := getKeyWithInput(netbirdDNSStateKeyFormat, localSuffix)
 	if s.systemDNSSettings.ServerIP.IsValid() && len(s.systemDNSSettings.Domains) != 0 {

client/internal/dns/host_windows.go

@@ -64,9 +64,10 @@ const (
 )
 
 type registryConfigurator struct {
-	guid       string
-	routingAll bool
-	gpo        bool
+	guid           string
+	routingAll     bool
+	gpo            bool
+	nrptEntryCount int
 }
 
 func newHostManager(wgInterface WGIface) (*registryConfigurator, error) {
@@ -177,7 +178,11 @@ func (r *registryConfigurator) applyDNSConfig(config HostDNSConfig, stateManager
 		log.Infof("removed %s as main DNS forwarder for this peer", config.ServerIP)
 	}
 
-	if err := stateManager.UpdateState(&ShutdownState{Guid: r.guid, GPO: r.gpo}); err != nil {
+	if err := stateManager.UpdateState(&ShutdownState{
+		Guid:           r.guid,
+		GPO:            r.gpo,
+		NRPTEntryCount: r.nrptEntryCount,
+	}); err != nil {
 		log.Errorf("failed to update shutdown state: %s", err)
 	}
 
@@ -193,13 +198,24 @@ func (r *registryConfigurator) applyDNSConfig(config HostDNSConfig, stateManager
 	}
 
 	if len(matchDomains) != 0 {
-		if err := r.addDNSMatchPolicy(matchDomains, config.ServerIP); err != nil {
+		count, err := r.addDNSMatchPolicy(matchDomains, config.ServerIP)
+		if err != nil {
 			return fmt.Errorf("add dns match policy: %w", err)
 		}
+		r.nrptEntryCount = count
 	} else {
 		if err := r.removeDNSMatchPolicies(); err != nil {
 			return fmt.Errorf("remove dns match policies: %w", err)
 		}
+		r.nrptEntryCount = 0
+	}
+
+	if err := stateManager.UpdateState(&ShutdownState{
+		Guid:           r.guid,
+		GPO:            r.gpo,
+		NRPTEntryCount: r.nrptEntryCount,
+	}); err != nil {
+		log.Errorf("failed to update shutdown state: %s", err)
 	}
 
 	if err := r.updateSearchDomains(searchDomains); err != nil {
@@ -220,28 +236,34 @@ func (r *registryConfigurator) addDNSSetupForAll(ip netip.Addr) error {
 	return nil
 }
 
-func (r *registryConfigurator) addDNSMatchPolicy(domains []string, ip netip.Addr) error {
+func (r *registryConfigurator) addDNSMatchPolicy(domains []string, ip netip.Addr) (int, error) {
 	// if the gpo key is present, we need to put our DNS settings there, otherwise our config might be ignored
 	// see https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-gpnrpt/8cc31cb9-20cb-4140-9e85-3e08703b4745
-	if r.gpo {
-		if err := r.configureDNSPolicy(gpoDnsPolicyConfigMatchPath, domains, ip); err != nil {
-			return fmt.Errorf("configure GPO DNS policy: %w", err)
+	for i, domain := range domains {
+		policyPath := fmt.Sprintf("%s-%d", dnsPolicyConfigMatchPath, i)
+		if r.gpo {
+			policyPath = fmt.Sprintf("%s-%d", gpoDnsPolicyConfigMatchPath, i)
 		}
 
+		singleDomain := []string{domain}
+
+		if err := r.configureDNSPolicy(policyPath, singleDomain, ip); err != nil {
+			return i, fmt.Errorf("configure DNS policy for domain %s: %w", domain, err)
+		}
+
+		log.Debugf("added NRPT entry for domain: %s", domain)
+	}
+
+	if r.gpo {
 		if err := refreshGroupPolicy(); err != nil {
 			log.Warnf("failed to refresh group policy: %v", err)
 		}
-	} else {
-		if err := r.configureDNSPolicy(dnsPolicyConfigMatchPath, domains, ip); err != nil {
-			return fmt.Errorf("configure local DNS policy: %w", err)
-		}
 	}
 
-	log.Infof("added %d match domains. Domain list: %s", len(domains), domains)
-	return nil
+	log.Infof("added %d separate NRPT entries. Domain list: %s", len(domains), domains)
+	return len(domains), nil
 }
 
-// configureDNSPolicy handles the actual configuration of a DNS policy at the specified path
 func (r *registryConfigurator) configureDNSPolicy(policyPath string, domains []string, ip netip.Addr) error {
 	if err := removeRegistryKeyFromDNSPolicyConfig(policyPath); err != nil {
 		return fmt.Errorf("remove existing dns policy: %w", err)
@@ -374,12 +396,25 @@ func (r *registryConfigurator) restoreHostDNS() error {
 
 func (r *registryConfigurator) removeDNSMatchPolicies() error {
 	var merr *multierror.Error
+
+	// Try to remove the base entries (for backward compatibility)
 	if err := removeRegistryKeyFromDNSPolicyConfig(dnsPolicyConfigMatchPath); err != nil {
-		merr = multierror.Append(merr, fmt.Errorf("remove local registry key: %w", err))
+		merr = multierror.Append(merr, fmt.Errorf("remove local base entry: %w", err))
+	}
+	if err := removeRegistryKeyFromDNSPolicyConfig(gpoDnsPolicyConfigMatchPath); err != nil {
+		merr = multierror.Append(merr, fmt.Errorf("remove GPO base entry: %w", err))
 	}
 
-	if err := removeRegistryKeyFromDNSPolicyConfig(gpoDnsPolicyConfigMatchPath); err != nil {
-		merr = multierror.Append(merr, fmt.Errorf("remove GPO registry key: %w", err))
+	for i := 0; i < r.nrptEntryCount; i++ {
+		localPath := fmt.Sprintf("%s-%d", dnsPolicyConfigMatchPath, i)
+		gpoPath := fmt.Sprintf("%s-%d", gpoDnsPolicyConfigMatchPath, i)
+
+		if err := removeRegistryKeyFromDNSPolicyConfig(localPath); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("remove local entry %d: %w", i, err))
+		}
+		if err := removeRegistryKeyFromDNSPolicyConfig(gpoPath); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("remove GPO entry %d: %w", i, err))
+		}
 	}
 
 	if err := refreshGroupPolicy(); err != nil {

client/internal/dns/server.go

@@ -695,6 +695,12 @@ func (s *DefaultServer) createHandlersForDomainGroup(domainGroup nsGroupsByDomai
 					ns.IP.String(), ns.NSType.String(), nbdns.UDPNameServerType.String())
 				continue
 			}
+
+			if ns.IP == s.service.RuntimeIP() {
+				log.Warnf("skipping nameserver %s as it matches our DNS server IP, preventing potential loop", ns.IP)
+				continue
+			}
+
 			handler.upstreamServers = append(handler.upstreamServers, ns.AddrPort())
 		}
 

client/internal/dns/server_js.go

@@ -0,0 +1,5 @@
+package dns
+
+func (s *DefaultServer) initialize() (hostManager, error) {
+	return &noopHostConfigurator{}, nil
+}

client/internal/dns/server_test.go

@@ -2056,3 +2056,124 @@ func TestLocalResolverPriorityConstants(t *testing.T) {
 	assert.Equal(t, PriorityLocal, localMuxUpdates[0].priority, "Local handler should use PriorityLocal")
 	assert.Equal(t, "local.example.com", localMuxUpdates[0].domain)
 }
+
+func TestDNSLoopPrevention(t *testing.T) {
+	wgInterface := &mocWGIface{}
+	service := NewServiceViaMemory(wgInterface)
+	dnsServerIP := service.RuntimeIP()
+
+	server := &DefaultServer{
+		ctx:           context.Background(),
+		wgInterface:   wgInterface,
+		service:       service,
+		localResolver: local.NewResolver(),
+		handlerChain:  NewHandlerChain(),
+		hostManager:   &noopHostConfigurator{},
+		dnsMuxMap:     make(registeredHandlerMap),
+	}
+
+	tests := []struct {
+		name              string
+		nsGroups          []*nbdns.NameServerGroup
+		expectedHandlers  int
+		expectedServers   []netip.Addr
+		shouldFilterOwnIP bool
+	}{
+		{
+			name: "FilterOwnDNSServerIP",
+			nsGroups: []*nbdns.NameServerGroup{
+				{
+					Primary: true,
+					NameServers: []nbdns.NameServer{
+						{IP: netip.MustParseAddr("8.8.8.8"), NSType: nbdns.UDPNameServerType, Port: 53},
+						{IP: dnsServerIP, NSType: nbdns.UDPNameServerType, Port: 53},
+						{IP: netip.MustParseAddr("1.1.1.1"), NSType: nbdns.UDPNameServerType, Port: 53},
+					},
+					Domains: []string{},
+				},
+			},
+			expectedHandlers:  1,
+			expectedServers:   []netip.Addr{netip.MustParseAddr("8.8.8.8"), netip.MustParseAddr("1.1.1.1")},
+			shouldFilterOwnIP: true,
+		},
+		{
+			name: "AllServersFiltered",
+			nsGroups: []*nbdns.NameServerGroup{
+				{
+					Primary: false,
+					NameServers: []nbdns.NameServer{
+						{IP: dnsServerIP, NSType: nbdns.UDPNameServerType, Port: 53},
+					},
+					Domains: []string{"example.com"},
+				},
+			},
+			expectedHandlers:  0,
+			expectedServers:   []netip.Addr{},
+			shouldFilterOwnIP: true,
+		},
+		{
+			name: "MixedServersWithOwnIP",
+			nsGroups: []*nbdns.NameServerGroup{
+				{
+					Primary: false,
+					NameServers: []nbdns.NameServer{
+						{IP: netip.MustParseAddr("8.8.8.8"), NSType: nbdns.UDPNameServerType, Port: 53},
+						{IP: dnsServerIP, NSType: nbdns.UDPNameServerType, Port: 53},
+						{IP: netip.MustParseAddr("1.1.1.1"), NSType: nbdns.UDPNameServerType, Port: 53},
+						{IP: dnsServerIP, NSType: nbdns.UDPNameServerType, Port: 53}, // duplicate
+					},
+					Domains: []string{"test.com"},
+				},
+			},
+			expectedHandlers:  1,
+			expectedServers:   []netip.Addr{netip.MustParseAddr("8.8.8.8"), netip.MustParseAddr("1.1.1.1")},
+			shouldFilterOwnIP: true,
+		},
+		{
+			name: "NoOwnIPInList",
+			nsGroups: []*nbdns.NameServerGroup{
+				{
+					Primary: true,
+					NameServers: []nbdns.NameServer{
+						{IP: netip.MustParseAddr("8.8.8.8"), NSType: nbdns.UDPNameServerType, Port: 53},
+						{IP: netip.MustParseAddr("1.1.1.1"), NSType: nbdns.UDPNameServerType, Port: 53},
+					},
+					Domains: []string{},
+				},
+			},
+			expectedHandlers:  1,
+			expectedServers:   []netip.Addr{netip.MustParseAddr("8.8.8.8"), netip.MustParseAddr("1.1.1.1")},
+			shouldFilterOwnIP: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			muxUpdates, err := server.buildUpstreamHandlerUpdate(tt.nsGroups)
+			assert.NoError(t, err)
+			assert.Len(t, muxUpdates, tt.expectedHandlers)
+
+			if tt.expectedHandlers > 0 {
+				handler := muxUpdates[0].handler.(*upstreamResolver)
+				assert.Len(t, handler.upstreamServers, len(tt.expectedServers))
+
+				if tt.shouldFilterOwnIP {
+					for _, upstream := range handler.upstreamServers {
+						assert.NotEqual(t, dnsServerIP, upstream.Addr())
+					}
+				}
+
+				for _, expected := range tt.expectedServers {
+					found := false
+					for _, upstream := range handler.upstreamServers {
+						if upstream.Addr() == expected {
+							found = true
+							break
+						}
+					}
+					assert.True(t, found, "Expected server %s not found", expected)
+				}
+			}
+		})
+	}
+}

