Feature/permanent dns (#967)

* Add DNS list argument for mobile client

* Write testable code

Many places are checked the wgInterface != nil condition.
It is doing it just because to avoid the real wgInterface creation for tests.
Instead of this involve a wgInterface interface what is moc-able.

* Refactor the DNS server internal code structure

With the fake resolver has been involved several
if-else statement and generated some unused
variables to distinguish the listener and fake
resolver solutions at running time. With this
commit the fake resolver and listener based
solution has been moved into two separated
structure. Name of this layer is the 'service'.
With this modification the unit test looks
simpler and open the option to add new logic for
the permanent DNS service usage for mobile
systems.



* Remove is running check in test

We can not ensure the state well so remove this
check. The test will fail if the server is not
running well.

client/android/client.go

@@ -7,6 +7,7 @@ import (
 	log "github.com/sirupsen/logrus"
 
 	"github.com/netbirdio/netbird/client/internal"
+	"github.com/netbirdio/netbird/client/internal/dns"
 	"github.com/netbirdio/netbird/client/internal/peer"
 	"github.com/netbirdio/netbird/client/internal/routemanager"
 	"github.com/netbirdio/netbird/client/internal/stdnet"
@@ -35,6 +36,11 @@ type RouteListener interface {
 	routemanager.RouteListener
 }
 
+// DnsReadyListener export internal dns ReadyListener for mobile
+type DnsReadyListener interface {
+	dns.ReadyListener
+}
+
 func init() {
 	formatter.SetLogcatFormatter(log.StandardLogger())
 }
@@ -49,6 +55,7 @@ type Client struct {
 	ctxCancelLock *sync.Mutex
 	deviceName    string
 	routeListener routemanager.RouteListener
+	onHostDnsFn   func([]string)
 }
 
 // NewClient instantiate a new Client
@@ -65,7 +72,7 @@ func NewClient(cfgFile, deviceName string, tunAdapter TunAdapter, iFaceDiscover
 }
 
 // Run start the internal client. It is a blocker function
-func (c *Client) Run(urlOpener URLOpener) error {
+func (c *Client) Run(urlOpener URLOpener, dns *DNSList, dnsReadyListener DnsReadyListener) error {
 	cfg, err := internal.UpdateOrCreateConfig(internal.ConfigInput{
 		ConfigPath: c.cfgFile,
 	})
@@ -90,7 +97,8 @@ func (c *Client) Run(urlOpener URLOpener) error {
 
 	// todo do not throw error in case of cancelled context
 	ctx = internal.CtxInitState(ctx)
-	return internal.RunClient(ctx, cfg, c.recorder, c.tunAdapter, c.iFaceDiscover, c.routeListener)
+	c.onHostDnsFn = func([]string) {}
+	return internal.RunClientMobile(ctx, cfg, c.recorder, c.tunAdapter, c.iFaceDiscover, c.routeListener, dns.items, dnsReadyListener)
 }
 
 // Stop the internal client and free the resources
@@ -126,6 +134,17 @@ func (c *Client) PeersList() *PeerInfoArray {
 	return &PeerInfoArray{items: peerInfos}
 }
 
+// OnUpdatedHostDNS update the DNS servers addresses for root zones
+func (c *Client) OnUpdatedHostDNS(list *DNSList) error {
+	dnsServer, err := dns.GetServerDns()
+	if err != nil {
+		return err
+	}
+
+	dnsServer.OnUpdatedHostDNSServer(list.items)
+	return nil
+}
+
 // SetConnectionListener set the network connection listener
 func (c *Client) SetConnectionListener(listener ConnectionListener) {
 	c.recorder.SetConnectionListener(listener)

client/android/dns_list.go

@@ -0,0 +1,26 @@
+package android
+
+import "fmt"
+
+// DNSList is a wrapper of []string
+type DNSList struct {
+	items []string
+}
+
+// Add new DNS address to the collection
+func (array *DNSList) Add(s string) {
+	array.items = append(array.items, s)
+}
+
+// Get return an element of the collection
+func (array *DNSList) Get(i int) (string, error) {
+	if i >= len(array.items) || i < 0 {
+		return "", fmt.Errorf("out of range")
+	}
+	return array.items[i], nil
+}
+
+// Size return with the size of the collection
+func (array *DNSList) Size() int {
+	return len(array.items)
+}

client/android/dns_list_test.go

@@ -0,0 +1,24 @@
+package android
+
+import "testing"
+
+func TestDNSList_Get(t *testing.T) {
+	l := DNSList{
+		items: make([]string, 1),
+	}
+
+	_, err := l.Get(0)
+	if err != nil {
+		t.Errorf("invalid error: %s", err)
+	}
+
+	_, err = l.Get(-1)
+	if err == nil {
+		t.Errorf("expected error but got nil")
+	}
+
+	_, err = l.Get(1)
+	if err == nil {
+		t.Errorf("expected error but got nil")
+	}
+}

client/cmd/up.go

@@ -104,7 +104,7 @@ func runInForegroundMode(ctx context.Context, cmd *cobra.Command) error {
 	var cancel context.CancelFunc
 	ctx, cancel = context.WithCancel(ctx)
 	SetupCloseHandler(ctx, cancel)
-	return internal.RunClient(ctx, config, peer.NewRecorder(config.ManagementURL.String()), nil, nil, nil)
+	return internal.RunClient(ctx, config, peer.NewRecorder(config.ManagementURL.String()))
 }
 
 func runInDaemonMode(ctx context.Context, cmd *cobra.Command) error {

client/internal/connect.go

@@ -12,6 +12,7 @@ import (
 	"google.golang.org/grpc/codes"
 	gstatus "google.golang.org/grpc/status"
 
+	"github.com/netbirdio/netbird/client/internal/dns"
 	"github.com/netbirdio/netbird/client/internal/peer"
 	"github.com/netbirdio/netbird/client/internal/routemanager"
 	"github.com/netbirdio/netbird/client/internal/stdnet"
@@ -24,7 +25,24 @@ import (
 )
 
