Merge branch 'main' into client-local-metrics

# Conflicts:
#	client/internal/debug/debug.go

client/internal/auth/auth.go

@@ -351,6 +351,7 @@ func (a *Auth) setSystemInfoFlags(info *system.Info) {
 		a.config.BlockLANAccess,
 		a.config.BlockInbound,
 		a.config.DisableIPv6,
+		a.config.SyncMessageVersion,
 		a.config.EnableSSHRoot,
 		a.config.EnableSSHSFTP,
 		a.config.EnableSSHLocalPortForwarding,

client/internal/auth/device_flow.go

@@ -299,7 +299,7 @@ func (d *DeviceAuthorizationFlow) WaitToken(ctx context.Context, info AuthFlowIn
 				UseIDToken:   d.providerConfig.UseIDToken,
 			}
 
-			err = isValidAccessToken(tokenInfo.GetTokenToUse(), d.providerConfig.Audience)
+			err = validateTokenAudience(tokenInfo.GetTokenToUse(), d.providerConfig.Audience)
 			if err != nil {
 				return TokenInfo{}, fmt.Errorf("validate access token failed with error: %v", err)
 			}

client/internal/auth/pkce_flow.go

@@ -306,7 +306,7 @@ func (p *PKCEAuthorizationFlow) parseOAuthToken(token *oauth2.Token) (TokenInfo,
 		audience = p.providerConfig.ClientID
 	}
 
-	if err := isValidAccessToken(tokenInfo.GetTokenToUse(), audience); err != nil {
+	if err := validateTokenAudience(tokenInfo.GetTokenToUse(), audience); err != nil {
 		return TokenInfo{}, fmt.Errorf("authentication failed: invalid access token - %w", err)
 	}
 
@@ -320,6 +320,11 @@ func (p *PKCEAuthorizationFlow) parseOAuthToken(token *oauth2.Token) (TokenInfo,
 	return tokenInfo, nil
 }
 
+// parseEmailFromIDToken extracts the email (or name) claim from an ID token
+// without verifying its signature. The value is best-effort and used only as a
+// UX convenience (login hint prefill and display); it never drives an
+// authorization decision. The authoritative identity is established server-side
+// from the signature-verified token.
 func parseEmailFromIDToken(token string) (string, error) {
 	parts := strings.Split(token, ".")
 	if len(parts) < 2 {

client/internal/auth/sessionwatch/watcher.go

@@ -24,11 +24,7 @@ import (
 )
 
 const (
-	// Skew tolerates a small clock difference between the management
-	// server and this peer before treating a deadline as "in the past".
-	// Slightly above typical NTP drift; tight enough that the UI doesn't
-	// paint a stale expiry as if it were valid.
-	Skew = 30 * time.Second
+	maxPastHorizon = 30 * 24 * time.Hour
 
 	// maxDeadlineHorizon caps how far in the future an accepted deadline
 	// can sit. A timestamp beyond this is almost certainly a protocol
@@ -57,7 +53,7 @@ var (
 	ErrDeadlineTooFarFuture = errors.New("session deadline too far in the future")
 
 	// ErrDeadlineInPast is returned by Update when the supplied deadline
-	// is more than Skew in the past.
+	// is more than maxPastHorizon in the past.
 	ErrDeadlineInPast = errors.New("session deadline in the past")
 )
 
@@ -66,15 +62,14 @@ var (
 // for deadline change/clear, PublishEvent for the two warnings); tests pass
 // a fake recorder so the same surface is observable without an engine.
 //
-// The watcher is the single owner of the deadline propagated to the
-// recorder: every set, clear, sanity-check rejection and Close routes the
-// value through SetSessionExpiresAt, so the SubscribeStatus snapshot the UI
-// reads can never drift from the watcher's timer state. (SetSessionExpiresAt
-// fans out its own state-change notification, so no separate notify is
-// needed.) The recorder is server-scoped and outlives this engine-scoped
-// watcher — without the Close-time clear a teardown (Down, or the Down+Up of
-// a profile switch) would leave the next session showing the previous one's
-// stale "expires in" value.
+// While the watcher runs, it owns the deadline propagated to the recorder:
+// every set, clear and sanity-check rejection routes the value through
+// SetSessionExpiresAt, so the SubscribeStatus snapshot the UI reads can
+// never drift from the watcher's timer state. (SetSessionExpiresAt fans
+// out its own state-change notification, so no separate notify is needed.)
+// The recorder is server-scoped and outlives this engine-scoped watcher;
+// Close deliberately leaves the recorder value in place so transient engine
+// restarts don't blank it — the client run loop clears it on real teardown.
 //
 // PublishEvent's signature mirrors peer.Status.PublishEvent: the watcher
 // composes the metadata internally so the wire format (MetaSession*) is
@@ -135,10 +130,13 @@ func NewWithLeads(lead, final time.Duration, recorder StatusRecorder) *Watcher {
 // was disabled).
 //
 // Same-value updates are no-ops. A different non-zero value cancels any
-// pending timer, resets the "already fired" guard, and arms a new one.
+// pending timer, resets the "already fired" guards, and — when the
+// deadline lies in the future — arms fresh warning timers. A deadline
+// already in the past (within maxPastHorizon) is recorded as-is with no
+// timers: the session has expired and consumers render it that way.
 //
 // Returns one of the sentinel Err* values when the deadline fails the
-// sanity checks (pre-epoch, far future, or in the past beyond Skew).
+// sanity checks (pre-epoch, far future, or past beyond maxPastHorizon).
 // In every error case the watcher first clears its state so it stays
 // consistent with what the caller will push into its other sinks (e.g.
 // applySessionDeadline forces a zero deadline into the status recorder
@@ -163,7 +161,7 @@ func (w *Watcher) Update(deadline time.Time) error {
 	case deadline.After(now.Add(maxDeadlineHorizon)):
 		w.clearLocked()
 		return fmt.Errorf("%w: %v", ErrDeadlineTooFarFuture, deadline)
-	case deadline.Before(now.Add(-Skew)):
+	case deadline.Before(now.Add(-maxPastHorizon)):
 		w.clearLocked()
 		return fmt.Errorf("%w: %v (now=%v)", ErrDeadlineInPast, deadline, now)
 	}
@@ -183,7 +181,9 @@ func (w *Watcher) Update(deadline time.Time) error {
 	w.finalFiredAt = time.Time{}
 	w.dismissedAt = time.Time{}
 
-	w.armTimerLocked(deadline)
+	if deadline.After(now) {
+		w.armTimerLocked(deadline)
+	}
 	recorder := w.recorder
 	w.mu.Unlock()
 	if recorder != nil {
@@ -227,30 +227,25 @@ func (w *Watcher) Dismiss() {
 	log.Infof("auth session final-warning dismissed for deadline %s", w.current.Format(time.RFC3339))
 }
 
-// Close stops any pending timer and drops the deadline on the status
-// recorder. Update calls after Close are ignored. Clearing the recorder
-// here is what keeps a teardown (Down, or the Down+Up of a profile switch)
-// from leaving the next session showing this one's stale "expires in"
-// value — the recorder is server-scoped and outlives this engine-scoped
-// watcher, so nothing else drops the anchor on teardown.
+// Close stops any pending timer. Update calls after Close are ignored.
+// The recorder keeps its deadline: the watcher is engine-scoped and closes
+// on every engine restart (network change, sleep/wake, stream errors)
+// while the SSO deadline stays valid across those, so clearing here would
+// blank the UI's "expires in" row on every transient reconnect. The
+// client run loop clears the server-scoped recorder when it exits for
+// real (Down, profile switch, permanent login failure).
 func (w *Watcher) Close() {
 	w.mu.Lock()
+	defer w.mu.Unlock()
 	if w.closed {
-		w.mu.Unlock()
 		return
 	}
 	w.closed = true
 	w.stopTimerLocked()
-	hadDeadline := !w.current.IsZero()
 	w.current = time.Time{}
 	w.firedAt = time.Time{}
 	w.finalFiredAt = time.Time{}
 	w.dismissedAt = time.Time{}
-	recorder := w.recorder
-	w.mu.Unlock()
-	if recorder != nil && hadDeadline {
-		recorder.SetSessionExpiresAt(time.Time{})
-	}
 }
 
 // clearLocked drops the tracked deadline and notifies the recorder so

client/internal/auth/sessionwatch/watcher_test.go

@@ -224,11 +224,13 @@ func TestNewDeadlineCancelsPriorTimer(t *testing.T) {
 
 func TestRefreshAfterFireArmsNewWarning(t *testing.T) {
 	r := &fakeRecorder{}
-	lead := 30 * time.Millisecond
+	lead := 150 * time.Millisecond
 	w := newWatcher(lead, r)
 	defer w.Close()
 
-	first := time.Now().Add(50 * time.Millisecond)
+	// Warning fires ~20ms in; the deadline itself stays 150ms away so the
+	// replacement below lands well before it.
+	first := time.Now().Add(170 * time.Millisecond)
 	_ = w.Update(first)
 
 	// Wait for stateChange + warning of the first cycle.
@@ -306,7 +308,29 @@ func TestUpdateRejectsTooFarFuture(t *testing.T) {
 	}
 }
 
-func TestUpdateInPastClearsDeadline(t *testing.T) {
+func TestUpdateRecentPastRecordedAsExpired(t *testing.T) {
+	r := &fakeRecorder{}
+	w := newWatcher(50*time.Millisecond, r)
+	defer w.Close()
+
+	d := time.Now().Add(-1 * time.Hour)
+	if err := w.Update(d); err != nil {
+		t.Fatalf("recent-past Update should succeed, got %v", err)
+	}
+	if !w.Deadline().Equal(d) {
+		t.Fatalf("expected deadline to be recorded, got %v want %v", w.Deadline(), d)
+	}
+	if got := r.deadline(); !got.Equal(d) {
+		t.Fatalf("recorder deadline = %v, want %v", got, d)
+	}
+
+	time.Sleep(80 * time.Millisecond)
+	if n := countWhere(r.snapshot(), func(e event) bool { return e.kind == publish }); n != 0 {
+		t.Fatalf("no warning events may fire for an already-past deadline, got %+v", r.snapshot())
+	}
+}
+
+func TestUpdateAncientPastRejected(t *testing.T) {
 	r := &fakeRecorder{}
 	w := newWatcher(50*time.Millisecond, r)
 	defer w.Close()
@@ -318,12 +342,12 @@ func TestUpdateInPastClearsDeadline(t *testing.T) {
 	// Drain the stateChange from the seed.
 	waitForEvents(t, r, 1)
 
-	err := w.Update(time.Now().Add(-1 * time.Hour))
+	err := w.Update(time.Now().Add(-31 * 24 * time.Hour))
 	if !errors.Is(err, ErrDeadlineInPast) {
 		t.Fatalf("want ErrDeadlineInPast, got %v", err)
 	}
 	if !w.Deadline().IsZero() {
-		t.Fatalf("in-past update must clear the deadline, got %v", w.Deadline())
+		t.Fatalf("rejected ancient-past update must clear the deadline, got %v", w.Deadline())
 	}
 	events := waitForEvents(t, r, 2)
 	if events[1].kind != stateChange {
@@ -331,39 +355,25 @@ func TestUpdateInPastClearsDeadline(t *testing.T) {
 	}
 }
 
-func TestUpdateWithinSkewAccepted(t *testing.T) {
-	r := &fakeRecorder{}
-	w := newWatcher(50*time.Millisecond, r)
-	defer w.Close()
-
-	// 5 seconds in the past is within the 30s Skew tolerance — accept it.
-	d := time.Now().Add(-5 * time.Second)
-	if err := w.Update(d); err != nil {
-		t.Fatalf("within-skew Update should succeed, got %v", err)
-	}
-	if !w.Deadline().Equal(d) {
-		t.Fatalf("expected deadline to be applied, got %v want %v", w.Deadline(), d)
-	}
-}
-
 func TestCloseSilencesUpdates(t *testing.T) {
 	r := &fakeRecorder{}
 	w := newWatcher(50*time.Millisecond, r)
 	w.Close()
 
-	_ = w.Update(time.Now().Add(time.Hour))
-
-	time.Sleep(20 * time.Millisecond)
+	if err := w.Update(time.Now().Add(time.Hour)); err != nil {
+		t.Fatalf("Update after Close: want nil, got %v", err)
+	}
 	if got := r.snapshot(); len(got) != 0 {
 		t.Fatalf("expected no events after Close, got %+v", got)
 	}
 }
 
-// TestCloseClearsRecorderDeadline pins the profile-switch fix: a watcher
-// holding a live deadline must zero the recorder on Close so the next
-// engine's watcher (and the UI reading the shared server-scoped recorder)
-// doesn't start out showing the previous session's stale "expires in".
-func TestCloseClearsRecorderDeadline(t *testing.T) {
+// TestCloseKeepsRecorderDeadline pins the reconnect-flap fix: the watcher
+// closes on every engine restart (network change, sleep/wake) while the
+// SSO deadline stays valid across those, so Close must leave the
+// server-scoped recorder's value in place. The client run loop clears the
+// recorder when it exits for real.
+func TestCloseKeepsRecorderDeadline(t *testing.T) {
 	r := &fakeRecorder{}
 	w := newWatcher(time.Hour, r)
 
@@ -377,8 +387,8 @@ func TestCloseClearsRecorderDeadline(t *testing.T) {
 
 	w.Close()
 
-	if got := r.deadline(); !got.IsZero() {
-		t.Fatalf("recorder deadline after Close = %v, want zero", got)
+	if got := r.deadline(); !got.Equal(d) {
+		t.Fatalf("recorder deadline after Close = %v, want %v", got, d)
 	}
 }
 

client/internal/auth/util.go

@@ -20,14 +20,26 @@ func randomBytesInHex(count int) (string, error) {
 	return hex.EncodeToString(buf), nil
 }
 
-// isValidAccessToken is a simple validation of the access token
-func isValidAccessToken(token string, audience string) error {
+// validateTokenAudience checks that the token is a well-formed JWT whose
+// audience claim matches the expected audience.
+//
+// It does NOT verify the token's cryptographic signature and therefore must not
+// be treated as an authenticity check. The token is obtained by the client
+// directly from the IdP token endpoint over TLS, and its signature is verified
+// server-side by the management server against the IdP's JWKS
+// (see shared/auth/jwt/validator.go). This function is only a client-side
+// sanity check that the returned token targets the expected audience.
+func validateTokenAudience(token string, audience string) error {
 	if token == "" {
 		return fmt.Errorf("token received is empty")
 	}
 
-	encodedClaims := strings.Split(token, ".")[1]
-	claimsString, err := base64.RawURLEncoding.DecodeString(encodedClaims)
+	parts := strings.Split(token, ".")
+	if len(parts) != 3 {
+		return fmt.Errorf("token is not a well-formed JWT")
+	}
+
+	claimsString, err := base64.RawURLEncoding.DecodeString(parts[1])
 	if err != nil {
 		return err
 	}

client/internal/auth/util_test.go

@@ -0,0 +1,108 @@
+package auth
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"testing"
+)
+
+// makeJWT builds an unsigned JWT-shaped string (header.payload.signature) with
+// the given claims payload. The signature part is arbitrary because
+// validateTokenAudience intentionally does not verify it.
+func makeJWT(t *testing.T, claims map[string]interface{}) string {
+	t.Helper()
+	header := base64.RawURLEncoding.EncodeToString([]byte(`{"alg":"RS256","typ":"JWT"}`))
+	payloadBytes, err := json.Marshal(claims)
+	if err != nil {
+		t.Fatalf("marshal claims: %v", err)
+	}
+	payload := base64.RawURLEncoding.EncodeToString(payloadBytes)
+	return header + "." + payload + ".unverified-signature"
+}
+
+func TestValidateTokenAudience(t *testing.T) {
+	tests := []struct {
+		name     string
+		token    string
+		audience string
+		wantErr  bool
+	}{
+		{
+			name:     "empty token",
+			token:    "",
+			audience: "netbird",
+			wantErr:  true,
+		},
+		{
+			name:     "not a JWT - no dots",
+			token:    "notajwt",
+			audience: "netbird",
+			wantErr:  true,
+		},
+		{
+			name:     "not a JWT - two parts only",
+			token:    "header.payload",
+			audience: "netbird",
+			wantErr:  true,
+		},
+		{
+			name:     "matching string audience",
+			token:    makeJWT(t, map[string]interface{}{"aud": "netbird"}),
+			audience: "netbird",
+			wantErr:  false,
+		},
+		{
+			name:     "mismatching string audience",
+			token:    makeJWT(t, map[string]interface{}{"aud": "other"}),
+			audience: "netbird",
+			wantErr:  true,
+		},
+		{
+			name:     "matching audience in array",
+			token:    makeJWT(t, map[string]interface{}{"aud": []interface{}{"other", "netbird"}}),
+			audience: "netbird",
+			wantErr:  false,
+		},
+		{
+			name:     "mismatching audience array",
+			token:    makeJWT(t, map[string]interface{}{"aud": []interface{}{"a", "b"}}),
+			audience: "netbird",
+			wantErr:  true,
+		},
+		{
+			name:     "missing audience claim",
+			token:    makeJWT(t, map[string]interface{}{"sub": "user"}),
+			audience: "netbird",
+			wantErr:  true,
+		},
+		{
+			name:     "invalid base64 payload",
+			token:    "header.!!!not-base64!!!.sig",
+			audience: "netbird",
+			wantErr:  true,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			err := validateTokenAudience(tc.token, tc.audience)
+			if tc.wantErr && err == nil {
+				t.Fatalf("expected error, got nil")
+			}
+			if !tc.wantErr && err != nil {
+				t.Fatalf("expected no error, got %v", err)
+			}
+		})
+	}
+}
+
+// TestValidateTokenAudienceNoPanic guards the regression where a non-empty
+// token without the JWT dot structure caused an index-out-of-range panic.
+func TestValidateTokenAudienceNoPanic(t *testing.T) {
+	inputs := []string{"a", ".", "a.", "aaaa", "no-dots-here"}
+	for _, in := range inputs {
+		if err := validateTokenAudience(in, "netbird"); err == nil {
+			t.Fatalf("expected error for malformed token %q, got nil", in)
+		}
+	}
+}

client/internal/conn_mgr.go

@@ -34,6 +34,8 @@ const (
 // - Handling connection establishment based on peer signaling
 //
 // The implementation is not thread-safe; it is protected by engine.syncMsgMux.
+// The only exception is ActivatePeer, which is safe for concurrent use so the
+// DNS warm-up path can call it without contending on the engine mutex.
 type ConnMgr struct {
 	peerStore        *peerstore.Store
 	statusRecorder   *peer.Status
@@ -42,12 +44,26 @@ type ConnMgr struct {
 	rosenpassEnabled bool
 
 	lazyConnMgr *manager.Manager
+	// lazyConnMgrMu guards the lazyConnMgr pointer for readers outside the
+	// engine loop (ActivatePeer). Writers hold it in addition to
+	// engine.syncMsgMux; all other reads stay under engine.syncMsgMux only.
+	lazyConnMgrMu sync.RWMutex
+
+	// reconcileRoutedIPs re-applies a peer's routed allowed IPs after its lazy wake endpoint is
+	// (re)armed (Mode A at arm time). Injected by the engine; nil disables the reconcile.
+	reconcileRoutedIPs func(peerKey string) error
 
 	wg            sync.WaitGroup
 	lazyCtx       context.Context
 	lazyCtxCancel context.CancelFunc
 }
 
+// SetRoutedIPsReconciler injects the callback used to re-apply a peer's routed allowed IPs when
+// its lazy wake endpoint is (re)armed. Must be called before the lazy manager starts.
+func (e *ConnMgr) SetRoutedIPsReconciler(fn func(peerKey string) error) {
+	e.reconcileRoutedIPs = fn
+}
+
 func NewConnMgr(engineConfig *EngineConfig, statusRecorder *peer.Status, peerStore *peerstore.Store, iface lazyconn.WGIface) *ConnMgr {
 	e := &ConnMgr{
 		peerStore:        peerStore,
@@ -238,12 +254,20 @@ func (e *ConnMgr) RemovePeerConn(peerKey string) {
 	conn.Log.Infof("removed peer from lazy conn manager")
 }
 
+// ActivatePeer wakes an idle lazy connection. Unlike the rest of ConnMgr it is
+// safe for concurrent use: the lazy manager pointer is read under lazyConnMgrMu
+// and the manager itself is internally synchronized, so callers outside the
+// engine loop (DNS warm-up) do not need engine.syncMsgMux.
 func (e *ConnMgr) ActivatePeer(ctx context.Context, conn *peer.Conn) {
-	if !e.isStartedWithLazyMgr() {
+	e.lazyConnMgrMu.RLock()
+	lazyConnMgr := e.lazyConnMgr
+	started := lazyConnMgr != nil && e.lazyCtxCancel != nil
+	e.lazyConnMgrMu.RUnlock()
+	if !started {
 		return
 	}
 
-	if found := e.lazyConnMgr.ActivatePeer(conn.GetKey()); found {
+	if found := lazyConnMgr.ActivatePeer(conn.GetKey()); found {
 		if err := conn.Open(ctx); err != nil {
 			conn.Log.Errorf("failed to open connection: %v", err)
 		}
@@ -268,16 +292,22 @@ func (e *ConnMgr) Close() {
 
 	e.lazyCtxCancel()
 	e.wg.Wait()
+
+	e.lazyConnMgrMu.Lock()
 	e.lazyConnMgr = nil
+	e.lazyConnMgrMu.Unlock()
 }
 
 func (e *ConnMgr) initLazyManager(engineCtx context.Context) {
 	cfg := manager.Config{
 		InactivityThreshold: inactivityThresholdEnv(),
+		ReconcileAllowedIPs: e.reconcileRoutedIPs,
 	}
-	e.lazyConnMgr = manager.NewManager(cfg, engineCtx, e.peerStore, e.iface)
 
+	e.lazyConnMgrMu.Lock()
+	e.lazyConnMgr = manager.NewManager(cfg, engineCtx, e.peerStore, e.iface)
 	e.lazyCtx, e.lazyCtxCancel = context.WithCancel(engineCtx)
+	e.lazyConnMgrMu.Unlock()
 
 	e.wg.Add(1)
 	go func() {
@@ -316,7 +346,10 @@ func (e *ConnMgr) closeManager(ctx context.Context) {
 
 	e.lazyCtxCancel()
 	e.wg.Wait()
+
+	e.lazyConnMgrMu.Lock()
 	e.lazyConnMgr = nil
+	e.lazyConnMgrMu.Unlock()
 
 	for _, peerID := range e.peerStore.PeersPubKey() {
 		e.peerStore.PeerConnOpen(ctx, peerID)
@@ -352,11 +385,20 @@ func inactivityThresholdEnv() *time.Duration {
 		return nil
 	}
 
-	parsedMinutes, err := strconv.Atoi(envValue)
-	if err != nil || parsedMinutes <= 0 {
-		return nil
+	// Documented format: a Go duration such as "30m" or "1h".
+	if d, err := time.ParseDuration(envValue); err == nil {
+		if d <= 0 {
+			return nil
+		}
+		return &d
 	}
 
-	d := time.Duration(parsedMinutes) * time.Minute
-	return &d
+	// Backwards compatibility: a bare integer used to be interpreted as minutes.
+	if parsedMinutes, err := strconv.Atoi(envValue); err == nil && parsedMinutes > 0 {
+		d := time.Duration(parsedMinutes) * time.Minute
+		return &d
+	}
+
+	log.Warnf("invalid %s value %q: expected a Go duration such as 30m or 1h", lazyconn.EnvInactivityThreshold, envValue)
+	return nil
 }

client/internal/conn_mgr_test.go

@@ -1,10 +1,21 @@
 package internal
 
 import (
+	"context"
+	"net"
+	"net/netip"
 	"os"
+	"sync"
 	"testing"
+	"time"
 
+	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
+
+	"github.com/netbirdio/netbird/client/iface/wgaddr"
 	"github.com/netbirdio/netbird/client/internal/lazyconn"
+	"github.com/netbirdio/netbird/client/internal/peer"
+	"github.com/netbirdio/netbird/client/internal/peerstore"
+	"github.com/netbirdio/netbird/monotime"
 )
 
 func TestResolveLazyForce(t *testing.T) {
@@ -38,3 +49,93 @@ func TestResolveLazyForce(t *testing.T) {
 		})
 	}
 }
+
+type mockLazyWGIface struct{}
+
+func (mockLazyWGIface) RemovePeer(string) error { return nil }
+func (mockLazyWGIface) UpdatePeer(string, []netip.Prefix, time.Duration, *net.UDPAddr, *wgtypes.Key) error {
+	return nil
+}
+func (mockLazyWGIface) IsUserspaceBind() bool                    { return false }
+func (mockLazyWGIface) Address() wgaddr.Address                  { return wgaddr.Address{} }
+func (mockLazyWGIface) LastActivities() map[string]monotime.Time { return nil }
+func (mockLazyWGIface) MTU() uint16                              { return 1280 }
+
+// TestConnMgr_ActivatePeerConcurrentWithLifecycle exercises ActivatePeer from
+// non-engine goroutines (the DNS warm-up path) racing the manager lifecycle,
+// which stays on the engine loop. Run with -race: it fails if ActivatePeer
+// still requires engine.syncMsgMux for safety.
+func TestConnMgr_ActivatePeerConcurrentWithLifecycle(t *testing.T) {
+	t.Setenv(lazyconn.EnvLazyConn, "on")
+
+	status := peer.NewRecorder("https://mgm")
+	store := peerstore.NewConnStore()
+	connMgr := NewConnMgr(&EngineConfig{}, status, store, mockLazyWGIface{})
+
+	conn := newTestPeerConn(t, "peerA")
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	connMgr.Start(ctx)
+
+	done := make(chan struct{})
+	var wg sync.WaitGroup
+	for range 4 {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			for {
+				select {
+				case <-done:
+					return
+				default:
+					connMgr.ActivatePeer(ctx, conn)
+				}
+			}
+		}()
+	}
+
+	// Let the activators spin against the started manager, then tear it down
+	// underneath them and let them spin against the stopped manager.
+	time.Sleep(100 * time.Millisecond)
+	connMgr.Close()
+	time.Sleep(50 * time.Millisecond)
+
+	close(done)
+	wg.Wait()
+}
+
+func TestInactivityThresholdEnv(t *testing.T) {
+	tests := []struct {
+		name string
+		val  string
+		want *time.Duration
+	}{
+		{name: "unset", val: "", want: nil},
+		{name: "go duration minutes", val: "30m", want: durPtr(30 * time.Minute)},
+		{name: "go duration hours", val: "1h", want: durPtr(time.Hour)},
+		{name: "go duration seconds", val: "90s", want: durPtr(90 * time.Second)},
+		{name: "bare integer is minutes (backwards compat)", val: "5", want: durPtr(5 * time.Minute)},
+		{name: "zero duration", val: "0s", want: nil},
+		{name: "zero integer", val: "0", want: nil},
+		{name: "negative duration", val: "-5m", want: nil},
+		{name: "garbage", val: "abc", want: nil},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Setenv(lazyconn.EnvInactivityThreshold, tc.val)
+			got := inactivityThresholdEnv()
+			switch {
+			case tc.want == nil && got != nil:
+				t.Fatalf("want nil, got %v", *got)
+			case tc.want != nil && got == nil:
+				t.Fatalf("want %v, got nil", *tc.want)
+			case tc.want != nil && *got != *tc.want:
+				t.Fatalf("want %v, got %v", *tc.want, *got)
+			}
+		})
+	}
+}
+
+func durPtr(d time.Duration) *time.Duration { return &d }

client/internal/connect.go

@@ -34,6 +34,7 @@ import (
 	"github.com/netbirdio/netbird/client/internal/profilemanager"
 	"github.com/netbirdio/netbird/client/internal/statemanager"
 	"github.com/netbirdio/netbird/client/internal/stdnet"
+	"github.com/netbirdio/netbird/client/internal/tunnelnotifier"
 	"github.com/netbirdio/netbird/client/internal/updater"
 	"github.com/netbirdio/netbird/client/internal/updater/installer"
 	nbnet "github.com/netbirdio/netbird/client/net"
@@ -136,10 +137,13 @@ func (c *ConnectClient) RunOniOS(
 	// Set GC percent to 5% to reduce memory usage as iOS only allows 50MB of memory for the extension.
 	debug.SetGCPercent(5)
 
+	notifier := tunnelnotifier.New(networkChangeListener, dnsManager)
+	defer notifier.Close()
+
 	mobileDependency := MobileDependency{
 		FileDescriptor:        fileDescriptor,
-		NetworkChangeListener: networkChangeListener,
-		DnsManager:            dnsManager,
+		NetworkChangeListener: notifier,
+		DnsManager:            notifier,
 		StateFilePath:         stateFilePath,
 		TempDir:               cacheDir,
 	}
@@ -257,7 +261,10 @@ func (c *ConnectClient) run(mobileDependency MobileDependency, runningChan chan
 		log.Errorf("failed to clean up temporary installer file: %v", err)
 	}
 
-	defer c.statusRecorder.ClientStop()
+	defer func() {
+		c.statusRecorder.SetSessionExpiresAt(time.Time{})
+		c.statusRecorder.ClientStop()
+	}()
 	operation := func() error {
 		// if context cancelled we not start new backoff cycle
 		if c.ctx.Err() != nil {
@@ -618,6 +625,7 @@ func createEngineConfig(key wgtypes.Key, config *profilemanager.Config, peerConf
 		BlockLANAccess:      config.BlockLANAccess,
 		BlockInbound:        config.BlockInbound,
 		DisableIPv6:         config.DisableIPv6,
+		SyncMessageVersion:  config.SyncMessageVersion,
 
