[client] Address review comments on DNS lazy-connection warm-up

- Use netip.Addr instead of string IPs in the local resolver's PeerConnectivity and PeerActivator interfaces; extract record addresses as netip.Addr (v4-mapped forms unmapped) and convert to string only at the peer.Status boundary. - Scope warm-up to match-only (non-authoritative) zones so the synthesized private-service records keep warming while plain peer-name lookups in the authoritative peer zone no longer wake every idle peer. - Parse NB_DNS_LAZY_WARMUP_TIMEOUT once in the resolver constructor instead of on every request, and log invalid values. - Stop reusing engine.syncMsgMux on the DNS path: ConnMgr.ActivatePeer is now safe for concurrent use (lazy manager pointer guarded by a dedicated RWMutex; the manager itself is internally synchronized), so network-map processing no longer blocks DNS resolution. - Add SetPeerActivator to the dns.Server interface (no-op on the mock) and drop the *dns.DefaultServer type assertion in the engine. - Drop WireGuard wording from dns/local comments; the layer is transport-agnostic. Tests: authoritative zones never trigger warm-up; warm-up timeout env parsing (valid/invalid/non-positive); extractRecordAddr unmaps v4-mapped record data; dnsPeerActivator skips connected/unknown/ conn-less peers, returns on connect, and releases at the budget when the peer stays idle; ConnMgr.ActivatePeer races the manager lifecycle cleanly under -race.
2026-07-22 16:31:28 +02:00 · 2026-07-22 03:22:22 +00:00
parent 7825036fae
commit a4d0f242b4
10 changed files with 419 additions and 87 deletions
--- a/client/internal/conn_mgr.go
+++ b/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
@@ -42,6 +44,10 @@ 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

 	wg            sync.WaitGroup
 	lazyCtx       context.Context
@@ -238,12 +244,20 @@ 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 +282,21 @@ 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(),
 	}
-	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 +335,10 @@ 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)
--- a/client/internal/conn_mgr_test.go
+++ b/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 +49,58 @@ 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()
+}
--- a/client/internal/dns/local/local.go
+++ b/client/internal/dns/local/local.go
@@ -37,31 +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) begins its WireGuard handshake at DNS-resolution time rather
-// than racing the client's first request packet. nil disables warm-up.
+// 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 ips and blocks
+	// 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 IPs.
-	ActivatePeersByIP(ctx context.Context, ips []string)
+	// fast no-op for unknown or already-connected addresses.
+	ActivatePeersByIP(ctx context.Context, addrs []netip.Addr)
 }

-const defaultLazyWarmupTimeout = 2 * time.Second
+const (
+	defaultLazyWarmupTimeout = 2 * time.Second
+	envLazyWarmupTimeout     = "NB_DNS_LAZY_WARMUP_TIMEOUT"
+)

-// lazyWarmupTimeout is 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).
-func lazyWarmupTimeout() time.Duration {
-	if v := os.Getenv("NB_DNS_LAZY_WARMUP_TIMEOUT"); v != "" {
-		if d, err := time.ParseDuration(v); err == nil && d > 0 {
-			return d
-		}
+// 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
 	}
-	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 {
@@ -79,6 +91,9 @@ type Resolver struct {
 	// 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
@@ -87,11 +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,
 	}
 }

@@ -160,7 +176,7 @@ func (d *Resolver) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 	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(result.records)
+	d.warmLazyPeers(question, result.records)
 	result.records = d.filterDisconnectedPeerAnswers(logger, question, result.records)
 	replyMessage.Authoritative = !result.hasExternalData
 	replyMessage.Answer = result.records
@@ -534,8 +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
 		}
@@ -559,47 +575,52 @@ func (d *Resolver) filterDisconnectedPeerAnswers(logger *log.Entry, question dns