 // RunClient with main logic.
-func RunClient(ctx context.Context, config *Config, statusRecorder *peer.Status, tunAdapter iface.TunAdapter, iFaceDiscover stdnet.ExternalIFaceDiscover, routeListener routemanager.RouteListener) error {
+func RunClient(ctx context.Context, config *Config, statusRecorder *peer.Status) error {
+	return runClient(ctx, config, statusRecorder, MobileDependency{})
+}
+
+// RunClientMobile with main logic on mobile system
+func RunClientMobile(ctx context.Context, config *Config, statusRecorder *peer.Status, tunAdapter iface.TunAdapter, iFaceDiscover stdnet.ExternalIFaceDiscover, routeListener routemanager.RouteListener, dnsAddresses []string, dnsReadyListener dns.ReadyListener) error {
+	// in case of non Android os these variables will be nil
+	mobileDependency := MobileDependency{
+		TunAdapter:       tunAdapter,
+		IFaceDiscover:    iFaceDiscover,
+		RouteListener:    routeListener,
+		HostDNSAddresses: dnsAddresses,
+		DnsReadyListener: dnsReadyListener,
+	}
+	return runClient(ctx, config, statusRecorder, mobileDependency)
+}
+
+func runClient(ctx context.Context, config *Config, statusRecorder *peer.Status, mobileDependency MobileDependency) error {
 	backOff := &backoff.ExponentialBackOff{
 		InitialInterval:     time.Second,
 		RandomizationFactor: 1,
@@ -151,14 +169,7 @@ func RunClient(ctx context.Context, config *Config, statusRecorder *peer.Status,
 			return wrapErr(err)
 		}
 
-		// in case of non Android os these variables will be nil
+		engine := NewEngine(engineCtx, cancel, signalClient, mgmClient, engineConfig, mobileDependency, statusRecorder)
-		md := MobileDependency{
-			TunAdapter:    tunAdapter,
-			IFaceDiscover: iFaceDiscover,
-			RouteListener: routeListener,
-		}
-
-		engine := NewEngine(engineCtx, cancel, signalClient, mgmClient, engineConfig, md, statusRecorder)
 		err = engine.Start()
 		if err != nil {
 			log.Errorf("error while starting Netbird Connection Engine: %s", err)

client/internal/dns/host_android.go

@@ -1,13 +1,9 @@
 package dns
 
-import (
-	"github.com/netbirdio/netbird/iface"
-)
-
 type androidHostManager struct {
 }
 
-func newHostManager(wgInterface *iface.WGIface) (hostManager, error) {
+func newHostManager(wgInterface WGIface) (hostManager, error) {
 	return &androidHostManager{}, nil
 }
 

client/internal/dns/host_darwin.go

@@ -9,8 +9,6 @@ import (
 	"strings"
 
 	log "github.com/sirupsen/logrus"
-
-	"github.com/netbirdio/netbird/iface"
 )
 
 const (
@@ -34,7 +32,7 @@ type systemConfigurator struct {
 	createdKeys      map[string]struct{}
 }
 
-func newHostManager(_ *iface.WGIface) (hostManager, error) {
+func newHostManager(_ WGIface) (hostManager, error) {
 	return &systemConfigurator{
 		createdKeys: make(map[string]struct{}),
 	}, nil

client/internal/dns/host_linux.go

@@ -5,10 +5,10 @@ package dns
 import (
 	"bufio"
 	"fmt"
-	"github.com/netbirdio/netbird/iface"
-	log "github.com/sirupsen/logrus"
 	"os"
 	"strings"
+
+	log "github.com/sirupsen/logrus"
 )
 
 const (
@@ -25,7 +25,7 @@ const (
 
 type osManagerType int
 
-func newHostManager(wgInterface *iface.WGIface) (hostManager, error) {
+func newHostManager(wgInterface WGIface) (hostManager, error) {
 	osManager, err := getOSDNSManagerType()
 	if err != nil {
 		return nil, err

client/internal/dns/host_windows.go

@@ -6,8 +6,6 @@ import (
 
 	log "github.com/sirupsen/logrus"
 	"golang.org/x/sys/windows/registry"
-
-	"github.com/netbirdio/netbird/iface"
 )
 
 const (
@@ -33,7 +31,7 @@ type registryConfigurator struct {
 	existingSearchDomains []string
 }
 
-func newHostManager(wgInterface *iface.WGIface) (hostManager, error) {
+func newHostManager(wgInterface WGIface) (hostManager, error) {
 	guid, err := wgInterface.GetInterfaceGUIDString()
 	if err != nil {
 		return nil, err

client/internal/dns/mockServer.go

@@ -31,6 +31,11 @@ func (m *MockServer) DnsIP() string {
 	return ""
 }
 
+func (m *MockServer) OnUpdatedHostDNSServer(strings []string) {
+	//TODO implement me
+	panic("implement me")
+}
+
 // UpdateDNSServer mock implementation of UpdateDNSServer from Server interface
 func (m *MockServer) UpdateDNSServer(serial uint64, update nbdns.Config) error {
 	if m.UpdateDNSServerFunc != nil {

client/internal/dns/network_manager_linux.go

@@ -14,8 +14,6 @@ import (
 	"github.com/hashicorp/go-version"
 	"github.com/miekg/dns"
 	log "github.com/sirupsen/logrus"
-
-	"github.com/netbirdio/netbird/iface"
 )
 
 const (
@@ -72,7 +70,7 @@ func (s networkManagerConnSettings) cleanDeprecatedSettings() {
 	}
 }
 
-func newNetworkManagerDbusConfigurator(wgInterface *iface.WGIface) (hostManager, error) {
+func newNetworkManagerDbusConfigurator(wgInterface WGIface) (hostManager, error) {
 	obj, closeConn, err := getDbusObject(networkManagerDest, networkManagerDbusObjectNode)
 	if err != nil {
 		return nil, err

client/internal/dns/resolvconf_linux.go

@@ -8,8 +8,6 @@ import (
 	"strings"
 
 	log "github.com/sirupsen/logrus"
-
-	"github.com/netbirdio/netbird/iface"
 )
 
 const resolvconfCommand = "resolvconf"
@@ -18,7 +16,7 @@ type resolvconf struct {
 	ifaceName string
 }
 