 		LazyConnection: lazyconn.ParseState(config.LazyConnection),
 
@@ -693,6 +701,7 @@ func loginToManagement(ctx context.Context, client mgm.Client, pubSSHKey []byte,
 		config.BlockLANAccess,
 		config.BlockInbound,
 		config.DisableIPv6,
+		config.SyncMessageVersion,
 		config.EnableSSHRoot,
 		config.EnableSSHSFTP,
 		config.EnableSSHLocalPortForwarding,

client/internal/daemonaddr/owner.go

@@ -0,0 +1,15 @@
+package daemonaddr
+
+// DaemonRunsAsSelf reports whether the daemon listening at addr runs as this very
+// user. That is what makes an unprivileged daemon authorize this process for the
+// changes it otherwise restricts to root or an administrator, so a client can tell
+// up front whether those controls are usable instead of letting a save fail.
+//
+// It is answered from the ownership of the socket or pipe the daemon created, so it
+// costs no round trip and needs no cooperation from the daemon. Ownership that
+// cannot be read is reported as false, including for a TCP address, so a caller
+// reading this as "the daemon would allow it" fails closed. The daemon remains the
+// only thing that authorizes anything: this only decides what a client offers.
+func DaemonRunsAsSelf(addr string) bool {
+	return daemonRunsAsSelf(addr)
+}

client/internal/daemonaddr/owner_unix.go

@@ -0,0 +1,40 @@
+//go:build !windows
+
+package daemonaddr
+
+import (
+	"os"
+	"strings"
+	"syscall"
+
+	log "github.com/sirupsen/logrus"
+)
+
+// daemonRunsAsSelf compares the owner of the daemon's Unix socket with this
+// process's uid. Root is not treated specially here: a root caller is privileged
+// on its own merits, and a root-owned socket says nothing about the caller.
+func daemonRunsAsSelf(addr string) bool {
+	path, ok := strings.CutPrefix(addr, "unix://")
+	if !ok {
+		return false
+	}
+
+	info, err := os.Stat(path)
+	if err != nil {
+		log.Debugf("stat daemon socket %s: %v", path, err)
+		return false
+	}
+
+	// Only a socket says anything about a daemon. A directory or a leftover
+	// regular file at that path is not one, and reading it as "the daemon runs as
+	// us" would offer controls the daemon then refuses.
+	if info.Mode()&os.ModeSocket == 0 {
+		return false
+	}
+
+	stat, ok := info.Sys().(*syscall.Stat_t)
+	if !ok {
+		return false
+	}
+	return stat.Uid == uint32(os.Getuid())
+}

client/internal/daemonaddr/owner_unix_test.go

@@ -0,0 +1,62 @@
+//go:build !windows
+
+package daemonaddr
+
+import (
+	"net"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+// A socket this user created means the daemon runs as this user, which is the
+// rootless case where the daemon delegates its authority to its own identity.
+func TestDaemonRunsAsSelf_OwnSocket(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "netbird.sock")
+	ln, err := net.Listen("unix", path)
+	if err != nil {
+		t.Fatalf("listen: %v", err)
+	}
+	t.Cleanup(func() {
+		if err := ln.Close(); err != nil {
+			t.Logf("close listener: %v", err)
+		}
+	})
+
+	if !DaemonRunsAsSelf("unix://" + path) {
+		t.Error("a socket owned by this user must count as the daemon running as us")
+	}
+}
+
+// Everything that is not a readable socket of ours has to answer false, because
+// the caller reads a true as "the daemon would authorize me".
+func TestDaemonRunsAsSelf_FailsClosed(t *testing.T) {
+	dir := t.TempDir()
+
+	// A socket owned by another user, which is what a root-run daemon looks like
+	// to an unprivileged client. Only assertable when we are not root ourselves.
+	rootOwned := "unix:///var/run/netbird.sock"
+	if _, err := os.Stat("/var/run/netbird.sock"); err == nil && os.Getuid() != 0 {
+		if DaemonRunsAsSelf(rootOwned) {
+			t.Error("a socket owned by another user must not count as ours")
+		}
+	}
+
+	for name, addr := range map[string]string{
+		"missing socket":  "unix://" + filepath.Join(dir, "absent.sock"),
+		"tcp address":     "tcp://127.0.0.1:41731",
+		"named pipe":      "npipe://netbird",
+		"empty":           "",
+		"no scheme":       filepath.Join(dir, "absent.sock"),
+		"directory":       "unix://" + dir,
+		"unknown scheme":  "http://localhost:8080",
+		"scheme only":     "unix://",
+		"relative socket": "unix://netbird.sock",
+	} {
+		t.Run(name, func(t *testing.T) {
+			if DaemonRunsAsSelf(addr) {
+				t.Errorf("%q must not count as a daemon running as us", addr)
+			}
+		})
+	}
+}

client/internal/daemonaddr/owner_windows.go

@@ -0,0 +1,42 @@
+//go:build windows
+
+package daemonaddr
+
+import (
+	"context"
+	"strings"
+
+	log "github.com/sirupsen/logrus"
+
+	"github.com/netbirdio/netbird/client/internal/ipcauth"
+)
+
+// daemonRunsAsSelf reads the owner of the daemon's pipe. A daemon running as the
+// service account owns its pipe as LocalSystem, and an elevated one as
+// BUILTIN\Administrators, so only a daemon the user started themselves matches.
+func daemonRunsAsSelf(addr string) bool {
+	name, ok := strings.CutPrefix(addr, pipeScheme)
+	if !ok {
+		return false
+	}
+
+	for _, path := range PipePaths(name) {
+		// Bounded: this runs on the UI's path for deciding which controls to
+		// offer, so a pipe that does not answer promptly must not stall it. A
+		// timeout leaves the caller unprivileged, which only disables controls.
+		ctx, cancel := context.WithTimeout(context.Background(), probeTimeout)
+		conn, err := dialPipe(ctx, path)
+		cancel()
+		if err != nil {
+			continue
+		}
+
+		owned := ipcauth.PipeOwnedBySelf(conn)
+		if cerr := conn.Close(); cerr != nil {
+			log.Debugf("close daemon pipe %s after ownership check: %v", path, cerr)
+		}
+		return owned
+	}
+
+	return false
+}

client/internal/daemonaddr/pipe.go

@@ -0,0 +1,103 @@
+package daemonaddr
+
+import (
+	"context"
+	"net"
+	"runtime"
+	"strings"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+)
+
+const (
+	// WindowsPipeAddr is the default daemon address on Windows. A named pipe
+	// carries the connecting process's token, which loopback TCP does not, so
+	// it is the only Windows transport on which the daemon can tell who is
+	// calling it.
+	WindowsPipeAddr = "npipe://netbird"
+
+	// legacyWindowsAddr is the loopback-TCP address the Windows daemon used
+	// before named-pipe support.
+	legacyWindowsAddr = "tcp://127.0.0.1:41731"
+
+	pipeScheme = "npipe://"
+
+	// protectedPrefix is the NPFS namespace in which only LocalSystem and
+	// members of BUILTIN\Administrators may create a pipe. A daemon running as
+	// the service account creates its pipe there so that an unprivileged process
+	// cannot pre-create the name, which would keep the daemon from starting and
+	// leave callers talking to the squatter. Opening such a pipe needs no
+	// privilege, so unprivileged clients still reach the daemon.
+	protectedPrefix = `ProtectedPrefix\Administrators\`
+)
+
+// DialTarget returns the gRPC dial target and transport options for a daemon
+// address. The npipe scheme needs a context dialer because gRPC has no
+// named-pipe resolver; unix and tcp are handled by gRPC itself.
+func DialTarget(addr string) (string, []grpc.DialOption) {
+	opts := []grpc.DialOption{grpc.WithTransportCredentials(insecure.NewCredentials())}
+
+	if name, ok := strings.CutPrefix(addr, pipeScheme); ok {
+		paths := PipePaths(name)
+		opts = append(opts, grpc.WithContextDialer(func(ctx context.Context, _ string) (net.Conn, error) {
+			return dialPipePaths(ctx, paths)
+		}))
+		return "passthrough:///netbird-daemon-pipe", opts
+	}
+
+	return strings.TrimPrefix(addr, "tcp://"), opts
+}
+
+// PipePath maps an npipe address name ("netbird", from "npipe://netbird") to a
+// Windows named-pipe path (\\.\pipe\netbird). A fully qualified path is left as
+// is.
+func PipePath(name string) string {
+	if strings.HasPrefix(name, `\\`) {
+		return name
+	}
+	return `\\.\pipe\` + name
+}
+
+// PipePaths returns the paths a daemon control pipe may live at for an npipe
+// address name, in the order both sides must try them: the protected name first,
+// then the plain one.
+//
+// The daemon serves the first it can create, which is the protected name when it
+// runs as the service account and the plain one when it runs as an ordinary user,
+// as it does in netstack mode. Clients therefore have to try both, and because a
+// client cannot tell from the name alone who created the pipe, the plain name is
+// only usable once the server's identity has been checked: see
+// verifyPipeServer.
+//
+// A fully qualified path is what the operator asked for and is used as is.
+func PipePaths(name string) []string {
+	if strings.HasPrefix(name, `\\`) {
+		return []string{name}
+	}
+	return []string{PipePath(protectedPrefix + name), PipePath(name)}
+}
+
+// IsProtectedPipePath reports whether a pipe path is in the namespace only an
+// administrator or LocalSystem can create in, which is what lets a client trust
+// such a pipe from its name alone.
+func IsProtectedPipePath(path string) bool {
+	return strings.HasPrefix(path, `\\.\pipe\`+protectedPrefix)
+}
+
+// MigrateLegacy upgrades the pre-named-pipe Windows daemon address to the named
+// pipe, reporting whether it rewrote the address. Existing installs persist the
+// daemon address, so without this an upgraded daemon would keep listening on
+// loopback TCP, where callers carry no identity and privileged operations would
+// have to be refused for everyone. Only the exact legacy default is rewritten:
+// a deliberately chosen custom address is left alone.
+func MigrateLegacy(addr string) (string, bool) {
+	return migrateLegacyForOS(runtime.GOOS, addr)
+}
+
+func migrateLegacyForOS(goos, addr string) (string, bool) {
+	if goos == "windows" && addr == legacyWindowsAddr {
+		return WindowsPipeAddr, true
+	}
+	return addr, false
+}

client/internal/daemonaddr/pipe_other.go

@@ -0,0 +1,15 @@
+//go:build !windows
+
+package daemonaddr
+
+import (
+	"context"
+	"fmt"
+	"net"
+)
+
+// dialPipePaths is Windows-only: no other platform serves the daemon on a named
+// pipe.
+func dialPipePaths(context.Context, []string) (net.Conn, error) {
+	return nil, fmt.Errorf("named pipes are only supported on Windows")
+}

client/internal/daemonaddr/pipe_test.go

@@ -0,0 +1,30 @@
+package daemonaddr
+
+import (
+	"slices"
+	"testing"
+)
+
+// The protected name must be tried before the plain one on both sides: it is the
+// one an unprivileged process cannot create, so preferring it is what keeps a
+// squatter from owning the name the service daemon would otherwise use.
+func TestPipePaths_PrefersTheProtectedName(t *testing.T) {
+	got := PipePaths("netbird")
+	want := []string{
+		`\\.\pipe\ProtectedPrefix\Administrators\netbird`,
+		`\\.\pipe\netbird`,
+	}
+	if !slices.Equal(got, want) {
+		t.Errorf("PipePaths = %q, want %q", got, want)
+	}
+}
+
+// An operator who passes a full path chose exactly one pipe, so neither side may
+// look anywhere else.
+func TestPipePaths_QualifiedPathIsUsedAsIs(t *testing.T) {
+	path := `\\.\pipe\custom-netbird`
+	got := PipePaths(path)
+	if !slices.Equal(got, []string{path}) {
+		t.Errorf("PipePaths = %q, want just %q", got, path)
+	}
+}

client/internal/daemonaddr/pipe_windows.go

@@ -0,0 +1,59 @@
+//go:build windows
+
+package daemonaddr
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net"
+
+	"github.com/Microsoft/go-winio"
+	log "github.com/sirupsen/logrus"
+	"golang.org/x/sys/windows"
+
+	"github.com/netbirdio/netbird/client/internal/ipcauth"
+)
+
+// dialPipePaths connects to the first path that answers with a pipe server this
+// client may trust, and returns the last error when none does.
+func dialPipePaths(ctx context.Context, paths []string) (net.Conn, error) {
+	var lastErr error
+	for _, path := range paths {
+		conn, err := dialPipe(ctx, path)
+		if err != nil {
+			log.Debugf("dial daemon pipe %s: %v", path, err)
+			lastErr = err
+			continue
+		}
+
+		// A pipe in the protected namespace could only have been created by an
+		// administrator or LocalSystem, so its name is the guarantee. Any other
+		// name has to be checked, because any local user can create one.
+		if !IsProtectedPipePath(path) {
+			if err := ipcauth.PipeServerTrusted(conn); err != nil {
+				if closeErr := conn.Close(); closeErr != nil {
+					log.Debugf("close untrusted pipe %s: %v", path, closeErr)
+				}
+				lastErr = fmt.Errorf("%s: %w", path, err)
+				continue
+			}
+		}
+
+		return conn, nil
+	}
+
+	if lastErr == nil {
+		lastErr = errors.New("no daemon pipe to connect to")
+	}
+	return nil, lastErr
+}
+
+// dialPipe connects to the daemon control pipe at SECURITY_IDENTIFICATION.
+// winio's plain DialPipe connects at SECURITY_ANONYMOUS, under which the daemon
+// cannot read the caller's token at all. Identification lets the daemon read the
+// caller's SID and groups without granting it the ability to act as the caller.
+func dialPipe(ctx context.Context, path string) (net.Conn, error) {
+	access := uint32(windows.GENERIC_READ | windows.GENERIC_WRITE)
+	return winio.DialPipeAccessImpLevel(ctx, path, access, winio.PipeImpLevelIdentification)
+}

client/internal/daemonaddr/resolve_pipe_other.go

@@ -0,0 +1,9 @@
+//go:build !windows
+
+package daemonaddr
+
+// ResolveDaemonAddr is a no-op off Windows, where there is no named-pipe
+// default to fall back from.
+func ResolveDaemonAddr(addr string) string {
+	return addr
+}

client/internal/daemonaddr/resolve_pipe_windows.go

@@ -0,0 +1,82 @@
+//go:build windows
+
+package daemonaddr
+
+import (
+	"net"
+	"strings"
+	"time"
+
+	"github.com/Microsoft/go-winio"
+	log "github.com/sirupsen/logrus"
+)
+
+// probeTimeout bounds each transport probe. Both are local, so a daemon that is
+// listening answers immediately and one that is not fails immediately.
+const probeTimeout = 300 * time.Millisecond
+
+// ResolveDaemonAddr keeps a client on the named pipe and never silently moves it
+// off. When the pipe does not answer it checks the legacy loopback TCP address, so
+// a client meeting a daemon that has not restarted since the upgrade can say what
+// is wrong, but it does not connect there.
+//
+// Using that address automatically would be a downgrade the user never asked for:
+// any local process can bind 127.0.0.1 while the daemon is not listening, and the
+// transport carries no caller identity, so a client that accepted whatever answered
+// would hand a setup key, a pre-shared key or an SSO prompt to a local impostor. An
+// operator who needs the legacy address during the upgrade window can still pass
+// --daemon-addr explicitly, which is a deliberate choice and still refuses the
+// privileged operations.
+//
+// Only the pipe address is resolved. A custom address is left alone, though passing
+// --daemon-addr npipe://netbird explicitly is indistinguishable from the default
+// here, so it is treated the same way.
+func ResolveDaemonAddr(addr string) string {
+	if addr != WindowsPipeAddr {
+		return addr
+	}
+
+	for _, path := range PipePaths("netbird") {
+		if pipeAvailable(path) {
+			return addr
+		}
+	}
+
+	if tcpAvailable(legacyWindowsAddr) {
+		log.Warnf("the daemon is not serving %s, but something is listening on the legacy %s. "+
+			"Restart the NetBird service so it serves the pipe. That address is not used automatically: "+
+			"any local user can bind it and it carries no caller identity, so pass --daemon-addr %s "+
+			"explicitly if you accept that",
+			WindowsPipeAddr, legacyWindowsAddr, legacyWindowsAddr)
+	}
+
+	return addr
+}
+
+func pipeAvailable(path string) bool {
+	timeout := probeTimeout
+	conn, err := winio.DialPipe(path, &timeout)
+	if err != nil {
+		return false
+	}
+	if err := conn.Close(); err != nil {
+		log.Debugf("close daemon pipe probe: %v", err)
+	}
+	return true
+}
+
+func tcpAvailable(addr string) bool {
+	host := addr
+	if _, after, ok := strings.Cut(addr, "://"); ok {
+		host = after
+	}
+
+	conn, err := net.DialTimeout("tcp", host, probeTimeout)
+	if err != nil {
+		return false
+	}
+	if err := conn.Close(); err != nil {
+		log.Debugf("close daemon TCP probe: %v", err)
+	}
+	return true
+}

client/internal/debug/debug.go

@@ -229,7 +229,6 @@ scutil_dns.txt (macOS only):
 
 const (
 	clientLogFile = "client.log"
-	uiLogFile     = "gui-client.log"
 	errorLogFile  = "netbird.err"
 	stdoutLogFile = "netbird.out"
 
@@ -248,6 +247,20 @@ type MetricsExporter interface {
 	Export(w io.Writer) error
 }
 
+// LogOpener opens a log file for inclusion in the bundle. It exists so that log
+// files whose path was supplied by an IPC caller can be opened under a check
+// the daemon defines, instead of being opened with the daemon's privileges
+// unconditionally.
+type LogOpener func(path string) (*os.File, error)
+
+func openLogFile(path string) (*os.File, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, fmt.Errorf("open %s: %w", path, err)
+	}
+	return f, nil
+}
+
 type BundleGenerator struct {
 	anonymizer *anonymize.Anonymizer
 
@@ -257,6 +270,7 @@ type BundleGenerator struct {
 	syncResponse   *mgmProto.SyncResponse
 	logPath        string
 	uiLogPath      string
+	uiLogOpener    LogOpener
 	tempDir        string
 	statePath      string
 	cpuProfile     []byte
@@ -285,14 +299,20 @@ type GeneratorDependencies struct {
 	SyncResponse   *mgmProto.SyncResponse
 	LogPath        string
 	UILogPath      string // Absolute path to the desktop UI's gui-client.log, reported via RegisterUILog. Empty if no UI registered one.
-	TempDir        string // Directory for temporary bundle zip files. If empty, os.TempDir() is used.
-	StatePath      string // Path to the state file. If empty, the ServiceManager default path is used.
-	CPUProfile     []byte
-	CapturePath    string
-	RefreshStatus  func()
-	ClientMetrics  MetricsExporter
-	DaemonVersion  string
-	CliVersion     string
+	// UILogOpener opens the UI log and its rotated siblings. The path comes from
+	// a local IPC caller, so the daemon must not open it with plain os.Open: the
+	// opener is where the caller's right to that file is enforced. Defaults to
+	// os.Open, which is only correct where the path is not caller-supplied
+	// (mobile).
+	UILogOpener   LogOpener
+	TempDir       string // Directory for temporary bundle zip files. If empty, os.TempDir() is used.
+	StatePath     string // Path to the state file. If empty, the ServiceManager default path is used.
+	CPUProfile    []byte
+	CapturePath   string
+	RefreshStatus func()
+	ClientMetrics MetricsExporter
+	DaemonVersion string
+	CliVersion    string
 }
 
 func NewBundleGenerator(deps GeneratorDependencies, cfg BundleConfig) *BundleGenerator {
@@ -302,6 +322,11 @@ func NewBundleGenerator(deps GeneratorDependencies, cfg BundleConfig) *BundleGen
 		logFileCount = 1
 	}
 
+	uiLogOpener := deps.UILogOpener
+	if uiLogOpener == nil {
+		uiLogOpener = openLogFile
+	}
+
 	return &BundleGenerator{
 		anonymizer: anonymize.NewAnonymizer(anonymize.DefaultAddresses()),
 
@@ -310,6 +335,7 @@ func NewBundleGenerator(deps GeneratorDependencies, cfg BundleConfig) *BundleGen
 		syncResponse:   deps.SyncResponse,
 		logPath:        deps.LogPath,
 		uiLogPath:      deps.UILogPath,
+		uiLogOpener:    uiLogOpener,
 		tempDir:        deps.TempDir,
 		statePath:      deps.StatePath,
 		cpuProfile:     deps.CPUProfile,
@@ -678,6 +704,7 @@ func (g *BundleGenerator) addCommonConfigFields(configContent *strings.Builder)
 	configContent.WriteString(fmt.Sprintf("DisableIPv6: %v\n", g.internalConfig.DisableIPv6))
 	configContent.WriteString(fmt.Sprintf("LocalMetricsEnabled: %v\n", g.internalConfig.LocalMetricsEnabled))
 	configContent.WriteString(fmt.Sprintf("LocalMetricsAddress: %s\n", g.internalConfig.LocalMetricsAddress))
+	configContent.WriteString(fmt.Sprintf("SyncMessageVersion: %v\n", g.internalConfig.SyncMessageVersion))
 
 	if g.internalConfig.DisableNotifications != nil {
 		configContent.WriteString(fmt.Sprintf("DisableNotifications: %v\n", *g.internalConfig.DisableNotifications))
@@ -997,11 +1024,11 @@ func (g *BundleGenerator) addLogfile() error {
 
 	logDir := filepath.Dir(g.logPath)
 
-	if err := g.addSingleLogfile(g.logPath, clientLogFile); err != nil {
+	if err := g.addSingleLogfile(openLogFile, g.logPath, clientLogFile); err != nil {
 		return fmt.Errorf("add client log file to zip: %w", err)
 	}
 
-	g.addRotatedLogFiles(logDir, clientLogPrefix)
+	g.addRotatedLogFiles(openLogFile, logDir, clientLogPrefix)
 
 	stdErrLogPath := filepath.Join(logDir, errorLogFile)
 	stdoutLogPath := filepath.Join(logDir, stdoutLogFile)
@@ -1010,11 +1037,11 @@ func (g *BundleGenerator) addLogfile() error {
 		stdoutLogPath = darwinStdoutLogPath
 	}
 
-	if err := g.addSingleLogfile(stdErrLogPath, errorLogFile); err != nil {
+	if err := g.addSingleLogfile(openLogFile, stdErrLogPath, errorLogFile); err != nil {
 		log.Warnf("Failed to add %s to zip: %v", errorLogFile, err)
 	}
 
-	if err := g.addSingleLogfile(stdoutLogPath, stdoutLogFile); err != nil {
+	if err := g.addSingleLogfile(openLogFile, stdoutLogPath, stdoutLogFile); err != nil {
 		log.Warnf("Failed to add %s to zip: %v", stdoutLogFile, err)
 	}
 
@@ -1031,18 +1058,18 @@ func (g *BundleGenerator) addUILog() error {
 		return nil
 	}
 
-	if err := g.addSingleLogfile(g.uiLogPath, uiLogFile); err != nil {
+	if err := g.addSingleLogfile(g.uiLogOpener, g.uiLogPath, configs.UILogFile); err != nil {
 		return fmt.Errorf("add UI log file to zip: %w", err)
 	}
 
-	g.addRotatedLogFiles(filepath.Dir(g.uiLogPath), uiLogPrefix)
+	g.addRotatedLogFiles(g.uiLogOpener, filepath.Dir(g.uiLogPath), uiLogPrefix)
 
 	return nil
 }
 
 // addSingleLogfile adds a single log file to the archive
-func (g *BundleGenerator) addSingleLogfile(logPath, targetName string) error {
-	logFile, err := os.Open(logPath)
+func (g *BundleGenerator) addSingleLogfile(open LogOpener, logPath, targetName string) error {
+	logFile, err := open(logPath)
 	if err != nil {
 		return fmt.Errorf("open log file %s: %w", targetName, err)
 	}
@@ -1067,8 +1094,8 @@ func (g *BundleGenerator) addSingleLogfile(logPath, targetName string) error {
 }
 
 // addSingleLogFileGz adds a single gzipped log file to the archive
-func (g *BundleGenerator) addSingleLogFileGz(logPath, targetName string) error {
-	f, err := os.Open(logPath)
+func (g *BundleGenerator) addSingleLogFileGz(open LogOpener, logPath, targetName string) error {
+	f, err := open(logPath)
 	if err != nil {
 		return fmt.Errorf("open gz log file %s: %w", targetName, err)
 	}
@@ -1115,7 +1142,7 @@ func (g *BundleGenerator) addSingleLogFileGz(logPath, targetName string) error {
 // addRotatedLogFiles adds rotated log files to the bundle based on logFileCount.
 // prefix is the base log name without extension (e.g. "client", "gui-client");
 // the glob matches both files rotated by us and by logrotate on linux.
-func (g *BundleGenerator) addRotatedLogFiles(logDir, prefix string) {
+func (g *BundleGenerator) addRotatedLogFiles(open LogOpener, logDir, prefix string) {
 	if g.logFileCount == 0 {
 		return
 	}
@@ -1155,9 +1182,9 @@ func (g *BundleGenerator) addRotatedLogFiles(logDir, prefix string) {
 	for i := 0; i < maxFiles; i++ {
 		name := filepath.Base(files[i])
 		if strings.HasSuffix(name, ".gz") {
-			err = g.addSingleLogFileGz(files[i], name)
+			err = g.addSingleLogFileGz(open, files[i], name)
 		} else {
-			err = g.addSingleLogfile(files[i], name)
+			err = g.addSingleLogfile(open, files[i], name)
 		}
 		if err != nil {
 			log.Warnf("failed to add rotated log %s: %v", name, err)

client/internal/debug/debug_ios.go

@@ -27,7 +27,7 @@ func (g *BundleGenerator) addPlatformLog() error {
 	}
 
 	swiftLogPath := filepath.Join(filepath.Dir(g.logPath), swiftLogFile)
-	if err := g.addSingleLogfile(swiftLogPath, swiftLogFile); err != nil {
+	if err := g.addSingleLogfile(openLogFile, swiftLogPath, swiftLogFile); err != nil {
 		// The Swift log is best-effort: the app may not have written it yet.
 		log.Warnf("failed to add %s to debug bundle: %v", swiftLogFile, err)
 	}

client/internal/debug/debug_logfiles_test.go

@@ -97,7 +97,7 @@ func runAddRotatedLogFilesPrefix(t *testing.T, dir, prefix string, logFileCount
 		archive:      zip.NewWriter(&buf),
 		logFileCount: logFileCount,
 	}
-	g.addRotatedLogFiles(dir, prefix)
+	g.addRotatedLogFiles(openLogFile, dir, prefix)
 	require.NoError(t, g.archive.Close())
 
 	zr, err := zip.NewReader(bytes.NewReader(buf.Bytes()), int64(buf.Len()))

client/internal/debug/debug_test.go

@@ -887,6 +887,8 @@ func TestAddConfig_AllFieldsCovered(t *testing.T) {
 		ClientCertKeyPath:             "/tmp/key",
 		LazyConnection:                "on",
 		MTU:                           1280,
+		DisableIPv6:                   true,
+		SyncMessageVersion:            func(v int) *int { return &v }(1),
 	}
 
 	for _, anonymize := range []bool{false, true} {

client/internal/debug/uilog_test.go

@@ -0,0 +1,64 @@
+package debug
+
+import (
+	"archive/zip"
+	"bytes"
+	"fmt"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/netbirdio/netbird/client/configs"
+)
+
+// bundleEntries generates a bundle with the given generator and returns the
+// set of entry names in the resulting archive.
+func bundleEntries(t *testing.T, g *BundleGenerator) map[string]struct{} {
+	t.Helper()
+
+	path, err := g.Generate()
+	require.NoError(t, err)
+	t.Cleanup(func() { _ = os.Remove(path) })
+
+	data, err := os.ReadFile(path)
+	require.NoError(t, err)
+
+	zr, err := zip.NewReader(bytes.NewReader(data), int64(len(data)))
+	require.NoError(t, err)
+
+	names := make(map[string]struct{}, len(zr.File))
+	for _, f := range zr.File {
+		names[f.Name] = struct{}{}
+	}
+	return names
+}
+
+func TestBundleIncludesUILogWhenOpenerAllows(t *testing.T) {
+	path := filepath.Join(t.TempDir(), configs.UILogFile)
+	require.NoError(t, os.WriteFile(path, []byte("gui log"), 0600))
+
+	g := NewBundleGenerator(GeneratorDependencies{
+		UILogPath:   path,
+		UILogOpener: openLogFile,
+	}, BundleConfig{})
+
+	require.Contains(t, bundleEntries(t, g), configs.UILogFile)
+}
+
+// A UILogOpener that refuses (as the ownership check does for a foreign file)
+// keeps the UI log out of the bundle without failing bundle generation.
+func TestBundleExcludesUILogWhenOpenerRefuses(t *testing.T) {
+	path := filepath.Join(t.TempDir(), configs.UILogFile)
+	require.NoError(t, os.WriteFile(path, []byte("secret"), 0600))
+
+	g := NewBundleGenerator(GeneratorDependencies{
+		UILogPath: path,
+		UILogOpener: func(string) (*os.File, error) {
+			return nil, fmt.Errorf("not owned by the caller")
+		},
+	}, BundleConfig{})
+
+	require.NotContains(t, bundleEntries(t, g), configs.UILogFile)
+}

client/internal/debug/upload.go

@@ -3,10 +3,12 @@ package debug
 import (
 	"context"
 	"crypto/sha256"
+	"crypto/tls"
 	"encoding/json"
 	"fmt"
 	"io"
 	"net/http"
+	neturl "net/url"
 	"os"
 
 	"github.com/netbirdio/netbird/upload-server/types"
@@ -14,20 +16,80 @@ import (
 
 const maxBundleUploadSize = 50 * 1024 * 1024
 
-func UploadDebugBundle(ctx context.Context, url, managementURL, filePath string) (key string, err error) {
-	response, err := getUploadURL(ctx, url, managementURL)
+// requireHTTPS refuses any URL the daemon would fetch or upload to that is not
+// https. The daemon runs as root and the bundle carries its logs and state, so a
+// plaintext hop is a place to intercept the bundle or the presigned redirect.
+// The server-side gate already enforces this for the desktop path; this also
+// covers the mobile and job-runner callers that reach this package directly.
+// Skipped when the caller opted into an insecure upload (self-hosted server).
+func requireHTTPS(what, rawURL string) error {
+	parsed, err := neturl.Parse(rawURL)
+	if err != nil {
+		return fmt.Errorf("parse %s: %w", what, err)
+	}
+	if parsed.Scheme != "https" {
+		return fmt.Errorf("%s must use https, got scheme %q", what, parsed.Scheme)
+	}
+	return nil
+}
+
+// uploadClient returns the HTTP client for the upload requests. The default
+// client verifies TLS and refuses a redirect that would downgrade to a non-https
+// hop, so a bundle can never leave over http after an https start. The insecure
+// variant accepts http and untrusted certificates, and is only reachable for a
+// privileged caller that passed --upload-bundle-insecure (see
+// requirePrivilegeForUploadURL).
+func uploadClient(insecure bool) *http.Client {
+	if !insecure {
+		return &http.Client{CheckRedirect: rejectInsecureRedirect}
+	}
+	return &http.Client{
+		Transport: &http.Transport{
+			//nolint:gosec // opt-in, privileged, self-hosted upload servers
+			TLSClientConfig: &tls.Config{InsecureSkipVerify: true, MinVersion: tls.VersionTLS12},
+		},
+	}
+}
+
+// rejectInsecureRedirect refuses a redirect to a non-https target and keeps the
+// standard library's 10-hop limit that a custom CheckRedirect would otherwise
+// disable.
+func rejectInsecureRedirect(req *http.Request, via []*http.Request) error {
+	if req.URL.Scheme != "https" {
+		return fmt.Errorf("refusing redirect to non-https URL %s", req.URL.Redacted())
+	}
+	if len(via) >= 10 {
+		return fmt.Errorf("stopped after 10 redirects")
+	}
+	return nil
+}
+
+func UploadDebugBundle(ctx context.Context, url, managementURL, filePath string, insecure bool) (key string, err error) {
+	if !insecure {
+		if err := requireHTTPS("upload service URL", url); err != nil {
+			return "", err
+		}
+	}
+
+	response, err := getUploadURL(ctx, url, managementURL, insecure)
 	if err != nil {
 		return "", err
 	}
 