client/internal/dns/unclean_shutdown_js.go

@@ -0,0 +1,19 @@
+package dns
+
+import (
+	"context"
+)
+
+type ShutdownState struct{}
+
+func (s *ShutdownState) Name() string {
+	return "dns_state"
+}
+
+func (s *ShutdownState) Cleanup() error {
+	return nil
+}
+
+func (s *ShutdownState) RestoreUncleanShutdownConfigs(context.Context) error {
+	return nil
+}

client/internal/dns/unclean_shutdown_windows.go

@@ -5,8 +5,9 @@ import (
 )
 
 type ShutdownState struct {
-	Guid string
-	GPO  bool
+	Guid           string
+	GPO            bool
+	NRPTEntryCount int
 }
 
 func (s *ShutdownState) Name() string {
@@ -15,8 +16,9 @@ func (s *ShutdownState) Name() string {
 
 func (s *ShutdownState) Cleanup() error {
 	manager := &registryConfigurator{
-		guid: s.Guid,
-		gpo:  s.GPO,
+		guid:           s.Guid,
+		gpo:            s.GPO,
+		nrptEntryCount: s.NRPTEntryCount,
 	}
 
 	if err := manager.restoreUncleanShutdownDNS(); err != nil {

client/internal/dns/upstream.go

@@ -26,6 +26,12 @@ import (
 	"github.com/netbirdio/netbird/client/proto"
 )
 
+var currentMTU uint16 = iface.DefaultMTU
+
+func SetCurrentMTU(mtu uint16) {
+	currentMTU = mtu
+}
+
 const (
 	UpstreamTimeout = 15 * time.Second
 
@@ -358,8 +364,8 @@ func (u *upstreamResolverBase) testNameserver(server netip.AddrPort, timeout tim
 // If the passed context is nil, this will use Exchange instead of ExchangeContext.
 func ExchangeWithFallback(ctx context.Context, client *dns.Client, r *dns.Msg, upstream string) (*dns.Msg, time.Duration, error) {
 	// MTU - ip + udp headers
-	// Note: this could be sent out on an interface that is not ours, but our MTU should always be lower.
-	client.UDPSize = iface.DefaultMTU - (60 + 8)
+	// Note: this could be sent out on an interface that is not ours, but higher MTU settings could break truncation handling.
+	client.UDPSize = uint16(currentMTU - (60 + 8))
 
 	var (
 		rm  *dns.Msg

client/internal/dnsfwd/forwarder.go

@@ -165,7 +165,7 @@ func (f *DNSForwarder) handleDNSQuery(w dns.ResponseWriter, query *dns.Msg) *dns
 	defer cancel()
 	ips, err := f.resolver.LookupNetIP(ctx, network, domain)
 	if err != nil {
-		f.handleDNSError(w, query, resp, domain, err)
+		f.handleDNSError(ctx, w, question, resp, domain, err)
 		return nil
 	}
 
@@ -244,20 +244,57 @@ func (f *DNSForwarder) updateFirewall(matchingEntries []*ForwarderEntry, prefixe
 	}
 }
 
+// setResponseCodeForNotFound determines and sets the appropriate response code when IsNotFound is true
+// It distinguishes between NXDOMAIN (domain doesn't exist) and NODATA (domain exists but no records of requested type)
+//
+// LIMITATION: This function only checks A and AAAA record types to determine domain existence.
+// If a domain has only other record types (MX, TXT, CNAME, etc.) but no A/AAAA records,
+// it may incorrectly return NXDOMAIN instead of NODATA. This is acceptable since the forwarder
+// only handles A/AAAA queries and returns NOTIMP for other types.
+func (f *DNSForwarder) setResponseCodeForNotFound(ctx context.Context, resp *dns.Msg, domain string, originalQtype uint16) {
+	// Try querying for a different record type to see if the domain exists
+	// If the original query was for AAAA, try A. If it was for A, try AAAA.
+	// This helps distinguish between NXDOMAIN and NODATA.
+	var alternativeNetwork string
+	switch originalQtype {
+	case dns.TypeAAAA:
+		alternativeNetwork = "ip4"
+	case dns.TypeA:
+		alternativeNetwork = "ip6"
+	default:
+		resp.Rcode = dns.RcodeNameError
+		return
+	}
+
+	if _, err := f.resolver.LookupNetIP(ctx, alternativeNetwork, domain); err != nil {
+		var dnsErr *net.DNSError
+		if errors.As(err, &dnsErr) && dnsErr.IsNotFound {
+			// Alternative query also returned not found - domain truly doesn't exist
+			resp.Rcode = dns.RcodeNameError
+			return
+		}
+		// Some other error (timeout, server failure, etc.) - can't determine, assume domain exists
+		resp.Rcode = dns.RcodeSuccess
+		return
+	}
+
+	// Alternative query succeeded - domain exists but has no records of this type
+	resp.Rcode = dns.RcodeSuccess
+}
+
 // handleDNSError processes DNS lookup errors and sends an appropriate error response
-func (f *DNSForwarder) handleDNSError(w dns.ResponseWriter, query, resp *dns.Msg, domain string, err error) {
+func (f *DNSForwarder) handleDNSError(ctx context.Context, w dns.ResponseWriter, question dns.Question, resp *dns.Msg, domain string, err error) {
 	var dnsErr *net.DNSError
 
 	switch {
 	case errors.As(err, &dnsErr):
 		resp.Rcode = dns.RcodeServerFailure
 		if dnsErr.IsNotFound {
-			// Pass through NXDOMAIN
-			resp.Rcode = dns.RcodeNameError
+			f.setResponseCodeForNotFound(ctx, resp, domain, question.Qtype)
 		}
 
 		if dnsErr.Server != "" {
-			log.Warnf("failed to resolve query for type=%s domain=%s server=%s: %v", dns.TypeToString[query.Question[0].Qtype], domain, dnsErr.Server, err)
+			log.Warnf("failed to resolve query for type=%s domain=%s server=%s: %v", dns.TypeToString[question.Qtype], domain, dnsErr.Server, err)
 		} else {
 			log.Warnf(errResolveFailed, domain, err)
 		}

client/internal/dnsfwd/forwarder_test.go

@@ -3,6 +3,7 @@ package dnsfwd
 import (
 	"context"
 	"fmt"
+	"net"
 	"net/netip"
 	"strings"
 	"testing"
@@ -16,8 +17,8 @@ import (
 	firewall "github.com/netbirdio/netbird/client/firewall/manager"
 	"github.com/netbirdio/netbird/client/internal/dns/test"
 	"github.com/netbirdio/netbird/client/internal/peer"
-	"github.com/netbirdio/netbird/shared/management/domain"
 	"github.com/netbirdio/netbird/route"
+	"github.com/netbirdio/netbird/shared/management/domain"
 )
 
 func Test_getMatchingEntries(t *testing.T) {
@@ -708,6 +709,131 @@ func TestDNSForwarder_MultipleOverlappingPatterns(t *testing.T) {
 	assert.Len(t, matches, 3, "Should match 3 patterns")
 }
 