-func newResolvConfConfigurator(wgInterface *iface.WGIface) (hostManager, error) {
+func newResolvConfConfigurator(wgInterface WGIface) (hostManager, error) {
 	return &resolvconf{
 		ifaceName: wgInterface.Name(),
 	}, nil

client/internal/dns/server.go

@@ -3,29 +3,20 @@ package dns
 import (
 	"context"
 	"fmt"
-	"math/big"
-	"net"
 	"net/netip"
-	"runtime"
 	"sync"
-	"time"
 
-	"github.com/google/gopacket"
-	"github.com/google/gopacket/layers"
 	"github.com/miekg/dns"
 	"github.com/mitchellh/hashstructure/v2"
 	log "github.com/sirupsen/logrus"
 
 	nbdns "github.com/netbirdio/netbird/dns"
-	"github.com/netbirdio/netbird/iface"
 )
 
-const (
+// ReadyListener is a notification mechanism what indicate the server is ready to handle host dns address changes
-	defaultPort = 53
+type ReadyListener interface {
-	customPort  = 5053
+	OnReady()
-	defaultIP   = "127.0.0.1"
+}
-	customIP    = "127.0.0.153"
-)
 
 // Server is a dns server interface
 type Server interface {
@@ -33,6 +24,7 @@ type Server interface {
 	Stop()
 	DnsIP() string
 	UpdateDNSServer(serial uint64, update nbdns.Config) error
+	OnUpdatedHostDNSServer(strings []string)
 }
 
 type registeredHandlerMap map[string]handlerWithStop
@@ -42,21 +34,19 @@ type DefaultServer struct {
 	ctx                context.Context
 	ctxCancel          context.CancelFunc
 	mux                sync.Mutex
-	udpFilterHookID    string
+	service            service
-	server             *dns.Server
-	dnsMux             *dns.ServeMux
 	dnsMuxMap          registeredHandlerMap
 	localResolver      *localResolver
-	wgInterface        *iface.WGIface
+	wgInterface        WGIface
 	hostManager        hostManager
 	updateSerial       uint64
-	listenerIsRunning  bool
-	runtimePort        int
-	runtimeIP          string
 	previousConfigHash uint64
 	currentConfig      hostDNSConfig
-	customAddress      *netip.AddrPort
+
-	enabled            bool
+	// permanent related properties
+	permanent        bool
+	hostsDnsList     []string
+	hostsDnsListLock sync.Mutex
 }
 
 type handlerWithStop interface {
@@ -70,9 +60,7 @@ type muxUpdate struct {
 }
 
 // NewDefaultServer returns a new dns server
-func NewDefaultServer(ctx context.Context, wgInterface *iface.WGIface, customAddress string, initialDnsCfg *nbdns.Config) (*DefaultServer, error) {
+func NewDefaultServer(ctx context.Context, wgInterface WGIface, customAddress string) (*DefaultServer, error) {
-	mux := dns.NewServeMux()
-
 	var addrPort *netip.AddrPort
 	if customAddress != "" {
 		parsedAddrPort, err := netip.ParseAddrPort(customAddress)
@@ -82,37 +70,44 @@ func NewDefaultServer(ctx context.Context, wgInterface *iface.WGIface, customAdd
 		addrPort = &parsedAddrPort
 	}
 
-	ctx, stop := context.WithCancel(ctx)
+	var dnsService service
+	if wgInterface.IsUserspaceBind() {
+		dnsService = newServiceViaMemory(wgInterface)
+	} else {
+		dnsService = newServiceViaListener(wgInterface, addrPort)
+	}
 
+	return newDefaultServer(ctx, wgInterface, dnsService), nil
+}
+
+// NewDefaultServerPermanentUpstream returns a new dns server. It optimized for mobile systems
+func NewDefaultServerPermanentUpstream(ctx context.Context, wgInterface WGIface, hostsDnsList []string) *DefaultServer {
+	log.Debugf("host dns address list is: %v", hostsDnsList)
+	ds := newDefaultServer(ctx, wgInterface, newServiceViaMemory(wgInterface))
+	ds.permanent = true
+	ds.hostsDnsList = hostsDnsList
+	ds.addHostRootZone()
+	setServerDns(ds)
+	return ds
+}
+
+func newDefaultServer(ctx context.Context, wgInterface WGIface, dnsService service) *DefaultServer {
+	ctx, stop := context.WithCancel(ctx)
 	defaultServer := &DefaultServer{
 		ctx:       ctx,
 		ctxCancel: stop,
-		server: &dns.Server{
+		service:   dnsService,
-			Net:     "udp",
-			Handler: mux,
-			UDPSize: 65535,
-		},
-		dnsMux:    mux,
 		dnsMuxMap: make(registeredHandlerMap),
 		localResolver: &localResolver{
 			registeredMap: make(registrationMap),
 		},
 		wgInterface: wgInterface,
-		customAddress: addrPort,
 	}
 
-	if initialDnsCfg != nil {
+	return defaultServer
-		defaultServer.enabled = hasValidDnsServer(initialDnsCfg)
-	}
-
-	if wgInterface.IsUserspaceBind() {
-		defaultServer.evelRuntimeAddressForUserspace()
-	}
-
-	return defaultServer, nil
 }
 
-// Initialize instantiate host manager. It required to be initialized wginterface
+// Initialize instantiate host manager and the dns service
 func (s *DefaultServer) Initialize() (err error) {
 	s.mux.Lock()
 	defer s.mux.Unlock()
@@ -121,72 +116,23 @@ func (s *DefaultServer) Initialize() (err error) {
 		return nil
 	}
 
-	if !s.wgInterface.IsUserspaceBind() {
+	if s.permanent {
-		s.evalRuntimeAddress()
+		err = s.service.Listen()
+		if err != nil {
+			return err
 		}
+	}
+
 	s.hostManager, err = newHostManager(s.wgInterface)
 	return
 }
 