-	err = upload(ctx, filePath, response)
+	if !insecure {
+		if err := requireHTTPS("upload URL from service", response.URL); err != nil {
+			return "", err
+		}
+	}
+
+	err = upload(ctx, filePath, response, insecure)
 	if err != nil {
 		return "", err
 	}
 	return response.Key, nil
 }
 
-func upload(ctx context.Context, filePath string, response *types.GetURLResponse) error {
+func upload(ctx context.Context, filePath string, response *types.GetURLResponse, insecure bool) error {
 	fileData, err := os.Open(filePath)
 	if err != nil {
 		return fmt.Errorf("open file: %w", err)
@@ -52,7 +114,7 @@ func upload(ctx context.Context, filePath string, response *types.GetURLResponse
 	req.ContentLength = stat.Size()
 	req.Header.Set("Content-Type", "application/octet-stream")
 
-	putResp, err := http.DefaultClient.Do(req)
+	putResp, err := uploadClient(insecure).Do(req)
 	if err != nil {
 		return fmt.Errorf("upload failed: %v", err)
 	}
@@ -65,16 +127,23 @@ func upload(ctx context.Context, filePath string, response *types.GetURLResponse
 	return nil
 }
 
-func getUploadURL(ctx context.Context, url string, managementURL string) (*types.GetURLResponse, error) {
-	id := getURLHash(managementURL)
-	getReq, err := http.NewRequestWithContext(ctx, "GET", url+"?id="+id, nil)
+func getUploadURL(ctx context.Context, serviceURL string, managementURL string, insecure bool) (*types.GetURLResponse, error) {
+	parsed, err := neturl.Parse(serviceURL)
+	if err != nil {
+		return nil, fmt.Errorf("parse upload service URL: %w", err)
+	}
+	q := parsed.Query()
+	q.Set("id", getURLHash(managementURL))
+	parsed.RawQuery = q.Encode()
+
+	getReq, err := http.NewRequestWithContext(ctx, "GET", parsed.String(), nil)
 	if err != nil {
 		return nil, fmt.Errorf("create GET request: %w", err)
 	}
 
 	getReq.Header.Set(types.ClientHeader, types.ClientHeaderValue)
 
-	resp, err := http.DefaultClient.Do(getReq)
+	resp, err := uploadClient(insecure).Do(getReq)
 	if err != nil {
 		return nil, fmt.Errorf("get presigned URL: %w", err)
 	}

client/internal/debug/upload_test.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"net"
 	"net/http"
+	"net/http/httptest"
 	"os"
 	"path/filepath"
 	"testing"
@@ -43,7 +44,7 @@ func TestUpload(t *testing.T) {
 	fileContent := []byte("test file content")
 	err := os.WriteFile(file, fileContent, 0640)
 	require.NoError(t, err)
-	key, err := UploadDebugBundle(context.Background(), testURL+types.GetURLPath, testURL, file)
+	key, err := UploadDebugBundle(context.Background(), testURL+types.GetURLPath, testURL, file, true)
 	require.NoError(t, err)
 	id := getURLHash(testURL)
 	require.Contains(t, key, id+"/")
@@ -79,3 +80,47 @@ func waitForServer(t *testing.T, addr string) {
 	}
 	t.Fatalf("server did not start listening on %s in time", addr)
 }
+
+func TestRequireHTTPS(t *testing.T) {
+	require.NoError(t, requireHTTPS("upload URL", "https://upload.example/path"))
+	require.Error(t, requireHTTPS("upload URL", "http://upload.example/path"))
+	require.Error(t, requireHTTPS("upload URL", "ftp://upload.example/path"))
+	require.Error(t, requireHTTPS("upload URL", "://malformed"))
+}
+
+func TestRejectInsecureRedirect(t *testing.T) {
+	httpsReq, err := http.NewRequest(http.MethodGet, "https://a.example/", nil)
+	require.NoError(t, err)
+	require.NoError(t, rejectInsecureRedirect(httpsReq, nil), "https redirect target must be allowed")
+
+	httpReq, err := http.NewRequest(http.MethodGet, "http://a.example/", nil)
+	require.NoError(t, err)
+	require.Error(t, rejectInsecureRedirect(httpReq, nil), "http redirect target must be refused")
+
+	require.Error(t, rejectInsecureRedirect(httpsReq, make([]*http.Request, 10)), "the 10-redirect limit must be enforced")
+}
+
+// The secure client refuses to follow an https response that redirects to http,
+// so a bundle can't be downgraded onto plaintext mid-flight.
+func TestUploadClientRefusesHTTPSToHTTPRedirect(t *testing.T) {
+	plain := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusOK)
+	}))
+	t.Cleanup(plain.Close)
+
+	secure := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		http.Redirect(w, r, plain.URL, http.StatusFound)
+	}))
+	t.Cleanup(secure.Close)
+
+	client := uploadClient(false)
+	// Trust the test server's cert without disabling verification globally.
+	client.Transport = secure.Client().Transport
+
+	resp, err := client.Get(secure.URL)
+	if resp != nil {
+		_ = resp.Body.Close()
+	}
+	require.Error(t, err, "redirect from https to http must be refused")
+	require.Contains(t, err.Error(), "non-https")
+}

client/internal/dns/local/local.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"net"
 	"net/netip"
+	"os"
 	"slices"
 	"strings"
 	"sync"
@@ -36,7 +37,43 @@ type resolver interface {
 // record is left alone (it points at something outside our mesh, e.g.
 // a non-peer upstream).
 type PeerConnectivity interface {
-	IsConnectedByIP(ip string) (known, connected bool)
+	IsConnectedByIP(ip netip.Addr) (known, connected bool)
+}
+
+// PeerActivator wakes lazy-connection peers on demand. The local resolver calls
+// it with the tunnel IPs an answer points at, so a peer that is idle (lazily
+// disconnected) starts connecting at DNS-resolution time rather than racing the
+// client's first request packet. nil disables warm-up.
+type PeerActivator interface {
+	// ActivatePeersByIP triggers wake-up for the peer(s) owning addrs and blocks
+	// until one is connected or ctx (a short per-query budget) expires. It is a
+	// fast no-op for unknown or already-connected addresses.
+	ActivatePeersByIP(ctx context.Context, addrs []netip.Addr)
+}
+
+const (
+	defaultLazyWarmupTimeout = 2 * time.Second
+	envLazyWarmupTimeout     = "NB_DNS_LAZY_WARMUP_TIMEOUT"
+)
+
+// lazyWarmupTimeoutFromEnv returns the per-query budget for waking a
+// lazy-connection peer a DNS answer points at. Tunable via
+// NB_DNS_LAZY_WARMUP_TIMEOUT (a Go duration). Parsed once at construction time.
+func lazyWarmupTimeoutFromEnv() time.Duration {
+	v := os.Getenv(envLazyWarmupTimeout)
+	if v == "" {
+		return defaultLazyWarmupTimeout
+	}
+	d, err := time.ParseDuration(v)
+	if err != nil {
+		log.Warnf("invalid %s value %q, using default %s: %v", envLazyWarmupTimeout, v, defaultLazyWarmupTimeout, err)
+		return defaultLazyWarmupTimeout
+	}
+	if d <= 0 {
+		log.Warnf("non-positive %s value %q, using default %s", envLazyWarmupTimeout, v, defaultLazyWarmupTimeout)
+		return defaultLazyWarmupTimeout
+	}
+	return d
 }
 
 type Resolver struct {
@@ -51,6 +88,12 @@ type Resolver struct {
 	// filter and preserves the legacy "return whatever is registered"
 	// behaviour for callers that never wire a status source.
 	peerConn PeerConnectivity
+	// peerActivator, when non-nil, is called at resolution time to warm the
+	// lazy connection to the peer(s) an answer points at. nil disables warm-up.
+	peerActivator PeerActivator
+	// warmupTimeout is the per-query budget for the lazy-connection warm-up
+	// wait, resolved from the environment once at construction time.
+	warmupTimeout time.Duration
 
 	ctx    context.Context
 	cancel context.CancelFunc
@@ -59,11 +102,12 @@ type Resolver struct {
 func NewResolver() *Resolver {
 	ctx, cancel := context.WithCancel(context.Background())
 	return &Resolver{
-		records: make(map[dns.Question][]dns.RR),
-		domains: make(map[domain.Domain]struct{}),
-		zones:   make(map[domain.Domain]bool),
-		ctx:     ctx,
-		cancel:  cancel,
+		records:       make(map[dns.Question][]dns.RR),
+		domains:       make(map[domain.Domain]struct{}),
+		zones:         make(map[domain.Domain]bool),
+		warmupTimeout: lazyWarmupTimeoutFromEnv(),
+		ctx:           ctx,
+		cancel:        cancel,
 	}
 }
 
@@ -76,6 +120,14 @@ func (d *Resolver) SetPeerConnectivity(p PeerConnectivity) {
 	d.peerConn = p
 }
 
+// SetPeerActivator wires the DNS-time lazy-connection warm-up. Pass nil to
+// disable. Safe to call multiple times; the latest value wins.
+func (d *Resolver) SetPeerActivator(a PeerActivator) {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	d.peerActivator = a
+}
+
 func (d *Resolver) MatchSubdomains() bool {
 	return true
 }
@@ -122,6 +174,9 @@ func (d *Resolver) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 	replyMessage.RecursionAvailable = true
 
 	result := d.lookupRecords(logger, question)
+	// Warm before filtering: activation flips a lazily-idle target to connected,
+	// which then lets it survive the disconnected-peer filter below.
+	d.warmLazyPeers(question, result.records)
 	result.records = d.filterDisconnectedPeerAnswers(logger, question, result.records)
 	replyMessage.Authoritative = !result.hasExternalData
 	replyMessage.Answer = result.records
@@ -495,8 +550,8 @@ func (d *Resolver) filterDisconnectedPeerAnswers(logger *log.Entry, question dns
 	kept := make([]dns.RR, 0, len(records))
 	var dropped int
 	for _, rr := range records {
-		ip := extractRecordIP(rr)
-		if ip == "" {
+		ip, ok := extractRecordAddr(rr)
+		if !ok {
 			kept = append(kept, rr)
 			continue
 		}
@@ -518,22 +573,57 @@ func (d *Resolver) filterDisconnectedPeerAnswers(logger *log.Entry, question dns
 	return kept
 }
 
-// extractRecordIP returns the dotted-decimal / colon-hex IP carried by
-// an A or AAAA record, or "" for any other record type.
-func extractRecordIP(rr dns.RR) string {
+// warmLazyPeers triggers lazy-connection wake-up for the peers a resolved
+// answer points at and waits briefly for one to connect, so the caller's first
+// request doesn't race the connection establishment. Warm-up is scoped to
+// match-only (non-authoritative) zones — the synthesized private-service zones
+// and user-created zones whose records point at specific peers. The account's
+// peer zone is authoritative, so plain peer-name lookups never trigger warm-up;
+// otherwise resolving any peer's name would wake its idle connection, defeating
+// laziness mesh-wide. No-op when no activator is wired (lazy connections
+// disabled) or the answer carries no peer IPs.
+func (d *Resolver) warmLazyPeers(question dns.Question, records []dns.RR) {
+	if len(records) < 2 {
+		return
+	}
+	d.mu.RLock()
+	activator := d.peerActivator
+	var nonAuth, found bool
+	if activator != nil {
+		nonAuth, found = d.findZone(question.Name)
+	}
+	d.mu.RUnlock()
+	if activator == nil || !found || !nonAuth {
+		return
+	}
+
+	var addrs []netip.Addr
+	for _, rr := range records {
+		if addr, ok := extractRecordAddr(rr); ok {
+			addrs = append(addrs, addr)
+		}
+	}
+	if len(addrs) == 0 {
+		return
+	}
+
+	ctx, cancel := context.WithTimeout(d.ctx, d.warmupTimeout)
+	defer cancel()
+	activator.ActivatePeersByIP(ctx, addrs)
+}
+
+// extractRecordAddr returns the IP address carried by an A or AAAA record.
+// ok is false for any other record type or a record with no address.
+func extractRecordAddr(rr dns.RR) (netip.Addr, bool) {
 	switch r := rr.(type) {
 	case *dns.A:
-		if r.A == nil {
-			return ""
-		}
-		return r.A.String()
+		addr, ok := netip.AddrFromSlice(r.A)
+		return addr.Unmap(), ok
 	case *dns.AAAA:
-		if r.AAAA == nil {
-			return ""
-		}
-		return r.AAAA.String()
+		addr, ok := netip.AddrFromSlice(r.AAAA)
+		return addr.Unmap(), ok
 	}
-	return ""
+	return netip.Addr{}, false
 }
 
 // Update replaces all zones and their records

client/internal/dns/local/local_test.go

@@ -37,8 +37,8 @@ type mockPeerConnectivity struct {
 	byIP map[string]struct{ known, connected bool }
 }
 
-func (m mockPeerConnectivity) IsConnectedByIP(ip string) (known, connected bool) {
-	v, ok := m.byIP[ip]
+func (m mockPeerConnectivity) IsConnectedByIP(ip netip.Addr) (known, connected bool) {
+	v, ok := m.byIP[ip.String()]
 	if !ok {
 		return false, false
 	}

client/internal/dns/local/warmup_test.go

@@ -0,0 +1,204 @@
+package local
+
+import (
+	"context"
+	"net"
+	"net/netip"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/miekg/dns"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/netbirdio/netbird/client/internal/dns/test"
+	nbdns "github.com/netbirdio/netbird/dns"
+)
+
+// recordingActivator records the addresses it was asked to warm and returns
+// immediately, so ServeDNS is not blocked by the test.
+type recordingActivator struct {
+	mu     sync.Mutex
+	called bool
+	addrs  []netip.Addr
+}
+
+func (r *recordingActivator) ActivatePeersByIP(_ context.Context, addrs []netip.Addr) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	r.called = true
+	r.addrs = append(r.addrs, addrs...)
+}
+
+func serveA(t *testing.T, resolver *Resolver, name string) *dns.Msg {
+	t.Helper()
+	var resp *dns.Msg
+	w := &test.MockResponseWriter{WriteMsgFunc: func(m *dns.Msg) error { resp = m; return nil }}
+	resolver.ServeDNS(w, new(dns.Msg).SetQuestion(name, dns.TypeA))
+	return resp
+}
+
+// serviceZone registers rec in a match-only (non-authoritative) zone, the shape
+// the synthesized private-service zones arrive in.
+func serviceZone(t *testing.T, resolver *Resolver, zone string, records ...nbdns.SimpleRecord) {
+	t.Helper()
+	resolver.Update([]nbdns.CustomZone{{
+		Domain:           zone,
+		Records:          records,
+		NonAuthoritative: true,
+	}})
+}
+
+func TestLocalResolver_WarmsLazyPeerOnResolve(t *testing.T) {
+	// Warm-up fires only for multi-record answers (the HA / round-robin shape of
+	// the synthesized private-service zones), so register two peer targets.
+	const name = "svc.proxy.netbird.cloud."
+	recs := []nbdns.SimpleRecord{
+		{Name: name, Type: 1, Class: nbdns.DefaultClass, TTL: 300, RData: "100.64.0.7"},
+		{Name: name, Type: 1, Class: nbdns.DefaultClass, TTL: 300, RData: "100.64.0.8"},
+	}
+	resolver := NewResolver()
+	serviceZone(t, resolver, "proxy.netbird.cloud", recs...)
+
+	act := &recordingActivator{}
+	resolver.SetPeerActivator(act)
+
+	resp := serveA(t, resolver, name)
+	require.NotNil(t, resp, "resolver must answer")
+	require.NotEmpty(t, resp.Answer, "answer must carry the A records")
+
+	act.mu.Lock()
+	defer act.mu.Unlock()
+	assert.True(t, act.called, "activator must be invoked for a multi-record service-zone answer")
+	assert.Contains(t, act.addrs, netip.MustParseAddr("100.64.0.7"), "activator must receive the first peer IP")
+	assert.Contains(t, act.addrs, netip.MustParseAddr("100.64.0.8"), "activator must receive the second peer IP")
+}
+
+func TestLocalResolver_NoWarmupForSingleRecord(t *testing.T) {
+	// A single-record answer does not trigger warm-up; the resolver only warms
+	// multi-record answers.
+	rec := nbdns.SimpleRecord{Name: "svc.proxy.netbird.cloud.", Type: 1, Class: nbdns.DefaultClass, TTL: 300, RData: "100.64.0.7"}
+	resolver := NewResolver()
+	serviceZone(t, resolver, "proxy.netbird.cloud", rec)
+
+	act := &recordingActivator{}
+	resolver.SetPeerActivator(act)
+
+	resp := serveA(t, resolver, rec.Name)
+	require.NotNil(t, resp, "resolver must answer")
+	require.NotEmpty(t, resp.Answer, "answer must carry the A record")
+
+	act.mu.Lock()
+	defer act.mu.Unlock()
+	assert.False(t, act.called, "activator must not be invoked for a single-record answer")
+}
+
+func TestLocalResolver_NoActivatorNoWarmup(t *testing.T) {
+	// With no activator wired the resolver behaves exactly as before.
+	rec := nbdns.SimpleRecord{Name: "svc.proxy.netbird.cloud.", Type: 1, Class: nbdns.DefaultClass, TTL: 300, RData: "100.64.0.7"}
+	resolver := NewResolver()
+	serviceZone(t, resolver, "proxy.netbird.cloud", rec)
+
+	resp := serveA(t, resolver, rec.Name)
+	require.NotNil(t, resp, "resolver must still answer without an activator")
+	require.NotEmpty(t, resp.Answer, "answer must carry the A record")
+}
+
+func TestLocalResolver_NoWarmupForMissingRecord(t *testing.T) {
+	// A query that resolves to nothing must not invoke the activator (no IPs).
+	resolver := NewResolver()
+	serviceZone(t, resolver, "proxy.netbird.cloud",
+		nbdns.SimpleRecord{Name: "svc.proxy.netbird.cloud.", Type: 1, Class: nbdns.DefaultClass, TTL: 300, RData: "100.64.0.7"})
+
+	act := &recordingActivator{}
+	resolver.SetPeerActivator(act)
+
+	serveA(t, resolver, "absent.proxy.netbird.cloud.")
+
+	act.mu.Lock()
+	defer act.mu.Unlock()
+	assert.False(t, act.called, "activator must not be invoked when there is no answer")
+}
+
+func TestLocalResolver_NoWarmupInAuthoritativeZone(t *testing.T) {
+	// The account's peer zone is authoritative; resolving a peer's name there
+	// must not wake its lazy connection — warm-up is scoped to match-only
+	// (non-authoritative) zones such as the synthesized private-service zones.
+	// Use a multi-record answer so the authoritative-zone scoping is the only
+	// reason warm-up is skipped, not the single-record guard.
+	const name = "peer.netbird.cloud."
+	recs := []nbdns.SimpleRecord{
+		{Name: name, Type: 1, Class: nbdns.DefaultClass, TTL: 300, RData: "100.64.0.9"},
+		{Name: name, Type: 1, Class: nbdns.DefaultClass, TTL: 300, RData: "100.64.0.10"},
+	}
+	resolver := NewResolver()
+	resolver.Update([]nbdns.CustomZone{{
+		Domain:  "netbird.cloud",
+		Records: recs,
+	}})
+
+	act := &recordingActivator{}
+	resolver.SetPeerActivator(act)
+
+	resp := serveA(t, resolver, name)
+	require.NotNil(t, resp, "resolver must answer")
+	require.NotEmpty(t, resp.Answer, "answer must carry the A records")
+
+	act.mu.Lock()
+	defer act.mu.Unlock()
+	assert.False(t, act.called, "activator must not be invoked for authoritative-zone answers")
+}
+
+func TestLazyWarmupTimeoutFromEnv(t *testing.T) {
+	tests := []struct {
+		name   string
+		value  string
+		envSet bool
+		want   time.Duration
+	}{
+		{name: "unset uses default", want: defaultLazyWarmupTimeout},
+		{name: "valid overrides", value: "5s", envSet: true, want: 5 * time.Second},
+		{name: "invalid falls back", value: "not-a-duration", envSet: true, want: defaultLazyWarmupTimeout},
+		{name: "negative falls back", value: "-1s", envSet: true, want: defaultLazyWarmupTimeout},
+		{name: "zero falls back", value: "0s", envSet: true, want: defaultLazyWarmupTimeout},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.envSet {
+				t.Setenv(envLazyWarmupTimeout, tt.value)
+			}
+			assert.Equal(t, tt.want, lazyWarmupTimeoutFromEnv())
+			assert.Equal(t, tt.want, NewResolver().warmupTimeout, "constructor must resolve the timeout once")
+		})
+	}
+}
+
+func TestExtractRecordAddr(t *testing.T) {
+	t.Run("A record yields unmapped v4", func(t *testing.T) {
+		// net.ParseIP returns the 16-byte v4-in-v6 form, the same shape
+		// miekg/dns stores after parsing an A record; the extracted address
+		// must compare equal to a plain v4 netip.Addr.
+		addr, ok := extractRecordAddr(&dns.A{A: net.ParseIP("100.64.0.7")})
+		require.True(t, ok)
+		assert.True(t, addr.Is4())
+		assert.Equal(t, netip.MustParseAddr("100.64.0.7"), addr)
+	})
+
+	t.Run("AAAA record yields v6", func(t *testing.T) {
+		addr, ok := extractRecordAddr(&dns.AAAA{AAAA: net.ParseIP("fd00::1")})
+		require.True(t, ok)
+		assert.Equal(t, netip.MustParseAddr("fd00::1"), addr)
+	})
+
+	t.Run("A record without address", func(t *testing.T) {
+		_, ok := extractRecordAddr(&dns.A{})
+		assert.False(t, ok)
+	})
+
+	t.Run("non-address record", func(t *testing.T) {
+		_, ok := extractRecordAddr(&dns.CNAME{Target: "target.netbird.cloud."})
+		assert.False(t, ok)
+	})
+}

client/internal/dns/mock_server.go

@@ -8,6 +8,7 @@ import (
 	"github.com/miekg/dns"
 
 	dnsconfig "github.com/netbirdio/netbird/client/internal/dns/config"
+	"github.com/netbirdio/netbird/client/internal/dns/local"
 	nbdns "github.com/netbirdio/netbird/dns"
 	"github.com/netbirdio/netbird/route"
 	"github.com/netbirdio/netbird/shared/management/domain"
@@ -92,6 +93,11 @@ func (m *MockServer) SetFirewall(Firewall) {
 	// Mock implementation - no-op
 }
 
+// SetPeerActivator mock implementation of SetPeerActivator from Server interface
+func (m *MockServer) SetPeerActivator(local.PeerActivator) {
+	// Mock implementation - no-op
+}
+
 // BeginBatch mock implementation of BeginBatch from Server interface
 func (m *MockServer) BeginBatch() {
 	// Mock implementation - no-op

client/internal/dns/server.go

@@ -82,6 +82,7 @@ type Server interface {
 	PopulateManagementDomain(mgmtURL *url.URL) error
 	SetRouteSources(selected, active func() route.HAMap)
 	SetFirewall(Firewall)
+	SetPeerActivator(local.PeerActivator)
 }
 
 type nsGroupsByDomain struct {
@@ -491,6 +492,13 @@ func (s *DefaultServer) SetFirewall(fw Firewall) {
 	}
 }
 
+// SetPeerActivator wires the DNS-time lazy-connection warm-up on the local
+// resolver. Injected after the connection manager exists (it does not at
+// DNS-server construction time). Pass nil to disable.
+func (s *DefaultServer) SetPeerActivator(a local.PeerActivator) {
+	s.localResolver.SetPeerActivator(a)
+}
+
 // Stop stops the server
 func (s *DefaultServer) Stop() {
 	s.ctxCancel()
@@ -1435,11 +1443,11 @@ type localPeerConnectivity struct {
 
 // IsConnectedByIP looks the IP up in the peerstore and surfaces both
 // the known and connected bits. Used by Resolver.filterDisconnectedPeerAnswers.
-func (l localPeerConnectivity) IsConnectedByIP(ip string) (known, connected bool) {
+func (l localPeerConnectivity) IsConnectedByIP(ip netip.Addr) (known, connected bool) {
 	if l.status == nil {
 		return false, false
 	}
-	state, ok := l.status.PeerStateByIP(ip)
+	state, ok := l.status.PeerStateByIP(ip.String())
 	if !ok {
 		return false, false
 	}

client/internal/dns/service_listener.go

@@ -292,18 +292,16 @@ func (s *serviceViaListener) generateFreePort() (uint16, error) {
 		return customPort, nil
 	}
 
-	udpAddr := net.UDPAddrFromAddrPort(netip.MustParseAddrPort("0.0.0.0:0"))
-	probeListener, err := net.ListenUDP("udp", udpAddr)
+	probeListener, err := net.ListenUDP("udp4", &net.UDPAddr{})
 	if err != nil {
 		log.Debugf("failed to bind random port for DNS: %s", err)
 		return 0, err
 	}
 
-	addrPort := netip.MustParseAddrPort(probeListener.LocalAddr().String()) // might panic if address is incorrect
-	err = probeListener.Close()
-	if err != nil {
+	port := uint16(probeListener.LocalAddr().(*net.UDPAddr).Port)
+	if err = probeListener.Close(); err != nil {
 		log.Debugf("failed to free up DNS port: %s", err)
 		return 0, err
 	}
-	return addrPort.Port(), nil
+	return port, nil
 }

client/internal/dns_peer_activator.go

@@ -0,0 +1,76 @@
+package internal
+
+import (
+	"context"
+	"net/netip"
+	"time"
+
+	"github.com/netbirdio/netbird/client/internal/peer"
+	"github.com/netbirdio/netbird/client/internal/peerstore"
+)
+
+const dnsActivationPollInterval = 50 * time.Millisecond
+
+// dnsPeerActivator wakes lazy-connection peers from the DNS resolution path. It
+// implements dns/local.PeerActivator. DNS queries run on their own goroutines,
+// so it only touches state that is safe for concurrent use — ConnMgr.ActivatePeer,
+// peerstore.Store and peer.Status — and never takes the engine's syncMsgMux,
+// keeping DNS resolution from contending with network-map processing.
+type dnsPeerActivator struct {
+	connMgr   *ConnMgr
+	peerStore *peerstore.Store
+	status    *peer.Status
+	// ctx is the engine's long-lived context. The connection dial is tied to it
+	// (not the per-query DNS wait budget) so a handshake that outlasts the wait
+	// still completes in the background rather than being cancelled at the deadline.
+	ctx context.Context
+}
+
+// ActivatePeersByIP triggers wake-up for the peer(s) owning addrs and waits
+// until one is connected or ctx (the per-query DNS wait budget) expires.
+// Activation itself is tied to the engine's long-lived context so the dial
+// survives a wait that times out. Unknown or already-connected addresses are
+// skipped, so the steady-state (warm) path adds no latency.
+func (a *dnsPeerActivator) ActivatePeersByIP(ctx context.Context, addrs []netip.Addr) {
+	if a == nil || a.connMgr == nil {
+		return
+	}
+
+	var pending []string
+	for _, addr := range addrs {
+		ip := addr.String()
+		st, ok := a.status.PeerStateByIP(ip)
+		if !ok || st.ConnStatus == peer.StatusConnected {
+			continue
+		}
+		conn, ok := a.peerStore.PeerConn(st.PubKey)
+		if !ok {
+			continue
+		}
+		a.connMgr.ActivatePeer(a.ctx, conn)
+		pending = append(pending, ip)
+	}
+
+	if len(pending) == 0 {
+		return
+	}
+	a.waitConnected(ctx, pending)
+}
+
+// waitConnected blocks until any of ips reports a connected peer or ctx expires.
+func (a *dnsPeerActivator) waitConnected(ctx context.Context, ips []string) {
+	ticker := time.NewTicker(dnsActivationPollInterval)
+	defer ticker.Stop()
+	for {
+		for _, ip := range ips {
+			if st, ok := a.status.PeerStateByIP(ip); ok && st.ConnStatus == peer.StatusConnected {
+				return
+			}
+		}
+		select {
+		case <-ctx.Done():
+			return
+		case <-ticker.C:
+		}
+	}
+}

client/internal/dns_peer_activator_test.go

@@ -0,0 +1,129 @@
+package internal
+
+import (
+	"context"
+	"net/netip"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/netbirdio/netbird/client/internal/peer"
+	"github.com/netbirdio/netbird/client/internal/peerstore"
+)
+
+func newTestPeerConn(t *testing.T, key string) *peer.Conn {
+	t.Helper()
+	conn, err := peer.NewConn(peer.ConnConfig{
+		Key:      key,
+		LocalKey: "local",
+		WgConfig: peer.WgConfig{
+			AllowedIps: []netip.Prefix{netip.MustParsePrefix("100.64.0.1/32")},
+		},
+	}, peer.ServiceDependencies{})
+	require.NoError(t, err)
+	return conn
+}
+
+func newTestDNSPeerActivator(t *testing.T) (*dnsPeerActivator, *peer.Status, *peerstore.Store) {
+	t.Helper()
+	status := peer.NewRecorder("https://mgm")
+	store := peerstore.NewConnStore()
+	// ConnMgr without Start: the lazy manager is nil, so ActivatePeer is a
+	// no-op — these tests exercise the activator's skip/wait logic.
+	connMgr := NewConnMgr(&EngineConfig{}, status, store, nil)
+	return &dnsPeerActivator{
+		connMgr:   connMgr,
+		peerStore: store,
+		status:    status,
+		ctx:       context.Background(),
+	}, status, store
+}
+
+func TestDNSPeerActivator_NilSafe(t *testing.T) {
+	var a *dnsPeerActivator
+	a.ActivatePeersByIP(context.Background(), []netip.Addr{netip.MustParseAddr("100.64.0.1")})
+}
+
+// TestDNSPeerActivator_SkipsUnknownAndConnectedPeers verifies the steady-state
+// (warm) path adds no latency: already-connected and unknown addresses never
+// enter the wait loop.
+func TestDNSPeerActivator_SkipsUnknownAndConnectedPeers(t *testing.T) {
+	a, status, store := newTestDNSPeerActivator(t)
+
+	require.NoError(t, status.AddPeer("peerA", "a.netbird.cloud", "100.64.0.1", "fd00::1"))
+	require.NoError(t, status.UpdatePeerState(peer.State{PubKey: "peerA", ConnStatus: peer.StatusConnected}))
+	store.AddPeerConn("peerA", newTestPeerConn(t, "peerA"))
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	start := time.Now()
+	a.ActivatePeersByIP(ctx, []netip.Addr{
+		netip.MustParseAddr("100.64.0.1"),  // known, connected -> skipped
+		netip.MustParseAddr("fd00::1"),     // known via IPv6, connected -> skipped
+		netip.MustParseAddr("100.64.0.99"), // unknown -> skipped
+	})
+	require.Less(t, time.Since(start), time.Second, "no pending peer must mean no wait")
+}
+
+// TestDNSPeerActivator_WaitsForPendingPeerToConnect verifies the wait loop
+// returns as soon as a pending peer reports connected, well before the
+// per-query budget expires.
+func TestDNSPeerActivator_WaitsForPendingPeerToConnect(t *testing.T) {
+	a, status, store := newTestDNSPeerActivator(t)
+
+	require.NoError(t, status.AddPeer("peerA", "a.netbird.cloud", "100.64.0.1", ""))
+	store.AddPeerConn("peerA", newTestPeerConn(t, "peerA"))
+
+	go func() {
+		time.Sleep(150 * time.Millisecond)
+		_ = status.UpdatePeerState(peer.State{PubKey: "peerA", ConnStatus: peer.StatusConnected})
+	}()
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	start := time.Now()
+	a.ActivatePeersByIP(ctx, []netip.Addr{netip.MustParseAddr("100.64.0.1")})
+	elapsed := time.Since(start)
+
+	require.GreaterOrEqual(t, elapsed, 100*time.Millisecond, "must wait for the pending peer")
+	require.Less(t, elapsed, 5*time.Second, "must return on connect, not at the deadline")
+}
+
+// TestDNSPeerActivator_ReturnsAtBudgetWhenPeerStaysIdle verifies a peer that
+// never connects releases the DNS response at the per-query budget instead of
+// blocking it indefinitely.
+func TestDNSPeerActivator_ReturnsAtBudgetWhenPeerStaysIdle(t *testing.T) {
+	a, status, store := newTestDNSPeerActivator(t)
+
+	require.NoError(t, status.AddPeer("peerA", "a.netbird.cloud", "100.64.0.1", ""))
+	store.AddPeerConn("peerA", newTestPeerConn(t, "peerA"))
+
+	ctx, cancel := context.WithTimeout(context.Background(), 300*time.Millisecond)
+	defer cancel()
+
+	start := time.Now()
+	a.ActivatePeersByIP(ctx, []netip.Addr{netip.MustParseAddr("100.64.0.1")})
+	elapsed := time.Since(start)
+
+	require.GreaterOrEqual(t, elapsed, 250*time.Millisecond, "must wait out the budget for a pending peer")
+	require.Less(t, elapsed, 5*time.Second, "must not block past the budget")
+}
+
+// TestDNSPeerActivator_NoWaitWithoutPeerConn verifies a known-but-idle peer
+// with no connection object in the store is not waited on: there is nothing to
+// activate, so waiting could only ever time out.
+func TestDNSPeerActivator_NoWaitWithoutPeerConn(t *testing.T) {
+	a, status, _ := newTestDNSPeerActivator(t)
+
+	require.NoError(t, status.AddPeer("peerA", "a.netbird.cloud", "100.64.0.1", ""))
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	start := time.Now()
+	a.ActivatePeersByIP(ctx, []netip.Addr{netip.MustParseAddr("100.64.0.1")})
+	require.Less(t, time.Since(start), time.Second, "peer without a conn must not be waited on")
+}