+// TestDNSForwarder_NodataVsNxdomain tests that the forwarder correctly distinguishes
+// between NXDOMAIN (domain doesn't exist) and NODATA (domain exists but no records of that type)
+func TestDNSForwarder_NodataVsNxdomain(t *testing.T) {
+	mockFirewall := &MockFirewall{}
+	mockResolver := &MockResolver{}
+
+	forwarder := NewDNSForwarder("127.0.0.1:0", 300, mockFirewall, &peer.Status{})
+	forwarder.resolver = mockResolver
+
+	d, err := domain.FromString("example.com")
+	require.NoError(t, err)
+
+	set := firewall.NewDomainSet([]domain.Domain{d})
+	entries := []*ForwarderEntry{{Domain: d, ResID: "test-res", Set: set}}
+	forwarder.UpdateDomains(entries)
+
+	tests := []struct {
+		name           string
+		queryType      uint16
+		setupMocks     func()
+		expectedCode   int
+		expectNoAnswer bool // true if we expect NOERROR with empty answer (NODATA case)
+		description    string
+	}{
+		{
+			name:      "domain exists but no AAAA records (NODATA)",
+			queryType: dns.TypeAAAA,
+			setupMocks: func() {
+				// First query for AAAA returns not found
+				mockResolver.On("LookupNetIP", mock.Anything, "ip6", "example.com.").
+					Return([]netip.Addr{}, &net.DNSError{IsNotFound: true, Name: "example.com"}).Once()
+				// Check query for A records succeeds (domain exists)
+				mockResolver.On("LookupNetIP", mock.Anything, "ip4", "example.com.").
+					Return([]netip.Addr{netip.MustParseAddr("1.2.3.4")}, nil).Once()
+			},
+			expectedCode:   dns.RcodeSuccess,
+			expectNoAnswer: true,
+			description:    "Should return NOERROR when domain exists but has no records of requested type",
+		},
+		{
+			name:      "domain exists but no A records (NODATA)",
+			queryType: dns.TypeA,
+			setupMocks: func() {
+				// First query for A returns not found
+				mockResolver.On("LookupNetIP", mock.Anything, "ip4", "example.com.").
+					Return([]netip.Addr{}, &net.DNSError{IsNotFound: true, Name: "example.com"}).Once()
+				// Check query for AAAA records succeeds (domain exists)
+				mockResolver.On("LookupNetIP", mock.Anything, "ip6", "example.com.").
+					Return([]netip.Addr{netip.MustParseAddr("2001:db8::1")}, nil).Once()
+			},
+			expectedCode:   dns.RcodeSuccess,
+			expectNoAnswer: true,
+			description:    "Should return NOERROR when domain exists but has no A records",
+		},
+		{
+			name:      "domain doesn't exist (NXDOMAIN)",
+			queryType: dns.TypeA,
+			setupMocks: func() {
+				// First query for A returns not found
+				mockResolver.On("LookupNetIP", mock.Anything, "ip4", "example.com.").
+					Return([]netip.Addr{}, &net.DNSError{IsNotFound: true, Name: "example.com"}).Once()
+				// Check query for AAAA also returns not found (domain doesn't exist)
+				mockResolver.On("LookupNetIP", mock.Anything, "ip6", "example.com.").
+					Return([]netip.Addr{}, &net.DNSError{IsNotFound: true, Name: "example.com"}).Once()
+			},
+			expectedCode:   dns.RcodeNameError,
+			expectNoAnswer: true,
+			description:    "Should return NXDOMAIN when domain doesn't exist at all",
+		},
+		{
+			name:      "domain exists with records (normal success)",
+			queryType: dns.TypeA,
+			setupMocks: func() {
+				mockResolver.On("LookupNetIP", mock.Anything, "ip4", "example.com.").
+					Return([]netip.Addr{netip.MustParseAddr("1.2.3.4")}, nil).Once()
+				// Expect firewall update for successful resolution
+				expectedPrefix := netip.PrefixFrom(netip.MustParseAddr("1.2.3.4"), 32)
+				mockFirewall.On("UpdateSet", set, []netip.Prefix{expectedPrefix}).Return(nil).Once()
+			},
+			expectedCode:   dns.RcodeSuccess,
+			expectNoAnswer: false,
+			description:    "Should return NOERROR with answer when records exist",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Reset mock expectations
+			mockResolver.ExpectedCalls = nil
+			mockResolver.Calls = nil
+			mockFirewall.ExpectedCalls = nil
+			mockFirewall.Calls = nil
+
+			tt.setupMocks()
+
+			query := &dns.Msg{}
+			query.SetQuestion(dns.Fqdn("example.com"), tt.queryType)
+
+			var writtenResp *dns.Msg
+			mockWriter := &test.MockResponseWriter{
+				WriteMsgFunc: func(m *dns.Msg) error {
+					writtenResp = m
+					return nil
+				},
+			}
+
+			resp := forwarder.handleDNSQuery(mockWriter, query)
+
+			// If a response was returned, it means it should be written (happens in wrapper functions)
+			if resp != nil && writtenResp == nil {
+				writtenResp = resp
+			}
+
+			require.NotNil(t, writtenResp, "Expected response to be written")
+			assert.Equal(t, tt.expectedCode, writtenResp.Rcode, tt.description)
+
+			if tt.expectNoAnswer {
+				assert.Empty(t, writtenResp.Answer, "Response should have no answer records")
+			}
+
+			mockResolver.AssertExpectations(t)
+		})
+	}
+}
+
 func TestDNSForwarder_EmptyQuery(t *testing.T) {
 	// Test handling of malformed query with no questions
 	forwarder := NewDNSForwarder("127.0.0.1:0", 300, nil, &peer.Status{})

client/internal/engine.go

@@ -55,11 +55,11 @@ import (
 	nbssh "github.com/netbirdio/netbird/client/ssh"
 	"github.com/netbirdio/netbird/client/system"
 	nbdns "github.com/netbirdio/netbird/dns"
+	"github.com/netbirdio/netbird/route"
 	mgm "github.com/netbirdio/netbird/shared/management/client"
 	mgmProto "github.com/netbirdio/netbird/shared/management/proto"
 	auth "github.com/netbirdio/netbird/shared/relay/auth/hmac"
 	relayClient "github.com/netbirdio/netbird/shared/relay/client"
-	"github.com/netbirdio/netbird/route"
 	signal "github.com/netbirdio/netbird/shared/signal/client"
 	sProto "github.com/netbirdio/netbird/shared/signal/proto"
 	"github.com/netbirdio/netbird/util"
@@ -125,6 +125,8 @@ type EngineConfig struct {
 	BlockInbound        bool
 
 	LazyConnectionEnabled bool
+
+	MTU uint16
 }
 
 // Engine is a mechanism responsible for reacting on Signal and Management stream events and managing connections to the remote peers.
@@ -254,6 +256,7 @@ func NewEngine(
 	}
 	engine.stateManager = statemanager.New(path)
 
+	log.Infof("I am: %s", config.WgPrivateKey.PublicKey().String())
 	return engine
 }
 
@@ -346,6 +349,10 @@ func (e *Engine) Start() error {
 	e.syncMsgMux.Lock()
 	defer e.syncMsgMux.Unlock()
 
+	if err := iface.ValidateMTU(e.config.MTU); err != nil {
+		return fmt.Errorf("invalid MTU configuration: %w", err)
+	}
+
 	if e.cancel != nil {
 		e.cancel()
 	}
@@ -443,14 +450,7 @@ func (e *Engine) Start() error {
 		return fmt.Errorf("initialize dns server: %w", err)
 	}
 
-	iceCfg := icemaker.Config{
-		StunTurn:             &e.stunTurn,
-		InterfaceBlackList:   e.config.IFaceBlackList,
-		DisableIPv6Discovery: e.config.DisableIPv6Discovery,
-		UDPMux:               e.udpMux.UDPMuxDefault,
-		UDPMuxSrflx:          e.udpMux,
-		NATExternalIPs:       e.parseNATExternalIPMappings(),
-	}
+	iceCfg := e.createICEConfig()
 
 	e.connMgr = NewConnMgr(e.config, e.statusRecorder, e.peerStore, wgIface)
 	e.connMgr.Start(e.ctx)
@@ -1110,15 +1110,16 @@ func toRoutes(protoRoutes []*mgmProto.Route) []*route.Route {
 		}
 
 		convertedRoute := &route.Route{
-			ID:          route.ID(protoRoute.ID),
-			Network:     prefix.Masked(),
-			Domains:     domain.FromPunycodeList(protoRoute.Domains),
-			NetID:       route.NetID(protoRoute.NetID),
-			NetworkType: route.NetworkType(protoRoute.NetworkType),
-			Peer:        protoRoute.Peer,
-			Metric:      int(protoRoute.Metric),
-			Masquerade:  protoRoute.Masquerade,
-			KeepRoute:   protoRoute.KeepRoute,
+			ID:            route.ID(protoRoute.ID),
+			Network:       prefix.Masked(),
+			Domains:       domain.FromPunycodeList(protoRoute.Domains),
+			NetID:         route.NetID(protoRoute.NetID),
+			NetworkType:   route.NetworkType(protoRoute.NetworkType),
+			Peer:          protoRoute.Peer,
+			Metric:        int(protoRoute.Metric),
+			Masquerade:    protoRoute.Masquerade,
+			KeepRoute:     protoRoute.KeepRoute,
+			SkipAutoApply: protoRoute.SkipAutoApply,
 		}
 		routes = append(routes, convertedRoute)
 	}
@@ -1280,14 +1281,7 @@ func (e *Engine) createPeerConn(pubKey string, allowedIPs []netip.Prefix, agentV
 			Addr:           e.getRosenpassAddr(),
 			PermissiveMode: e.config.RosenpassPermissive,
 		},
-		ICEConfig: icemaker.Config{
-			StunTurn:             &e.stunTurn,
-			InterfaceBlackList:   e.config.IFaceBlackList,
-			DisableIPv6Discovery: e.config.DisableIPv6Discovery,
-			UDPMux:               e.udpMux.UDPMuxDefault,
-			UDPMuxSrflx:          e.udpMux,
-			NATExternalIPs:       e.parseNATExternalIPMappings(),
-		},
+		ICEConfig: e.createICEConfig(),
 	}
 
 	serviceDependencies := peer.ServiceDependencies{
@@ -1330,52 +1324,17 @@ func (e *Engine) receiveSignalEvents() {
 			}
 
 			switch msg.GetBody().Type {
-			case sProto.Body_OFFER:
-				remoteCred, err := signal.UnMarshalCredential(msg)
+			case sProto.Body_OFFER, sProto.Body_ANSWER:
+				offerAnswer, err := convertToOfferAnswer(msg)
 				if err != nil {
 					return err
 				}
 