-// listen runs the listener in a go routine
-func (s *DefaultServer) listen() {
-	// nil check required in unit tests
-	if s.wgInterface != nil && s.wgInterface.IsUserspaceBind() {
-		s.udpFilterHookID = s.filterDNSTraffic()
-		s.setListenerStatus(true)
-		return
-	}
-
-	log.Debugf("starting dns on %s", s.server.Addr)
-
-	go func() {
-		s.setListenerStatus(true)
-		defer s.setListenerStatus(false)
-
-		err := s.server.ListenAndServe()
-		if err != nil {
-			log.Errorf("dns server running with %d port returned an error: %v. Will not retry", s.runtimePort, err)
-		}
-	}()
-}
-
 // DnsIP returns the DNS resolver server IP address
 //
 // When kernel space interface used it return real DNS server listener IP address
 // For bind interface, fake DNS resolver address returned (second last IP address from Nebird network)
 func (s *DefaultServer) DnsIP() string {
-	if !s.enabled {
+	return s.service.RuntimeIP()
-		return ""
-	}
-	return s.runtimeIP
-}
-
-func (s *DefaultServer) getFirstListenerAvailable() (string, int, error) {
-	ips := []string{defaultIP, customIP}
-	if runtime.GOOS != "darwin" && s.wgInterface != nil {
-		ips = append([]string{s.wgInterface.Address().IP.String()}, ips...)
-	}
-	ports := []int{defaultPort, customPort}
-	for _, port := range ports {
-		for _, ip := range ips {
-			addrString := fmt.Sprintf("%s:%d", ip, port)
-			udpAddr := net.UDPAddrFromAddrPort(netip.MustParseAddrPort(addrString))
-			probeListener, err := net.ListenUDP("udp", udpAddr)
-			if err == nil {
-				err = probeListener.Close()
-				if err != nil {
-					log.Errorf("got an error closing the probe listener, error: %s", err)
-				}
-				return ip, port, nil
-			}
-			log.Warnf("binding dns on %s is not available, error: %s", addrString, err)
-		}
-	}
-	return "", 0, fmt.Errorf("unable to find an unused ip and port combination. IPs tested: %v and ports %v", ips, ports)
-}
-
-func (s *DefaultServer) setListenerStatus(running bool) {
-	s.listenerIsRunning = running
 }
 
 // Stop stops the server
@@ -202,37 +148,23 @@ func (s *DefaultServer) Stop() {
 		}
 	}
 
-	err := s.stopListener()
+	s.service.Stop()
-	if err != nil {
-		log.Error(err)
-	}
 }
 
-func (s *DefaultServer) stopListener() error {
+// OnUpdatedHostDNSServer update the DNS servers addresses for root zones
-	if s.wgInterface != nil && s.wgInterface.IsUserspaceBind() && s.listenerIsRunning {
+// It will be applied if the mgm server do not enforce DNS settings for root zone
-		// udpFilterHookID here empty only in the unit tests
+func (s *DefaultServer) OnUpdatedHostDNSServer(hostsDnsList []string) {
-		if filter := s.wgInterface.GetFilter(); filter != nil && s.udpFilterHookID != "" {
+	s.hostsDnsListLock.Lock()
-			if err := filter.RemovePacketHook(s.udpFilterHookID); err != nil {
+	defer s.hostsDnsListLock.Unlock()
-				log.Errorf("unable to remove DNS packet hook: %s", err)
-			}
-		}
-		s.udpFilterHookID = ""
-		s.listenerIsRunning = false
-		return nil
-	}
 
-	if !s.listenerIsRunning {
+	s.hostsDnsList = hostsDnsList
-		return nil
+	_, ok := s.dnsMuxMap[nbdns.RootZone]
+	if ok {
+		log.Debugf("on new host DNS config but skip to apply it")
+		return
 	}
-
+	log.Debugf("update host DNS settings: %+v", hostsDnsList)
-	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	s.addHostRootZone()
-	defer cancel()
-
-	err := s.server.ShutdownContext(ctx)
-	if err != nil {
-		return fmt.Errorf("stopping dns server listener returned an error: %v", err)
-	}
-	return nil
 }
 
 // UpdateDNSServer processes an update received from the management service
@@ -283,12 +215,10 @@ func (s *DefaultServer) UpdateDNSServer(serial uint64, update nbdns.Config) erro
 func (s *DefaultServer) applyConfiguration(update nbdns.Config) error {
 	// is the service should be disabled, we stop the listener or fake resolver
 	// and proceed with a regular update to clean up the handlers and records
-	if !update.ServiceEnable {
+	if update.ServiceEnable {
-		if err := s.stopListener(); err != nil {
+		_ = s.service.Listen()
-			log.Error(err)
+	} else if !s.permanent {
-		}
+		s.service.Stop()
-	} else if !s.listenerIsRunning {
-		s.listen()
 	}
 
 	localMuxUpdates, localRecords, err := s.buildLocalHandlerUpdate(update.CustomZones)
@@ -299,15 +229,14 @@ func (s *DefaultServer) applyConfiguration(update nbdns.Config) error {
 	if err != nil {
 		return fmt.Errorf("not applying dns update, error: %v", err)
 	}
-
 	muxUpdates := append(localMuxUpdates, upstreamMuxUpdates...)
 
 	s.updateMux(muxUpdates)
 	s.updateLocalResolver(localRecords)
-	s.currentConfig = dnsConfigToHostDNSConfig(update, s.runtimeIP, s.runtimePort)
+	s.currentConfig = dnsConfigToHostDNSConfig(update, s.service.RuntimeIP(), s.service.RuntimePort())
 
 	hostUpdate := s.currentConfig
-	if s.runtimePort != defaultPort && !s.hostManager.supportCustomPort() {
+	if s.service.RuntimePort() != defaultPort && !s.hostManager.supportCustomPort() {
 		log.Warnf("the DNS manager of this peer doesn't support custom port. Disabling primary DNS setup. " +
 			"Learn more at: https://netbird.io/docs/how-to-guides/nameservers#local-resolver")
 		hostUpdate.routeAll = false
@@ -412,19 +341,32 @@ func (s *DefaultServer) buildUpstreamHandlerUpdate(nameServerGroups []*nbdns.Nam
 func (s *DefaultServer) updateMux(muxUpdates []muxUpdate) {
 	muxUpdateMap := make(registeredHandlerMap)
 