client/internal/ebpf/ebpf/src/dns_fwd.c

@@ -52,11 +52,14 @@ int xdp_dns_fwd(struct iphdr  *ip, struct udphdr *udp) {
 
     if (udp->dest == GENERAL_DNS_PORT && ip->daddr == dns_ip) {
         udp->dest = dns_port;
+        // Clear the now-stale checksum; zero means "not computed" for IPv4.
+        udp->check = 0;
         return XDP_PASS;
     }
 
     if (udp->source == dns_port && ip->saddr == dns_ip) {
         udp->source = GENERAL_DNS_PORT;
+        udp->check = 0;
         return XDP_PASS;
     }
 

client/internal/ebpf/ebpf/src/wg_proxy.c

@@ -50,5 +50,11 @@ int xdp_wg_proxy(struct iphdr  *ip, struct udphdr *udp) {
     __be16 new_dst_port = htons(proxy_port);
     udp->dest = new_dst_port;
     udp->source = new_src_port;
+
+    // The ports are covered by the UDP checksum. This is an IPv4 loopback hop
+    // and the payload is already integrity-protected, so clear the checksum (a
+    // zero UDP checksum means "not computed" for IPv4) rather than leave a
+    // stale value the kernel would drop as UDP_CSUM.
+    udp->check = 0;
 	return XDP_PASS;
 }

client/internal/engine.go

@@ -64,7 +64,10 @@ import (
 	"github.com/netbirdio/netbird/route"
 	mgm "github.com/netbirdio/netbird/shared/management/client"
 	"github.com/netbirdio/netbird/shared/management/domain"
+	sharedgrpc "github.com/netbirdio/netbird/shared/management/grpc"
+	nbnetworkmap "github.com/netbirdio/netbird/shared/management/networkmap"
 	mgmProto "github.com/netbirdio/netbird/shared/management/proto"
+	types "github.com/netbirdio/netbird/shared/management/types"
 	"github.com/netbirdio/netbird/shared/netiputil"
 	auth "github.com/netbirdio/netbird/shared/relay/auth/hmac"
 	relayClient "github.com/netbirdio/netbird/shared/relay/client"
@@ -147,6 +150,7 @@ type EngineConfig struct {
 	BlockLANAccess      bool
 	BlockInbound        bool
 	DisableIPv6         bool
+	SyncMessageVersion  *int
 
 	// LazyConnection is the MDM-sourced lazy-connection override; StateUnset defers to
 	// the env var and management feature flag.
@@ -220,6 +224,13 @@ type Engine struct {
 	// networkSerial is the latest CurrentSerial (state ID) of the network sent by the Management service
 	networkSerial uint64
 
+	// latestComponents is the most-recent NetworkMapComponents decoded from
+	// a NetworkMapEnvelope (capability=3 peers only). Held alongside the
+	// NetworkMap that Calculate() produced from it so future incremental
+	// updates have a base to apply changes against. nil for legacy-format
+	// peers. Guarded by syncMsgMux.
+	latestComponents *types.NetworkMapComponents
+
 	networkMonitor *networkmonitor.NetworkMonitor
 
 	sshServer sshServer
@@ -652,8 +663,24 @@ func (e *Engine) Start(netbirdConfig *mgmProto.NetbirdConfig, mgmtURL *url.URL)
 	iceCfg := e.createICEConfig()
 
 	e.connMgr = NewConnMgr(e.config, e.statusRecorder, e.peerStore, wgIface)
+	e.connMgr.SetRoutedIPsReconciler(func(peerKey string) error {
+		if e.routeManager == nil {
+			return nil
+		}
+		return e.routeManager.ReconcilePeerAllowedIPs(peerKey)
+	})
 	e.connMgr.Start(e.ctx)
 
+	// Wire DNS-time lazy-connection warm-up now that the connection manager
+	// exists (it does not at DNS-server construction time). A DNS answer that
+	// points at an idle peer then wakes it before the client's first request.
+	e.dnsServer.SetPeerActivator(&dnsPeerActivator{
+		connMgr:   e.connMgr,
+		peerStore: e.peerStore,
+		status:    e.statusRecorder,
+		ctx:       e.ctx,
+	})
+
 	e.srWatcher = guard.NewSRWatcher(e.signal, e.relayManager, e.mobileDep.IFaceDiscover, iceCfg)
 	e.srWatcher.Start(peer.IsForceRelayed())
 
@@ -963,8 +990,12 @@ func (e *Engine) handleSync(update *mgmProto.SyncResponse) error {
 
 	e.ApplySessionDeadline(update.GetSessionExpiresAt())
 
-	if update.NetworkMap != nil && update.NetworkMap.PeerConfig != nil {
-		e.handleAutoUpdateVersion(update.NetworkMap.PeerConfig.AutoUpdate)
+	// Envelope sync responses carry PeerConfig at the top level; legacy
+	// NetworkMap syncs carry it under NetworkMap.PeerConfig.
+	if pc := update.GetPeerConfig(); pc != nil {
+		e.handleAutoUpdateVersion(pc.GetAutoUpdate())
+	} else if nm := update.GetNetworkMap(); nm != nil && nm.GetPeerConfig() != nil {
+		e.handleAutoUpdateVersion(nm.GetPeerConfig().GetAutoUpdate())
 	}
 
 	done := e.phase("netbird_config")
@@ -974,12 +1005,47 @@ func (e *Engine) handleSync(update *mgmProto.SyncResponse) error {
 		return err
 	}
 
+	// Decode the network map from either the components envelope or the
+	// legacy proto.NetworkMap before the posture-check gating below, so the
+	// "is there a network map" decision covers both wire shapes.
+	var (
+		nm         *mgmProto.NetworkMap
+		components *types.NetworkMapComponents
+	)
+	if version := update.GetVersion(); version == int32(sharedgrpc.ComponentNetworkMap) {
+		// Components-format peer: decode the envelope back to typed
+		// components, run Calculate() locally, and convert to the wire
+		// NetworkMap shape the rest of the engine consumes. Components are
+		// retained so future incremental updates can apply deltas instead
+		// of doing a full reconstruction.
+		envelope := update.GetNetworkMapEnvelope()
+		if envelope == nil {
+			return fmt.Errorf("received a SyncReponse indicating use of components network map, but components are missing")
+		}
+
+		localKey := e.config.WgPrivateKey.PublicKey().String()
+		dnsName := ""
+		if pc := update.GetPeerConfig(); pc != nil {
+			// PeerConfig.Fqdn = "<dns_label>.<dns_domain>" — extract the
+			// shared domain by stripping the peer's own label prefix. Falls
+			// back to empty if the FQDN doesn't have the expected shape.
+			dnsName = extractDNSDomainFromFQDN(pc.GetFqdn())
+		}
+		result, err := nbnetworkmap.EnvelopeToNetworkMap(e.ctx, envelope, localKey, dnsName)
+		if err != nil {
+			return fmt.Errorf("decode network map envelope: %w", err)
+		}
+		nm = result.NetworkMap
+		components = result.Components
+	} else {
+		nm = update.GetNetworkMap()
+	}
+
 	// Posture checks are bound to the network map presence:
 	//   NetworkMap != nil, checks present -> apply the received checks
 	//   NetworkMap != nil, checks nil     -> posture checks were removed, clear them
 	//   NetworkMap == nil                 -> config-only update (e.g. relay token rotation),
 	//                                        leave the previously applied checks untouched
-	nm := update.GetNetworkMap()
 	if nm == nil {
 		return nil
 	}
@@ -992,6 +1058,14 @@ func (e *Engine) handleSync(update *mgmProto.SyncResponse) error {
 	}
 
 	done = e.phase("persist")
+	// Only retain the components view when the server sent the envelope
+	// path. A legacy proto.NetworkMap means components == nil; writing it
+	// here would clobber a previously-cached snapshot, breaking the
+	// incremental-delta base on a future envelope sync.
+	if components != nil {
+		e.latestComponents = components
+	}
+
 	e.persistSyncResponse(update)
 	done()
 
@@ -1005,6 +1079,19 @@ func (e *Engine) handleSync(update *mgmProto.SyncResponse) error {
 	return nil
 }
 
+// extractDNSDomainFromFQDN returns the trailing dotted domain part of the
+// receiving peer's FQDN — the same value the management server fills as
+// dnsName when it builds the legacy NetworkMap. "peer42.netbird.cloud" →
+// "netbird.cloud". An empty string is returned for unrecognized formats.
+func extractDNSDomainFromFQDN(fqdn string) string {
+	for i := 0; i < len(fqdn); i++ {
+		if fqdn[i] == '.' && i+1 < len(fqdn) {
+			return fqdn[i+1:]
+		}
+	}
+	return ""
+}
+
 // updateNetbirdConfig applies the management-provided NetBird configuration:
 // STUN/TURN and relay servers, flow logging and DNS settings. A nil config is a no-op,
 // which is the case for sync updates carrying only a network map.
@@ -1164,6 +1251,7 @@ func (e *Engine) applyInfoFlags(info *system.Info) {
 		e.config.BlockLANAccess,
 		e.config.BlockInbound,
 		e.config.DisableIPv6,
+		e.config.SyncMessageVersion,
 		e.config.EnableSSHRoot,
 		e.config.EnableSSHSFTP,
 		e.config.EnableSSHLocalPortForwarding,
@@ -2032,6 +2120,7 @@ func (e *Engine) readInitialSettings() ([]*route.Route, *nbdns.Config, bool, err
 		e.config.BlockLANAccess,
 		e.config.BlockInbound,
 		e.config.DisableIPv6,
+		e.config.SyncMessageVersion,
 		e.config.EnableSSHRoot,
 		e.config.EnableSSHSFTP,
 		e.config.EnableSSHLocalPortForwarding,

client/internal/engine_session_deadline_test.go

@@ -75,4 +75,14 @@ func TestApplySessionDeadline_ThreeState(t *testing.T) {
 		require.True(t, e.statusRecorder.GetSessionExpiresAt().IsZero(),
 			"invalid timestamp must clear the deadline")
 	})
+
+	t.Run("recently expired timestamp stays visible as expired", func(t *testing.T) {
+		e := newEngine()
+		expired := time.Now().Add(-5 * time.Minute).UTC().Truncate(time.Second)
+
+		e.ApplySessionDeadline(timestamppb.New(expired))
+
+		require.True(t, e.statusRecorder.GetSessionExpiresAt().Equal(expired),
+			"recently-expired deadline must stay on the recorder so consumers render it as expired")
+	})
 }

client/internal/ipcauth/creds_stub.go

@@ -0,0 +1,31 @@
+//go:build !linux && !darwin && !freebsd && !windows
+
+package ipcauth
+
+import (
+	"errors"
+	"net"
+
+	"google.golang.org/grpc/credentials"
+)
+
+// errUnsupported is returned on platforms with no local peer-identity
+// primitive, so consumers fail closed instead of guessing an identity.
+var errUnsupported = errors.New("peer identity is not available on this platform")
+
+// NewTransportCredentials returns nil: without a peer-identity primitive the
+// daemon cannot authenticate local callers, and the caller must treat that as
+// "authorization cannot be enforced".
+func NewTransportCredentials() credentials.TransportCredentials {
+	return nil
+}
+
+// PeerIdentity always fails on this platform.
+func PeerIdentity(net.Conn) (Identity, error) {
+	return Identity{}, errUnsupported
+}
+
+// ConnIdentity always fails on this platform.
+func ConnIdentity(net.Conn) (Identity, error) {
+	return Identity{}, errUnsupported
+}

client/internal/ipcauth/creds_unix.go

@@ -0,0 +1,56 @@
+//go:build linux || darwin || freebsd
+
+package ipcauth
+
+import (
+	"context"
+	"net"
+
+	"google.golang.org/grpc/credentials"
+)
+
+// NewTransportCredentials returns gRPC transport credentials that expose the
+// caller's kernel-authenticated identity via IdentityFromContext. It returns
+// nil on platforms that have no peer-identity primitive, which the caller must
+// treat as "authorization cannot be enforced".
+//
+// The handshake exchanges no bytes on the wire, so a client dialing with
+// insecure credentials interoperates with a server using these. That keeps
+// older CLI and UI binaries working against an upgraded daemon.
+func NewTransportCredentials() credentials.TransportCredentials {
+	return unixCreds{}
+}
+
+// ConnIdentity extracts the caller's identity from an accepted local IPC
+// connection. It is shared by the gRPC transport credentials and by the JSON
+// gateway, which reads the identity of its own HTTP clients.
+func ConnIdentity(conn net.Conn) (Identity, error) {
+	return PeerIdentity(conn)
+}
+
+type unixCreds struct{}
+
+func (unixCreds) ClientHandshake(_ context.Context, _ string, conn net.Conn) (net.Conn, credentials.AuthInfo, error) {
+	return conn, AuthInfo{}, nil
+}
+
+// ServerHandshake extracts the peer identity and fails closed when it cannot
+// be read, so a connection whose caller is unknown never reaches a handler.
+func (unixCreds) ServerHandshake(conn net.Conn) (net.Conn, credentials.AuthInfo, error) {
+	id, err := ConnIdentity(conn)
+	if err != nil {
+		return nil, nil, err
+	}
+	return conn, AuthInfo{
+		CommonAuthInfo: credentials.CommonAuthInfo{SecurityLevel: credentials.NoSecurity},
+		Identity:       id,
+	}, nil
+}
+
+func (unixCreds) Info() credentials.ProtocolInfo {
+	return credentials.ProtocolInfo{SecurityProtocol: AuthInfo{}.AuthType()}
+}
+
+func (unixCreds) Clone() credentials.TransportCredentials { return unixCreds{} }
+
+func (unixCreds) OverrideServerName(string) error { return nil }

client/internal/ipcauth/creds_windows.go

@@ -0,0 +1,194 @@
+//go:build windows
+
+package ipcauth
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"runtime"
+
+	log "github.com/sirupsen/logrus"
+	"golang.org/x/sys/windows"
+	"google.golang.org/grpc/credentials"
+)
+
+var (
+	modadvapi32                    = windows.NewLazySystemDLL("advapi32.dll")
+	procImpersonateNamedPipeClient = modadvapi32.NewProc("ImpersonateNamedPipeClient")
+)
+
+// DefaultPipeSDDL is the security descriptor for the daemon control pipe.
+//
+//	D:P          protected DACL, no inheritance
+//	(A;;GA;;;SY) allow GENERIC_ALL to LocalSystem (the daemon's service account)
+//	(A;;GA;;;WD) allow GENERIC_ALL to Everyone
+//
+// Any local caller may connect, as with a Unix socket at 0666; what a caller may
+// actually do is decided from its token, not from the DACL. Remote callers are not
+// a concern here: winio.ListenPipe creates the pipe with
+// FILE_PIPE_REJECT_REMOTE_CLIENTS, so NPFS rejects connections from other machines
+// before the descriptor is consulted.
+//
+// A deny ACE on the NETWORK SID would not add anything and would break callers:
+// that SID is present in any network-logon token, which includes OpenSSH and WinRM
+// sessions, so it denies administrators driving the CLI over SSH and denies the
+// daemon itself when started from such a session.
+func DefaultPipeSDDL() string {
+	return "D:P(A;;GA;;;SY)(A;;GA;;;WD)"
+}
+
+// NewTransportCredentials returns gRPC transport credentials that derive the
+// caller's identity from the named-pipe client token.
+//
+// The client must connect at SECURITY_IDENTIFICATION for the daemon to be able
+// to read its token, which is what DialNamedPipe does.
+func NewTransportCredentials() credentials.TransportCredentials {
+	return winpipeCreds{}
+}
+
+// ConnIdentity extracts the caller's identity from an accepted named-pipe
+// connection by impersonating the pipe client and reading its token. It is
+// shared by the gRPC transport credentials and by the JSON gateway, which
+// reads the identity of its own HTTP clients.
+func ConnIdentity(conn net.Conn) (Identity, error) {
+	// go-winio's pipe connection embeds *win32File, which exposes Fd().
+	fdConn, ok := conn.(interface{ Fd() uintptr })
+	if !ok {
+		return Identity{}, fmt.Errorf("connection %T does not expose a pipe handle", conn)
+	}
+	return pipeClientIdentity(windows.Handle(fdConn.Fd()))
+}
+
+type winpipeCreds struct{}
+
+func (winpipeCreds) ClientHandshake(_ context.Context, _ string, conn net.Conn) (net.Conn, credentials.AuthInfo, error) {
+	return conn, AuthInfo{}, nil
+}
+
+// ServerHandshake extracts the connecting client's identity and fails closed
+// when the handle or token cannot be read, so a connection whose caller is
+// unknown never reaches a handler.
+func (winpipeCreds) ServerHandshake(conn net.Conn) (net.Conn, credentials.AuthInfo, error) {
+	id, err := ConnIdentity(conn)
+	if err != nil {
+		return nil, nil, err
+	}
+	return conn, AuthInfo{
+		CommonAuthInfo: credentials.CommonAuthInfo{SecurityLevel: credentials.NoSecurity},
+		Identity:       id,
+	}, nil
+}
+
+func (winpipeCreds) Info() credentials.ProtocolInfo {
+	return credentials.ProtocolInfo{SecurityProtocol: AuthInfo{}.AuthType()}
+}
+
+func (winpipeCreds) Clone() credentials.TransportCredentials { return winpipeCreds{} }
+
+func (winpipeCreds) OverrideServerName(string) error { return nil }
+
+// pipeClientIdentity reads the connecting client's user SID, usable group
+// SIDs, and elevation state by impersonating the pipe client on this thread
+// and reading the resulting impersonation token.
+func pipeClientIdentity(handle windows.Handle) (id Identity, err error) {
+	// Impersonation is per-thread, so the goroutine must stay on this thread
+	// until RevertToSelf, otherwise an unrelated goroutine could inherit the
+	// impersonated context.
+	runtime.LockOSThread()
+
+	// The thread only goes back to the runtime's pool once it is provably no
+	// longer impersonating the client. If the revert fails, leaving it locked
+	// makes Go terminate it when this goroutine exits, which costs one thread
+	// and keeps a thread running as the client from ever being reused.
+	clean := false
+	defer func() {
+		if clean {
+			runtime.UnlockOSThread()
+		}
+	}()
+
+	if err = impersonateNamedPipeClient(handle); err != nil {
+		clean = true
+		return Identity{}, fmt.Errorf("impersonate named pipe client: %w", err)
+	}
+	defer func() {
+		// Surface the revert failure only when nothing else failed: leaving
+		// the thread impersonated is worse than the original error.
+		revErr := windows.RevertToSelf()
+		if revErr != nil {
+			if err == nil {
+				err = fmt.Errorf("revert impersonation: %w", revErr)
+			}
+			return
+		}
+		clean = true
+	}()
+
+	// openAsSelf=true opens the token with the daemon's own process context
+	// rather than the impersonated client's, so the open cannot fail because
+	// the client lacks access to its own token.
+	var token windows.Token
+	if err = windows.OpenThreadToken(windows.CurrentThread(), windows.TOKEN_QUERY, true, &token); err != nil {
+		return Identity{}, fmt.Errorf("open thread token: %w", err)
+	}
+	defer func() {
+		if cerr := token.Close(); cerr != nil {
+			log.Debugf("close client token: %v", cerr)
+		}
+	}()
+
+	return identityFromToken(token)
+}
+
+// identityFromToken reads the user SID, usable group SIDs and elevation state
+// out of a Windows token.
+func identityFromToken(token windows.Token) (Identity, error) {
+	user, err := token.GetTokenUser()
+	if err != nil {
+		return Identity{}, fmt.Errorf("read token user: %w", err)
+	}
+
+	groups, err := tokenGroupSIDs(token)
+	if err != nil {
+		return Identity{}, err
+	}
+
+	return Identity{
+		SID:      user.User.Sid.String(),
+		Groups:   groups,
+		Elevated: token.IsElevated(),
+	}, nil
+}
+
+// tokenGroupSIDs returns the SIDs of the groups the token can actually
+// exercise. Groups that are disabled or marked deny-only are skipped: a
+// UAC-filtered administrator carries BUILTIN\Administrators as deny-only, and
+// treating that as membership would hand every admin account privilege it
+// cannot currently use.
+func tokenGroupSIDs(token windows.Token) ([]string, error) {
+	tg, err := token.GetTokenGroups()
+	if err != nil {
+		return nil, fmt.Errorf("read token groups: %w", err)
+	}
+
+	var sids []string
+	for _, g := range tg.AllGroups() {
+		if g.Attributes&windows.SE_GROUP_ENABLED == 0 {
+			continue
+		}
+		if g.Attributes&windows.SE_GROUP_USE_FOR_DENY_ONLY != 0 {
+			continue
+		}
+		sids = append(sids, g.Sid.String())
+	}
+	return sids, nil
+}
+
+func impersonateNamedPipeClient(h windows.Handle) error {
+	r, _, e := procImpersonateNamedPipeClient.Call(uintptr(h))
+	if r == 0 {
+		return e
+	}
+	return nil
+}

client/internal/ipcauth/forward.go

@@ -0,0 +1,272 @@
+package ipcauth
+
+import (
+	"context"
+	"crypto/rand"
+	"crypto/subtle"
+	"encoding/hex"
+	"fmt"
+	"slices"
+	"strconv"
+	"strings"
+
+	"google.golang.org/grpc/metadata"
+)
+
+// Metadata keys the local JSON gateway uses to forward the identity of its own
+// HTTP client to the daemon. The gateway runs inside the daemon process and
+// re-dials the daemon over the control socket, so without forwarding every
+// JSON request would appear to come from the daemon itself.
+const (
+	// mdFwd marks a request as forwarded by the JSON gateway. It is always
+	// set, even when the gateway could not read its client's identity, so the
+	// daemon can tell "no identity available" apart from "not forwarded".
+	mdFwd         = "x-netbird-fwd"
+	mdFwdUID      = "x-netbird-fwd-uid"      // Unix user ID
+	mdFwdGID      = "x-netbird-fwd-gid"      // Unix primary group ID
+	mdFwdSID      = "x-netbird-fwd-sid"      // Windows user SID
+	mdFwdGroup    = "x-netbird-fwd-group"    // Windows group SID, repeated
+	mdFwdElevated = "x-netbird-fwd-elevated" // Windows, "1" when elevated
+
+	// mdFwdProof proves the forwarded identity was stamped by this process. The
+	// gateway runs inside the daemon, so a secret held in memory is available to
+	// the only legitimate producer and to nothing else.
+	mdFwdProof = "x-netbird-fwd-proof"
+)
+
+// forwardKeys is every metadata key the gateway sets. An HTTP client must never
+// be able to supply one itself: see IsReservedForwardKey.
+var forwardKeys = []string{mdFwd, mdFwdUID, mdFwdGID, mdFwdSID, mdFwdGroup, mdFwdElevated, mdFwdProof}
+
+// forwardProof authenticates the gateway's forwarding metadata. It is generated
+// once per daemon process and never leaves it: it is not written to disk, not
+// logged, and not sent anywhere except over the daemon's own control socket to
+// itself.
+//
+// Without it, trusting a forwarded identity rests on every layer in front of it
+// stripping incoming forwarding keys, and on each key's value shape being
+// distinguishable from an injected one. A single injected group SID or an
+// injected "elevated" flag has the same shape as a legitimate one, so no
+// cardinality rule can catch it. Requiring the proof means metadata that did not
+// come from this process is refused whatever it contains.
+var forwardProof = mustForwardProof()
+
+func mustForwardProof() string {
+	var buf [32]byte
+	if _, err := rand.Read(buf[:]); err != nil {
+		// Continuing would leave the forwarded path authenticated by a
+		// predictable value, which is worse than not starting.
+		panic(fmt.Sprintf("generate identity forwarding proof: %v", err))
+	}
+	return hex.EncodeToString(buf[:])
+}
+
+// IsReservedForwardKey reports whether a gRPC metadata key belongs to the
+// gateway's identity forwarding, and therefore must be dropped when it arrives
+// from outside.
+//
+// grpc-gateway maps "Grpc-Metadata-<key>" request headers into gRPC metadata and
+// joins them ahead of the values its own annotators add. Without dropping these,
+// an HTTP client could hand the daemon "x-netbird-fwd-uid: 0" and be believed,
+// because the daemon trusts forwarded metadata when the transport peer is the
+// (privileged) gateway.
+func IsReservedForwardKey(key string) bool {
+	key = strings.ToLower(key)
+	return slices.Contains(forwardKeys, key)
+}
+
+// ForwardIdentityMetadata encodes an HTTP client's identity for the JSON
+// gateway to forward to the daemon. When known is false only the marker is
+// set, which makes the daemon treat the caller as unidentified rather than as
+// the daemon itself.
+func ForwardIdentityMetadata(id Identity, known bool) metadata.MD {
+	md := metadata.MD{}
+	md.Set(mdFwd, "1")
+	md.Set(mdFwdProof, forwardProof)
+	if !known {
+		return md
+	}
+
+	if id.IsWindows() {
+		md.Set(mdFwdSID, id.SID)
+		if len(id.Groups) > 0 {
+			md.Set(mdFwdGroup, id.Groups...)
+		}
+		if id.Elevated {
+			md.Set(mdFwdElevated, "1")
+		}
+		return md
+	}
+
+	md.Set(mdFwdUID, strconv.FormatUint(uint64(id.UID), 10))
+	md.Set(mdFwdGID, strconv.FormatUint(uint64(id.GID), 10))
+	return md
+}
+
+// CallerIdentity returns the identity to authorize a request against. For a
+// direct connection that is the transport peer's kernel identity. For a
+// request relayed by the local JSON gateway it is the identity the gateway
+// forwarded, since the transport peer is then the daemon itself.
+//
+// A forwarded identity is only honoured when the transport peer is the daemon's
+// own identity and the metadata carries this process's forwarding proof, so
+// forged forwarding metadata gains a caller nothing. A forwarded request that
+// carries no identity is reported as unidentified, never as the daemon.
+//
+// The second return value is false when no identity could be established, and
+// callers MUST fail closed in that case.
+func CallerIdentity(ctx context.Context) (Identity, bool) {
+	id, ok := IdentityFromContext(ctx)
+	if !ok {
+		return Identity{}, false
+	}
+
+	// A forwarding key that arrives more than once did not come from the gateway
+	// alone, so nothing about the request can be trusted to describe its caller.
+	// Refusing outright matters because the alternative reading, "not forwarded",
+	// would authorize the request as the transport peer, which on the gateway's
+	// connection is the daemon itself.
+	if duplicatedForwardKey(ctx) {
+		return Identity{}, false
+	}
+
+	forwarded := isForwarded(ctx)
+
+	// Our own process on the other end of the socket is the JSON gateway, the only
+	// thing that dials the daemon from inside it. Such a call must carry a
+	// forwarded identity; without one there is no caller to authorize, and
+	// treating it as the daemon would authorize whatever reached the JSON socket.
+	// Only Linux reports the peer PID, so this is a belt on top of the gateway's
+	// interceptor rather than the sole guarantee.
+	if id.PID != 0 && int(id.PID) == selfPID && !forwarded {
+		return Identity{}, false
+	}
+
+	// Only the gateway's own connection may speak for someone else. Being
+	// privileged is not enough and not the point: the gateway runs inside the
+	// daemon, so it dials as the daemon's identity whatever user that is, which
+	// also covers a rootless container.
+	if !forwarded || !IsDaemonSelf(id) {
+		return id, true
+	}
+
+	// Speaking for someone else additionally requires the proof only this process
+	// holds. Refusing is the only safe reading: the transport peer here is the
+	// daemon itself, so falling back to it would authorize the request as the
+	// daemon. This is also what makes the forwarded values trustworthy once
+	// accepted, so they need no shape checks of their own.
+	if !authenticForward(ctx) {
+		return Identity{}, false
+	}
+
+	return forwardedIdentity(ctx)
+}
+
+// duplicatedForwardKey reports whether any forwarding key carries more than one
+// value. The gateway's interceptor sets each key exactly once and replaces what
+// was already there, so a repeat means a second source supplied it.
+func duplicatedForwardKey(ctx context.Context) bool {
+	md, ok := metadata.FromIncomingContext(ctx)
+	if !ok {
+		return false
+	}
+	for _, key := range forwardKeys {
+		// Group SIDs are legitimately repeated; the rest identify the caller.
+		if key == mdFwdGroup {
+			continue
+		}
+		if len(md.Get(key)) > 1 {
+			return true
+		}
+	}
+	return false
+}
+
+// authenticForward reports whether the request carries this process's forwarding
+// proof, which only the in-process JSON gateway can supply.
+func authenticForward(ctx context.Context) bool {
+	md, ok := metadata.FromIncomingContext(ctx)
+	if !ok {
+		return false
+	}
+	got := mdSingle(md, mdFwdProof)
+	return subtle.ConstantTimeCompare([]byte(got), []byte(forwardProof)) == 1
+}
+
+// isForwarded reports whether the request carries the JSON gateway marker.
+func isForwarded(ctx context.Context) bool {
+	md, ok := metadata.FromIncomingContext(ctx)
+	if !ok {
+		return false
+	}
+	return mdSingle(md, mdFwd) != ""
+}
+
+// forwardedIdentity decodes the identity the JSON gateway attached.
+func forwardedIdentity(ctx context.Context) (Identity, bool) {
+	md, ok := metadata.FromIncomingContext(ctx)
+	if !ok {
+		return Identity{}, false
+	}
+
+	if sid := mdSingle(md, mdFwdSID); sid != "" {
+		return Identity{
+			SID: sid,
+			// Repeated by design, one value per group, and only reachable once
+			// the forwarding proof has been verified.
+			Groups:   md.Get(mdFwdGroup),
+			Elevated: mdSingle(md, mdFwdElevated) == "1",
+		}, true
+	}
+
+	uid, err := strconv.ParseUint(mdSingle(md, mdFwdUID), 10, 32)
+	if err != nil {
+		return Identity{}, false
+	}
+
+	id := Identity{UID: uint32(uid)}
+	if gid, err := strconv.ParseUint(mdSingle(md, mdFwdGID), 10, 32); err == nil {
+		id.GID = uint32(gid)
+	}
+	return id, true
+}
+
+// mdSingle returns the value of a forwarded key only when exactly one was
+// supplied. The gateway's interceptor sets each key exactly once, so more than one
+// value means something else also supplied it, and the whole identity is treated as
+// unknown rather than picking a winner. Defence in depth behind the gateway's
+// header filter.
+func mdSingle(md metadata.MD, key string) string {
+	if v := md.Get(key); len(v) == 1 {
+		return v[0]
+	}
+	return ""
+}
+
+// WithForwardedIdentity stamps id onto a context's outgoing metadata for the JSON
+// gateway's call to the daemon, replacing any forwarding keys already present so
+// values supplied from outside cannot survive alongside it.
+//
+// This is deliberately not done with runtime.WithMetadata: grpc-gateway skips its
+// annotators entirely when no request header maps to metadata ("if len(pairs) == 0
+// { return ctx, nil, nil }", runtime/context.go), which an HTTP/1.0 request with no
+// Host header over a unix socket achieves. The daemon would then see an unmarked
+// call whose transport peer is the daemon's own identity, and authorize it as the
+// daemon. A client interceptor runs for every RPC regardless of headers.
+func WithForwardedIdentity(ctx context.Context, id Identity, known bool) context.Context {
+	md, ok := metadata.FromOutgoingContext(ctx)
+	if !ok {
+		md = metadata.MD{}
+	} else {
+		md = md.Copy()
+	}
+
+	for _, key := range forwardKeys {
+		delete(md, key)
+	}
+	for key, values := range ForwardIdentityMetadata(id, known) {
+		md[key] = values
+	}
+
+	return metadata.NewOutgoingContext(ctx, md)
+}