-				var rosenpassPubKey []byte
-				rosenpassAddr := ""
-				if msg.GetBody().GetRosenpassConfig() != nil {
-					rosenpassPubKey = msg.GetBody().GetRosenpassConfig().GetRosenpassPubKey()
-					rosenpassAddr = msg.GetBody().GetRosenpassConfig().GetRosenpassServerAddr()
+				if msg.Body.Type == sProto.Body_OFFER {
+					conn.OnRemoteOffer(*offerAnswer)
+				} else {
+					conn.OnRemoteAnswer(*offerAnswer)
 				}
-				conn.OnRemoteOffer(peer.OfferAnswer{
-					IceCredentials: peer.IceCredentials{
-						UFrag: remoteCred.UFrag,
-						Pwd:   remoteCred.Pwd,
-					},
-					WgListenPort:    int(msg.GetBody().GetWgListenPort()),
-					Version:         msg.GetBody().GetNetBirdVersion(),
-					RosenpassPubKey: rosenpassPubKey,
-					RosenpassAddr:   rosenpassAddr,
-					RelaySrvAddress: msg.GetBody().GetRelayServerAddress(),
-				})
-			case sProto.Body_ANSWER:
-				remoteCred, err := signal.UnMarshalCredential(msg)
-				if err != nil {
-					return err
-				}
-
-				var rosenpassPubKey []byte
-				rosenpassAddr := ""
-				if msg.GetBody().GetRosenpassConfig() != nil {
-					rosenpassPubKey = msg.GetBody().GetRosenpassConfig().GetRosenpassPubKey()
-					rosenpassAddr = msg.GetBody().GetRosenpassConfig().GetRosenpassServerAddr()
-				}
-				conn.OnRemoteAnswer(peer.OfferAnswer{
-					IceCredentials: peer.IceCredentials{
-						UFrag: remoteCred.UFrag,
-						Pwd:   remoteCred.Pwd,
-					},
-					WgListenPort:    int(msg.GetBody().GetWgListenPort()),
-					Version:         msg.GetBody().GetNetBirdVersion(),
-					RosenpassPubKey: rosenpassPubKey,
-					RosenpassAddr:   rosenpassAddr,
-					RelaySrvAddress: msg.GetBody().GetRelayServerAddress(),
-				})
 			case sProto.Body_CANDIDATE:
 				candidate, err := ice.UnmarshalCandidate(msg.GetBody().Payload)
 				if err != nil {
@@ -1525,7 +1484,7 @@ func (e *Engine) newWgIface() (*iface.WGIface, error) {
 		Address:      e.config.WgAddr,
 		WGPort:       e.config.WgPort,
 		WGPrivKey:    e.config.WgPrivateKey.String(),
-		MTU:          iface.DefaultMTU,
+		MTU:          e.config.MTU,
 		TransportNet: transportNet,
 		FilterFn:     e.addrViaRoutes,
 		DisableDNS:   e.config.DisableDNS,
@@ -2073,3 +2032,44 @@ func createFile(path string) error {
 	}
 	return file.Close()
 }
+
+func convertToOfferAnswer(msg *sProto.Message) (*peer.OfferAnswer, error) {
+	remoteCred, err := signal.UnMarshalCredential(msg)
+	if err != nil {
+		return nil, err
+	}
+
+	var (
+		rosenpassPubKey []byte
+		rosenpassAddr   string
+	)
+	if cfg := msg.GetBody().GetRosenpassConfig(); cfg != nil {
+		rosenpassPubKey = cfg.GetRosenpassPubKey()
+		rosenpassAddr = cfg.GetRosenpassServerAddr()
+	}
+
+	// Handle optional SessionID
+	var sessionID *peer.ICESessionID
+	if sessionBytes := msg.GetBody().GetSessionId(); sessionBytes != nil {
+		if id, err := peer.ICESessionIDFromBytes(sessionBytes); err != nil {
+			log.Warnf("Invalid session ID in message: %v", err)
+			sessionID = nil // Set to nil if conversion fails
+		} else {
+			sessionID = &id
+		}
+	}
+
+	offerAnswer := peer.OfferAnswer{
+		IceCredentials: peer.IceCredentials{
+			UFrag: remoteCred.UFrag,
+			Pwd:   remoteCred.Pwd,
+		},
+		WgListenPort:    int(msg.GetBody().GetWgListenPort()),
+		Version:         msg.GetBody().GetNetBirdVersion(),
+		RosenpassPubKey: rosenpassPubKey,
+		RosenpassAddr:   rosenpassAddr,
+		RelaySrvAddress: msg.GetBody().GetRelayServerAddress(),
+		SessionID:       sessionID,
+	}
+	return &offerAnswer, nil
+}

client/internal/engine_generic.go

@@ -0,0 +1,19 @@
+//go:build !js
+
+package internal
+
+import (
+	icemaker "github.com/netbirdio/netbird/client/internal/peer/ice"
+)
+
+// createICEConfig creates ICE configuration for non-WASM environments
+func (e *Engine) createICEConfig() icemaker.Config {
+	return icemaker.Config{
+		StunTurn:             &e.stunTurn,
+		InterfaceBlackList:   e.config.IFaceBlackList,
+		DisableIPv6Discovery: e.config.DisableIPv6Discovery,
+		UDPMux:               e.udpMux.UDPMuxDefault,
+		UDPMuxSrflx:          e.udpMux,
+		NATExternalIPs:       e.parseNATExternalIPMappings(),
+	}
+}

client/internal/engine_js.go

@@ -0,0 +1,24 @@
+//go:build js
+
+package internal
+
+import (
+	icemaker "github.com/netbirdio/netbird/client/internal/peer/ice"
+)
+
+// createICEConfig creates ICE configuration for WASM environment.
+func (e *Engine) createICEConfig() icemaker.Config {
+	cfg := icemaker.Config{
+		StunTurn:             &e.stunTurn,
+		InterfaceBlackList:   e.config.IFaceBlackList,
+		DisableIPv6Discovery: e.config.DisableIPv6Discovery,
+		NATExternalIPs:       e.parseNATExternalIPMappings(),
+	}
+
+	if e.udpMux != nil {
+		cfg.UDPMux = e.udpMux.UDPMuxDefault
+		cfg.UDPMuxSrflx = e.udpMux
+	}
+
+	return cfg
+}

client/internal/engine_test.go

@@ -27,6 +27,8 @@ import (
 	"golang.zx2c4.com/wireguard/tun/netstack"
 
 	"github.com/netbirdio/management-integrations/integrations"
+	"github.com/netbirdio/netbird/management/internals/server/config"
+	"github.com/netbirdio/netbird/management/server/groups"
 
 	"github.com/netbirdio/netbird/client/iface"
 	"github.com/netbirdio/netbird/client/iface/bind"
@@ -43,8 +45,6 @@ import (
 	"github.com/netbirdio/netbird/client/ssh"
 	"github.com/netbirdio/netbird/client/system"
 	nbdns "github.com/netbirdio/netbird/dns"
-	mgmt "github.com/netbirdio/netbird/shared/management/client"
-	mgmtProto "github.com/netbirdio/netbird/shared/management/proto"
 	"github.com/netbirdio/netbird/management/server"
 	"github.com/netbirdio/netbird/management/server/activity"
 	"github.com/netbirdio/netbird/management/server/integrations/port_forwarding"
@@ -54,8 +54,10 @@ import (
 	"github.com/netbirdio/netbird/management/server/telemetry"
 	"github.com/netbirdio/netbird/management/server/types"
 	"github.com/netbirdio/netbird/monotime"
-	relayClient "github.com/netbirdio/netbird/shared/relay/client"
 	"github.com/netbirdio/netbird/route"
+	mgmt "github.com/netbirdio/netbird/shared/management/client"
+	mgmtProto "github.com/netbirdio/netbird/shared/management/proto"
+	relayClient "github.com/netbirdio/netbird/shared/relay/client"
 	signal "github.com/netbirdio/netbird/shared/signal/client"
 	"github.com/netbirdio/netbird/shared/signal/proto"
 	signalServer "github.com/netbirdio/netbird/signal/server"
@@ -216,7 +218,7 @@ func TestEngine_SSH(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
-	relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String())
+	relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String(), iface.DefaultMTU)
 	engine := NewEngine(
 		ctx, cancel,
 		&signal.MockClient{},
@@ -228,6 +230,7 @@ func TestEngine_SSH(t *testing.T) {
 			WgPrivateKey:     key,
 			WgPort:           33100,
 			ServerSSHAllowed: true,
+			MTU:              iface.DefaultMTU,
 		},
 		MobileDependency{},
 		peer.NewRecorder("https://mgm"),
@@ -361,7 +364,7 @@ func TestEngine_UpdateNetworkMap(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
-	relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String())
+	relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String(), iface.DefaultMTU)
 	engine := NewEngine(
 		ctx, cancel,
 		&signal.MockClient{},
@@ -372,6 +375,7 @@ func TestEngine_UpdateNetworkMap(t *testing.T) {
 			WgAddr:       "100.64.0.1/24",
 			WgPrivateKey: key,
 			WgPort:       33100,
+			MTU:          iface.DefaultMTU,
 		},
 		MobileDependency{},
 		peer.NewRecorder("https://mgm"),
@@ -410,7 +414,7 @@ func TestEngine_UpdateNetworkMap(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	engine.udpMux = bind.NewUniversalUDPMuxDefault(bind.UniversalUDPMuxParams{UDPConn: conn})
+	engine.udpMux = bind.NewUniversalUDPMuxDefault(bind.UniversalUDPMuxParams{UDPConn: conn, MTU: 1280})
 	engine.ctx = ctx
 	engine.srWatcher = guard.NewSRWatcher(nil, nil, nil, icemaker.Config{})
 	engine.connMgr = NewConnMgr(engine.config, engine.statusRecorder, engine.peerStore, wgIface)
@@ -587,12 +591,13 @@ func TestEngine_Sync(t *testing.T) {
 		}
 		return nil
 	}
-	relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String())
+	relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String(), iface.DefaultMTU)
 	engine := NewEngine(ctx, cancel, &signal.MockClient{}, &mgmt.MockClient{SyncFunc: syncFunc}, relayMgr, &EngineConfig{
 		WgIfaceName:  "utun103",
 		WgAddr:       "100.64.0.1/24",
 		WgPrivateKey: key,
 		WgPort:       33100,
+		MTU:          iface.DefaultMTU,
 	}, MobileDependency{}, peer.NewRecorder("https://mgm"), nil)
 	engine.ctx = ctx
 
@@ -751,12 +756,13 @@ func TestEngine_UpdateNetworkMapWithRoutes(t *testing.T) {
 			wgIfaceName := fmt.Sprintf("utun%d", 104+n)
 			wgAddr := fmt.Sprintf("100.66.%d.1/24", n)
 
-			relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String())
+			relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String(), iface.DefaultMTU)
 			engine := NewEngine(ctx, cancel, &signal.MockClient{}, &mgmt.MockClient{}, relayMgr, &EngineConfig{
 				WgIfaceName:  wgIfaceName,
 				WgAddr:       wgAddr,
 				WgPrivateKey: key,
 				WgPort:       33100,
+				MTU:          iface.DefaultMTU,
 			}, MobileDependency{}, peer.NewRecorder("https://mgm"), nil)
 			engine.ctx = ctx
 			newNet, err := stdnet.NewNet()
@@ -952,12 +958,13 @@ func TestEngine_UpdateNetworkMapWithDNSUpdate(t *testing.T) {
 			wgIfaceName := fmt.Sprintf("utun%d", 104+n)
 			wgAddr := fmt.Sprintf("100.66.%d.1/24", n)
 
-			relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String())
+			relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String(), iface.DefaultMTU)
 			engine := NewEngine(ctx, cancel, &signal.MockClient{}, &mgmt.MockClient{}, relayMgr, &EngineConfig{
 				WgIfaceName:  wgIfaceName,
 				WgAddr:       wgAddr,
 				WgPrivateKey: key,
 				WgPort:       33100,
+				MTU:          iface.DefaultMTU,
 			}, MobileDependency{}, peer.NewRecorder("https://mgm"), nil)
 			engine.ctx = ctx
 