+	var isContainRootUpdate bool
+
 	for _, update := range muxUpdates {
-		s.registerMux(update.domain, update.handler)
+		s.service.RegisterMux(update.domain, update.handler)
 		muxUpdateMap[update.domain] = update.handler
 		if existingHandler, ok := s.dnsMuxMap[update.domain]; ok {
 			existingHandler.stop()
 		}
+
+		if update.domain == nbdns.RootZone {
+			isContainRootUpdate = true
+		}
 	}
 
 	for key, existingHandler := range s.dnsMuxMap {
 		_, found := muxUpdateMap[key]
 		if !found {
+			if !isContainRootUpdate && key == nbdns.RootZone {
+				s.hostsDnsListLock.Lock()
+				s.addHostRootZone()
+				s.hostsDnsListLock.Unlock()
 				existingHandler.stop()
-			s.deregisterMux(key)
+			} else {
+				existingHandler.stop()
+				s.service.DeregisterMux(key)
+			}
 		}
 	}
 
@@ -455,14 +397,6 @@ func getNSHostPort(ns nbdns.NameServer) string {
 	return fmt.Sprintf("%s:%d", ns.IP.String(), ns.Port)
 }
 
-func (s *DefaultServer) registerMux(pattern string, handler dns.Handler) {
-	s.dnsMux.Handle(pattern, handler)
-}
-
-func (s *DefaultServer) deregisterMux(pattern string) {
-	s.dnsMux.HandleRemove(pattern)
-}
-
 // upstreamCallbacks returns two functions, the first one is used to deactivate
 // the upstream resolver from the configuration, the second one is used to
 // reactivate it. Not allowed to call reactivate before deactivate.
@@ -490,7 +424,7 @@ func (s *DefaultServer) upstreamCallbacks(
 		for i, item := range s.currentConfig.domains {
 			if _, found := removeIndex[item.domain]; found {
 				s.currentConfig.domains[i].disabled = true
-				s.deregisterMux(item.domain)
+				s.service.DeregisterMux(item.domain)
 				removeIndex[item.domain] = i
 			}
 		}
@@ -507,7 +441,7 @@ func (s *DefaultServer) upstreamCallbacks(
 				continue
 			}
 			s.currentConfig.domains[i].disabled = false
-			s.registerMux(domain, handler)
+			s.service.RegisterMux(domain, handler)
 		}
 
 		l := log.WithField("nameservers", nsGroup.NameServers)
@@ -523,93 +457,13 @@ func (s *DefaultServer) upstreamCallbacks(
 	return
 }
 
-func (s *DefaultServer) filterDNSTraffic() string {
+func (s *DefaultServer) addHostRootZone() {
-	filter := s.wgInterface.GetFilter()
+	handler := newUpstreamResolver(s.ctx)
-	if filter == nil {
+	handler.upstreamServers = make([]string, len(s.hostsDnsList))
-		log.Error("can't set DNS filter, filter not initialized")
+	for n, ua := range s.hostsDnsList {
-		return ""
+		handler.upstreamServers[n] = fmt.Sprintf("%s:53", ua)
 	}
-
+	handler.deactivate = func() {}
-	firstLayerDecoder := layers.LayerTypeIPv4
+	handler.reactivate = func() {}
-	if s.wgInterface.Address().Network.IP.To4() == nil {
+	s.service.RegisterMux(nbdns.RootZone, handler)
-		firstLayerDecoder = layers.LayerTypeIPv6
-	}
-
-	hook := func(packetData []byte) bool {
-		// Decode the packet
-		packet := gopacket.NewPacket(packetData, firstLayerDecoder, gopacket.Default)
-
-		// Get the UDP layer
-		udpLayer := packet.Layer(layers.LayerTypeUDP)
-		udp := udpLayer.(*layers.UDP)
-
-		msg := new(dns.Msg)
-		if err := msg.Unpack(udp.Payload); err != nil {
-			log.Tracef("parse DNS request: %v", err)
-			return true
-		}
-
-		writer := responseWriter{
-			packet: packet,
-			device: s.wgInterface.GetDevice().Device,
-		}
-		go s.dnsMux.ServeDNS(&writer, msg)
-		return true
-	}
-
-	return filter.AddUDPPacketHook(false, net.ParseIP(s.runtimeIP), uint16(s.runtimePort), hook)
-}
-
-func (s *DefaultServer) evelRuntimeAddressForUserspace() {
-	s.runtimeIP = getLastIPFromNetwork(s.wgInterface.Address().Network, 1)
-	s.runtimePort = defaultPort
-	s.server.Addr = fmt.Sprintf("%s:%d", s.runtimeIP, s.runtimePort)
-}
-
-func (s *DefaultServer) evalRuntimeAddress() {
-	defer func() {
-		s.server.Addr = fmt.Sprintf("%s:%d", s.runtimeIP, s.runtimePort)
-	}()
-
-	if s.customAddress != nil {
-		s.runtimeIP = s.customAddress.Addr().String()
-		s.runtimePort = int(s.customAddress.Port())
-		return
-	}
-
-	ip, port, err := s.getFirstListenerAvailable()
-	if err != nil {
-		log.Error(err)
-		return
-	}
-	s.runtimeIP = ip
-	s.runtimePort = port
-}
-
-func getLastIPFromNetwork(network *net.IPNet, fromEnd int) string {
-	// Calculate the last IP in the CIDR range
-	var endIP net.IP
-	for i := 0; i < len(network.IP); i++ {
-		endIP = append(endIP, network.IP[i]|^network.Mask[i])
-	}
-
-	// convert to big.Int
-	endInt := big.NewInt(0)
-	endInt.SetBytes(endIP)
-
-	// subtract fromEnd from the last ip
-	fromEndBig := big.NewInt(int64(fromEnd))
-	resultInt := big.NewInt(0)
-	resultInt.Sub(endInt, fromEndBig)
-
-	return net.IP(resultInt.Bytes()).String()
-}
-
-func hasValidDnsServer(cfg *nbdns.Config) bool {
-	for _, c := range cfg.NameServerGroups {
-		if c.Primary {
-			return true
-		}
-	}
-	return false
 }