client/internal/ipcauth/forward_test.go

@@ -0,0 +1,214 @@
+package ipcauth
+
+import (
+	"context"
+	"testing"
+
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/peer"
+)
+
+// transportCtx builds a request context as the daemon's transport credentials
+// would: the identity of whoever opened the socket, plus whatever metadata the
+// request carried.
+func transportCtx(id Identity, md metadata.MD) context.Context {
+	ctx := peer.NewContext(context.Background(), &peer.Peer{
+		AuthInfo: AuthInfo{
+			CommonAuthInfo: credentials.CommonAuthInfo{SecurityLevel: credentials.NoSecurity},
+			Identity:       id,
+		},
+	})
+	if md != nil {
+		ctx = metadata.NewIncomingContext(ctx, md)
+	}
+	return ctx
+}
+
+var (
+	root       = Identity{UID: 0}
+	unprivUser = Identity{UID: 1000, GID: 1000}
+)
+
+// asDaemon pins which identity counts as this process for the duration of a test.
+// Without it the test binary's own uid decides, which silently changes what
+// "the gateway" means.
+func asDaemon(t *testing.T, id Identity) {
+	t.Helper()
+	prevID, prevKnown, prevDelegate := selfIdentity, selfKnown, selfMayDelegate
+	t.Cleanup(func() { selfIdentity, selfKnown, selfMayDelegate = prevID, prevKnown, prevDelegate })
+	selfIdentity, selfKnown = id, true
+	selfMayDelegate = !id.IsPrivileged()
+}
+
+func TestCallerIdentity_DirectConnections(t *testing.T) {
+	t.Run("no transport credentials is not an identity", func(t *testing.T) {
+		if _, ok := CallerIdentity(context.Background()); ok {
+			t.Fatal("a caller with no credentials must not be identified")
+		}
+	})
+
+	t.Run("a direct caller is its transport identity", func(t *testing.T) {
+		id, ok := CallerIdentity(transportCtx(unprivUser, nil))
+		if !ok || id.UID != 1000 {
+			t.Fatalf("got %v ok=%t, want uid 1000", id, ok)
+		}
+	})
+
+	// The whole point of honouring forwarded metadata only from a privileged
+	// transport peer: an unprivileged caller can set any metadata it likes on its
+	// own connection to the daemon socket.
+	t.Run("an unprivileged caller cannot forge an identity", func(t *testing.T) {
+		asDaemon(t, root)
+		forged := metadata.Pairs(mdFwd, "1", mdFwdUID, "0", mdFwdGID, "0")
+		id, ok := CallerIdentity(transportCtx(unprivUser, forged))
+		if !ok {
+			t.Fatal("caller should still be identified, as itself")
+		}
+		if id.IsPrivileged() || id.UID != 1000 {
+			t.Fatalf("forged metadata was believed: got %v", id)
+		}
+	})
+}
+
+func TestCallerIdentity_GatewayForwarding(t *testing.T) {
+	t.Run("the gateway's client identity is used, not the gateway's own", func(t *testing.T) {
+		asDaemon(t, root)
+		md := ForwardIdentityMetadata(unprivUser, true)
+		id, ok := CallerIdentity(transportCtx(root, md))
+		if !ok {
+			t.Fatal("forwarded identity should be usable")
+		}
+		if id.IsPrivileged() || id.UID != 1000 {
+			t.Fatalf("got %v, want the forwarded uid 1000 and not privileged", id)
+		}
+	})
+
+	t.Run("a privileged gateway client stays privileged", func(t *testing.T) {
+		asDaemon(t, root)
+		md := ForwardIdentityMetadata(root, true)
+		id, ok := CallerIdentity(transportCtx(root, md))
+		if !ok || !id.IsPrivileged() {
+			t.Fatalf("got %v ok=%t, want a privileged identity", id, ok)
+		}
+	})
+
+	// A JSON socket the gateway cannot read peer credentials from (a TCP socket,
+	// say) must not make every request look like the daemon itself.
+	t.Run("an unreadable client identity is unknown, not the daemon", func(t *testing.T) {
+		asDaemon(t, root)
+		md := ForwardIdentityMetadata(Identity{}, false)
+		if _, ok := CallerIdentity(transportCtx(root, md)); ok {
+			t.Fatal("a forwarded request with no identity must not be identified")
+		}
+	})
+
+	// grpc-gateway turns Grpc-Metadata-<key> headers into gRPC metadata and joins
+	// them ahead of its annotators' values. If an HTTP client's header survived
+	// that, this is the shape the daemon would see: the attacker's uid 0 first,
+	// the real uid second. The gateway filters those headers out, and reading a
+	// duplicated key as unknown makes the daemon safe even if it did not.
+	t.Run("a duplicated key from an injected header is not believed", func(t *testing.T) {
+		asDaemon(t, root)
+		md := metadata.MD{}
+		md.Append(mdFwd, "1")
+		md.Append(mdFwdUID, "0")    // injected by the HTTP client
+		md.Append(mdFwdUID, "1000") // appended by the gateway's annotator
+		if id, ok := CallerIdentity(transportCtx(root, md)); ok {
+			t.Fatalf("injected uid was accepted: got %v", id)
+		}
+	})
+
+	t.Run("a duplicated marker is not believed either", func(t *testing.T) {
+		asDaemon(t, root)
+		md := metadata.MD{}
+		md.Append(mdFwd, "1")
+		md.Append(mdFwd, "1")
+		md.Append(mdFwdUID, "1000")
+		// A repeated marker must not be read as "not forwarded": that would
+		// authorize the request as the transport peer, which on the gateway's
+		// connection is the daemon itself.
+		if id, ok := CallerIdentity(transportCtx(root, md)); ok {
+			t.Fatalf("a duplicated marker was believed: got %v", id)
+		}
+	})
+
+	// The layers in front of this (the gateway's header matcher, and its
+	// interceptor replacing every forwarding key) are what keep outside metadata
+	// from arriving at all. The proof is what the daemon can check for itself, and
+	// it is the only defence that works for a value whose legitimate shape is
+	// indistinguishable from an injected one: a lone group SID, or "elevated".
+	t.Run("forwarding metadata without this process's proof is refused", func(t *testing.T) {
+		asDaemon(t, root)
+		for name, md := range map[string]metadata.MD{
+			"no proof":    metadata.Pairs(mdFwd, "1", mdFwdUID, "0"),
+			"wrong proof": metadata.Pairs(mdFwd, "1", mdFwdUID, "0", mdFwdProof, "deadbeef"),
+			"windows identity without a proof": metadata.Pairs(mdFwd, "1",
+				mdFwdSID, "S-1-5-21-1-2-3-1001", mdFwdGroup, sidAdministrators, mdFwdElevated, "1"),
+		} {
+			t.Run(name, func(t *testing.T) {
+				if id, ok := CallerIdentity(transportCtx(root, md)); ok {
+					t.Fatalf("unstamped forwarding metadata was believed: got %v", id)
+				}
+			})
+		}
+	})
+
+	// A caller that reaches the gateway cannot see the proof, so it cannot append
+	// a group of its own to a genuine forwarded identity: doing so would have to
+	// go through the interceptor, which replaces the whole set.
+	t.Run("a group appended to a stamped identity does not survive the interceptor", func(t *testing.T) {
+		asDaemon(t, root)
+		injected := metadata.MD{}
+		injected.Append(mdFwdGroup, sidAdministrators)
+
+		ctx := WithForwardedIdentity(metadata.NewOutgoingContext(context.Background(), injected),
+			Identity{SID: "S-1-5-21-1-2-3-1001"}, true)
+		out, ok := metadata.FromOutgoingContext(ctx)
+		if !ok {
+			t.Fatal("no outgoing metadata")
+		}
+		if groups := out.Get(mdFwdGroup); len(groups) != 0 {
+			t.Fatalf("injected group survived: %v", groups)
+		}
+	})
+}
+
+func TestIsReservedForwardKey(t *testing.T) {
+	for _, key := range forwardKeys {
+		if !IsReservedForwardKey(key) {
+			t.Errorf("%q must be reserved", key)
+		}
+	}
+
+	// grpc-gateway canonicalises header names, so the check has to be
+	// case-insensitive.
+	if !IsReservedForwardKey("X-Netbird-Fwd-Uid") {
+		t.Error("the check must be case-insensitive")
+	}
+
+	for _, key := range []string{"authorization", "x-netbird", "x-netbird-fwd-uid-extra", ""} {
+		if IsReservedForwardKey(key) {
+			t.Errorf("%q must not be reserved", key)
+		}
+	}
+}
+
+func TestForwardIdentityMetadata_AlwaysMarksForwarded(t *testing.T) {
+	for _, tc := range []struct {
+		name  string
+		id    Identity
+		known bool
+	}{
+		{"known unix identity", unprivUser, true},
+		{"unknown identity", Identity{}, false},
+		{"windows identity", Identity{SID: "S-1-5-21-1-2-3-1001", Elevated: true}, true},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			md := ForwardIdentityMetadata(tc.id, tc.known)
+			if got := md.Get(mdFwd); len(got) != 1 || got[0] != "1" {
+				t.Fatalf("marker = %v, want exactly one \"1\"", got)
+			}
+		})
+	}
+}

client/internal/ipcauth/identity.go

@@ -0,0 +1,127 @@
+// Package ipcauth provides the kernel-authenticated identity of a local IPC
+// (gRPC) caller and the transport credentials that surface it into the gRPC
+// context, so the daemon can authorize individual RPCs by caller identity.
+//
+// On Unix the identity is read from the kernel via SO_PEERCRED (Linux) or
+// LOCAL_PEERCRED (Darwin/FreeBSD). On Windows it is derived from the
+// named-pipe client token. Platforms without a peer-identity primitive get no
+// credentials, and every consumer must fail closed when no identity is
+// available.
+package ipcauth
+
+import (
+	"context"
+	"fmt"
+	"slices"
+
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/peer"
+)
+
+// Well-known Windows SIDs that identify a fully privileged principal.
+const (
+	sidLocalSystem    = "S-1-5-18"     // NT AUTHORITY\SYSTEM
+	sidLocalService   = "S-1-5-19"     // NT AUTHORITY\LOCAL SERVICE
+	sidNetworkService = "S-1-5-20"     // NT AUTHORITY\NETWORK SERVICE
+	sidAdministrators = "S-1-5-32-544" // BUILTIN\Administrators
+)
+
+// Identity is the kernel-authenticated identity of a local IPC caller. The
+// zero value is not a valid identity: consumers must only use one obtained
+// with a true ok/nil error return.
+type Identity struct {
+	// UID and GID are the caller's Unix user ID and primary group ID. Both are
+	// zero on Windows, where SID is authoritative instead.
+	UID uint32
+	GID uint32
+
+	// SID is the caller's Windows security identifier, empty on Unix.
+	SID string
+
+	// Groups holds the caller's Windows group SIDs, captured from the client
+	// token at handshake time. Only groups that are enabled and not
+	// deny-only are captured, so a group listed here is one the caller can
+	// actually exercise. Empty on Unix.
+	Groups []string
+
+	// Elevated reports whether the Windows client token is elevated (running
+	// as administrator, or an administrator with UAC turned off). Always false
+	// on Unix, where privilege is uid 0.
+	Elevated bool
+
+	// PID is the caller's process ID where the platform reports it (Linux's
+	// SO_PEERCRED), and 0 where it does not. It identifies the daemon's own
+	// process dialling itself, which is what the JSON gateway does, and is never
+	// used to grant anything.
+	PID int32
+}
+
+// IsWindows reports whether this identity is a Windows principal (SID-based)
+// rather than a Unix uid/gid principal.
+func (i Identity) IsWindows() bool {
+	return i.SID != ""
+}
+
+// IsPrivileged reports whether the caller is the platform's administrative
+// principal, which is what the daemon requires for changes that cross the
+// user-to-root boundary.
+//
+// On Windows the decision comes from the caller's token rather than from
+// account names or group RIDs: an elevated token, one of the service accounts
+// the daemon itself may run as, or a token with BUILTIN\Administrators
+// enabled. A UAC-filtered administrator has that group marked deny-only, and
+// deny-only groups are dropped when the identity is captured, so such a
+// caller is correctly reported as unprivileged. Domain group memberships
+// (Domain Admins and friends) are deliberately not consulted: they say
+// nothing about what this token may do on this machine.
+func (i Identity) IsPrivileged() bool {
+	if !i.IsWindows() {
+		return i.UID == 0
+	}
+
+	if i.Elevated {
+		return true
+	}
+
+	switch i.SID {
+	case sidLocalSystem, sidLocalService, sidNetworkService:
+		return true
+	}
+
+	return slices.Contains(i.Groups, sidAdministrators)
+}
+
+// String renders the identity for audit logs and denial messages.
+func (i Identity) String() string {
+	if i.IsWindows() {
+		return fmt.Sprintf("sid=%s elevated=%t", i.SID, i.Elevated)
+	}
+	return fmt.Sprintf("uid=%d gid=%d", i.UID, i.GID)
+}
+
+// AuthInfo carries the peer Identity as a gRPC credentials.AuthInfo so
+// handlers can retrieve it from the request context via IdentityFromContext.
+type AuthInfo struct {
+	credentials.CommonAuthInfo
+	Identity Identity
+}
+
+// AuthType identifies the authentication scheme.
+func (AuthInfo) AuthType() string { return "netbird-ipc-peercred" }
+
+// IdentityFromContext extracts the caller's kernel-authenticated identity from
+// the gRPC peer context. The second return value is false when no IPC
+// transport credentials were negotiated, which happens on a TCP daemon socket
+// and on platforms without a peer-identity primitive. Callers MUST fail closed
+// in that case.
+func IdentityFromContext(ctx context.Context) (Identity, bool) {
+	p, ok := peer.FromContext(ctx)
+	if !ok {
+		return Identity{}, false
+	}
+	info, ok := p.AuthInfo.(AuthInfo)
+	if !ok {
+		return Identity{}, false
+	}
+	return info.Identity, true
+}

client/internal/ipcauth/ownedfile.go

@@ -0,0 +1,63 @@
+package ipcauth
+
+import (
+	"fmt"
+	"os"
+)
+
+// OpenOwnedFile opens path for reading on behalf of the IPC caller identified by
+// id, and fails unless the opened file is a regular file that id owns.
+//
+// It exists for the paths a local caller hands to the daemon over the IPC. The
+// daemon runs as root, so opening such a path unchecked lets any local user read
+// any file through it. Ownership is the invariant that keeps the daemon from
+// reading, with its own privileges, a file the caller could not read itself: a
+// symlink or hard link planted at the path resolves to a file someone else owns
+// and is refused.
+//
+// The check is made against the open descriptor rather than the path, so
+// swapping the path between the check and the read cannot change the answer.
+//
+// A privileged caller is exempt: it can read the file directly, so refusing it
+// here would protect nothing. The regular-file requirement still applies to
+// everyone, since a fifo or device planted at the path is never a log file.
+func OpenOwnedFile(id Identity, path string) (*os.File, error) {
+	f, err := openForRead(path)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := checkOwnership(id, f); err != nil {
+		if cerr := f.Close(); cerr != nil {
+			return nil, fmt.Errorf("%w (close: %v)", err, cerr)
+		}
+		return nil, err
+	}
+
+	return f, nil
+}
+
+func checkOwnership(id Identity, f *os.File) error {
+	info, err := f.Stat()
+	if err != nil {
+		return fmt.Errorf("stat %s: %w", f.Name(), err)
+	}
+
+	if !info.Mode().IsRegular() {
+		return fmt.Errorf("%s is not a regular file", f.Name())
+	}
+
+	if IsPrivilegedCaller(id) {
+		return nil
+	}
+
+	owned, err := fileOwnedBy(id, f)
+	if err != nil {
+		return fmt.Errorf("read owner of %s: %w", f.Name(), err)
+	}
+	if !owned {
+		return fmt.Errorf("%s is not owned by the caller (%s)", f.Name(), id)
+	}
+
+	return nil
+}

client/internal/ipcauth/ownedfile_test.go

@@ -0,0 +1,64 @@
+package ipcauth
+
+import (
+	"io"
+	"os"
+	"path/filepath"
+	"runtime"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+// otherIdentity is an unprivileged caller that owns nothing the test creates.
+func otherIdentity(t *testing.T) Identity {
+	t.Helper()
+	if runtime.GOOS == "windows" {
+		return Identity{SID: "S-1-5-21-1-2-3-1001"}
+	}
+	return Identity{UID: uint32(os.Geteuid() + 1), GID: uint32(os.Getegid() + 1)}
+}
+
+func TestOpenOwnedFileReadsFileOwnedByCaller(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "gui-client.log")
+	require.NoError(t, os.WriteFile(path, []byte("hello"), 0600))
+
+	id, err := CurrentProcessIdentity()
+	require.NoError(t, err)
+
+	f, err := OpenOwnedFile(id, path)
+	require.NoError(t, err)
+	t.Cleanup(func() { _ = f.Close() })
+
+	content, err := io.ReadAll(f)
+	require.NoError(t, err)
+	require.Equal(t, "hello", string(content))
+}
+
+func TestOpenOwnedFileRefusesFileOwnedByAnother(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "gui-client.log")
+	require.NoError(t, os.WriteFile(path, []byte("secret"), 0600))
+
+	_, err := OpenOwnedFile(otherIdentity(t), path)
+	require.ErrorContains(t, err, "not owned by the caller")
+}
+
+func TestOpenOwnedFileRefusesNonRegularFile(t *testing.T) {
+	dir := t.TempDir()
+
+	// The caller owns the directory, so this is the regular-file requirement
+	// talking, not the ownership check.
+	id, err := CurrentProcessIdentity()
+	require.NoError(t, err)
+
+	_, err = OpenOwnedFile(id, dir)
+	require.ErrorContains(t, err, "not a regular file")
+}
+
+func TestOpenOwnedFileRefusesMissingFile(t *testing.T) {
+	id, err := CurrentProcessIdentity()
+	require.NoError(t, err)
+
+	_, err = OpenOwnedFile(id, filepath.Join(t.TempDir(), "absent.log"))
+	require.Error(t, err)
+}

client/internal/ipcauth/ownedfile_unix.go

@@ -0,0 +1,35 @@
+//go:build !windows
+
+package ipcauth
+
+import (
+	"fmt"
+	"os"
+	"syscall"
+)
+
+// openForRead opens a caller-supplied path without following a symlink at its
+// final component and without blocking: a fifo planted at the path would
+// otherwise stall the open until a writer appears, and the daemon holds a lock
+// while it collects the file.
+func openForRead(path string) (*os.File, error) {
+	f, err := os.OpenFile(path, os.O_RDONLY|syscall.O_NOFOLLOW|syscall.O_NONBLOCK, 0)
+	if err != nil {
+		return nil, fmt.Errorf("open %s: %w", path, err)
+	}
+	return f, nil
+}
+
+func fileOwnedBy(id Identity, f *os.File) (bool, error) {
+	info, err := f.Stat()
+	if err != nil {
+		return false, err
+	}
+
+	stat, ok := info.Sys().(*syscall.Stat_t)
+	if !ok {
+		return false, fmt.Errorf("no owner information in %T", info.Sys())
+	}
+
+	return stat.Uid == id.UID, nil
+}

client/internal/ipcauth/ownedfile_unix_test.go

@@ -0,0 +1,57 @@
+//go:build !windows
+
+package ipcauth
+
+import (
+	"errors"
+	"os"
+	"path/filepath"
+	"syscall"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+// A symlink is the shape the arbitrary-read attempt takes: the caller owns the
+// link, the file it points at belongs to someone else.
+func TestOpenOwnedFileRefusesSymlink(t *testing.T) {
+	dir := t.TempDir()
+	target := filepath.Join(dir, "target.log")
+	require.NoError(t, os.WriteFile(target, []byte("secret"), 0600))
+
+	link := filepath.Join(dir, "gui-client.log")
+	require.NoError(t, os.Symlink(target, link))
+
+	id, err := CurrentProcessIdentity()
+	require.NoError(t, err)
+
+	_, err = OpenOwnedFile(id, link)
+	// O_NOFOLLOW on a symlink reports ELOOP on Linux/Darwin and EMLINK on FreeBSD.
+	if !errors.Is(err, syscall.ELOOP) && !errors.Is(err, syscall.EMLINK) {
+		t.Fatalf("symlink open: got %v, want ELOOP or EMLINK", err)
+	}
+}
+
+// A fifo would block the open until a writer showed up, stalling the daemon
+// while it holds its lock.
+func TestOpenOwnedFileRefusesFifoWithoutBlocking(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "gui-client.log")
+	require.NoError(t, syscall.Mkfifo(path, 0600))
+
+	id, err := CurrentProcessIdentity()
+	require.NoError(t, err)
+
+	done := make(chan error, 1)
+	go func() {
+		_, err := OpenOwnedFile(id, path)
+		done <- err
+	}()
+
+	select {
+	case err := <-done:
+		require.ErrorContains(t, err, "not a regular file")
+	case <-time.After(5 * time.Second):
+		t.Fatal("opening a fifo blocked")
+	}
+}

client/internal/ipcauth/ownedfile_windows.go

@@ -0,0 +1,59 @@
+//go:build windows
+
+package ipcauth
+
+import (
+	"fmt"
+	"os"
+
+	"golang.org/x/sys/windows"
+)
+
+// openForRead opens a caller-supplied path without following a reparse point at
+// it. FILE_FLAG_OPEN_REPARSE_POINT is the Windows analogue of O_NOFOLLOW: it
+// opens a symlink/junction itself rather than its target, so the regular-file
+// check in checkOwnership refuses a link the caller planted to redirect the
+// read. FILE_FLAG_BACKUP_SEMANTICS lets a directory open too (as os.Open does),
+// so a directory planted at the path is refused as non-regular rather than
+// erroring here. The share mode matches os.Open so a log being written stays
+// openable.
+func openForRead(path string) (*os.File, error) {
+	p, err := windows.UTF16PtrFromString(path)
+	if err != nil {
+		return nil, fmt.Errorf("convert path %s: %w", path, err)
+	}
+
+	handle, err := windows.CreateFile(
+		p,
+		windows.GENERIC_READ,
+		windows.FILE_SHARE_READ|windows.FILE_SHARE_WRITE|windows.FILE_SHARE_DELETE,
+		nil,
+		windows.OPEN_EXISTING,
+		windows.FILE_FLAG_OPEN_REPARSE_POINT|windows.FILE_FLAG_BACKUP_SEMANTICS,
+		0,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("open %s: %w", path, err)
+	}
+
+	return os.NewFile(uintptr(handle), path), nil
+}
+
+// fileOwnedBy compares the file's owner SID with the caller's. Files an elevated
+// process creates are owned by BUILTIN\Administrators rather than by the user,
+// but such a caller is privileged and never reaches this check.
+func fileOwnedBy(id Identity, f *os.File) (bool, error) {
+	// x/sys/windows GetSecurityInfo frees the OS buffer itself and returns a
+	// Go-heap copy, so there is nothing to LocalFree here.
+	sd, err := windows.GetSecurityInfo(windows.Handle(f.Fd()), windows.SE_FILE_OBJECT, windows.OWNER_SECURITY_INFORMATION)
+	if err != nil {
+		return false, fmt.Errorf("read security info: %w", err)
+	}
+
+	owner, _, err := sd.Owner()
+	if err != nil {
+		return false, fmt.Errorf("read owner: %w", err)
+	}
+
+	return id.SID != "" && owner.String() == id.SID, nil
+}

client/internal/ipcauth/ownedfile_windows_test.go

@@ -0,0 +1,78 @@
+//go:build windows
+
+package ipcauth
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"golang.org/x/sys/windows"
+)
+
+// fileOwnerSID reads the owner SID of path the same way OpenOwnedFile does, so
+// the test can construct an Identity that matches (or deliberately does not).
+func fileOwnerSID(t *testing.T, path string) string {
+	t.Helper()
+	f, err := os.Open(path)
+	require.NoError(t, err)
+	t.Cleanup(func() { _ = f.Close() })
+
+	sd, err := windows.GetSecurityInfo(windows.Handle(f.Fd()), windows.SE_FILE_OBJECT, windows.OWNER_SECURITY_INFORMATION)
+	require.NoError(t, err)
+	owner, _, err := sd.Owner()
+	require.NoError(t, err)
+	return owner.String()
+}
+
+// The allow branch of fileOwnedBy is the SID-equality path the legitimate GUI
+// flow depends on. Running elevated, a created file is owned by
+// BUILTIN\Administrators; an Identity carrying that SID with Elevated=false and
+// no groups is unprivileged by IsPrivileged (which reads the token, not the
+// SID's RID), so this exercises the real GetSecurityInfo equality rather than
+// the privileged-caller shortcut.
+func TestOpenOwnedFileWindowsOwnerMatchAllows(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "gui-client.log")
+	require.NoError(t, os.WriteFile(path, []byte("hello"), 0600))
+
+	ownerSID := fileOwnerSID(t, path)
+	id := Identity{SID: ownerSID}
+	require.False(t, id.IsPrivileged(), "identity built from the owner SID must be unprivileged for this to test the match path")
+
+	f, err := OpenOwnedFile(id, path)
+	require.NoError(t, err)
+	_ = f.Close()
+}
+
+func TestOpenOwnedFileWindowsOwnerMismatchRefuses(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "gui-client.log")
+	require.NoError(t, os.WriteFile(path, []byte("secret"), 0600))
+
+	other := Identity{SID: "S-1-5-21-9-9-9-9999"}
+	require.False(t, other.IsPrivileged())
+
+	_, err := OpenOwnedFile(other, path)
+	require.ErrorContains(t, err, "not owned by the caller")
+}
+
+// FILE_FLAG_OPEN_REPARSE_POINT must make OpenOwnedFile refuse a symlink the same
+// way O_NOFOLLOW does on Unix, so a planted link can't redirect the read to
+// another file. Creating a symlink needs a privilege the runner may lack, so the
+// test skips rather than fails when it can't.
+func TestOpenOwnedFileWindowsRefusesSymlink(t *testing.T) {
+	dir := t.TempDir()
+	target := filepath.Join(dir, "target.log")
+	require.NoError(t, os.WriteFile(target, []byte("secret"), 0600))
+
+	link := filepath.Join(dir, "gui-client.log")
+	if err := os.Symlink(target, link); err != nil {
+		t.Skipf("cannot create symlink (privilege not held?): %v", err)
+	}
+
+	id, err := CurrentProcessIdentity()
+	require.NoError(t, err)
+
+	_, err = OpenOwnedFile(id, link)
+	require.Error(t, err, "a symlink must be refused")
+}

client/internal/ipcauth/peercred_bsd.go

@@ -0,0 +1,43 @@
+//go:build darwin || freebsd
+
+package ipcauth
+
+import (
+	"fmt"
+	"net"
+
+	"golang.org/x/sys/unix"
+)
+
+// PeerIdentity reads the kernel-authenticated identity of the process on the
+// other end of a Unix socket via LOCAL_PEERCRED. The xucred is recorded by the
+// kernel at connect() time and carries the peer's uid and its group list, of
+// which the first entry is the primary group.
+func PeerIdentity(conn net.Conn) (Identity, error) {
+	uc, ok := conn.(*net.UnixConn)
+	if !ok {
+		return Identity{}, fmt.Errorf("connection is not a unix socket: %T", conn)
+	}
+
+	raw, err := uc.SyscallConn()
+	if err != nil {
+		return Identity{}, fmt.Errorf("raw conn: %w", err)
+	}
+
+	var cred *unix.Xucred
+	var credErr error
+	if err := raw.Control(func(fd uintptr) {
+		cred, credErr = unix.GetsockoptXucred(int(fd), unix.SOL_LOCAL, unix.LOCAL_PEERCRED)
+	}); err != nil {
+		return Identity{}, fmt.Errorf("control raw conn: %w", err)
+	}
+	if credErr != nil {
+		return Identity{}, fmt.Errorf("read LOCAL_PEERCRED: %w", credErr)
+	}
+
+	id := Identity{UID: cred.Uid}
+	if cred.Ngroups > 0 {
+		id.GID = cred.Groups[0]
+	}
+	return id, nil
+}