@@ -1179,6 +1186,7 @@ func Test_ParseNATExternalIPMappings(t *testing.T) {
 				config: &EngineConfig{
 					IFaceBlackList: testCase.inputBlacklistInterface,
 					NATExternalIPs: testCase.inputMapList,
+					MTU:            iface.DefaultMTU,
 				},
 			}
 			parsedList := engine.parseNATExternalIPMappings()
@@ -1479,9 +1487,10 @@ func createEngine(ctx context.Context, cancel context.CancelFunc, setupKey strin
 		WgAddr:       resp.PeerConfig.Address,
 		WgPrivateKey: key,
 		WgPort:       wgPort,
+		MTU:          iface.DefaultMTU,
 	}
 
-	relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String())
+	relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String(), iface.DefaultMTU)
 	e, err := NewEngine(ctx, cancel, signalClient, mgmtClient, relayMgr, conf, MobileDependency{}, peer.NewRecorder("https://mgm"), nil), nil
 	e.ctx = ctx
 	return e, err
@@ -1513,15 +1522,15 @@ func startSignal(t *testing.T) (*grpc.Server, string, error) {
 func startManagement(t *testing.T, dataDir, testFile string) (*grpc.Server, string, error) {
 	t.Helper()
 
-	config := &types.Config{
-		Stuns:      []*types.Host{},
-		TURNConfig: &types.TURNConfig{},
-		Relay: &types.Relay{
+	config := &config.Config{
+		Stuns:      []*config.Host{},
+		TURNConfig: &config.TURNConfig{},
+		Relay: &config.Relay{
 			Addresses:      []string{"127.0.0.1:1234"},
 			CredentialsTTL: util.Duration{Duration: time.Hour},
 			Secret:         "222222222222222222",
 		},
-		Signal: &types.Host{
+		Signal: &config.Host{
 			Proto: "http",
 			URI:   "localhost:10000",
 		},
@@ -1564,13 +1573,14 @@ func startManagement(t *testing.T, dataDir, testFile string) (*grpc.Server, stri
 		AnyTimes()
 
 	permissionsManager := permissions.NewManager(store)
+	groupsManager := groups.NewManagerMock()
 
 	accountManager, err := server.BuildManager(context.Background(), store, peersUpdateManager, nil, "", "netbird.selfhosted", eventStore, nil, false, ia, metrics, port_forwarding.NewControllerMock(), settingsMockManager, permissionsManager, false)
 	if err != nil {
 		return nil, "", err
 	}
 
-	secretsManager := server.NewTimeBasedAuthSecretsManager(peersUpdateManager, config.TURNConfig, config.Relay, settingsMockManager)
+	secretsManager := server.NewTimeBasedAuthSecretsManager(peersUpdateManager, config.TURNConfig, config.Relay, settingsMockManager, groupsManager)
 	mgmtServer, err := server.NewServer(context.Background(), config, accountManager, settingsMockManager, peersUpdateManager, secretsManager, nil, nil, nil, &server.MockIntegratedValidator{})
 	if err != nil {
 		return nil, "", err

client/internal/networkmonitor/check_change_js.go

@@ -0,0 +1,12 @@
+package networkmonitor
+
+import (
+	"context"
+
+	"github.com/netbirdio/netbird/client/internal/routemanager/systemops"
+)
+
+func checkChange(ctx context.Context, nexthopv4, nexthopv6 systemops.Nexthop) error {
+	// No-op for WASM - network changes don't apply
+	return nil
+}

client/internal/peer/conn.go

@@ -24,8 +24,8 @@ import (
 	"github.com/netbirdio/netbird/client/internal/peer/id"
 	"github.com/netbirdio/netbird/client/internal/peer/worker"
 	"github.com/netbirdio/netbird/client/internal/stdnet"
-	relayClient "github.com/netbirdio/netbird/shared/relay/client"
 	"github.com/netbirdio/netbird/route"
+	relayClient "github.com/netbirdio/netbird/shared/relay/client"
 	semaphoregroup "github.com/netbirdio/netbird/util/semaphore-group"
 )
 
@@ -200,19 +200,11 @@ func (conn *Conn) Open(engineCtx context.Context) error {
 	conn.wg.Add(1)
 	go func() {
 		defer conn.wg.Done()
+
 		conn.waitInitialRandomSleepTime(conn.ctx)
 		conn.semaphore.Done(conn.ctx)
 
-		conn.dumpState.SendOffer()
-		if err := conn.handshaker.sendOffer(); err != nil {
-			conn.Log.Errorf("failed to send initial offer: %v", err)
-		}
-
-		conn.wg.Add(1)
-		go func() {
-			conn.guard.Start(conn.ctx, conn.onGuardEvent)
-			conn.wg.Done()
-		}()
+		conn.guard.Start(conn.ctx, conn.onGuardEvent)
 	}()
 	conn.opened = true
 	return nil
@@ -274,10 +266,10 @@ func (conn *Conn) Close(signalToRemote bool) {
 
 // OnRemoteAnswer handles an offer from the remote peer and returns true if the message was accepted, false otherwise
 // doesn't block, discards the message if connection wasn't ready
-func (conn *Conn) OnRemoteAnswer(answer OfferAnswer) bool {
+func (conn *Conn) OnRemoteAnswer(answer OfferAnswer) {
 	conn.dumpState.RemoteAnswer()
 	conn.Log.Infof("OnRemoteAnswer, priority: %s, status ICE: %s, status relay: %s", conn.currentConnPriority, conn.statusICE, conn.statusRelay)
-	return conn.handshaker.OnRemoteAnswer(answer)
+	conn.handshaker.OnRemoteAnswer(answer)
 }
 
 // OnRemoteCandidate Handles ICE connection Candidate provided by the remote peer.
@@ -296,10 +288,10 @@ func (conn *Conn) SetOnDisconnected(handler func(remotePeer string)) {
 	conn.onDisconnected = handler
 }
 
-func (conn *Conn) OnRemoteOffer(offer OfferAnswer) bool {
+func (conn *Conn) OnRemoteOffer(offer OfferAnswer) {
 	conn.dumpState.RemoteOffer()
 	conn.Log.Infof("OnRemoteOffer, on status ICE: %s, status Relay: %s", conn.statusICE, conn.statusRelay)
-	return conn.handshaker.OnRemoteOffer(offer)
+	conn.handshaker.OnRemoteOffer(offer)
 }
 
 // WgConfig returns the WireGuard config
@@ -548,7 +540,6 @@ func (conn *Conn) onRelayDisconnected() {
 }
 
 func (conn *Conn) onGuardEvent() {
-	conn.Log.Debugf("send offer to peer")
 	conn.dumpState.SendOffer()
 	if err := conn.handshaker.SendOffer(); err != nil {
 		conn.Log.Errorf("failed to send offer: %v", err)
@@ -672,7 +663,7 @@ func (conn *Conn) isConnectedOnAllWay() (connected bool) {
 		}
 	}()
 
-	if conn.statusICE.Get() == worker.StatusDisconnected {
+	if conn.statusICE.Get() == worker.StatusDisconnected && !conn.workerICE.InProgress() {
 		return false
 	}
 

client/internal/peer/conn_test.go

@@ -1,9 +1,9 @@
 package peer
 
 import (
+	"context"
 	"fmt"
 	"os"
-	"sync"
 	"testing"
 	"time"
 
@@ -79,31 +79,30 @@ func TestConn_OnRemoteOffer(t *testing.T) {
 		return
 	}
 
-	wg := sync.WaitGroup{}
-	wg.Add(2)
-	go func() {
-		<-conn.handshaker.remoteOffersCh
-		wg.Done()
-	}()
+	onNewOffeChan := make(chan struct{})
 
-	go func() {
-		for {
-			accepted := conn.OnRemoteOffer(OfferAnswer{
-				IceCredentials: IceCredentials{
-					UFrag: "test",
-					Pwd:   "test",
-				},
-				WgListenPort: 0,
-				Version:      "",
-			})
-			if accepted {
-				wg.Done()
-				return
-			}
-		}
-	}()
+	conn.handshaker.AddOnNewOfferListener(func(remoteOfferAnswer *OfferAnswer) {
+		onNewOffeChan <- struct{}{}
+	})
 
-	wg.Wait()
+	conn.OnRemoteOffer(OfferAnswer{
+		IceCredentials: IceCredentials{
+			UFrag: "test",
+			Pwd:   "test",
+		},
+		WgListenPort: 0,
+		Version:      "",
+	})
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	select {
+	case <-onNewOffeChan:
+		// success
+	case <-ctx.Done():
+		t.Error("expected to receive a new offer notification, but timed out")
+	}
 }
 
 func TestConn_OnRemoteAnswer(t *testing.T) {
@@ -119,31 +118,29 @@ func TestConn_OnRemoteAnswer(t *testing.T) {
 		return
 	}
 
-	wg := sync.WaitGroup{}
-	wg.Add(2)
-	go func() {
-		<-conn.handshaker.remoteAnswerCh
-		wg.Done()
-	}()
+	onNewOffeChan := make(chan struct{})
 
-	go func() {
-		for {
-			accepted := conn.OnRemoteAnswer(OfferAnswer{
-				IceCredentials: IceCredentials{
-					UFrag: "test",
-					Pwd:   "test",
-				},
-				WgListenPort: 0,
-				Version:      "",
-			})
-			if accepted {
-				wg.Done()
-				return
-			}
-		}
-	}()
+	conn.handshaker.AddOnNewOfferListener(func(remoteOfferAnswer *OfferAnswer) {
+		onNewOffeChan <- struct{}{}
+	})
 
-	wg.Wait()
+	conn.OnRemoteAnswer(OfferAnswer{
+		IceCredentials: IceCredentials{
+			UFrag: "test",
+			Pwd:   "test",
+		},
+		WgListenPort: 0,
+		Version:      "",
+	})
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	select {
+	case <-onNewOffeChan:
+		// success
+	case <-ctx.Done():
+		t.Error("expected to receive a new offer notification, but timed out")
+	}
 }
 
 func TestConn_presharedKey(t *testing.T) {

client/internal/peer/guard/guard.go

@@ -19,7 +19,6 @@ type isConnectedFunc func() bool
 // - Relayed connection disconnected
 // - ICE candidate changes
 type Guard struct {
-	Reconnect               chan struct{}
 	log                     *log.Entry
 	isConnectedOnAllWay     isConnectedFunc
 	timeout                 time.Duration
@@ -30,7 +29,6 @@ type Guard struct {
 
 func NewGuard(log *log.Entry, isConnectedFn isConnectedFunc, timeout time.Duration, srWatcher *SRWatcher) *Guard {
 	return &Guard{
-		Reconnect:               make(chan struct{}, 1),
 		log:                     log,
 		isConnectedOnAllWay:     isConnectedFn,
 		timeout:                 timeout,
@@ -41,6 +39,7 @@ func NewGuard(log *log.Entry, isConnectedFn isConnectedFunc, timeout time.Durati
 }
 
 func (g *Guard) Start(ctx context.Context, eventCallback func()) {
+	g.log.Infof("starting guard for reconnection with MaxInterval: %s", g.timeout)
 	g.reconnectLoopWithRetry(ctx, eventCallback)
 }
 