client/internal/dns/server_export.go

@@ -0,0 +1,29 @@
+package dns
+
+import (
+	"fmt"
+	"sync"
+)
+
+var (
+	mutex  sync.Mutex
+	server Server
+)
+
+// GetServerDns export the DNS server instance in static way. It used by the Mobile client
+func GetServerDns() (Server, error) {
+	mutex.Lock()
+	if server == nil {
+		mutex.Unlock()
+		return nil, fmt.Errorf("DNS server not instantiated yet")
+	}
+	s := server
+	mutex.Unlock()
+	return s, nil
+}
+
+func setServerDns(newServerServer Server) {
+	mutex.Lock()
+	server = newServerServer
+	defer mutex.Unlock()
+}

client/internal/dns/server_export_test.go

@@ -0,0 +1,24 @@
+package dns
+
+import (
+	"testing"
+)
+
+func TestGetServerDns(t *testing.T) {
+	_, err := GetServerDns()
+	if err == nil {
+		t.Errorf("invalid dns server instance")
+	}
+
+	srv := &MockServer{}
+	setServerDns(srv)
+
+	srvB, err := GetServerDns()
+	if err != nil {
+		t.Errorf("invalid dns server instance: %s", err)
+	}
+
+	if srvB != srv {
+		t.Errorf("missmatch dns instances")
+	}
+}

client/internal/dns/server_test.go

@@ -11,14 +11,53 @@ import (
 	"time"
 
 	"github.com/golang/mock/gomock"
-	"github.com/miekg/dns"
+	log "github.com/sirupsen/logrus"
 
+	"github.com/netbirdio/netbird/client/firewall/uspfilter"
 	"github.com/netbirdio/netbird/client/internal/stdnet"
 	nbdns "github.com/netbirdio/netbird/dns"
+	"github.com/netbirdio/netbird/formatter"
 	"github.com/netbirdio/netbird/iface"
 	pfmock "github.com/netbirdio/netbird/iface/mocks"
 )
 
+type mocWGIface struct {
+	filter iface.PacketFilter
+}
+
+func (w *mocWGIface) Name() string {
+	panic("implement me")
+}
+
+func (w *mocWGIface) Address() iface.WGAddress {
+	ip, network, _ := net.ParseCIDR("100.66.100.0/24")
+	return iface.WGAddress{
+		IP:      ip,
+		Network: network,
+	}
+}
+
+func (w *mocWGIface) GetFilter() iface.PacketFilter {
+	return w.filter
+}
+
+func (w *mocWGIface) GetDevice() *iface.DeviceWrapper {
+	panic("implement me")
+}
+
+func (w *mocWGIface) GetInterfaceGUIDString() (string, error) {
+	panic("implement me")
+}
+
+func (w *mocWGIface) IsUserspaceBind() bool {
+	return false
+}
+
+func (w *mocWGIface) SetFilter(filter iface.PacketFilter) error {
+	w.filter = filter
+	return nil
+}
+
 var zoneRecords = []nbdns.SimpleRecord{
 	{
 		Name:  "peera.netbird.cloud",
@@ -29,6 +68,11 @@ var zoneRecords = []nbdns.SimpleRecord{
 	},
 }
 
+func init() {
+	log.SetLevel(log.TraceLevel)
+	formatter.SetTextFormatter(log.StandardLogger())
+}
+
 func TestUpdateDNSServer(t *testing.T) {
 	nameServers := []nbdns.NameServer{
 		{
@@ -224,7 +268,7 @@ func TestUpdateDNSServer(t *testing.T) {
 					t.Log(err)
 				}
 			}()
-			dnsServer, err := NewDefaultServer(context.Background(), wgIface, "", nil)
+			dnsServer, err := NewDefaultServer(context.Background(), wgIface, "")
 			if err != nil {
 				t.Fatal(err)
 			}
@@ -242,8 +286,6 @@ func TestUpdateDNSServer(t *testing.T) {
 			dnsServer.dnsMuxMap = testCase.initUpstreamMap
 			dnsServer.localResolver.registeredMap = testCase.initLocalMap
 			dnsServer.updateSerial = testCase.initSerial
-			// pretend we are running
-			dnsServer.listenerIsRunning = true
 
 			err = dnsServer.UpdateDNSServer(testCase.inputSerial, testCase.inputUpdate)
 			if err != nil {
@@ -282,7 +324,7 @@ func TestDNSFakeResolverHandleUpdates(t *testing.T) {
 	ov := os.Getenv("NB_WG_KERNEL_DISABLED")
 	defer os.Setenv("NB_WG_KERNEL_DISABLED", ov)
 
-	os.Setenv("NB_WG_KERNEL_DISABLED", "true")
+	_ = os.Setenv("NB_WG_KERNEL_DISABLED", "true")
 	newNet, err := stdnet.NewNet(nil)
 	if err != nil {
 		t.Errorf("create stdnet: %v", err)
@@ -316,17 +358,17 @@ func TestDNSFakeResolverHandleUpdates(t *testing.T) {
 	}
 
 	packetfilter := pfmock.NewMockPacketFilter(ctrl)
-	packetfilter.EXPECT().SetNetwork(ipNet)
 	packetfilter.EXPECT().DropOutgoing(gomock.Any()).AnyTimes()
-	packetfilter.EXPECT().AddUDPPacketHook(gomock.Any(), gomock.Any(), gomock.Any(), gomock.Any()).AnyTimes()
+	packetfilter.EXPECT().AddUDPPacketHook(gomock.Any(), gomock.Any(), gomock.Any(), gomock.Any())
-	packetfilter.EXPECT().RemovePacketHook(gomock.Any()).AnyTimes()
+	packetfilter.EXPECT().RemovePacketHook(gomock.Any())
+	packetfilter.EXPECT().SetNetwork(ipNet)
 
 	if err := wgIface.SetFilter(packetfilter); err != nil {
 		t.Errorf("set packet filter: %v", err)
 		return
 	}
 