client/internal/ipcauth/peercred_linux.go

@@ -0,0 +1,39 @@
+//go:build linux
+
+package ipcauth
+
+import (
+	"fmt"
+	"net"
+
+	"golang.org/x/sys/unix"
+)
+
+// PeerIdentity reads the kernel-authenticated identity of the process on the
+// other end of a Unix socket via SO_PEERCRED. The credentials are recorded by
+// the kernel at connect() time and cannot be changed for the life of the
+// connection, so they are not spoofable by the caller.
+func PeerIdentity(conn net.Conn) (Identity, error) {
+	uc, ok := conn.(*net.UnixConn)
+	if !ok {
+		return Identity{}, fmt.Errorf("connection is not a unix socket: %T", conn)
+	}
+
+	raw, err := uc.SyscallConn()
+	if err != nil {
+		return Identity{}, fmt.Errorf("raw conn: %w", err)
+	}
+
+	var cred *unix.Ucred
+	var credErr error
+	if err := raw.Control(func(fd uintptr) {
+		cred, credErr = unix.GetsockoptUcred(int(fd), unix.SOL_SOCKET, unix.SO_PEERCRED)
+	}); err != nil {
+		return Identity{}, fmt.Errorf("control raw conn: %w", err)
+	}
+	if credErr != nil {
+		return Identity{}, fmt.Errorf("read SO_PEERCRED: %w", credErr)
+	}
+
+	return Identity{UID: cred.Uid, GID: cred.Gid, PID: cred.Pid}, nil
+}

client/internal/ipcauth/pipeserver_windows.go

@@ -0,0 +1,87 @@
+//go:build windows
+
+package ipcauth
+
+import (
+	"fmt"
+	"net"
+
+	log "github.com/sirupsen/logrus"
+	"golang.org/x/sys/windows"
+)
+
+// PipeServerTrusted reports an error unless the pipe behind conn was created by a
+// principal this client may hand secrets to. Clients call it for a pipe whose name
+// carries no guarantee of its own, which is any name outside the
+// ProtectedPrefix\Administrators namespace: that namespace already restricts
+// creation to administrators and LocalSystem, while a plain name can be created by
+// any local user before the daemon gets there.
+//
+// The decision is made from the pipe object's owner, not from the serving process,
+// because a client cannot open a process running as another user at all, and the
+// legitimate case is precisely an unprivileged client talking to a privileged
+// daemon. Trusted owners are the service accounts, BUILTIN\Administrators, and
+// this client's own user, the last of which is the daemon a user runs themselves
+// as in netstack mode. A pipe owned by anyone else gets no setup key, pre-shared
+// key or SSO prompt out of this client.
+func PipeServerTrusted(conn net.Conn) error {
+	// go-winio's pipe connection embeds *win32File, which exposes Fd().
+	fdConn, ok := conn.(interface{ Fd() uintptr })
+	if !ok {
+		return fmt.Errorf("connection %T does not expose a pipe handle", conn)
+	}
+
+	owner, err := pipeOwnerSID(windows.Handle(fdConn.Fd()))
+	if err != nil {
+		return err
+	}
+
+	if !trustedPipeOwner(owner) {
+		return fmt.Errorf("pipe owned by %s, which is neither an administrator nor this user", owner)
+	}
+	return nil
+}
+
+// PipeOwnedBySelf reports whether the pipe behind conn was created by this very
+// user, which is how a client recognises a daemon running as itself. Ownership it
+// cannot read is reported as false.
+func PipeOwnedBySelf(conn net.Conn) bool {
+	fdConn, ok := conn.(interface{ Fd() uintptr })
+	if !ok {
+		return false
+	}
+
+	owner, err := pipeOwnerSID(windows.Handle(fdConn.Fd()))
+	if err != nil {
+		log.Debugf("read daemon pipe owner: %v", err)
+		return false
+	}
+	return selfKnown && selfIdentity.SID != "" && owner == selfIdentity.SID
+}
+
+// pipeOwnerSID reads the owner of the pipe object a client is connected to. The
+// handle was opened with GENERIC_READ, which includes READ_CONTROL, so no extra
+// access is needed.
+func pipeOwnerSID(handle windows.Handle) (string, error) {
+	sd, err := windows.GetSecurityInfo(handle, windows.SE_KERNEL_OBJECT, windows.OWNER_SECURITY_INFORMATION)
+	if err != nil {
+		return "", fmt.Errorf("read pipe security info: %w", err)
+	}
+
+	owner, _, err := sd.Owner()
+	if err != nil {
+		return "", fmt.Errorf("read pipe owner: %w", err)
+	}
+	return owner.String(), nil
+}
+
+// trustedPipeOwner reports whether a pipe's owner is a principal a client may
+// speak to. An elevated process's objects are owned by BUILTIN\Administrators by
+// default, an unelevated one's by the user, which is why both forms appear here.
+func trustedPipeOwner(owner string) bool {
+	switch owner {
+	case sidLocalSystem, sidLocalService, sidNetworkService, sidAdministrators:
+		return true
+	}
+	return selfKnown && selfIdentity.SID != "" && owner == selfIdentity.SID
+}

client/internal/ipcauth/privileged.go

@@ -0,0 +1,125 @@
+package ipcauth
+
+import (
+	"os"
+	"runtime"
+)
+
+// Fields of the ErrorInfo detail the daemon attaches to a PermissionDenied it
+// raises for an operation that requires root/administrator. Clients match on
+// Reason and Domain rather than on the message text, and render the summary and
+// command themselves so the user gets guidance instead of a gRPC error dump.
+const (
+	// ErrorReasonPrivilegeRequired identifies the detail.
+	ErrorReasonPrivilegeRequired = "PRIVILEGE_REQUIRED"
+	// ErrorDomain scopes the reason to the NetBird daemon.
+	ErrorDomain = "daemon.netbird.io"
+	// ErrorMetaSummary is the one-sentence explanation of what was refused.
+	ErrorMetaSummary = "summary"
+	// ErrorMetaCommand is the command that performs the same operation with the
+	// privileges it needs, ready to copy and run.
+	ErrorMetaCommand = "command"
+)
+
+// The identity of the process evaluating callers, captured once because it cannot
+// change. selfKnown is false when it could not be read, in which case nothing is
+// ever treated as this process. selfMayDelegate additionally requires this
+// process to be unprivileged: see IsPrivilegedCaller.
+var (
+	selfIdentity    Identity
+	selfKnown       bool
+	selfMayDelegate bool
+	// selfPID is this process's PID, used to recognise the daemon dialling itself.
+	selfPID = os.Getpid()
+)
+
+func init() {
+	id, err := CurrentProcessIdentity()
+	if err != nil {
+		return
+	}
+	selfIdentity, selfKnown = id, true
+	// Only an unprivileged daemon delegates its authority to its own identity.
+	// When it is root or LocalSystem, sharing its identity does not mean sharing
+	// its power: on Windows a filtered and a full token carry the same SID, so
+	// matching there would let a non-elevated shell of an administrator account
+	// act as an administrator, which is the boundary the token check exists to
+	// keep.
+	selfMayDelegate = !id.IsPrivileged()
+}
+
+// IsDaemonSelf reports whether an identity is this very process. The JSON gateway
+// runs inside the daemon and re-dials it locally, so this is what distinguishes
+// the gateway from any other caller, whatever user the daemon runs as.
+func IsDaemonSelf(id Identity) bool {
+	if !selfKnown || id.IsWindows() != selfIdentity.IsWindows() {
+		return false
+	}
+	if id.IsWindows() {
+		return id.SID != "" && id.SID == selfIdentity.SID
+	}
+	return id.UID == selfIdentity.UID
+}
+
+// IsPrivilegedCaller reports whether an identity may make the changes the daemon
+// restricts to the platform administrator. This is the daemon's own rule and
+// cannot be evaluated by a client, which does not know what the daemon runs as.
+//
+// Beyond root/administrator it accepts a caller running as the daemon's own
+// identity when the daemon is itself unprivileged. That keeps a rootless container
+// working, where there is no uid 0 at all, and a Windows daemon in netstack mode,
+// which needs no administrator rights. In those setups a caller sharing the
+// daemon's identity can already rewrite the config files it reads and replace the
+// binary it runs, so refusing it a config change would protect nothing; and an
+// unprivileged daemon cannot hand out a root shell in the first place.
+func IsPrivilegedCaller(id Identity) bool {
+	if id.IsPrivileged() {
+		return true
+	}
+	return selfMayDelegate && IsDaemonSelf(id)
+}
+
+// SelfDelegatesTo returns the identity this process delegates its authority to,
+// and whether it delegates at all. Only an unprivileged daemon does: see
+// IsPrivilegedCaller. It exists so a refusal can name who may actually perform the
+// operation, because on such a host root is neither required nor necessarily
+// available.
+func SelfDelegatesTo() (Identity, bool) {
+	if !selfKnown || !selfMayDelegate {
+		return Identity{}, false
+	}
+	return selfIdentity, true
+}
+
+// PrivilegedActor names the principal a privileged operation requires, for use
+// in messages shown to the user.
+func PrivilegedActor() string {
+	if runtime.GOOS == "windows" {
+		return "administrator privileges"
+	}
+	return "root"
+}
+
+// ElevatedCommand renders a command so that running it grants the privileges the
+// operation needs. Windows has no in-line equivalent of sudo, so the command is
+// returned unchanged and the user is expected to run it from an elevated
+// terminal.
+func ElevatedCommand(command string) string {
+	if runtime.GOOS == "windows" {
+		return command
+	}
+	return "sudo " + command
+}
+
+// UpCommand renders an elevated `netbird up` with the given flags, preceded by a
+// `down`. The down is what makes the command work on a connected client: `netbird
+// up` prints "Already connected" and returns without applying any config flag, so
+// on its own the command would appear to do nothing. It is a no-op, exit 0, when
+// the client is not connected.
+//
+// ";" rather than "&&" so the line can be pasted into any of the shells a user
+// might have: PowerShell 5.1, still the default on Windows Server, rejects "&&"
+// as a syntax error.
+func UpCommand(flags string) string {
+	return ElevatedCommand("netbird down") + "; " + ElevatedCommand("netbird up "+flags)
+}

client/internal/ipcauth/privileged_test.go

@@ -0,0 +1,134 @@
+package ipcauth
+
+import "testing"
+
+// The self rule is the one place privilege is granted to something other than the
+// platform administrator, so its two guards matter: it must apply only when the
+// daemon is itself unprivileged, and only to a caller with the daemon's identity.
+func TestIsPrivilegedCaller_SelfRule(t *testing.T) {
+	tests := []struct {
+		name string
+		// self stands in for the process the daemon runs as.
+		self      Identity
+		selfKnown bool
+		caller    Identity
+		want      bool
+	}{
+		{
+			name:      "root is privileged whatever the daemon runs as",
+			self:      Identity{UID: 1000},
+			selfKnown: true,
+			caller:    Identity{UID: 0},
+			want:      true,
+		},
+		{
+			name:      "an unprivileged daemon delegates to its own user (rootless container)",
+			self:      Identity{UID: 1000},
+			selfKnown: true,
+			caller:    Identity{UID: 1000},
+			want:      true,
+		},
+		{
+			name:      "an unprivileged daemon delegates to nobody else",
+			self:      Identity{UID: 1000},
+			selfKnown: true,
+			caller:    Identity{UID: 1001},
+			want:      false,
+		},
+		{
+			// The daemon is root on a normal install, so sharing its identity is
+			// already covered by being root; nothing else may match.
+			name:      "a root daemon delegates to nobody",
+			self:      Identity{UID: 0},
+			selfKnown: true,
+			caller:    Identity{UID: 1000},
+			want:      false,
+		},
+		{
+			// Windows netstack mode: the daemon needs no administrator rights.
+			name:      "an unprivileged windows daemon delegates to its own SID",
+			self:      Identity{SID: "S-1-5-21-1-2-3-1001"},
+			selfKnown: true,
+			caller:    Identity{SID: "S-1-5-21-1-2-3-1001"},
+			want:      true,
+		},
+		{
+			name:      "an unprivileged windows daemon delegates to no other SID",
+			self:      Identity{SID: "S-1-5-21-1-2-3-1001"},
+			selfKnown: true,
+			caller:    Identity{SID: "S-1-5-21-1-2-3-1002"},
+			want:      false,
+		},
+		{
+			// The UAC boundary: a filtered and a full token of the same account
+			// carry the same SID but not the same power, so an elevated daemon must
+			// never delegate to its own SID.
+			name:      "an elevated windows daemon does not delegate to its own SID",
+			self:      Identity{SID: "S-1-5-21-1-2-3-500", Elevated: true},
+			selfKnown: true,
+			caller:    Identity{SID: "S-1-5-21-1-2-3-500"},
+			want:      false,
+		},
+		{
+			name:      "LocalSystem is privileged on its own merits, not by delegation",
+			self:      Identity{SID: sidLocalSystem},
+			selfKnown: true,
+			caller:    Identity{SID: sidLocalSystem},
+			want:      true, // LocalSystem is privileged on its own merits
+		},
+		{
+			name:      "identities of different kinds never match",
+			self:      Identity{UID: 1000},
+			selfKnown: true,
+			caller:    Identity{SID: "S-1-5-21-1-2-3-1001"},
+			want:      false,
+		},
+		{
+			name:      "an unknown self identity delegates to nobody",
+			self:      Identity{},
+			selfKnown: false,
+			caller:    Identity{UID: 1000},
+			want:      false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			prevID, prevKnown, prevDelegate := selfIdentity, selfKnown, selfMayDelegate
+			t.Cleanup(func() { selfIdentity, selfKnown, selfMayDelegate = prevID, prevKnown, prevDelegate })
+
+			selfIdentity, selfKnown = tt.self, tt.selfKnown
+			selfMayDelegate = tt.selfKnown && !tt.self.IsPrivileged()
+
+			if got := IsPrivilegedCaller(tt.caller); got != tt.want {
+				t.Fatalf("IsPrivilegedCaller(%v) with daemon %v = %t, want %t",
+					tt.caller, tt.self, got, tt.want)
+			}
+		})
+	}
+}
+
+// The real process must never accidentally delegate: a test binary running as a
+// normal user is unprivileged, so it may match itself, but nothing else.
+func TestIsPrivilegedCaller_ThisProcess(t *testing.T) {
+	id, err := CurrentProcessIdentity()
+	if err != nil {
+		t.Skipf("cannot read this process's identity: %v", err)
+	}
+
+	// This process is always allowed to act as itself: either it is privileged, or
+	// it is unprivileged and therefore delegates to its own identity.
+	if !IsPrivilegedCaller(id) {
+		t.Errorf("this process %v was refused its own identity", id)
+	}
+
+	// A caller that is neither root nor this process must be refused, whatever
+	// this process happens to be.
+	other := Identity{UID: id.UID + 1}
+	if id.IsWindows() {
+		other = Identity{SID: id.SID + "9"}
+	}
+	if IsPrivilegedCaller(other) {
+		t.Errorf("an unrelated identity %v was treated as privileged", other)
+	}
+}

client/internal/ipcauth/self_unix.go

@@ -0,0 +1,17 @@
+//go:build !windows
+
+package ipcauth
+
+import "os"
+
+// CurrentProcessIdentity returns this process's identity as the daemon would
+// see it if this process connected to the local IPC. It lets a client (the UI)
+// decide up front whether a privileged operation can succeed, without a
+// round-trip and without duplicating the rules: the answer comes from the same
+// Identity.IsPrivileged the daemon applies.
+func CurrentProcessIdentity() (Identity, error) {
+	return Identity{
+		UID: uint32(os.Geteuid()),
+		GID: uint32(os.Getegid()),
+	}, nil
+}

client/internal/ipcauth/self_windows.go

@@ -0,0 +1,35 @@
+//go:build windows
+
+package ipcauth
+
+import (
+	"fmt"
+
+	"golang.org/x/sys/windows"
+)
+
+// CurrentProcessIdentity returns this process's identity as the daemon would see
+// it if this process connected to the local IPC. It lets a client (the UI)
+// decide up front whether a privileged operation can succeed, without a
+// round-trip and without duplicating the rules: the answer comes from the same
+// Identity.IsPrivileged the daemon applies to the token it reads off the pipe.
+func CurrentProcessIdentity() (Identity, error) {
+	// A pseudo-token, so it must not be closed.
+	token := windows.GetCurrentProcessToken()
+
+	user, err := token.GetTokenUser()
+	if err != nil {
+		return Identity{}, fmt.Errorf("read token user: %w", err)
+	}
+
+	groups, err := tokenGroupSIDs(token)
+	if err != nil {
+		return Identity{}, err
+	}
+
+	return Identity{
+		SID:      user.User.Sid.String(),
+		Groups:   groups,
+		Elevated: token.IsElevated(),
+	}, nil
+}

client/internal/lazyconn/manager/manager.go

@@ -29,6 +29,11 @@ type managedPeer struct {
 
 type Config struct {
 	InactivityThreshold *time.Duration
+	// ReconcileAllowedIPs re-applies a peer's routed allowed IPs after its wake endpoint is
+	// armed. The activity listener creates the wake peer with the overlay /32 only; without the
+	// routed prefixes WireGuard would not steer subnet-bound traffic to the wake endpoint, so an
+	// idle routing peer could never be woken by that traffic. Optional; nil disables the reconcile.
+	ReconcileAllowedIPs func(peerKey string) error
 }
 
 // Manager manages lazy connections
@@ -56,6 +61,9 @@ type Manager struct {
 	peerToHAGroups map[string][]route.HAUniqueID // peer ID -> HA groups they belong to
 	haGroupToPeers map[route.HAUniqueID][]string // HA group -> peer IDs in the group
 	routesMu       sync.RWMutex
+
+	// reconcileAllowedIPs re-applies a peer's routed allowed IPs after its wake endpoint is armed.
+	reconcileAllowedIPs func(peerKey string) error
 }
 
 // NewManager creates a new lazy connection manager
@@ -73,6 +81,7 @@ func NewManager(config Config, engineCtx context.Context, peerStore *peerstore.S
 		activityManager:      activity.NewManager(wgIface),
 		peerToHAGroups:       make(map[string][]route.HAUniqueID),
 		haGroupToPeers:       make(map[route.HAUniqueID][]string),
+		reconcileAllowedIPs:  config.ReconcileAllowedIPs,
 	}
 
 	if wgIface.IsUserspaceBind() {
@@ -201,7 +210,7 @@ func (m *Manager) AddPeer(peerCfg lazyconn.PeerConfig) (bool, error) {
 		return false, nil
 	}
 
-	if err := m.activityManager.MonitorPeerActivity(peerCfg); err != nil {
+	if err := m.armActivityListener(peerCfg); err != nil {
 		return false, err
 	}
 
@@ -288,7 +297,7 @@ func (m *Manager) DeactivatePeer(peerID peerid.ConnID) {
 
 	m.inactivityManager.RemovePeer(mp.peerCfg.PublicKey)
 
-	if err := m.activityManager.MonitorPeerActivity(*mp.peerCfg); err != nil {
+	if err := m.armActivityListener(*mp.peerCfg); err != nil {
 		mp.peerCfg.Log.Errorf("failed to create activity monitor: %v", err)
 		return
 	}
@@ -465,6 +474,31 @@ func (m *Manager) close() {
 }
 
 // shouldDeferIdleForHA checks if peer should stay connected due to HA group requirements
+// armRoutedAllowedIPs re-applies the peer's routed allowed IPs onto its freshly armed wake
+// endpoint. The activity listener creates the wake peer with the overlay /32 only, so without
+// this the routed prefixes would be missing and traffic to a routed subnet could not wake the
+// idle routing peer. It is a no-op when no reconciler is configured.
+// armActivityListener (re)arms the peer's wake endpoint via the activity manager and then
+// re-applies its routed allowed IPs, so traffic to a routed subnet can wake an idle routing
+// peer. The routed prefixes must be re-applied after the wake endpoint exists because the
+// listener creates it with the overlay /32 only.
+func (m *Manager) armActivityListener(peerCfg lazyconn.PeerConfig) error {
+	if err := m.activityManager.MonitorPeerActivity(peerCfg); err != nil {
+		return err
+	}
+	m.armRoutedAllowedIPs(&peerCfg)
+	return nil
+}
+
+func (m *Manager) armRoutedAllowedIPs(peerCfg *lazyconn.PeerConfig) {
+	if m.reconcileAllowedIPs == nil {
+		return
+	}
+	if err := m.reconcileAllowedIPs(peerCfg.PublicKey); err != nil {
+		peerCfg.Log.Errorf("failed to reconcile routed allowed IPs on wake endpoint: %v", err)
+	}
+}
+
 func (m *Manager) shouldDeferIdleForHA(inactivePeers map[string]struct{}, peerID string) bool {
 	m.routesMu.RLock()
 	defer m.routesMu.RUnlock()
@@ -577,7 +611,7 @@ func (m *Manager) onPeerInactivityTimedOut(peerIDs map[string]struct{}) {
 
 		mp.peerCfg.Log.Infof("start activity monitor")
 
-		if err := m.activityManager.MonitorPeerActivity(*mp.peerCfg); err != nil {
+		if err := m.armActivityListener(*mp.peerCfg); err != nil {
 			mp.peerCfg.Log.Errorf("failed to create activity monitor: %v", err)
 			continue
 		}

client/internal/mobile_dependency.go

@@ -11,12 +11,14 @@ import (
 
 // MobileDependency collect all dependencies for mobile platform
 type MobileDependency struct {
-	// Android only
-	TunAdapter            device.TunAdapter
-	IFaceDiscover         stdnet.ExternalIFaceDiscover
+	// Android and iOS
 	NetworkChangeListener listener.NetworkChangeListener
-	HostDNSAddresses      []netip.AddrPort
-	DnsReadyListener      dns.ReadyListener
+
+	// Android only
+	TunAdapter       device.TunAdapter
+	IFaceDiscover    stdnet.ExternalIFaceDiscover
+	HostDNSAddresses []netip.AddrPort
+	DnsReadyListener dns.ReadyListener
 
 	//	iOS only
 	DnsManager     dns.IosDnsManager

client/internal/peer/status.go

@@ -813,19 +813,14 @@ func (d *Status) SetSessionExpiresAt(deadline time.Time) {
 }
 
 // GetSessionExpiresAt returns the most recently recorded SSO session deadline,
-// or the zero value when no deadline is tracked. A deadline that has already
-// slipped into the past reports as "none": once the session has expired it is
-// no longer a meaningful countdown, and the sessionwatch.Watcher does not
-// arm a timer at the deadline itself to clear it (only the two pre-expiry
-// warnings). Without this guard the UI would keep painting a stale
-// "expires in …" against a moment that has passed until the next login,
-// extend, or teardown rewrote the value.
+// or the zero value when no deadline is tracked. A deadline in the past is
+// returned as-is: it means the session has expired, and consumers (tray row,
+// CLI status) render it as "expired" rather than hiding it — masking it as
+// "none" would blank the UI at the exact moment it should say the session
+// ended.
 func (d *Status) GetSessionExpiresAt() time.Time {
 	d.mux.Lock()
 	defer d.mux.Unlock()
-	if !d.sessionExpiresAt.IsZero() && d.sessionExpiresAt.Before(time.Now()) {
-		return time.Time{}
-	}
 	return d.sessionExpiresAt
 }
 

client/internal/profilemanager/config.go

@@ -96,6 +96,7 @@ type ConfigInput struct {
 	BlockLANAccess      *bool
 	BlockInbound        *bool
 	DisableIPv6         *bool
+	SyncMessageVersion  *int
 
 	DisableNotifications *bool
 
@@ -140,6 +141,7 @@ type Config struct {
 	BlockLANAccess      bool
 	BlockInbound        bool
 	DisableIPv6         bool
+	SyncMessageVersion  *int
 
 	DisableNotifications *bool
 
@@ -607,6 +609,12 @@ func (config *Config) apply(input ConfigInput) (updated bool, err error) {
 		updated = true
 	}
 
+	if input.SyncMessageVersion != nil && *input.SyncMessageVersion != *config.SyncMessageVersion {
+		log.Infof("setting SyncMessageVersion to %v", *input.SyncMessageVersion)
+		*config.SyncMessageVersion = *input.SyncMessageVersion
+		updated = true
+	}
+
 	if input.DisableNotifications != nil && (config.DisableNotifications == nil || *input.DisableNotifications != *config.DisableNotifications) {
 		if *input.DisableNotifications {
 			log.Infof("disabling notifications")
@@ -764,6 +772,13 @@ func (config *Config) applyMDMPolicy(policy *mdm.Policy) {
 // appended for https or ":80" for http. The serviceName parameter is
 // used to contextualise error messages. On success returns the parsed
 // *url.URL; on failure returns a non-nil error.
+// ParseServiceURL normalises a service URL exactly as the config layer does when
+// it stores one, so callers comparing a requested URL against a stored one do not
+// have to reimplement the scheme validation and default-port handling.
+func ParseServiceURL(serviceName, serviceURL string) (*url.URL, error) {
+	return parseURL(serviceName, serviceURL)
+}
+
 func parseURL(serviceName, serviceURL string) (*url.URL, error) {
 	parsedMgmtURL, err := url.ParseRequestURI(serviceURL)
 	if err != nil {

client/internal/routemanager/dnsinterceptor/handler.go

@@ -95,7 +95,7 @@ func (d *DnsInterceptor) RemoveRoute() error {
 
 			// AllowedIPs should use real IPs
 			if d.currentPeerKey != "" {
-				if _, err := d.allowedIPsRefcounter.Decrement(prefix); err != nil {
+				if _, err := d.allowedIPsRefcounter.Decrement(prefix, d.currentPeerKey); err != nil {
 					merr = multierror.Append(merr, fmt.Errorf("remove allowed IP %s: %v", prefix, err))
 				}
 			}
@@ -172,7 +172,7 @@ func (d *DnsInterceptor) removeAllowedIP(realPrefix netip.Prefix) error {
 	}
 
 	// AllowedIPs use real IPs
-	if _, err := d.allowedIPsRefcounter.Decrement(realPrefix); err != nil {
+	if _, err := d.allowedIPsRefcounter.Decrement(realPrefix, d.currentPeerKey); err != nil {
 		return fmt.Errorf("remove allowed IP %s: %v", realPrefix, err)
 	}
 
@@ -205,7 +205,7 @@ func (d *DnsInterceptor) RemoveAllowedIPs() error {
 	for _, prefixes := range d.interceptedDomains {
 		for _, prefix := range prefixes {
 			// AllowedIPs use real IPs
-			if _, err := d.allowedIPsRefcounter.Decrement(prefix); err != nil {
+			if _, err := d.allowedIPsRefcounter.Decrement(prefix, d.currentPeerKey); err != nil {
 				merr = multierror.Append(merr, fmt.Errorf("remove allowed IP %s: %v", prefix, err))
 			}
 		}

client/internal/routemanager/dynamic/route.go

@@ -135,7 +135,7 @@ func (r *Route) RemoveAllowedIPs() error {
 	var merr *multierror.Error
 	for _, domainPrefixes := range r.dynamicDomains {
 		for _, prefix := range domainPrefixes {
-			if _, err := r.allowedIPsRefcounter.Decrement(prefix); err != nil {
+			if _, err := r.allowedIPsRefcounter.Decrement(prefix, r.currentPeerKey); err != nil {
 				merr = multierror.Append(merr, fmt.Errorf("remove allowed IP %s: %w", prefix, err))
 			}
 		}
@@ -185,7 +185,7 @@ func (r *Route) startResolver(ctx context.Context) {
 }
 
 func (r *Route) update(ctx context.Context) error {
-	resolved, err := r.resolveDomains()
+	resolved, err := r.resolveDomains(ctx)
 	if err != nil {
 		if len(resolved) == 0 {
 			return fmt.Errorf("resolve domains: %w", err)
@@ -199,9 +199,9 @@ func (r *Route) update(ctx context.Context) error {
 	return nil
 }
 
-func (r *Route) resolveDomains() (domainMap, error) {
+func (r *Route) resolveDomains(ctx context.Context) (domainMap, error) {
 	results := make(chan resolveResult)
-	go r.resolve(results)
+	go r.resolve(ctx, results)
 
 	resolved := domainMap{}
 	var merr *multierror.Error
@@ -217,7 +217,7 @@ func (r *Route) resolveDomains() (domainMap, error) {
 	return resolved, nberrors.FormatErrorOrNil(merr)
 }
 
-func (r *Route) resolve(results chan resolveResult) {
+func (r *Route) resolve(ctx context.Context, results chan resolveResult) {
 	var wg sync.WaitGroup
 
 	for _, d := range r.route.Domains {
@@ -225,10 +225,10 @@ func (r *Route) resolve(results chan resolveResult) {
 		go func(domain domain.Domain) {
 			defer wg.Done()
 
-			ips, err := r.getIPsFromResolver(domain)
+			ips, err := r.getIPsFromResolver(ctx, domain)
 			if err != nil {
 				log.Tracef("Failed to resolve domain %s with private resolver: %v", domain.SafeString(), err)
-				ips, err = net.LookupIP(domain.PunycodeString())
+				ips, err = lookupHostIPs(ctx, domain)
 				if err != nil {
 					results <- resolveResult{domain: domain, err: fmt.Errorf("resolve d %s: %w", domain.SafeString(), err)}
 					return
@@ -320,7 +320,7 @@ func (r *Route) removeRoutes(prefixes []netip.Prefix) ([]netip.Prefix, error) {
 			merr = multierror.Append(merr, fmt.Errorf("remove dynamic route for IP %s: %w", prefix, err))
 		}
 		if r.currentPeerKey != "" {
-			if _, err := r.allowedIPsRefcounter.Decrement(prefix); err != nil {
+			if _, err := r.allowedIPsRefcounter.Decrement(prefix, r.currentPeerKey); err != nil {
 				merr = multierror.Append(merr, fmt.Errorf("remove allowed IP %s: %w", prefix, err))
 			}
 		}
@@ -364,6 +364,20 @@ func determinePrefixChanges(oldPrefixes, newPrefixes []netip.Prefix) (toAdd, toR
 	return
 }
 
+// lookupHostIPs resolves d via the system resolver, honoring ctx cancellation.
+func lookupHostIPs(ctx context.Context, d domain.Domain) ([]net.IP, error) {
+	addrs, err := net.DefaultResolver.LookupIPAddr(ctx, d.PunycodeString())
+	if err != nil {
+		return nil, err
+	}
+
+	ips := make([]net.IP, 0, len(addrs))
+	for _, addr := range addrs {
+		ips = append(ips, addr.IP)
+	}
+	return ips, nil
+}
+
 func combinePrefixes(oldPrefixes, removedPrefixes, addedPrefixes []netip.Prefix) []netip.Prefix {
 	prefixSet := make(map[netip.Prefix]struct{})
 	for _, prefix := range oldPrefixes {

client/internal/routemanager/dynamic/route_generic.go

@@ -3,11 +3,12 @@
 package dynamic
 
 import (
+	"context"
 	"net"
 