@@ -61,17 +60,14 @@ func (g *Guard) SetICEConnDisconnected() {
 // reconnectLoopWithRetry periodically check the connection status.
 // Try to send offer while the P2P is not established or while the Relay is not connected if is it supported
 func (g *Guard) reconnectLoopWithRetry(ctx context.Context, callback func()) {
-	waitForInitialConnectionTry(ctx)
-
 	srReconnectedChan := g.srWatcher.NewListener()
 	defer g.srWatcher.RemoveListener(srReconnectedChan)
 
-	ticker := g.prepareExponentTicker(ctx)
+	ticker := g.initialTicker(ctx)
 	defer ticker.Stop()
 
 	tickerChannel := ticker.C
 
-	g.log.Infof("start reconnect loop...")
 	for {
 		select {
 		case t := <-tickerChannel:
@@ -85,7 +81,6 @@ func (g *Guard) reconnectLoopWithRetry(ctx context.Context, callback func()) {
 			if !g.isConnectedOnAllWay() {
 				callback()
 			}
-
 		case <-g.relayedConnDisconnected:
 			g.log.Debugf("Relay connection changed, reset reconnection ticker")
 			ticker.Stop()
@@ -111,6 +106,20 @@ func (g *Guard) reconnectLoopWithRetry(ctx context.Context, callback func()) {
 	}
 }
 
+// initialTicker give chance to the peer to establish the initial connection.
+func (g *Guard) initialTicker(ctx context.Context) *backoff.Ticker {
+	bo := backoff.WithContext(&backoff.ExponentialBackOff{
+		InitialInterval:     3 * time.Second,
+		RandomizationFactor: 0.1,
+		Multiplier:          2,
+		MaxInterval:         g.timeout,
+		Stop:                backoff.Stop,
+		Clock:               backoff.SystemClock,
+	}, ctx)
+
+	return backoff.NewTicker(bo)
+}
+
 func (g *Guard) prepareExponentTicker(ctx context.Context) *backoff.Ticker {
 	bo := backoff.WithContext(&backoff.ExponentialBackOff{
 		InitialInterval:     800 * time.Millisecond,
@@ -126,13 +135,3 @@ func (g *Guard) prepareExponentTicker(ctx context.Context) *backoff.Ticker {
 
 	return ticker
 }
-
-// Give chance to the peer to establish the initial connection.
-// With it, we can decrease to send necessary offer
-func waitForInitialConnectionTry(ctx context.Context) {
-	select {
-	case <-ctx.Done():
-		return
-	case <-time.After(3 * time.Second):
-	}
-}

client/internal/peer/handshaker.go

@@ -39,6 +39,15 @@ type OfferAnswer struct {
 
 	// relay server address
 	RelaySrvAddress string
+	// SessionID is the unique identifier of the session, used to discard old messages
+	SessionID *ICESessionID
+}
+
+func (oa *OfferAnswer) SessionIDString() string {
+	if oa.SessionID == nil {
+		return "unknown"
+	}
+	return oa.SessionID.String()
 }
 
 type Handshaker struct {
@@ -74,21 +83,25 @@ func (h *Handshaker) AddOnNewOfferListener(offer func(remoteOfferAnswer *OfferAn
 
 func (h *Handshaker) Listen(ctx context.Context) {
 	for {
-		h.log.Info("wait for remote offer confirmation")
-		remoteOfferAnswer, err := h.waitForRemoteOfferConfirmation(ctx)
-		if err != nil {
-			var connectionClosedError *ConnectionClosedError
-			if errors.As(err, &connectionClosedError) {
-				h.log.Info("exit from handshaker")
-				return
+		select {
+		case remoteOfferAnswer := <-h.remoteOffersCh:
+			// received confirmation from the remote peer -> ready to proceed
+			if err := h.sendAnswer(); err != nil {
+				h.log.Errorf("failed to send remote offer confirmation: %s", err)
+				continue
 			}
-			h.log.Errorf("failed to received remote offer confirmation: %s", err)
-			continue
-		}
-
-		h.log.Infof("received connection confirmation, running version %s and with remote WireGuard listen port %d", remoteOfferAnswer.Version, remoteOfferAnswer.WgListenPort)
-		for _, listener := range h.onNewOfferListeners {
-			go listener(remoteOfferAnswer)
+			for _, listener := range h.onNewOfferListeners {
+				listener(&remoteOfferAnswer)
+			}
+			h.log.Infof("received offer, running version %s, remote WireGuard listen port %d, session id: %s", remoteOfferAnswer.Version, remoteOfferAnswer.WgListenPort, remoteOfferAnswer.SessionIDString())
+		case remoteOfferAnswer := <-h.remoteAnswerCh:
+			h.log.Infof("received answer, running version %s, remote WireGuard listen port %d, session id: %s", remoteOfferAnswer.Version, remoteOfferAnswer.WgListenPort, remoteOfferAnswer.SessionIDString())
+			for _, listener := range h.onNewOfferListeners {
+				listener(&remoteOfferAnswer)
+			}
+		case <-ctx.Done():
+			h.log.Infof("stop listening for remote offers and answers")
+			return
 		}
 	}
 }
@@ -101,43 +114,27 @@ func (h *Handshaker) SendOffer() error {
 
 // OnRemoteOffer handles an offer from the remote peer and returns true if the message was accepted, false otherwise
 // doesn't block, discards the message if connection wasn't ready
-func (h *Handshaker) OnRemoteOffer(offer OfferAnswer) bool {
+func (h *Handshaker) OnRemoteOffer(offer OfferAnswer) {
 	select {
 	case h.remoteOffersCh <- offer:
-		return true
+		return
 	default:
-		h.log.Warnf("OnRemoteOffer skipping message because is not ready")
+		h.log.Warnf("skipping remote offer message because receiver not ready")
 		// connection might not be ready yet to receive so we ignore the message
-		return false
+		return
 	}
 }
 
 // OnRemoteAnswer handles an offer from the remote peer and returns true if the message was accepted, false otherwise
 // doesn't block, discards the message if connection wasn't ready
-func (h *Handshaker) OnRemoteAnswer(answer OfferAnswer) bool {
+func (h *Handshaker) OnRemoteAnswer(answer OfferAnswer) {
 	select {
 	case h.remoteAnswerCh <- answer:
-		return true
+		return
 	default:
 		// connection might not be ready yet to receive so we ignore the message
-		h.log.Debugf("OnRemoteAnswer skipping message because is not ready")
-		return false
-	}
-}
-
-func (h *Handshaker) waitForRemoteOfferConfirmation(ctx context.Context) (*OfferAnswer, error) {
-	select {
-	case remoteOfferAnswer := <-h.remoteOffersCh:
-		// received confirmation from the remote peer -> ready to proceed
-		if err := h.sendAnswer(); err != nil {
-			return nil, err
-		}
-		return &remoteOfferAnswer, nil
-	case remoteOfferAnswer := <-h.remoteAnswerCh:
-		return &remoteOfferAnswer, nil
-	case <-ctx.Done():
-		// closed externally
-		return nil, NewConnectionClosedError(h.config.Key)
+		h.log.Warnf("skipping remote answer message because receiver not ready")
+		return
 	}
 }
 
@@ -147,43 +144,34 @@ func (h *Handshaker) sendOffer() error {
 		return ErrSignalIsNotReady
 	}
 
-	iceUFrag, icePwd := h.ice.GetLocalUserCredentials()
-	offer := OfferAnswer{
-		IceCredentials:  IceCredentials{iceUFrag, icePwd},
-		WgListenPort:    h.config.LocalWgPort,
-		Version:         version.NetbirdVersion(),
-		RosenpassPubKey: h.config.RosenpassConfig.PubKey,
-		RosenpassAddr:   h.config.RosenpassConfig.Addr,
-	}
-
-	addr, err := h.relay.RelayInstanceAddress()
-	if err == nil {
-		offer.RelaySrvAddress = addr
-	}
+	offer := h.buildOfferAnswer()
+	h.log.Infof("sending offer with serial: %s", offer.SessionIDString())
 
 	return h.signaler.SignalOffer(offer, h.config.Key)
 }
 
 func (h *Handshaker) sendAnswer() error {
-	h.log.Infof("sending answer")
-	uFrag, pwd := h.ice.GetLocalUserCredentials()
+	answer := h.buildOfferAnswer()
+	h.log.Infof("sending answer with serial: %s", answer.SessionIDString())
 
+	return h.signaler.SignalAnswer(answer, h.config.Key)
+}
+
+func (h *Handshaker) buildOfferAnswer() OfferAnswer {
+	uFrag, pwd := h.ice.GetLocalUserCredentials()
+	sid := h.ice.SessionID()
 	answer := OfferAnswer{
 		IceCredentials:  IceCredentials{uFrag, pwd},
 		WgListenPort:    h.config.LocalWgPort,
 		Version:         version.NetbirdVersion(),
 		RosenpassPubKey: h.config.RosenpassConfig.PubKey,
 		RosenpassAddr:   h.config.RosenpassConfig.Addr,
+		SessionID:       &sid,
 	}
-	addr, err := h.relay.RelayInstanceAddress()
-	if err == nil {
+
+	if addr, err := h.relay.RelayInstanceAddress(); err == nil {
 		answer.RelaySrvAddress = addr
 	}
 
-	err = h.signaler.SignalAnswer(answer, h.config.Key)
-	if err != nil {
-		return err
-	}
-
-	return nil
+	return answer
 }

client/internal/peer/ice/agent.go

@@ -1,6 +1,7 @@
 package ice
 
 import (
+	"sync"
 	"time"
 
 	"github.com/pion/ice/v3"
@@ -23,7 +24,20 @@ const (
 	iceRelayAcceptanceMinWaitDefault = 2 * time.Second
 )
 