 // 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 WireGuard handshake. No-op when no activator is
-// wired (lazy connections disabled) or the answer carries no peer IPs.
-func (d *Resolver) warmLazyPeers(records []dns.RR) {
+// 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) {
 	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 {
+	if activator == nil || !found || !nonAuth {
 		return
 	}

-	var ips []string
+	var addrs []netip.Addr
 	for _, rr := range records {
-		if ip := extractRecordIP(rr); ip != "" {
-			ips = append(ips, ip)
+		if addr, ok := extractRecordAddr(rr); ok {
+			addrs = append(addrs, addr)
 		}
 	}
-	if len(ips) == 0 {
+	if len(addrs) == 0 {
 		return
 	}

-	ctx, cancel := context.WithTimeout(d.ctx, lazyWarmupTimeout())
+	ctx, cancel := context.WithTimeout(d.ctx, d.warmupTimeout)
 	defer cancel()
-	activator.ActivatePeersByIP(ctx, ips)
+	activator.ActivatePeersByIP(ctx, addrs)
 }

-// 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 {
+// 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
--- a/client/internal/dns/local/local_test.go
+++ b/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
 	}
--- a/client/internal/dns/local/warmup_test.go
+++ b/client/internal/dns/local/warmup_test.go
@@ -2,8 +2,11 @@ package local

 import (
 	"context"
+	"net"
+	"net/netip"
 	"sync"
 	"testing"
+	"time"

 	"github.com/miekg/dns"
 	"github.com/stretchr/testify/assert"
@@ -13,19 +16,19 @@ import (
 	nbdns "github.com/netbirdio/netbird/dns"
 )

-// recordingActivator records the IPs it was asked to warm and returns
+// 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
-	ips    []string
+	addrs  []netip.Addr
 }

-func (r *recordingActivator) ActivatePeersByIP(_ context.Context, ips []string) {
+func (r *recordingActivator) ActivatePeersByIP(_ context.Context, addrs []netip.Addr) {
 	r.mu.Lock()
 	defer r.mu.Unlock()
 	r.called = true
-	r.ips = append(r.ips, ips...)
+	r.addrs = append(r.addrs, addrs...)
 }

 func serveA(t *testing.T, resolver *Resolver, name string) *dns.Msg {
@@ -36,10 +39,21 @@ func serveA(t *testing.T, resolver *Resolver, name string) *dns.Msg {
 	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) {
-	rec := nbdns.SimpleRecord{Name: "svc.netbird.cloud.", Type: 1, Class: nbdns.DefaultClass, TTL: 300, RData: "100.64.0.7"}
+	rec := nbdns.SimpleRecord{Name: "svc.proxy.netbird.cloud.", Type: 1, Class: nbdns.DefaultClass, TTL: 300, RData: "100.64.0.7"}
 	resolver := NewResolver()
-	require.NoError(t, resolver.RegisterRecord(rec))
+	serviceZone(t, resolver, "proxy.netbird.cloud", rec)

 	act := &recordingActivator{}
 	resolver.SetPeerActivator(act)
@@ -50,15 +64,15 @@ func TestLocalResolver_WarmsLazyPeerOnResolve(t *testing.T) {

 	act.mu.Lock()
 	defer act.mu.Unlock()
-	assert.True(t, act.called, "activator must be invoked for an overlay A answer")
-	assert.Contains(t, act.ips, "100.64.0.7", "activator must receive the answer's peer IP")
+	assert.True(t, act.called, "activator must be invoked for a service-zone A answer")
+	assert.Contains(t, act.addrs, netip.MustParseAddr("100.64.0.7"), "activator must receive the answer's peer IP")
 }

 func TestLocalResolver_NoActivatorNoWarmup(t *testing.T) {
 	// With no activator wired the resolver behaves exactly as before.
-	rec := nbdns.SimpleRecord{Name: "svc.netbird.cloud.", Type: 1, Class: nbdns.DefaultClass, TTL: 300, RData: "100.64.0.7"}
+	rec := nbdns.SimpleRecord{Name: "svc.proxy.netbird.cloud.", Type: 1, Class: nbdns.DefaultClass, TTL: 300, RData: "100.64.0.7"}
 	resolver := NewResolver()
-	require.NoError(t, resolver.RegisterRecord(rec))
+	serviceZone(t, resolver, "proxy.netbird.cloud", rec)