 	"github.com/netbirdio/netbird/shared/management/domain"
 )
 
-func (r *Route) getIPsFromResolver(domain domain.Domain) ([]net.IP, error) {
-	return net.LookupIP(domain.PunycodeString())
+func (r *Route) getIPsFromResolver(ctx context.Context, domain domain.Domain) ([]net.IP, error) {
+	return lookupHostIPs(ctx, domain)
 }

client/internal/routemanager/dynamic/route_ios.go

@@ -3,6 +3,7 @@
 package dynamic
 
 import (
+	"context"
 	"fmt"
 	"net"
 	"time"
@@ -16,7 +17,7 @@ import (
 
 const dialTimeout = 10 * time.Second
 
-func (r *Route) getIPsFromResolver(domain domain.Domain) ([]net.IP, error) {
+func (r *Route) getIPsFromResolver(ctx context.Context, domain domain.Domain) ([]net.IP, error) {
 	privateClient, err := nbdns.GetClientPrivate(r.wgInterface, r.resolverAddr.Addr(), dialTimeout)
 	if err != nil {
 		return nil, fmt.Errorf("error while creating private client: %s", err)
@@ -32,7 +33,7 @@ func (r *Route) getIPsFromResolver(domain domain.Domain) ([]net.IP, error) {
 		msg := new(dns.Msg)
 		msg.SetQuestion(fqdn, qtype)
 
-		response, _, err := nbdns.ExchangeWithFallback(nil, privateClient, msg, r.resolverAddr.String())
+		response, _, err := nbdns.ExchangeWithFallback(ctx, privateClient, msg, r.resolverAddr.String())
 		if err != nil {
 			if queryErr == nil {
 				queryErr = fmt.Errorf("DNS query for %s (type %d) after %s: %w", domain.SafeString(), qtype, time.Since(startTime), err)

client/internal/routemanager/manager.go

@@ -52,6 +52,10 @@ type Manager interface {
 	UpdateRoutes(updateSerial uint64, serverRoutes map[route.ID]*route.Route, clientRoutes route.HAMap, useNewDNSRoute bool) error
 	ClassifyRoutes(newRoutes []*route.Route) (map[route.ID]*route.Route, route.HAMap)
 	TriggerSelection(route.HAMap)
+	SelectRoutes(ids []route.NetID, appendRoute bool) error
+	DeselectRoutes(ids []route.NetID) error
+	SelectAllRoutes()
+	DeselectAllRoutes()
 	GetRouteSelector() *routeselector.RouteSelector
 	GetClientRoutes() route.HAMap
 	GetSelectedClientRoutes() route.HAMap
@@ -61,6 +65,7 @@ type Manager interface {
 	InitialRouteRange() []string
 	SetFirewall(firewall.Manager) error
 	SetDNSForwarderPort(port uint16)
+	ReconcilePeerAllowedIPs(peerKey string) error
 	Stop(stateManager *statemanager.Manager)
 }
 
@@ -215,7 +220,7 @@ func (m *DefaultManager) setupRefCounters(useNoop bool) {
 		)
 	}
 
-	m.allowedIPsRefCounter = refcounter.New(
+	m.allowedIPsRefCounter = refcounter.NewAllowedIPs(
 		func(prefix netip.Prefix, peerKey string) (string, error) {
 			// save peerKey to use it in the remove function
 			return peerKey, m.wgInterface.AddAllowedIP(peerKey, prefix)
@@ -232,6 +237,30 @@ func (m *DefaultManager) setupRefCounters(useNoop bool) {
 	)
 }
 
+// ReconcilePeerAllowedIPs re-applies every routed allowed IP currently tracked for the peer
+// onto the WireGuard device. The allowed-IP refcounter only calls its AddFunc (which pushes to
+// the device) on a prefix's 0->1 transition, so a peer whose device entry was rebuilt without a
+// matching refcounter change — e.g. a lazy connection cycling through idle->wake, which recreates
+// the WireGuard peer with the overlay /32 only — ends up missing routed prefixes the refcounter
+// still considers installed, and nothing retries. Calling this when the peer's WireGuard entry is
+// (re)created restores convergence. It is add-only and idempotent: AddAllowedIP is update-only, so
+// prefixes are re-added to an existing peer and an absent peer is left untouched.
+func (m *DefaultManager) ReconcilePeerAllowedIPs(peerKey string) error {
+	if m.allowedIPsRefCounter == nil {
+		return nil
+	}
+
+	return m.allowedIPsRefCounter.ReapplyMatching(
+		func(out string) bool { return out == peerKey },
+		func(prefix netip.Prefix) error {
+			if err := m.wgInterface.AddAllowedIP(peerKey, prefix); err != nil {
+				return fmt.Errorf("add allowed IP %s for peer %s: %w", prefix, peerKey, err)
+			}
+			return nil
+		},
+	)
+}
+
 // Init sets up the routing
 func (m *DefaultManager) Init() error {
 	m.routeSelector = m.initSelector()
@@ -775,7 +804,7 @@ func (m *DefaultManager) collectExitNodeInfo(clientRoutes route.HAMap) exitNodeI
 	var info exitNodeInfo
 
 	for haID, routes := range clientRoutes {
-		if !m.isExitNodeRoute(routes) {
+		if !isExitNodeRoutes(routes) {
 			continue
 		}
 
@@ -795,13 +824,6 @@ func (m *DefaultManager) collectExitNodeInfo(clientRoutes route.HAMap) exitNodeI
 	return info
 }
 
-func (m *DefaultManager) isExitNodeRoute(routes []*route.Route) bool {
-	if len(routes) == 0 {
-		return false
-	}
-	return route.IsV4DefaultRoute(routes[0].Network) || route.IsV6DefaultRoute(routes[0].Network)
-}
-
 func (m *DefaultManager) categorizeUserSelection(netID route.NetID, info *exitNodeInfo) {
 	if m.routeSelector.IsSelected(netID) {
 		info.userSelected = append(info.userSelected, netID)

client/internal/routemanager/mock.go

@@ -16,6 +16,8 @@ type MockManager struct {
 	ClassifyRoutesFunc           func(routes []*route.Route) (map[route.ID]*route.Route, route.HAMap)
 	UpdateRoutesFunc             func(updateSerial uint64, serverRoutes map[route.ID]*route.Route, clientRoutes route.HAMap, useNewDNSRoute bool) error
 	TriggerSelectionFunc         func(haMap route.HAMap)
+	SelectRoutesFunc             func(ids []route.NetID, appendRoute bool) error
+	DeselectRoutesFunc           func(ids []route.NetID) error
 	GetRouteSelectorFunc         func() *routeselector.RouteSelector
 	GetClientRoutesFunc          func() route.HAMap
 	GetSelectedClientRoutesFunc  func() route.HAMap
@@ -55,6 +57,30 @@ func (m *MockManager) TriggerSelection(networks route.HAMap) {
 	}
 }
 
+// SelectRoutes mock implementation of SelectRoutes from Manager interface
+func (m *MockManager) SelectRoutes(ids []route.NetID, appendRoute bool) error {
+	if m.SelectRoutesFunc != nil {
+		return m.SelectRoutesFunc(ids, appendRoute)
+	}
+	return nil
+}
+
+// DeselectRoutes mock implementation of DeselectRoutes from Manager interface
+func (m *MockManager) DeselectRoutes(ids []route.NetID) error {
+	if m.DeselectRoutesFunc != nil {
+		return m.DeselectRoutesFunc(ids)
+	}
+	return nil
+}
+
+// SelectAllRoutes mock implementation of SelectAllRoutes from Manager interface
+func (m *MockManager) SelectAllRoutes() {
+}
+
+// DeselectAllRoutes mock implementation of DeselectAllRoutes from Manager interface
+func (m *MockManager) DeselectAllRoutes() {
+}
+
 // GetRouteSelector mock implementation of GetRouteSelector from Manager interface
 func (m *MockManager) GetRouteSelector() *routeselector.RouteSelector {
 	if m.GetRouteSelectorFunc != nil {
@@ -112,6 +138,11 @@ func (m *MockManager) SetFirewall(firewall.Manager) error {
 func (m *MockManager) SetDNSForwarderPort(port uint16) {
 }
 
+// ReconcilePeerAllowedIPs mock implementation of ReconcilePeerAllowedIPs from Manager interface
+func (m *MockManager) ReconcilePeerAllowedIPs(peerKey string) error {
+	return nil
+}
+
 // Stop mock implementation of Stop from Manager interface
 func (m *MockManager) Stop(stateManager *statemanager.Manager) {
 	if m.StopFunc != nil {

client/internal/routemanager/notifier/notifier_ios.go

@@ -3,7 +3,6 @@
 package notifier
 
 import (
-	"container/list"
 	"net/netip"
 	"slices"
 	"sort"
@@ -16,20 +15,12 @@ import (
 
 type Notifier struct {
 	mu              sync.Mutex
-	cond            *sync.Cond
 	currentPrefixes []string
 	listener        listener.NetworkChangeListener
-	queue           *list.List
-	closed          bool
 }
 
 func NewNotifier() *Notifier {
-	n := &Notifier{
-		queue: list.New(),
-	}
-	n.cond = sync.NewCond(&n.mu)
-	go n.deliverLoop()
-	return n
+	return &Notifier{}
 }
 
 func (n *Notifier) SetListener(listener listener.NetworkChangeListener) {
@@ -59,44 +50,19 @@ func (n *Notifier) OnNewPrefixes(prefixes []netip.Prefix) {
 	sort.Strings(newNets)
 
 	n.mu.Lock()
+	defer n.mu.Unlock()
 	if slices.Equal(n.currentPrefixes, newNets) {
-		n.mu.Unlock()
 		return
 	}
 	n.currentPrefixes = newNets
-	routes := strings.Join(n.currentPrefixes, ",")
-	n.queue.PushBack(routes)
-	n.cond.Signal()
-	n.mu.Unlock()
+	if n.listener != nil {
+		n.listener.OnNetworkChanged(strings.Join(n.currentPrefixes, ","))
+	}
 }
 
 func (n *Notifier) Close() {
-	n.mu.Lock()
-	n.closed = true
-	n.cond.Signal()
-	n.mu.Unlock()
 }
 
 func (n *Notifier) GetInitialRouteRanges() []string {
 	return nil
 }
-
-func (n *Notifier) deliverLoop() {
-	for {
-		n.mu.Lock()
-		for n.queue.Len() == 0 && !n.closed {
-			n.cond.Wait()
-		}
-		if n.closed && n.queue.Len() == 0 {
-			n.mu.Unlock()
-			return
-		}
-		routes := n.queue.Remove(n.queue.Front()).(string)
-		l := n.listener
-		n.mu.Unlock()
-
-		if l != nil {
-			l.OnNetworkChanged(routes)
-		}
-	}
-}

client/internal/routemanager/reconcile_test.go

@@ -0,0 +1,90 @@
+//go:build !windows
+
+package routemanager
+
+import (
+	"net"
+	"net/netip"
+	"sync"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"golang.zx2c4.com/wireguard/tun/netstack"
+
+	"github.com/netbirdio/netbird/client/iface/device"
+	"github.com/netbirdio/netbird/client/iface/wgaddr"
+	"github.com/netbirdio/netbird/client/internal/routemanager/refcounter"
+)
+
+// reconcileWGMock is a minimal iface.WGIface that only records AddAllowedIP calls; every other
+// method is an inert stub because ReconcilePeerAllowedIPs exercises none of them.
+type reconcileWGMock struct {
+	mu   sync.Mutex
+	adds map[string][]netip.Prefix
+}
+
+func (m *reconcileWGMock) AddAllowedIP(peerKey string, allowedIP netip.Prefix) error {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	if m.adds == nil {
+		m.adds = map[string][]netip.Prefix{}
+	}
+	m.adds[peerKey] = append(m.adds[peerKey], allowedIP)
+	return nil
+}
+
+func (m *reconcileWGMock) added(peerKey string) []netip.Prefix {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	return m.adds[peerKey]
+}
+
+func (m *reconcileWGMock) RemoveAllowedIP(string, netip.Prefix) error { return nil }
+func (m *reconcileWGMock) Name() string                               { return "utun-test" }
+func (m *reconcileWGMock) Address() wgaddr.Address                    { return wgaddr.Address{} }
+func (m *reconcileWGMock) ToInterface() *net.Interface                { return nil }
+func (m *reconcileWGMock) IsUserspaceBind() bool                      { return false }
+func (m *reconcileWGMock) GetFilter() device.PacketFilter             { return nil }
+func (m *reconcileWGMock) GetDevice() *device.FilteredDevice          { return nil }
+func (m *reconcileWGMock) GetNet() *netstack.Net                      { return nil }
+
+// TestReconcilePeerAllowedIPs verifies the declarative reconcile re-applies every routed prefix
+// tracked for the peer (self-heal, independent of refcount level) and stays scoped to that peer.
+func TestReconcilePeerAllowedIPs(t *testing.T) {
+	wg := &reconcileWGMock{}
+	m := &DefaultManager{wgInterface: wg}
+	m.allowedIPsRefCounter = refcounter.NewAllowedIPs(
+		func(_ netip.Prefix, peerKey string) (string, error) { return peerKey, nil },
+		func(netip.Prefix, string) error { return nil },
+	)
+
+	peerA1 := netip.MustParsePrefix("10.0.0.0/24")
+	peerA2 := netip.MustParsePrefix("10.1.0.0/24")
+	peerB1 := netip.MustParsePrefix("10.2.0.0/24")
+
+	for prefix, peer := range map[netip.Prefix]string{peerA1: "peerA", peerA2: "peerA", peerB1: "peerB"} {
+		_, err := m.allowedIPsRefCounter.Increment(prefix, peer)
+		require.NoError(t, err)
+	}
+	// Extra reference: reconcile must still re-apply the prefix even though its refcount never
+	// hit 0 again (the exact case the plain incremental path skips).
+	_, err := m.allowedIPsRefCounter.Increment(peerA1, "peerA")
+	require.NoError(t, err)
+
+	require.NoError(t, m.ReconcilePeerAllowedIPs("peerA"))
+
+	assert.ElementsMatch(t, []netip.Prefix{peerA1, peerA2}, wg.added("peerA"),
+		"reconcile must re-apply all routed prefixes of the peer")
+	assert.Empty(t, wg.added("peerB"), "reconcile must not touch another peer's prefixes")
+}
+
+// TestReconcilePeerAllowedIPsNoCounter verifies reconcile is a safe no-op before the refcounter is
+// set up.
+func TestReconcilePeerAllowedIPsNoCounter(t *testing.T) {
+	wg := &reconcileWGMock{}
+	m := &DefaultManager{wgInterface: wg}
+
+	require.NoError(t, m.ReconcilePeerAllowedIPs("peerA"))
+	assert.Empty(t, wg.added("peerA"))
+}

client/internal/routemanager/refcounter/allowedips.go

@@ -0,0 +1,206 @@
+package refcounter
+
+import (
+	"errors"
+	"fmt"
+	"net/netip"
+	"sort"
+	"sync"
+
+	"github.com/hashicorp/go-multierror"
+
+	nberrors "github.com/netbirdio/netbird/client/errors"
+)
+
+// allowedIPsEntry holds the per-peer reference counts for a single prefix and which peer is
+// currently installed in WireGuard. WireGuard allows a prefix on exactly one peer, so at most
+// one peer is active at a time even when several peers reference the prefix.
+type allowedIPsEntry struct {
+	// peers maps a peerKey to the number of references holding the prefix for that peer.
+	peers map[string]int
+	// active is the peerKey currently installed in WireGuard for this prefix ("" if none).
+	active string
+	// total is the sum of all per-peer reference counts (kept in sync with peers).
+	total int
+}
+
+// AllowedIPsRefCounter is a peer-aware reference counter for WireGuard AllowedIPs.
+//
+// The generic Counter keys only by prefix and remembers a single Out value set by the first
+// caller, which it never changes. That is wrong for AllowedIPs: two independent watchers (or
+// multiple resolved domains) can reference the same prefix through different peers, and when the
+// peer currently installed in WireGuard releases its last reference the prefix must be handed over
+// to a surviving peer instead of being left pointing at the released one.
+//
+// It calls add/remove (which program WireGuard) only on the transitions that matter:
+//   - add on the first reference for a prefix, or when swapping the active peer;
+//   - remove on the last reference for a prefix, or on the old peer during a swap.
+type AllowedIPsRefCounter struct {
+	mu      sync.Mutex
+	entries map[netip.Prefix]*allowedIPsEntry
+	add     AddFunc[netip.Prefix, string, string]
+	remove  RemoveFunc[netip.Prefix, string]
+}
+
+// NewAllowedIPs creates a new peer-aware AllowedIPs reference counter.
+// add programs a prefix on a peer in WireGuard and returns the peerKey to store as the active peer.
+// remove unprograms the prefix from the given peer.
+func NewAllowedIPs(add AddFunc[netip.Prefix, string, string], remove RemoveFunc[netip.Prefix, string]) *AllowedIPsRefCounter {
+	return &AllowedIPsRefCounter{
+		entries: map[netip.Prefix]*allowedIPsEntry{},
+		add:     add,
+		remove:  remove,
+	}
+}
+
+// Increment adds a reference to prefix for peerKey. WireGuard is programmed only for the first
+// reference to a prefix; while a different peer is already installed the prefix is left with it
+// (first peer wins, HA at the WireGuard layer is not possible) and only the reference count is kept.
+func (rm *AllowedIPsRefCounter) Increment(prefix netip.Prefix, peerKey string) (Ref[string], error) {
+	rm.mu.Lock()
+	defer rm.mu.Unlock()
+
+	e, ok := rm.entries[prefix]
+	if !ok {
+		e = &allowedIPsEntry{peers: map[string]int{}}
+		rm.entries[prefix] = e
+	}
+
+	logCallerF("Increasing allowed IP ref count for prefix %v peer %s [peer %d -> %d, total %d -> %d, active %q]",
+		prefix, peerKey, e.peers[peerKey], e.peers[peerKey]+1, e.total, e.total+1, e.active)
+
+	// Program WireGuard only when nothing is installed yet for this prefix.
+	if e.active == "" {
+		out, err := rm.add(prefix, peerKey)
+		if errors.Is(err, ErrIgnore) {
+			if e.total == 0 {
+				delete(rm.entries, prefix)
+			}
+			return Ref[string]{Count: e.total, Out: e.active}, nil
+		}
+		if err != nil {
+			if e.total == 0 {
+				delete(rm.entries, prefix)
+			}
+			return Ref[string]{}, fmt.Errorf("failed to add allowed IP %v for peer %s: %w", prefix, peerKey, err)
+		}
+		e.active = out
+	}
+
+	e.peers[peerKey]++
+	e.total++
+
+	return Ref[string]{Count: e.total, Out: e.active}, nil
+}
+
+// Decrement removes a reference to prefix for peerKey. When the peer currently installed in
+// WireGuard releases its last reference, the prefix is swapped to a surviving peer if one exists,
+// otherwise it is removed from WireGuard.
+func (rm *AllowedIPsRefCounter) Decrement(prefix netip.Prefix, peerKey string) (Ref[string], error) {
+	rm.mu.Lock()
+	defer rm.mu.Unlock()
+
+	e, ok := rm.entries[prefix]
+	if !ok {
+		logCallerF("No allowed IP reference found for prefix %v", prefix)
+		return Ref[string]{}, nil
+	}
+
+	if e.peers[peerKey] > 0 {
+		logCallerF("Decreasing allowed IP ref count for prefix %v peer %s [peer %d -> %d, total %d -> %d, active %q]",
+			prefix, peerKey, e.peers[peerKey], e.peers[peerKey]-1, e.total, e.total-1, e.active)
+		e.peers[peerKey]--
+		e.total--
+		if e.peers[peerKey] == 0 {
+			delete(e.peers, peerKey)
+		}
+	} else {
+		logCallerF("No allowed IP reference found for prefix %v peer %s", prefix, peerKey)
+	}
+
+	// If the peer currently installed in WireGuard still holds references, nothing to reprogram.
+	// Keying the check on the active peer (not the one just released) makes this self-healing:
+	// a prior swap whose remove/add failed leaves e.active pointing at a peer with no references,
+	// and this retries the hand-off on the next Decrement instead of getting stuck.
+	if e.active != "" && e.peers[e.active] > 0 {
+		return Ref[string]{Count: e.total, Out: e.active}, nil
+	}
+
+	// Detach the stale/gone active peer from WireGuard before reprogramming.
+	if e.active != "" {
+		if err := rm.remove(prefix, e.active); err != nil {
+			return Ref[string]{Count: e.total, Out: e.active}, fmt.Errorf("remove allowed IP %v for peer %s: %w", prefix, e.active, err)
+		}
+		e.active = ""
+	}
+
+	// Hand the prefix over to a surviving peer, or drop the entry when none remain.
+	if survivor, ok := pickSurvivor(e.peers); ok {
+		out, err := rm.add(prefix, survivor)
+		if err != nil {
+			return Ref[string]{Count: e.total, Out: ""}, fmt.Errorf("swap allowed IP %v to peer %s: %w", prefix, survivor, err)
+		}
+		e.active = out
+		return Ref[string]{Count: e.total, Out: e.active}, nil
+	}
+
+	delete(rm.entries, prefix)
+	return Ref[string]{Count: 0, Out: ""}, nil
+}
+
+// Flush removes all prefixes from WireGuard and clears the counter.
+func (rm *AllowedIPsRefCounter) Flush() error {
+	rm.mu.Lock()
+	defer rm.mu.Unlock()
+
+	var merr *multierror.Error
+	for prefix, e := range rm.entries {
+		if e.active == "" {
+			continue
+		}
+		logCallerF("Flushing allowed IP for prefix %v peer %s", prefix, e.active)
+		if err := rm.remove(prefix, e.active); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("remove allowed IP %v for peer %s: %w", prefix, e.active, err))
+		}
+	}
+
+	clear(rm.entries)
+
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+// ReapplyMatching calls apply for every prefix whose currently installed (active) peer satisfies
+// pred, holding the lock for the whole pass. It is used to re-push allowed IPs onto a peer whose
+// WireGuard entry was rebuilt (e.g. a lazy connection cycling idle->wake) without a matching
+// refcounter change, which would otherwise leave the prefix installed in the counter but missing
+// on the device. Only the active peer is considered — a prefix that lost its installed peer to a
+// failed swap is skipped here and reconciled by the next Increment/Decrement.
+func (rm *AllowedIPsRefCounter) ReapplyMatching(pred func(out string) bool, apply func(key netip.Prefix) error) error {
+	rm.mu.Lock()
+	defer rm.mu.Unlock()
+
+	var merr *multierror.Error
+	for prefix, e := range rm.entries {
+		if e.active != "" && pred(e.active) {
+			if err := apply(prefix); err != nil {
+				merr = multierror.Append(merr, err)
+			}
+		}
+	}
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+// pickSurvivor deterministically selects a peer still referencing the prefix. WireGuard cannot do
+// multipath for a single prefix, so any surviving peer is a valid winner; the choice is made stable
+// (lowest peerKey) for predictable behavior and testability.
+func pickSurvivor(peers map[string]int) (string, bool) {
+	if len(peers) == 0 {
+		return "", false
+	}
+	keys := make([]string, 0, len(peers))
+	for k := range peers {
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+	return keys[0], true
+}

client/internal/routemanager/refcounter/allowedips_test.go

@@ -0,0 +1,241 @@
+package refcounter
+
+import (
+	"errors"
+	"net/netip"
+	"testing"
+)
+
+// fakeWG models WireGuard's cryptokey routing: a prefix can be installed on exactly one peer.
+// failAdd/failRemove make the next add/remove fail once, to exercise the self-healing error paths.
+type fakeWG struct {
+	installed  map[netip.Prefix]string
+	adds       int
+	removes    int
+	failAdd    bool
+	failRemove bool
+}
+
+func newFakeWG() *fakeWG {
+	return &fakeWG{installed: map[netip.Prefix]string{}}
+}
+
+func (f *fakeWG) counter() *AllowedIPsRefCounter {
+	return NewAllowedIPs(
+		func(prefix netip.Prefix, peerKey string) (string, error) {
+			if f.failAdd {
+				f.failAdd = false
+				return "", errors.New("add failed")
+			}
+			f.adds++
+			f.installed[prefix] = peerKey
+			return peerKey, nil
+		},
+		func(prefix netip.Prefix, peerKey string) error {
+			if f.failRemove {
+				f.failRemove = false
+				return errors.New("remove failed")
+			}
+			f.removes++
+			// only clear if this peer is the one installed, mirroring wg semantics
+			if f.installed[prefix] == peerKey {
+				delete(f.installed, prefix)
+			}
+			return nil
+		},
+	)
+}
+
+func mustPrefix(t *testing.T, s string) netip.Prefix {
+	t.Helper()
+	p, err := netip.ParsePrefix(s)
+	if err != nil {
+		t.Fatalf("parse prefix %q: %v", s, err)
+	}
+	return p
+}
+
+func mustIncrement(t *testing.T, c *AllowedIPsRefCounter, p netip.Prefix, peer string) Ref[string] {
+	t.Helper()
+	ref, err := c.Increment(p, peer)
+	if err != nil {
+		t.Fatalf("Increment(%v, %s): %v", p, peer, err)
+	}
+	return ref
+}
+
+func mustDecrement(t *testing.T, c *AllowedIPsRefCounter, p netip.Prefix, peer string) Ref[string] {
+	t.Helper()
+	ref, err := c.Decrement(p, peer)
+	if err != nil {
+		t.Fatalf("Decrement(%v, %s): %v", p, peer, err)
+	}
+	return ref
+}
+
+// TestAllowedIPs_SwapOnActivePeerRemoval reproduces the reported bug: two networks with the same
+// prefix routed by different peers. Removing the network whose peer is installed must hand the
+// prefix over to the surviving peer instead of leaving it on the removed one.
+func TestAllowedIPs_SwapOnActivePeerRemoval(t *testing.T) {
+	f := newFakeWG()
+	c := f.counter()
+	p := mustPrefix(t, "10.44.8.0/24")
+
+	mustIncrement(t, c, p, "peerA")
+	mustIncrement(t, c, p, "peerB")
+	// First peer wins while both are present.
+	if got := f.installed[p]; got != "peerA" {
+		t.Fatalf("expected peerA installed, got %q", got)
+	}
+
+	// Remove the active peer's network -> must swap to peerB.
+	mustDecrement(t, c, p, "peerA")
+	if got := f.installed[p]; got != "peerB" {
+		t.Fatalf("BUG: prefix stuck on removed peer, want peerB got %q", got)
+	}
+
+	// Remove the last one -> prefix gone.
+	mustDecrement(t, c, p, "peerB")
+	if _, ok := f.installed[p]; ok {
+		t.Fatalf("expected prefix removed, still installed on %q", f.installed[p])
+	}
+}
+
+// TestAllowedIPs_RemoveNonActivePeer removing a non-installed peer must not touch WireGuard.
+func TestAllowedIPs_RemoveNonActivePeer(t *testing.T) {
+	f := newFakeWG()
+	c := f.counter()
+	p := mustPrefix(t, "10.44.8.0/24")
+
+	mustIncrement(t, c, p, "peerA")
+	mustIncrement(t, c, p, "peerB")
+	removesBefore := f.removes
+
+	mustDecrement(t, c, p, "peerB")
+	if f.installed[p] != "peerA" {
+		t.Fatalf("active peer must stay peerA, got %q", f.installed[p])
+	}
+	if f.removes != removesBefore {
+		t.Fatalf("removing a non-active peer must not call wg remove")
+	}
+}
+
+// TestAllowedIPs_SamePeerMultipleRefs two references via the same peer must keep the prefix until
+// the last reference is released (the reason the per-peer count must be an int, not a set).
+func TestAllowedIPs_SamePeerMultipleRefs(t *testing.T) {
+	f := newFakeWG()
+	c := f.counter()
+	p := mustPrefix(t, "10.44.8.0/24")
+
+	mustIncrement(t, c, p, "peerA")
+	mustIncrement(t, c, p, "peerA")
+	if f.adds != 1 {
+		t.Fatalf("expected a single wg add for the same peer, got %d", f.adds)
+	}
+
+	mustDecrement(t, c, p, "peerA")
+	if f.installed[p] != "peerA" {
+		t.Fatalf("prefix must stay while a reference remains, got %q", f.installed[p])
+	}
+	if f.removes != 0 {
+		t.Fatalf("no wg remove expected while a reference remains, got %d", f.removes)
+	}
+
+	mustDecrement(t, c, p, "peerA")
+	if _, ok := f.installed[p]; ok {
+		t.Fatalf("prefix must be removed after last reference")
+	}
+}
+
+// TestAllowedIPs_RefCountAndActive checks the Ref returned to callers (used for the HA-disabled log).
+func TestAllowedIPs_RefCountAndActive(t *testing.T) {
+	f := newFakeWG()
+	c := f.counter()
+	p := mustPrefix(t, "10.44.8.0/24")
+
+	ref := mustIncrement(t, c, p, "peerA")
+	if ref.Count != 1 || ref.Out != "peerA" {
+		t.Fatalf("want {1, peerA}, got {%d, %q}", ref.Count, ref.Out)
+	}
+	ref = mustIncrement(t, c, p, "peerB")
+	if ref.Count != 2 || ref.Out != "peerA" {
+		t.Fatalf("want {2, peerA}, got {%d, %q}", ref.Count, ref.Out)
+	}
+}
+
+// TestAllowedIPs_Flush removes everything installed and clears the counter.
+func TestAllowedIPs_Flush(t *testing.T) {
+	f := newFakeWG()
+	c := f.counter()
+	p1 := mustPrefix(t, "10.44.8.0/24")
+	p2 := mustPrefix(t, "10.44.9.0/24")
+
+	mustIncrement(t, c, p1, "peerA")
+	mustIncrement(t, c, p2, "peerB")
+
+	if err := c.Flush(); err != nil {
+		t.Fatal(err)
+	}
+	if len(f.installed) != 0 {
+		t.Fatalf("expected all prefixes removed, got %v", f.installed)
+	}
+	// After flush, a fresh increment must add again.
+	mustIncrement(t, c, p1, "peerC")
+	if f.installed[p1] != "peerC" {
+		t.Fatalf("counter not reset after flush")
+	}
+}
+
+// TestAllowedIPs_SelfHealAfterSwapAddError ensures a failed add during a swap does not permanently
+// strand the prefix: the next Decrement (or Increment) must retry and install a surviving peer.
+func TestAllowedIPs_SelfHealAfterSwapAddError(t *testing.T) {
+	f := newFakeWG()
+	c := f.counter()
+	p := mustPrefix(t, "10.44.8.0/24")
+
+	mustIncrement(t, c, p, "peerA")
+	mustIncrement(t, c, p, "peerB")
+	mustIncrement(t, c, p, "peerC")
+
+	// Removing the active peerA triggers a swap to a survivor; make the add fail once.
+	f.failAdd = true
+	if _, err := c.Decrement(p, "peerA"); err == nil {
+		t.Fatalf("expected error from failed swap add")
+	}
+	if _, ok := f.installed[p]; ok {
+		t.Fatalf("nothing should be installed after a failed swap add, got %q", f.installed[p])
+	}
+
+	// A later Decrement of a non-active survivor must retry the hand-off (self-heal), not stay stuck.
+	ref := mustDecrement(t, c, p, "peerC")
+	if got := f.installed[p]; got == "" {
+		t.Fatalf("self-heal failed: prefix left unrouted after add recovered")
+	}
+	if ref.Out == "" {
+		t.Fatalf("expected an active peer after self-heal, got empty")
+	}
+}
+
+// TestAllowedIPs_SelfHealAfterRemoveError ensures a failed remove during a swap is retried instead
+// of leaving e.active stuck on a peer that no longer holds references.
+func TestAllowedIPs_SelfHealAfterRemoveError(t *testing.T) {
+	f := newFakeWG()
+	c := f.counter()
+	p := mustPrefix(t, "10.44.8.0/24")
+
+	mustIncrement(t, c, p, "peerA")
+	mustIncrement(t, c, p, "peerB")
+
+	// Releasing active peerA must detach it (remove) then add peerB; fail the remove once.
+	f.failRemove = true
+	if _, err := c.Decrement(p, "peerA"); err == nil {
+		t.Fatalf("expected error from failed remove")
+	}
+
+	// Next Decrement of the non-active survivor retries: removes stale peerA, installs peerB.
+	mustDecrement(t, c, p, "peerB")
+	// peerB had only one ref, so after retry the prefix is fully released.
+	if _, ok := f.installed[p]; ok {
+		t.Fatalf("expected prefix released after self-heal, still on %q", f.installed[p])
+	}
+}

client/internal/routemanager/refcounter/refcounter.go

@@ -94,6 +94,26 @@ func (rm *Counter[Key, I, O]) Get(key Key) (Ref[O], bool) {
 	return ref, ok
 }
 