-func NewAgent(iFaceDiscover stdnet.ExternalIFaceDiscover, config Config, candidateTypes []ice.CandidateType, ufrag string, pwd string) (*ice.Agent, error) {
+type ThreadSafeAgent struct {
+	*ice.Agent
+	once sync.Once
+}
+
+func (a *ThreadSafeAgent) Close() error {
+	var err error
+	a.once.Do(func() {
+		err = a.Agent.Close()
+	})
+	return err
+}
+
+func NewAgent(iFaceDiscover stdnet.ExternalIFaceDiscover, config Config, candidateTypes []ice.CandidateType, ufrag string, pwd string) (*ThreadSafeAgent, error) {
 	iceKeepAlive := iceKeepAlive()
 	iceDisconnectedTimeout := iceDisconnectedTimeout()
 	iceFailedTimeout := iceFailedTimeout()
@@ -61,7 +75,12 @@ func NewAgent(iFaceDiscover stdnet.ExternalIFaceDiscover, config Config, candida
 		agentConfig.NetworkTypes = []ice.NetworkType{ice.NetworkTypeUDP4}
 	}
 
-	return ice.NewAgent(agentConfig)
+	agent, err := ice.NewAgent(agentConfig)
+	if err != nil {
+		return nil, err
+	}
+
+	return &ThreadSafeAgent{Agent: agent}, nil
 }
 
 func GenerateICECredentials() (string, string, error) {

client/internal/peer/session_id.go

@@ -0,0 +1,47 @@
+package peer
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+	"fmt"
+	"io"
+)
+
+const sessionIDSize = 5
+
+type ICESessionID string
+
+// NewICESessionID generates a new session ID for distinguishing sessions
+func NewICESessionID() (ICESessionID, error) {
+	b := make([]byte, sessionIDSize)
+	if _, err := io.ReadFull(rand.Reader, b); err != nil {
+		return "", fmt.Errorf("failed to generate session ID: %w", err)
+	}
+	return ICESessionID(hex.EncodeToString(b)), nil
+}
+
+func ICESessionIDFromBytes(b []byte) (ICESessionID, error) {
+	if len(b) != sessionIDSize {
+		return "", fmt.Errorf("invalid session ID length: %d", len(b))
+	}
+	return ICESessionID(hex.EncodeToString(b)), nil
+}
+
+// Bytes returns the raw bytes of the session ID for protobuf serialization
+func (id ICESessionID) Bytes() ([]byte, error) {
+	if len(id) == 0 {
+		return nil, fmt.Errorf("ICE session ID is empty")
+	}
+	b, err := hex.DecodeString(string(id))
+	if err != nil {
+		return nil, fmt.Errorf("invalid ICE session ID encoding: %w", err)
+	}
+	if len(b) != sessionIDSize {
+		return nil, fmt.Errorf("invalid ICE session ID length: expected %d bytes, got %d", sessionIDSize, len(b))
+	}
+	return b, nil
+}
+
+func (id ICESessionID) String() string {
+	return string(id)
+}

client/internal/peer/signaler.go

@@ -2,6 +2,7 @@ package peer
 
 import (
 	"github.com/pion/ice/v3"
+	log "github.com/sirupsen/logrus"
 	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
 
 	signal "github.com/netbirdio/netbird/shared/signal/client"
@@ -45,6 +46,10 @@ func (s *Signaler) Ready() bool {
 
 // SignalOfferAnswer signals either an offer or an answer to remote peer
 func (s *Signaler) signalOfferAnswer(offerAnswer OfferAnswer, remoteKey string, bodyType sProto.Body_Type) error {
+	sessionIDBytes, err := offerAnswer.SessionID.Bytes()
+	if err != nil {
+		log.Warnf("failed to get session ID bytes: %v", err)
+	}
 	msg, err := signal.MarshalCredential(
 		s.wgPrivateKey,
 		offerAnswer.WgListenPort,
@@ -56,13 +61,13 @@ func (s *Signaler) signalOfferAnswer(offerAnswer OfferAnswer, remoteKey string,
 		bodyType,
 		offerAnswer.RosenpassPubKey,
 		offerAnswer.RosenpassAddr,
-		offerAnswer.RelaySrvAddress)
+		offerAnswer.RelaySrvAddress,
+		sessionIDBytes)
 	if err != nil {
 		return err
 	}
 
-	err = s.signal.Send(msg)
-	if err != nil {
+	if err = s.signal.Send(msg); err != nil {
 		return err
 	}
 

client/internal/peer/worker_ice.go

@@ -42,8 +42,18 @@ type WorkerICE struct {
 	statusRecorder    *Status
 	hasRelayOnLocally bool
 
-	agent    *ice.Agent
-	muxAgent sync.Mutex
+	agent             *icemaker.ThreadSafeAgent
+	agentDialerCancel context.CancelFunc
+	agentConnecting   bool      // while it is true, drop all incoming offers
+	lastSuccess       time.Time // with this avoid the too frequent ICE agent recreation
+	// remoteSessionID represents the peer's session identifier from the latest remote offer.
+	remoteSessionID ICESessionID
+	// sessionID is used to track the current session ID of the ICE agent
+	// increase by one when disconnecting the agent
+	// with it the remote peer can discard the already deprecated offer/answer
+	// Without it the remote peer may recreate a workable ICE connection
+	sessionID ICESessionID
+	muxAgent  sync.Mutex
 
 	StunTurn []*stun.URI
 
@@ -57,6 +67,11 @@ type WorkerICE struct {
 }
 
 func NewWorkerICE(ctx context.Context, log *log.Entry, config ConnConfig, conn *Conn, signaler *Signaler, ifaceDiscover stdnet.ExternalIFaceDiscover, statusRecorder *Status, hasRelayOnLocally bool) (*WorkerICE, error) {
+	sessionID, err := NewICESessionID()
+	if err != nil {
+		return nil, err
+	}
+
 	w := &WorkerICE{
 		ctx:               ctx,
 		log:               log,
@@ -67,6 +82,7 @@ func NewWorkerICE(ctx context.Context, log *log.Entry, config ConnConfig, conn *
 		statusRecorder:    statusRecorder,
 		hasRelayOnLocally: hasRelayOnLocally,
 		lastKnownState:    ice.ConnectionStateDisconnected,
+		sessionID:         sessionID,
 	}
 
 	localUfrag, localPwd, err := icemaker.GenerateICECredentials()
@@ -79,15 +95,36 @@ func NewWorkerICE(ctx context.Context, log *log.Entry, config ConnConfig, conn *
 }
 
 func (w *WorkerICE) OnNewOffer(remoteOfferAnswer *OfferAnswer) {
-	w.log.Debugf("OnNewOffer for ICE")
+	w.log.Debugf("OnNewOffer for ICE, serial: %s", remoteOfferAnswer.SessionIDString())
 	w.muxAgent.Lock()
 
-	if w.agent != nil {
-		w.log.Debugf("agent already exists, skipping the offer")
+	if w.agentConnecting {
+		w.log.Debugf("agent connection is in progress, skipping the offer")
 		w.muxAgent.Unlock()
 		return
 	}
 
+	if w.agent != nil {
+		// backward compatibility with old clients that do not send session ID
+		if remoteOfferAnswer.SessionID == nil {
+			w.log.Debugf("agent already exists, skipping the offer")
+			w.muxAgent.Unlock()
+			return
+		}
+		if w.remoteSessionID == *remoteOfferAnswer.SessionID {
+			w.log.Debugf("agent already exists and session ID matches, skipping the offer: %s", remoteOfferAnswer.SessionIDString())
+			w.muxAgent.Unlock()
+			return
+		}
+		w.log.Debugf("agent already exists, recreate the connection")
+		w.agentDialerCancel()
+		if err := w.agent.Close(); err != nil {
+			w.log.Warnf("failed to close ICE agent: %s", err)
+		}
+		w.agent = nil
+		// todo consider to switch to Relay connection while establishing a new ICE connection
+	}
+
 	var preferredCandidateTypes []ice.CandidateType
 	if w.hasRelayOnLocally && remoteOfferAnswer.RelaySrvAddress != "" {
 		preferredCandidateTypes = icemaker.CandidateTypesP2P()
@@ -96,36 +133,124 @@ func (w *WorkerICE) OnNewOffer(remoteOfferAnswer *OfferAnswer) {
 	}
 
 	w.log.Debugf("recreate ICE agent")
-	agentCtx, agentCancel := context.WithCancel(w.ctx)
-	agent, err := w.reCreateAgent(agentCancel, preferredCandidateTypes)
+	dialerCtx, dialerCancel := context.WithCancel(w.ctx)
+	agent, err := w.reCreateAgent(dialerCancel, preferredCandidateTypes)
 	if err != nil {
 		w.log.Errorf("failed to recreate ICE Agent: %s", err)
 		w.muxAgent.Unlock()
 		return
 	}
+	w.sentExtraSrflx = false
 	w.agent = agent
+	w.agentDialerCancel = dialerCancel
+	w.agentConnecting = true
 	w.muxAgent.Unlock()
 
-	w.log.Debugf("gather candidates")
-	err = w.agent.GatherCandidates()
-	if err != nil {
-		w.log.Debugf("failed to gather candidates: %s", err)
+	go w.connect(dialerCtx, agent, remoteOfferAnswer)
+}
+
+// OnRemoteCandidate Handles ICE connection Candidate provided by the remote peer.
+func (w *WorkerICE) OnRemoteCandidate(candidate ice.Candidate, haRoutes route.HAMap) {
+	w.muxAgent.Lock()
+	defer w.muxAgent.Unlock()
+	w.log.Debugf("OnRemoteCandidate from peer %s -> %s", w.config.Key, candidate.String())
+	if w.agent == nil {
+		w.log.Warnf("ICE Agent is not initialized yet")
+		return
+	}
+
+	if candidateViaRoutes(candidate, haRoutes) {
+		return
+	}
+
+	if err := w.agent.AddRemoteCandidate(candidate); err != nil {
+		w.log.Errorf("error while handling remote candidate")
+		return
+	}
+}
+
+func (w *WorkerICE) GetLocalUserCredentials() (frag string, pwd string) {
+	return w.localUfrag, w.localPwd
+}
+
+func (w *WorkerICE) InProgress() bool {
+	w.muxAgent.Lock()
+	defer w.muxAgent.Unlock()
+
+	return w.agentConnecting
+}
+
+func (w *WorkerICE) Close() {
+	w.muxAgent.Lock()
+	defer w.muxAgent.Unlock()
+
+	if w.agent == nil {
+		return
+	}
+
+	w.agentDialerCancel()
+	if err := w.agent.Close(); err != nil {
+		w.log.Warnf("failed to close ICE agent: %s", err)
+	}
+
+	w.agent = nil
+}
+
+func (w *WorkerICE) reCreateAgent(dialerCancel context.CancelFunc, candidates []ice.CandidateType) (*icemaker.ThreadSafeAgent, error) {
+	agent, err := icemaker.NewAgent(w.iFaceDiscover, w.config.ICEConfig, candidates, w.localUfrag, w.localPwd)
+	if err != nil {
+		return nil, fmt.Errorf("create agent: %w", err)
+	}
+
+	if err := agent.OnCandidate(w.onICECandidate); err != nil {
+		return nil, err
+	}
+
+	if err := agent.OnConnectionStateChange(w.onConnectionStateChange(agent, dialerCancel)); err != nil {
+		return nil, err
+	}
+
+	if err := agent.OnSelectedCandidatePairChange(w.onICESelectedCandidatePair); err != nil {
+		return nil, err
+	}
+
+	if err := agent.OnSuccessfulSelectedPairBindingResponse(w.onSuccessfulSelectedPairBindingResponse); err != nil {
+		return nil, fmt.Errorf("failed setting binding response callback: %w", err)
+	}
+
+	return agent, nil
+}
+
+func (w *WorkerICE) SessionID() ICESessionID {
+	w.muxAgent.Lock()
+	defer w.muxAgent.Unlock()
+
+	return w.sessionID
+}
+
+// will block until connection succeeded
+// but it won't release if ICE Agent went into Disconnected or Failed state,
+// so we have to cancel it with the provided context once agent detected a broken connection
+func (w *WorkerICE) connect(ctx context.Context, agent *icemaker.ThreadSafeAgent, remoteOfferAnswer *OfferAnswer) {
+	w.log.Debugf("gather candidates")
+	if err := agent.GatherCandidates(); err != nil {
+		w.log.Warnf("failed to gather candidates: %s", err)
+		w.closeAgent(agent, w.agentDialerCancel)
 		return
 	}
 