 	resp := serveA(t, resolver, rec.Name)
 	require.NotNil(t, resp, "resolver must still answer without an activator")
@@ -68,14 +82,91 @@ func TestLocalResolver_NoActivatorNoWarmup(t *testing.T) {
 func TestLocalResolver_NoWarmupForMissingRecord(t *testing.T) {
 	// A query that resolves to nothing must not invoke the activator (no IPs).
 	resolver := NewResolver()
-	require.NoError(t, resolver.RegisterRecord(nbdns.SimpleRecord{Name: "svc.netbird.cloud.", Type: 1, Class: nbdns.DefaultClass, TTL: 300, RData: "100.64.0.7"}))
+	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.netbird.cloud.")
+	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.
+	rec := nbdns.SimpleRecord{Name: "peer.netbird.cloud.", Type: 1, Class: nbdns.DefaultClass, TTL: 300, RData: "100.64.0.9"}
+	resolver := NewResolver()
+	resolver.Update([]nbdns.CustomZone{{
+		Domain:  "netbird.cloud",
+		Records: []nbdns.SimpleRecord{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 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)
+	})
+}
--- a/client/internal/dns/mock_server.go
+++ b/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
--- a/client/internal/dns/server.go
+++ b/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 {
@@ -1442,11 +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
 	}
--- a/client/internal/dns_peer_activator.go
+++ b/client/internal/dns_peer_activator.go
@@ -2,7 +2,7 @@ package internal

 import (
 	"context"
-	"sync"
+	"net/netip"
 	"time"

 	"github.com/netbirdio/netbird/client/internal/peer"
@@ -12,33 +12,33 @@ import (
 const dnsActivationPollInterval = 50 * time.Millisecond

 // dnsPeerActivator wakes lazy-connection peers from the DNS resolution path. It
-// implements dns/local.PeerActivator. ConnMgr is not thread-safe (guarded by
-// the engine's syncMsgMux) while DNS queries run on their own goroutines, so
-// activation runs under that mutex; the connection wait runs without 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
-	mu        *sync.Mutex
 	// 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 ips 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 IPs are skipped, so the
-// steady-state (warm) path adds no latency.
-func (a *dnsPeerActivator) ActivatePeersByIP(ctx context.Context, ips []string) {
+// 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
-	a.mu.Lock()
-	for _, ip := range ips {
+	for _, addr := range addrs {
+		ip := addr.String()
 		st, ok := a.status.PeerStateByIP(ip)
 		if !ok || st.ConnStatus == peer.StatusConnected {
 			continue
@@ -50,7 +50,6 @@ func (a *dnsPeerActivator) ActivatePeersByIP(ctx context.Context, ips []string)
 		a.connMgr.ActivatePeer(a.ctx, conn)
 		pending = append(pending, ip)
 	}
-	a.mu.Unlock()

 	if len(pending) == 0 {
 		return
--- a/client/internal/dns_peer_activator_test.go
+++ b/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")
+}
--- a/client/internal/engine.go
+++ b/client/internal/engine.go
@@ -657,15 +657,12 @@ func (e *Engine) Start(netbirdConfig *mgmProto.NetbirdConfig, mgmtURL *url.URL)
 	// 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.
-	if ds, ok := e.dnsServer.(*dns.DefaultServer); ok {
-		ds.SetPeerActivator(&dnsPeerActivator{
-			connMgr:   e.connMgr,
-			peerStore: e.peerStore,
-			status:    e.statusRecorder,
-			mu:        e.syncMsgMux,
-			ctx:       e.ctx,
-		})
-	}
+	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())