+// ReapplyMatching calls apply for every key whose stored Out satisfies pred, holding the
+// counter lock for the whole pass. Running apply under the lock keeps it atomic with respect
+// to Increment/Decrement: a prefix dropped to zero is removed from the map (and had its
+// RemoveFunc called) before this pass observes it, so a stale key can never be re-applied.
+// pred and apply are invoked under the lock, so they must not call back into the counter.
+func (rm *Counter[Key, I, O]) ReapplyMatching(pred func(out O) bool, apply func(key Key) error) error {
+	rm.mu.Lock()
+	defer rm.mu.Unlock()
+
+	var merr *multierror.Error
+	for key, ref := range rm.refCountMap {
+		if pred(ref.Out) {
+			if err := apply(key); err != nil {
+				merr = multierror.Append(merr, err)
+			}
+		}
+	}
+	return nberrors.FormatErrorOrNil(merr)
+}
+
 // Increment increments the reference count for the given key.
 // If this is the first reference to the key, the AddFunc is called.
 func (rm *Counter[Key, I, O]) Increment(key Key, in I) (Ref[O], error) {

client/internal/routemanager/refcounter/refcounter_test.go

@@ -0,0 +1,47 @@
+package refcounter
+
+import (
+	"net/netip"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// TestReapplyMatching verifies ReapplyMatching invokes apply for exactly the keys whose stored
+// Out satisfies the predicate (no duplicates for multiply-referenced keys) — the primitive
+// ReconcilePeerAllowedIPs relies on to re-apply a single peer's routed prefixes.
+func TestReapplyMatching(t *testing.T) {
+	rc := New[netip.Prefix, string, string](
+		func(_ netip.Prefix, peerKey string) (string, error) { return peerKey, nil },
+		func(netip.Prefix, string) error { return nil },
+	)
+
+	peerA1 := netip.MustParsePrefix("10.0.0.0/24")
+	peerA2 := netip.MustParsePrefix("10.1.0.0/24")
+	peerB1 := netip.MustParsePrefix("10.2.0.0/24")
+
+	for prefix, peer := range map[netip.Prefix]string{peerA1: "peerA", peerA2: "peerA", peerB1: "peerB"} {
+		_, err := rc.Increment(prefix, peer)
+		require.NoError(t, err)
+	}
+	// a second reference must not make the key applied twice
+	_, err := rc.Increment(peerA1, "peerA")
+	require.NoError(t, err)
+
+	var applied []netip.Prefix
+	err = rc.ReapplyMatching(
+		func(out string) bool { return out == "peerA" },
+		func(key netip.Prefix) error { applied = append(applied, key); return nil },
+	)
+	require.NoError(t, err)
+	assert.ElementsMatch(t, []netip.Prefix{peerA1, peerA2}, applied)
+
+	var none []netip.Prefix
+	err = rc.ReapplyMatching(
+		func(out string) bool { return out == "missing" },
+		func(key netip.Prefix) error { none = append(none, key); return nil },
+	)
+	require.NoError(t, err)
+	assert.Empty(t, none)
+}

client/internal/routemanager/refcounter/types.go

@@ -5,5 +5,7 @@ import "net/netip"
 // RouteRefCounter is a Counter for Route, it doesn't take any input on Increment and doesn't use any output on Decrement
 type RouteRefCounter = Counter[netip.Prefix, struct{}, struct{}]
 
-// AllowedIPsRefCounter is a Counter for AllowedIPs, it takes a peer key on Increment and passes it back to Decrement
-type AllowedIPsRefCounter = Counter[netip.Prefix, string, string]
+// AllowedIPsRefCounter tracks WireGuard AllowedIPs per prefix. Unlike the generic Counter it is peer-aware:
+// a prefix can be claimed by several peers at once and WireGuard allows a given prefix on exactly one peer,
+// so the counter records the per-peer reference count and swaps the installed peer when the active one is released.
+// See allowedips.go.

client/internal/routemanager/selection.go

@@ -0,0 +1,138 @@
+package routemanager
+
+import (
+	"fmt"
+	"slices"
+
+	"github.com/hashicorp/go-multierror"
+	log "github.com/sirupsen/logrus"
+	"golang.org/x/exp/maps"
+
+	nberrors "github.com/netbirdio/netbird/client/errors"
+	"github.com/netbirdio/netbird/route"
+)
+
+// SelectRoutes selects the routes with the given network IDs and applies the
+// new selection. V4/v6 exit-node pairs are expanded automatically. Exit nodes
+// are mutually exclusive: if the selection activates an exit node, every other
+// available exit node is deselected so two can't be active at once. With
+// appendRoute=false the previous selection is replaced instead of extended.
+func (m *DefaultManager) SelectRoutes(ids []route.NetID, appendRoute bool) error {
+	if err := m.selectRoutes(ids, appendRoute); err != nil {
+		return err
+	}
+	m.TriggerSelection(m.GetClientRoutes())
+	return nil
+}
+
+// DeselectRoutes removes the routes with the given network IDs from the
+// selection and applies the change. V4/v6 exit-node pairs are expanded
+// automatically.
+func (m *DefaultManager) DeselectRoutes(ids []route.NetID) error {
+	if err := m.deselectRoutes(ids); err != nil {
+		return err
+	}
+	m.TriggerSelection(m.GetClientRoutes())
+	return nil
+}
+
+func (m *DefaultManager) deselectRoutes(ids []route.NetID) error {
+	routesMap := m.GetClientRoutesWithNetID()
+	routes := route.ExpandV6ExitPairs(slices.Clone(ids), routesMap)
+
+	log.Debugf("deselecting routes with ids: %v", routes)
+
+	if err := m.routeSelector.DeselectRoutes(routes, maps.Keys(routesMap)); err != nil {
+		return fmt.Errorf("deselect routes: %w", err)
+	}
+
+	return nil
+}
+
+// SelectAllRoutes selects every available route and applies the selection.
+// Exit nodes stay mutually exclusive: at most one remains active.
+func (m *DefaultManager) SelectAllRoutes() {
+	m.selectAllRoutes()
+	m.TriggerSelection(m.GetClientRoutes())
+}
+
+func (m *DefaultManager) selectAllRoutes() {
+	m.routeSelector.SelectAllRoutes()
+
+	// Select-all wipes every explicit selection, so exit nodes fall back to
+	// management's auto-apply flags — which may mark several at once.
+	// Reconcile immediately so at most one exit node stays active instead of
+	// waiting for the next network map to enforce it.
+	m.mux.Lock()
+	defer m.mux.Unlock()
+	m.updateRouteSelectorFromManagement(m.clientRoutes)
+}
+
+// DeselectAllRoutes deselects every route and applies the change.
+func (m *DefaultManager) DeselectAllRoutes() {
+	m.routeSelector.DeselectAllRoutes()
+	m.TriggerSelection(m.GetClientRoutes())
+}
+
+func (m *DefaultManager) selectRoutes(ids []route.NetID, appendRoute bool) error {
+	routesMap := m.GetClientRoutesWithNetID()
+	routes := route.ExpandV6ExitPairs(slices.Clone(ids), routesMap)
+	allIDs := maps.Keys(routesMap)
+
+	log.Debugf("selecting routes with ids: %v", routes)
+
+	// A partial failure (e.g. an unknown ID in the request) still selects the
+	// valid routes, so exclusivity below must run regardless of the error.
+	var merr *multierror.Error
+	if err := m.routeSelector.SelectRoutes(routes, appendRoute, allIDs); err != nil {
+		merr = multierror.Append(merr, fmt.Errorf("select routes: %w", err))
+	}
+
+	// Exit nodes are mutually exclusive: if this selection activates an
+	// exit node, deselect every other available exit node so two can't be
+	// selected at once. Non-exit route selections are left untouched.
+	if requestActivatesExitNode(routes, routesMap) {
+		if others := otherExitNodeIDs(routesMap, routes); len(others) > 0 {
+			if err := m.routeSelector.DeselectRoutes(others, allIDs); err != nil {
+				merr = multierror.Append(merr, fmt.Errorf("deselect sibling exit nodes: %w", err))
+			}
+		}
+	}
+
+	return nberrors.FormatErrorOrNil(merr)
+}
+
+func isExitNodeRoutes(routes []*route.Route) bool {
+	return len(routes) > 0 && (route.IsV4DefaultRoute(routes[0].Network) || route.IsV6DefaultRoute(routes[0].Network))
+}
+
+// requestActivatesExitNode reports whether any requested NetID maps to an exit
+// node (default route) in the current route table.
+func requestActivatesExitNode(requested []route.NetID, routesMap map[route.NetID][]*route.Route) bool {
+	for _, id := range requested {
+		if isExitNodeRoutes(routesMap[id]) {
+			return true
+		}
+	}
+	return false
+}
+
+// otherExitNodeIDs returns every available exit-node NetID that is not in the
+// requested set — the siblings to deselect so a single exit node stays active.
+func otherExitNodeIDs(routesMap map[route.NetID][]*route.Route, requested []route.NetID) []route.NetID {
+	keep := make(map[route.NetID]struct{}, len(requested))
+	for _, id := range requested {
+		keep[id] = struct{}{}
+	}
+	var others []route.NetID
+	for id, routes := range routesMap {
+		if !isExitNodeRoutes(routes) {
+			continue
+		}
+		if _, ok := keep[id]; ok {
+			continue
+		}
+		others = append(others, id)
+	}
+	return others
+}

client/internal/routemanager/selection_test.go

@@ -0,0 +1,129 @@
+package routemanager
+
+import (
+	"net/netip"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/netbirdio/netbird/client/internal/routeselector"
+	"github.com/netbirdio/netbird/route"
+)
+
+func v6ExitRoute(netID, peer string) *route.Route {
+	return &route.Route{
+		NetID:   route.NetID(netID),
+		Network: netip.MustParsePrefix("::/0"),
+		Peer:    peer,
+	}
+}
+
+func newSelectionTestManager() *DefaultManager {
+	return &DefaultManager{
+		routeSelector: routeselector.NewRouteSelector(),
+		clientRoutes: route.HAMap{
+			"exitA|0.0.0.0/0":    {exitRoute("exitA", "p1", true)},
+			"exitA-v6|::/0":      {v6ExitRoute("exitA-v6", "p1")},
+			"exitB|0.0.0.0/0":    {exitRoute("exitB", "p2", true)},
+			"lan|192.168.1.0/24": {{NetID: "lan", Network: netip.MustParsePrefix("192.168.1.0/24"), Peer: "p3"}},
+		},
+	}
+}
+
+func TestSelectRoutes_ExitNodeExclusivity(t *testing.T) {
+	m := newSelectionTestManager()
+
+	// Selecting an exit node selects its v6 pair and deselects the sibling.
+	require.NoError(t, m.selectRoutes([]route.NetID{"exitA"}, true))
+	assert.True(t, m.routeSelector.IsSelected("exitA"), "exitA should be selected")
+	assert.True(t, m.routeSelector.IsSelected("exitA-v6"), "the v6 pair follows its v4 base")
+	assert.False(t, m.routeSelector.IsSelected("exitB"), "the sibling exit node must be deselected")
+
+	// Switching to the sibling deselects the previous exit node and its v6 pair.
+	require.NoError(t, m.selectRoutes([]route.NetID{"exitB"}, true))
+	assert.True(t, m.routeSelector.IsSelected("exitB"), "exitB should now be selected")
+	assert.False(t, m.routeSelector.IsSelected("exitA"), "the previous exit node must be deselected")
+	assert.False(t, m.routeSelector.IsSelected("exitA-v6"), "the previous exit node's v6 pair must be deselected")
+	assert.True(t, m.routeSelector.IsSelected("lan"), "non-exit route selection is untouched")
+
+	// Selecting a non-exit route leaves the active exit node alone.
+	require.NoError(t, m.selectRoutes([]route.NetID{"lan"}, true))
+	assert.True(t, m.routeSelector.IsSelected("exitB"), "selecting a non-exit route keeps the exit node")
+
+	// Deselecting the active exit node turns every exit node off.
+	require.NoError(t, m.deselectRoutes([]route.NetID{"exitB"}))
+	assert.False(t, m.routeSelector.IsSelected("exitB"), "exitB should be deselected")
+	assert.False(t, m.routeSelector.IsSelected("exitA"), "exitA stays deselected")
+	assert.True(t, m.routeSelector.IsSelected("lan"), "non-exit route selection is untouched")
+}
+
+func TestSelectRoutes_PartialErrorStillEnforcesExclusivity(t *testing.T) {
+	// The unknown ID must be reported, but the valid exit node in the same
+	// request is still selected — so its sibling must still be deselected.
+	// Both orderings are covered: processing must continue past the invalid
+	// ID wherever it sits in the request.
+	requests := map[string][]route.NetID{
+		"invalid id first": {"missing", "exitB"},
+		"invalid id last":  {"exitB", "missing"},
+	}
+
+	for name, ids := range requests {
+		t.Run(name, func(t *testing.T) {
+			m := newSelectionTestManager()
+
+			require.NoError(t, m.selectRoutes([]route.NetID{"exitA"}, true))
+
+			err := m.selectRoutes(ids, true)
+			assert.Error(t, err, "unknown id must be reported")
+			assert.True(t, m.routeSelector.IsSelected("exitB"), "valid exit node from the request is selected")
+			assert.False(t, m.routeSelector.IsSelected("exitA"), "sibling exit node must be deselected despite the error")
+			assert.False(t, m.routeSelector.IsSelected("exitA-v6"), "sibling's v6 pair must be deselected too")
+		})
+	}
+}
+
+func TestSelectAllRoutes_KeepsSingleExitNode(t *testing.T) {
+	// Both exit nodes are marked for auto-apply by management
+	// (SkipAutoApply=false), the state where select-all could turn on two at
+	// once without the immediate reconciliation.
+	m := &DefaultManager{
+		routeSelector: routeselector.NewRouteSelector(),
+		clientRoutes: route.HAMap{
+			"exitA|0.0.0.0/0":    {exitRoute("exitA", "p1", false)},
+			"exitB|0.0.0.0/0":    {exitRoute("exitB", "p2", false)},
+			"lan|192.168.1.0/24": {{NetID: "lan", Network: netip.MustParsePrefix("192.168.1.0/24"), Peer: "p3"}},
+		},
+	}
+
+	require.NoError(t, m.selectRoutes([]route.NetID{"exitB"}, true))
+
+	m.selectAllRoutes()
+
+	assert.True(t, m.routeSelector.IsSelected("lan"), "non-exit routes are all selected")
+	assert.True(t, m.routeSelector.IsSelected("exitA"), "the deterministic management pick stays active")
+	assert.False(t, m.routeSelector.IsSelected("exitB"), "select-all must not leave a second exit node active")
+}
+
+func TestSelectRoutes_UnknownRoute(t *testing.T) {
+	m := newSelectionTestManager()
+
+	assert.Error(t, m.selectRoutes([]route.NetID{"missing"}, true), "selecting an unavailable route must fail")
+	assert.Error(t, m.deselectRoutes([]route.NetID{"missing"}), "deselecting an unavailable route must fail")
+}
+
+func TestExitNodeSelectionHelpers(t *testing.T) {
+	routesMap := map[route.NetID][]*route.Route{
+		"exitA": {{Network: netip.MustParsePrefix("0.0.0.0/0")}},
+		"exitB": {{Network: netip.MustParsePrefix("::/0")}},
+		"lan":   {{Network: netip.MustParsePrefix("192.168.0.0/16")}},
+	}
+
+	assert.True(t, requestActivatesExitNode([]route.NetID{"exitA"}, routesMap), "v4 default route is an exit node")
+	assert.True(t, requestActivatesExitNode([]route.NetID{"exitB"}, routesMap), "v6 default route is an exit node")
+	assert.False(t, requestActivatesExitNode([]route.NetID{"lan"}, routesMap), "lan route is not an exit node")
+	assert.False(t, requestActivatesExitNode([]route.NetID{"missing"}, routesMap), "unknown id is not an exit node")
+
+	others := otherExitNodeIDs(routesMap, []route.NetID{"exitB"})
+	assert.ElementsMatch(t, []route.NetID{"exitA"}, others, "only the other exit node is a sibling; the lan route is ignored")
+}

client/internal/routemanager/static/route.go

@@ -15,6 +15,11 @@ type Route struct {
 	route                *route.Route
 	routeRefCounter      *refcounter.RouteRefCounter
 	allowedIPsRefcounter *refcounter.AllowedIPsRefCounter
+	// currentPeerKey is the routing peer this watcher currently has the prefix installed on
+	// (the HA winner elected by the watcher). It can differ from route.Peer and change on
+	// failover, so it is recorded on AddAllowedIPs and used on RemoveAllowedIPs to decrement
+	// the exact peer that was incremented.
+	currentPeerKey string
 }
 
 func NewRoute(params common.HandlerParams) *Route {
@@ -52,12 +57,15 @@ func (r *Route) AddAllowedIPs(peerKey string) error {
 			ref.Out,
 		)
 	}
+	r.currentPeerKey = peerKey
 	return nil
 }
 
 func (r *Route) RemoveAllowedIPs() error {
-	if _, err := r.allowedIPsRefcounter.Decrement(r.route.Network); err != nil {
-		return err
+	var err error
+	if _, decErr := r.allowedIPsRefcounter.Decrement(r.route.Network, r.currentPeerKey); decErr != nil {
+		err = fmt.Errorf("remove allowed IP %s: %w", r.route.Network, decErr)
 	}
-	return nil
+	r.currentPeerKey = ""
+	return err
 }

client/internal/routemanager/sysctl/sysctl_linux.go

@@ -20,6 +20,8 @@ const (
 	rpFilterPath          = "net.ipv4.conf.all.rp_filter"
 	rpFilterInterfacePath = "net.ipv4.conf.%s.rp_filter"
 	srcValidMarkPath      = "net.ipv4.conf.all.src_valid_mark"
+	percentEscape         = "%25"
+	dotEscape             = "%2E"
 )
 
 type iface interface {
@@ -56,7 +58,11 @@ func Setup(wgIface iface) (map[string]int, error) {
 			continue
 		}
 
-		i := fmt.Sprintf(rpFilterInterfacePath, intf.Name)
+		// Escape '%' and '.' so they survive the dot-to-slash conversion in Set()
+		safeName := strings.ReplaceAll(intf.Name, "%", percentEscape)
+		safeName = strings.ReplaceAll(safeName, ".", dotEscape)
+
+		i := fmt.Sprintf(rpFilterInterfacePath, safeName)
 		oldVal, err := Set(i, 2, true)
 		if err != nil {
 			result = multierror.Append(result, err)
@@ -70,7 +76,11 @@ func Setup(wgIface iface) (map[string]int, error) {
 
 // Set sets a sysctl configuration, if onlyIfOne is true it will only set the new value if it's set to 1
 func Set(key string, desiredValue int, onlyIfOne bool) (int, error) {
-	path := fmt.Sprintf("/proc/sys/%s", strings.ReplaceAll(key, ".", "/"))
+	path := strings.ReplaceAll(key, ".", "/")
+	// Unescape interface dots and percent signs
+	path = strings.ReplaceAll(path, dotEscape, ".")
+	path = strings.ReplaceAll(path, percentEscape, "%")
+	path = fmt.Sprintf("/proc/sys/%s", path)
 	currentValue, err := os.ReadFile(path)
 	if err != nil {
 		return -1, fmt.Errorf("read sysctl %s: %w", key, err)

client/internal/statemanager/manager.go

@@ -1,6 +1,7 @@
 package statemanager
 
 import (
+	"bytes"
 	"context"
 	"encoding/json"
 	"errors"
@@ -305,6 +306,11 @@ func (m *Manager) loadStateFile(deleteCorrupt bool) (map[string]json.RawMessage,
 
 	var rawStates map[string]json.RawMessage
 	if err := json.Unmarshal(data, &rawStates); err != nil {
+		if len(bytes.TrimSpace(data)) == 0 {
+			log.Warnf("state file %s is empty (%d bytes)", m.filePath, len(data))
+		} else {
+			log.Warnf("state file %s has malformed content (%d bytes)", m.filePath, len(data))
+		}
 		m.handleCorruptedState(deleteCorrupt)
 		return nil, fmt.Errorf("unmarshal states: %w", err)
 	}

client/internal/tunnelnotifier/notifier.go

@@ -0,0 +1,124 @@
+package tunnelnotifier
+
+import (
+	"container/list"
+	"sync"
+
+	"github.com/netbirdio/netbird/client/internal/dns"
+	"github.com/netbirdio/netbird/client/internal/listener"
+)
+
+type eventKind int
+
+const (
+	eventRoutes eventKind = iota
+	eventIfaceIP
+	eventIfaceIPv6
+	eventDNS
+)
+
+var (
+	_ listener.NetworkChangeListener = (*Notifier)(nil)
+	_ dns.IosDnsManager              = (*Notifier)(nil)
+)
+
+type event struct {
+	kind    eventKind
+	payload string
+}
+
+type Notifier struct {
+	mu     sync.Mutex
+	cond   *sync.Cond
+	queue  *list.List
+	closed bool
+	done   chan struct{}
+
+	listener   listener.NetworkChangeListener
+	dnsManager dns.IosDnsManager
+}
+
+func New(l listener.NetworkChangeListener, dm dns.IosDnsManager) *Notifier {
+	n := &Notifier{
+		queue:      list.New(),
+		done:       make(chan struct{}),
+		listener:   l,
+		dnsManager: dm,
+	}
+	n.cond = sync.NewCond(&n.mu)
+	go n.deliverLoop()
+	return n
+}
+
+func (n *Notifier) OnNetworkChanged(routes string) {
+	n.enqueue(event{kind: eventRoutes, payload: routes})
+}
+
+func (n *Notifier) SetInterfaceIP(ip string) {
+	n.enqueue(event{kind: eventIfaceIP, payload: ip})
+}
+
+func (n *Notifier) SetInterfaceIPv6(ip string) {
+	n.enqueue(event{kind: eventIfaceIPv6, payload: ip})
+}
+
+func (n *Notifier) ApplyDns(config string) {
+	n.enqueue(event{kind: eventDNS, payload: config})
+}
+
+// Close stops accepting new events and blocks until the delivery loop has
+// drained all queued events and exited.
+func (n *Notifier) Close() {
+	n.mu.Lock()
+	n.closed = true
+	n.cond.Signal()
+	n.mu.Unlock()
+	<-n.done
+}
+
+func (n *Notifier) enqueue(ev event) {
+	n.mu.Lock()
+	defer n.mu.Unlock()
+	if n.closed {
+		return
+	}
+	n.queue.PushBack(ev)
+	n.cond.Signal()
+}
+
+func (n *Notifier) deliverLoop() {
+	defer close(n.done)
+	for {
+		n.mu.Lock()
+		for n.queue.Len() == 0 && !n.closed {
+			n.cond.Wait()
+		}
+		if n.closed && n.queue.Len() == 0 {
+			n.mu.Unlock()
+			return
+		}
+		ev := n.queue.Remove(n.queue.Front()).(event)
+		l := n.listener
+		dm := n.dnsManager
+		n.mu.Unlock()
+
+		switch ev.kind {
+		case eventRoutes:
+			if l != nil {
+				l.OnNetworkChanged(ev.payload)
+			}
+		case eventIfaceIP:
+			if l != nil {
+				l.SetInterfaceIP(ev.payload)
+			}
+		case eventIfaceIPv6:
+			if l != nil {
+				l.SetInterfaceIPv6(ev.payload)
+			}
+		case eventDNS:
+			if dm != nil {
+				dm.ApplyDns(ev.payload)
+			}
+		}
+	}
+}

client/internal/tunnelnotifier/notifier_test.go

@@ -0,0 +1,192 @@
+package tunnelnotifier
+
+import (
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+type call struct {
+	kind    string
+	payload string
+}
+
+type recorder struct {
+	mu       sync.Mutex
+	calls    []call
+	inFlight atomic.Int32
+	overlap  atomic.Bool
+	delay    time.Duration
+}
+
+func (r *recorder) record(kind, payload string) {
+	if r.inFlight.Add(1) != 1 {
+		r.overlap.Store(true)
+	}
+	if r.delay > 0 {
+		time.Sleep(r.delay)
+	}
+	r.mu.Lock()
+	r.calls = append(r.calls, call{kind: kind, payload: payload})
+	r.mu.Unlock()
+	r.inFlight.Add(-1)
+}
+
+func (r *recorder) count() int {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	return len(r.calls)
+}
+
+func (r *recorder) snapshot() []call {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	out := make([]call, len(r.calls))
+	copy(out, r.calls)
+	return out
+}
+
+type fakeListener struct {
+	rec *recorder
+}
+
+func (f *fakeListener) OnNetworkChanged(routes string) {
+	f.rec.record("routes", routes)
+}
+
+func (f *fakeListener) SetInterfaceIP(ip string) {
+	f.rec.record("ip", ip)
+}
+
+func (f *fakeListener) SetInterfaceIPv6(ip string) {
+	f.rec.record("ipv6", ip)
+}
+
+type fakeDNSManager struct {
+	rec *recorder
+}
+
+func (f *fakeDNSManager) ApplyDns(config string) {
+	f.rec.record("dns", config)
+}
+
+func TestFIFOOrder(t *testing.T) {
+	rec := &recorder{}
+	n := New(&fakeListener{rec: rec}, &fakeDNSManager{rec: rec})
+	defer n.Close()
+
+	n.SetInterfaceIP("10.0.0.1")
+	n.SetInterfaceIPv6("fd00::1")
+	n.ApplyDns(`{"domains":[]}`)
+	n.OnNetworkChanged("10.0.0.0/8,192.168.0.0/16")
+	n.ApplyDns(`{"domains":["example.com"]}`)
+
+	require.Eventually(t, func() bool { return rec.count() == 5 }, time.Second, time.Millisecond)
+
+	expected := []call{
+		{kind: "ip", payload: "10.0.0.1"},
+		{kind: "ipv6", payload: "fd00::1"},
+		{kind: "dns", payload: `{"domains":[]}`},
+		{kind: "routes", payload: "10.0.0.0/8,192.168.0.0/16"},
+		{kind: "dns", payload: `{"domains":["example.com"]}`},
+	}
+	assert.Equal(t, expected, rec.snapshot())
+}
+
+func TestNoOverlappingCalls(t *testing.T) {
+	rec := &recorder{delay: 100 * time.Microsecond}
+	n := New(&fakeListener{rec: rec}, &fakeDNSManager{rec: rec})
+	defer n.Close()
+
+	const producers = 8
+	const perProducer = 25
+
+	var wg sync.WaitGroup
+	for i := 0; i < producers; i++ {
+		wg.Add(1)
+		go func(id int) {
+			defer wg.Done()
+			for j := 0; j < perProducer; j++ {
+				payload := fmt.Sprintf("%d-%d", id, j)
+				switch j % 4 {
+				case 0:
+					n.OnNetworkChanged(payload)
+				case 1:
+					n.SetInterfaceIP(payload)
+				case 2:
+					n.SetInterfaceIPv6(payload)
+				case 3:
+					n.ApplyDns(payload)
+				}
+			}
+		}(i)
+	}
+	wg.Wait()
+
+	require.Eventually(t, func() bool { return rec.count() == producers*perProducer }, 5*time.Second, time.Millisecond)
+	assert.False(t, rec.overlap.Load())
+}
+
+func TestDNSAndRoutesInterleaved(t *testing.T) {
+	rec := &recorder{delay: 100 * time.Microsecond}
+	n := New(&fakeListener{rec: rec}, &fakeDNSManager{rec: rec})
+	defer n.Close()
+
+	const events = 50
+
+	var wg sync.WaitGroup
+	wg.Add(2)
+	go func() {
+		defer wg.Done()
+		for i := 0; i < events; i++ {
+			n.ApplyDns(fmt.Sprintf("dns-%d", i))
+		}
+	}()
+	go func() {
+		defer wg.Done()
+		for i := 0; i < events; i++ {
+			n.OnNetworkChanged(fmt.Sprintf("routes-%d", i))
+		}
+	}()
+	wg.Wait()
+
+	require.Eventually(t, func() bool { return rec.count() == 2*events }, 5*time.Second, time.Millisecond)
+	assert.False(t, rec.overlap.Load())
+
+	var dnsSeen, routesSeen int
+	for _, c := range rec.snapshot() {
+		switch c.kind {
+		case "dns":
+			assert.Equal(t, fmt.Sprintf("dns-%d", dnsSeen), c.payload)
+			dnsSeen++
+		case "routes":
+			assert.Equal(t, fmt.Sprintf("routes-%d", routesSeen), c.payload)
+			routesSeen++
+		}
+	}
+	assert.Equal(t, events, dnsSeen)
+	assert.Equal(t, events, routesSeen)
+}
+
+func TestCloseDrainsQueue(t *testing.T) {
+	rec := &recorder{delay: time.Millisecond}
+	n := New(&fakeListener{rec: rec}, &fakeDNSManager{rec: rec})
+
+	const events = 20
+	for i := 0; i < events; i++ {
+		n.OnNetworkChanged(fmt.Sprintf("routes-%d", i))
+	}
+	n.Close()
+
+	require.Equal(t, events, rec.count(), "Close must not return before all queued events are delivered")
+
+	n.OnNetworkChanged("after-close")
+	n.ApplyDns("after-close")
+	time.Sleep(50 * time.Millisecond)
+	assert.Equal(t, events, rec.count())
+}