-	// will block until connection succeeded
-	// but it won't release if ICE Agent went into Disconnected or Failed state,
-	// so we have to cancel it with the provided context once agent detected a broken connection
 	w.log.Debugf("turn agent dial")
-	remoteConn, err := w.turnAgentDial(agentCtx, remoteOfferAnswer)
+	remoteConn, err := w.turnAgentDial(ctx, agent, remoteOfferAnswer)
 	if err != nil {
 		w.log.Debugf("failed to dial the remote peer: %s", err)
+		w.closeAgent(agent, w.agentDialerCancel)
 		return
 	}
 	w.log.Debugf("agent dial succeeded")
 
-	pair, err := w.agent.GetSelectedCandidatePair()
+	pair, err := agent.GetSelectedCandidatePair()
 	if err != nil {
+		w.closeAgent(agent, w.agentDialerCancel)
 		return
 	}
 
@@ -152,114 +277,39 @@ func (w *WorkerICE) OnNewOffer(remoteOfferAnswer *OfferAnswer) {
 		RelayedOnLocal:             isRelayCandidate(pair.Local),
 	}
 	w.log.Debugf("on ICE conn is ready to use")
-	go w.conn.onICEConnectionIsReady(selectedPriority(pair), ci)
-}
 
-// OnRemoteCandidate Handles ICE connection Candidate provided by the remote peer.
-func (w *WorkerICE) OnRemoteCandidate(candidate ice.Candidate, haRoutes route.HAMap) {
+	w.log.Infof("connection succeeded with offer session: %s", remoteOfferAnswer.SessionIDString())
 	w.muxAgent.Lock()
-	defer w.muxAgent.Unlock()
-	w.log.Debugf("OnRemoteCandidate from peer %s -> %s", w.config.Key, candidate.String())
-	if w.agent == nil {
-		w.log.Warnf("ICE Agent is not initialized yet")
-		return
+	w.agentConnecting = false
+	w.lastSuccess = time.Now()
+	if remoteOfferAnswer.SessionID != nil {
+		w.remoteSessionID = *remoteOfferAnswer.SessionID
 	}
+	w.muxAgent.Unlock()
 
-	if candidateViaRoutes(candidate, haRoutes) {
-		return
-	}
-
-	err := w.agent.AddRemoteCandidate(candidate)
-	if err != nil {
-		w.log.Errorf("error while handling remote candidate")
-		return
-	}
+	// todo: the potential problem is a race between the onConnectionStateChange
+	w.conn.onICEConnectionIsReady(selectedPriority(pair), ci)
 }
 
-func (w *WorkerICE) GetLocalUserCredentials() (frag string, pwd string) {
-	w.muxAgent.Lock()
-	defer w.muxAgent.Unlock()
-	return w.localUfrag, w.localPwd
-}
-
-func (w *WorkerICE) Close() {
-	w.muxAgent.Lock()
-	defer w.muxAgent.Unlock()
-
-	if w.agent == nil {
-		return
-	}
-
-	if err := w.agent.Close(); err != nil {
-		w.log.Warnf("failed to close ICE agent: %s", err)
-	}
-}
-
-func (w *WorkerICE) reCreateAgent(agentCancel context.CancelFunc, candidates []ice.CandidateType) (*ice.Agent, error) {
-	w.sentExtraSrflx = false
-
-	agent, err := icemaker.NewAgent(w.iFaceDiscover, w.config.ICEConfig, candidates, w.localUfrag, w.localPwd)
-	if err != nil {
-		return nil, fmt.Errorf("create agent: %w", err)
-	}
-
-	err = agent.OnCandidate(w.onICECandidate)
-	if err != nil {
-		return nil, err
-	}
-
-	err = agent.OnConnectionStateChange(func(state ice.ConnectionState) {
-		w.log.Debugf("ICE ConnectionState has changed to %s", state.String())
-		switch state {
-		case ice.ConnectionStateConnected:
-			w.lastKnownState = ice.ConnectionStateConnected
-			return
-		case ice.ConnectionStateFailed, ice.ConnectionStateDisconnected:
-			if w.lastKnownState == ice.ConnectionStateConnected {
-				w.lastKnownState = ice.ConnectionStateDisconnected
-				w.conn.onICEStateDisconnected()
-			}
-			w.closeAgent(agentCancel)
-		default:
-			return
-		}
-	})
-	if err != nil {
-		return nil, err
-	}
-
-	err = agent.OnSelectedCandidatePairChange(w.onICESelectedCandidatePair)
-	if err != nil {
-		return nil, err
-	}
-
-	err = agent.OnSuccessfulSelectedPairBindingResponse(func(p *ice.CandidatePair) {
-		err := w.statusRecorder.UpdateLatency(w.config.Key, p.Latency())
-		if err != nil {
-			w.log.Debugf("failed to update latency for peer: %s", err)
-			return
-		}
-	})
-	if err != nil {
-		return nil, fmt.Errorf("failed setting binding response callback: %w", err)
-	}
-
-	return agent, nil
-}
-
-func (w *WorkerICE) closeAgent(cancel context.CancelFunc) {
-	w.muxAgent.Lock()
-	defer w.muxAgent.Unlock()
-
+func (w *WorkerICE) closeAgent(agent *icemaker.ThreadSafeAgent, cancel context.CancelFunc) {
 	cancel()
-	if w.agent == nil {
-		return
-	}
-
-	if err := w.agent.Close(); err != nil {
+	if err := agent.Close(); err != nil {
 		w.log.Warnf("failed to close ICE agent: %s", err)
 	}
-	w.agent = nil
+
+	w.muxAgent.Lock()
+	// todo review does it make sense to generate new session ID all the time when w.agent==agent
+	sessionID, err := NewICESessionID()
+	if err != nil {
+		w.log.Errorf("failed to create new session ID: %s", err)
+	}
+	w.sessionID = sessionID
+
+	if w.agent == agent {
+		w.agent = nil
+		w.agentConnecting = false
+	}
+	w.muxAgent.Unlock()
 }
 
 func (w *WorkerICE) punchRemoteWGPort(pair *ice.CandidatePair, remoteWgPort int) {
@@ -331,6 +381,32 @@ func (w *WorkerICE) onICESelectedCandidatePair(c1 ice.Candidate, c2 ice.Candidat
 		w.config.Key)
 }
 
+func (w *WorkerICE) onConnectionStateChange(agent *icemaker.ThreadSafeAgent, dialerCancel context.CancelFunc) func(ice.ConnectionState) {
+	return func(state ice.ConnectionState) {
+		w.log.Debugf("ICE ConnectionState has changed to %s", state.String())
+		switch state {
+		case ice.ConnectionStateConnected:
+			w.lastKnownState = ice.ConnectionStateConnected
+			return
+		case ice.ConnectionStateFailed, ice.ConnectionStateDisconnected:
+			if w.lastKnownState == ice.ConnectionStateConnected {
+				w.lastKnownState = ice.ConnectionStateDisconnected
+				w.conn.onICEStateDisconnected()
+			}
+			w.closeAgent(agent, dialerCancel)
+		default:
+			return
+		}
+	}
+}
+
+func (w *WorkerICE) onSuccessfulSelectedPairBindingResponse(pair *ice.CandidatePair) {
+	if err := w.statusRecorder.UpdateLatency(w.config.Key, pair.Latency()); err != nil {
+		w.log.Debugf("failed to update latency for peer: %s", err)
+		return
+	}
+}
+
 func (w *WorkerICE) shouldSendExtraSrflxCandidate(candidate ice.Candidate) bool {
 	if !w.sentExtraSrflx && candidate.Type() == ice.CandidateTypeServerReflexive && candidate.Port() != candidate.RelatedAddress().Port {
 		return true
@@ -338,12 +414,12 @@ func (w *WorkerICE) shouldSendExtraSrflxCandidate(candidate ice.Candidate) bool
 	return false
 }
 
-func (w *WorkerICE) turnAgentDial(ctx context.Context, remoteOfferAnswer *OfferAnswer) (*ice.Conn, error) {
+func (w *WorkerICE) turnAgentDial(ctx context.Context, agent *icemaker.ThreadSafeAgent, remoteOfferAnswer *OfferAnswer) (*ice.Conn, error) {
 	isControlling := w.config.LocalKey > w.config.Key
 	if isControlling {
-		return w.agent.Dial(ctx, remoteOfferAnswer.IceCredentials.UFrag, remoteOfferAnswer.IceCredentials.Pwd)
+		return agent.Dial(ctx, remoteOfferAnswer.IceCredentials.UFrag, remoteOfferAnswer.IceCredentials.Pwd)
 	} else {
-		return w.agent.Accept(ctx, remoteOfferAnswer.IceCredentials.UFrag, remoteOfferAnswer.IceCredentials.Pwd)
+		return agent.Accept(ctx, remoteOfferAnswer.IceCredentials.UFrag, remoteOfferAnswer.IceCredentials.Pwd)
 	}
 }