-	dnsServer, err := NewDefaultServer(context.Background(), wgIface, "", nil)
+	dnsServer, err := NewDefaultServer(context.Background(), wgIface, "")
 	if err != nil {
 		t.Errorf("create DNS server: %v", err)
 		return
@@ -421,21 +463,23 @@ func TestDNSServerStartStop(t *testing.T) {
 
 	for _, testCase := range testCases {
 		t.Run(testCase.name, func(t *testing.T) {
-			dnsServer := getDefaultServerWithNoHostManager(t, testCase.addrPort)
+			dnsServer, err := NewDefaultServer(context.Background(), &mocWGIface{}, testCase.addrPort)
-
+			if err != nil {
-			dnsServer.hostManager = newNoopHostMocker()
+				t.Fatalf("%v", err)
-			dnsServer.listen()
-			time.Sleep(100 * time.Millisecond)
-			if !dnsServer.listenerIsRunning {
-				t.Fatal("dns server listener is not running")
 			}
+			dnsServer.hostManager = newNoopHostMocker()
+			err = dnsServer.service.Listen()
+			if err != nil {
+				t.Fatalf("dns server is not running: %s", err)
+			}
+			time.Sleep(100 * time.Millisecond)
 			defer dnsServer.Stop()
-			err := dnsServer.localResolver.registerRecord(zoneRecords[0])
+			err = dnsServer.localResolver.registerRecord(zoneRecords[0])
 			if err != nil {
 				t.Error(err)
 			}
 
-			dnsServer.dnsMux.Handle("netbird.cloud", dnsServer.localResolver)
+			dnsServer.service.RegisterMux("netbird.cloud", dnsServer.localResolver)
 
 			resolver := &net.Resolver{
 				PreferGo: true,
@@ -443,7 +487,7 @@ func TestDNSServerStartStop(t *testing.T) {
 					d := net.Dialer{
 						Timeout: time.Second * 5,
 					}
-					addr := fmt.Sprintf("%s:%d", dnsServer.runtimeIP, dnsServer.runtimePort)
+					addr := fmt.Sprintf("%s:%d", dnsServer.service.RuntimeIP(), dnsServer.service.RuntimePort())
 					conn, err := d.DialContext(ctx, network, addr)
 					if err != nil {
 						t.Log(err)
@@ -478,7 +522,7 @@ func TestDNSServerStartStop(t *testing.T) {
 func TestDNSServerUpstreamDeactivateCallback(t *testing.T) {
 	hostManager := &mockHostConfigurator{}
 	server := DefaultServer{
-		dnsMux: dns.DefaultServeMux,
+		service: newServiceViaMemory(&mocWGIface{}),
 		localResolver: &localResolver{
 			registeredMap: make(registrationMap),
 		},
@@ -541,62 +585,237 @@ func TestDNSServerUpstreamDeactivateCallback(t *testing.T) {
 	}
 }
 
-func getDefaultServerWithNoHostManager(t *testing.T, addrPort string) *DefaultServer {
+func TestDNSPermanent_updateHostDNS_emptyUpstream(t *testing.T) {
-	mux := dns.NewServeMux()
+	wgIFace, err := createWgInterfaceWithBind(t)
-
-	var parsedAddrPort *netip.AddrPort
-	if addrPort != "" {
-		parsed, err := netip.ParseAddrPort(addrPort)
 	if err != nil {
-			t.Fatal(err)
+		t.Fatal("failed to initialize wg interface")
-		}
-		parsedAddrPort = &parsed
 	}
+	defer wgIFace.Close()
 
-	dnsServer := &dns.Server{
+	var dnsList []string
-		Net:     "udp",
+	dnsServer := NewDefaultServerPermanentUpstream(context.Background(), wgIFace, dnsList)
-		Handler: mux,
+	err = dnsServer.Initialize()
-		UDPSize: 65535,
-	}
-
-	ctx, cancel := context.WithCancel(context.TODO())
-
-	ds := &DefaultServer{
-		ctx:       ctx,
-		ctxCancel: cancel,
-		server:    dnsServer,
-		dnsMux:    mux,
-		dnsMuxMap: make(registeredHandlerMap),
-		localResolver: &localResolver{
-			registeredMap: make(registrationMap),
-		},
-		customAddress: parsedAddrPort,
-	}
-	ds.evalRuntimeAddress()
-	return ds
-}
-
-func TestGetLastIPFromNetwork(t *testing.T) {
-	tests := []struct {
-		addr string
-		ip   string
-	}{
-		{"2001:db8::/32", "2001:db8:ffff:ffff:ffff:ffff:ffff:fffe"},
-		{"192.168.0.0/30", "192.168.0.2"},
-		{"192.168.0.0/16", "192.168.255.254"},
-		{"192.168.0.0/24", "192.168.0.254"},
-	}
-
-	for _, tt := range tests {
-		_, ipnet, err := net.ParseCIDR(tt.addr)
 	if err != nil {
-			t.Errorf("Error parsing CIDR: %v", err)
+		t.Errorf("failed to initialize DNS server: %v", err)
 		return
 	}
+	defer dnsServer.Stop()
 
-		lastIP := getLastIPFromNetwork(ipnet, 1)
+	dnsServer.OnUpdatedHostDNSServer([]string{"8.8.8.8"})
-		if lastIP != tt.ip {
+
-			t.Errorf("wrong IP address, expected %s: got %s", tt.ip, lastIP)
+	resolver := newDnsResolver(dnsServer.service.RuntimeIP(), dnsServer.service.RuntimePort())
-		}
+	_, err = resolver.LookupHost(context.Background(), "netbird.io")
+	if err != nil {
+		t.Errorf("failed to resolve: %s", err)
+	}
+}
+
+func TestDNSPermanent_updateUpstream(t *testing.T) {
+	wgIFace, err := createWgInterfaceWithBind(t)
+	if err != nil {
+		t.Fatal("failed to initialize wg interface")
+	}
+	defer wgIFace.Close()
+
+	dnsServer := NewDefaultServerPermanentUpstream(context.Background(), wgIFace, []string{"8.8.8.8"})
+	err = dnsServer.Initialize()
+	if err != nil {
+		t.Errorf("failed to initialize DNS server: %v", err)
+		return
+	}
+	defer dnsServer.Stop()
+
+	// check initial state
+	resolver := newDnsResolver(dnsServer.service.RuntimeIP(), dnsServer.service.RuntimePort())
+	_, err = resolver.LookupHost(context.Background(), "netbird.io")
+	if err != nil {
+		t.Errorf("failed to resolve: %s", err)
+	}
+
+	update := nbdns.Config{
+		ServiceEnable: true,
+		CustomZones: []nbdns.CustomZone{
+			{
+				Domain:  "netbird.cloud",
+				Records: zoneRecords,
+			},
+		},
+		NameServerGroups: []*nbdns.NameServerGroup{
+			{
+				NameServers: []nbdns.NameServer{
+					{
+						IP:     netip.MustParseAddr("8.8.4.4"),
+						NSType: nbdns.UDPNameServerType,
+						Port:   53,
+					},
+				},
+				Enabled: true,
+				Primary: true,
+			},
+		},
+	}
+
+	err = dnsServer.UpdateDNSServer(1, update)
+	if err != nil {
+		t.Errorf("failed to update dns server: %s", err)
+	}
+
+	_, err = resolver.LookupHost(context.Background(), "netbird.io")
+	if err != nil {
+		t.Errorf("failed to resolve: %s", err)
+	}
+	ips, err := resolver.LookupHost(context.Background(), zoneRecords[0].Name)
+	if err != nil {
+		t.Fatalf("failed resolve zone record: %v", err)
+	}
+	if ips[0] != zoneRecords[0].RData {
+		t.Fatalf("invalid zone record: %v", err)
+	}
+
+	update2 := nbdns.Config{
+		ServiceEnable: true,
+		CustomZones: []nbdns.CustomZone{
+			{
+				Domain:  "netbird.cloud",
+				Records: zoneRecords,
+			},
+		},
+		NameServerGroups: []*nbdns.NameServerGroup{},
+	}
+
+	err = dnsServer.UpdateDNSServer(2, update2)
+	if err != nil {
+		t.Errorf("failed to update dns server: %s", err)
+	}
+
+	_, err = resolver.LookupHost(context.Background(), "netbird.io")
+	if err != nil {
+		t.Errorf("failed to resolve: %s", err)
+	}
+
+	ips, err = resolver.LookupHost(context.Background(), zoneRecords[0].Name)
+	if err != nil {
+		t.Fatalf("failed resolve zone record: %v", err)
+	}
+	if ips[0] != zoneRecords[0].RData {
+		t.Fatalf("invalid zone record: %v", err)
+	}
+}
+
+func TestDNSPermanent_matchOnly(t *testing.T) {
+	wgIFace, err := createWgInterfaceWithBind(t)
+	if err != nil {
+		t.Fatal("failed to initialize wg interface")
+	}
+	defer wgIFace.Close()
+
+	dnsServer := NewDefaultServerPermanentUpstream(context.Background(), wgIFace, []string{"8.8.8.8"})
+	err = dnsServer.Initialize()
+	if err != nil {
+		t.Errorf("failed to initialize DNS server: %v", err)
+		return
+	}
+	defer dnsServer.Stop()
+
+	// check initial state
+	resolver := newDnsResolver(dnsServer.service.RuntimeIP(), dnsServer.service.RuntimePort())
+	_, err = resolver.LookupHost(context.Background(), "netbird.io")
+	if err != nil {
+		t.Errorf("failed to resolve: %s", err)
+	}
+
+	update := nbdns.Config{
+		ServiceEnable: true,
+		CustomZones: []nbdns.CustomZone{
+			{
+				Domain:  "netbird.cloud",
+				Records: zoneRecords,
+			},
+		},
+		NameServerGroups: []*nbdns.NameServerGroup{
+			{
+				NameServers: []nbdns.NameServer{
+					{
+						IP:     netip.MustParseAddr("8.8.4.4"),
+						NSType: nbdns.UDPNameServerType,
+						Port:   53,
+					},
+				},
+				Domains: []string{"customdomain.com"},
+				Primary: false,
+			},
+		},
+	}
+
+	err = dnsServer.UpdateDNSServer(1, update)
+	if err != nil {
+		t.Errorf("failed to update dns server: %s", err)
+	}
+
+	_, err = resolver.LookupHost(context.Background(), "netbird.io")
+	if err != nil {
+		t.Errorf("failed to resolve: %s", err)
+	}
+	ips, err := resolver.LookupHost(context.Background(), zoneRecords[0].Name)
+	if err != nil {
+		t.Fatalf("failed resolve zone record: %v", err)
+	}
+	if ips[0] != zoneRecords[0].RData {
+		t.Fatalf("invalid zone record: %v", err)
+	}
+	_, err = resolver.LookupHost(context.Background(), "customdomain.com")
+	if err != nil {
+		t.Errorf("failed to resolve: %s", err)
+	}
+}
+
+func createWgInterfaceWithBind(t *testing.T) (*iface.WGIface, error) {
+	ov := os.Getenv("NB_WG_KERNEL_DISABLED")
+	defer os.Setenv("NB_WG_KERNEL_DISABLED", ov)
+
+	_ = os.Setenv("NB_WG_KERNEL_DISABLED", "true")
+	newNet, err := stdnet.NewNet(nil)
+	if err != nil {
+		t.Fatalf("create stdnet: %v", err)
+		return nil, nil
+	}
+
+	wgIface, err := iface.NewWGIFace("utun2301", "100.66.100.2/24", iface.DefaultMTU, nil, newNet)
+	if err != nil {
+		t.Fatalf("build interface wireguard: %v", err)
+		return nil, err
+	}
+
+	err = wgIface.Create()
+	if err != nil {
+		t.Fatalf("crate and init wireguard interface: %v", err)
+		return nil, err
+	}
+
+	pf, err := uspfilter.Create(wgIface)
+	if err != nil {
+		t.Fatalf("failed to create uspfilter: %v", err)
+		return nil, err
+	}
+
+	err = wgIface.SetFilter(pf)
+	if err != nil {
+		t.Fatalf("set packet filter: %v", err)
+		return nil, err
+	}
+
+	return wgIface, nil
+}
+
+func newDnsResolver(ip string, port int) *net.Resolver {
+	return &net.Resolver{
+		PreferGo: true,
+		Dial: func(ctx context.Context, network, address string) (net.Conn, error) {
+			d := net.Dialer{
+				Timeout: time.Second * 3,
+			}
+			addr := fmt.Sprintf("%s:%d", ip, port)
+			return d.DialContext(ctx, network, addr)
+		},
 	}
 }

client/internal/dns/service.go

@@ -0,0 +1,18 @@
+package dns
+
+import (
+	"github.com/miekg/dns"
+)
+
+const (
+	defaultPort = 53
+)
+
+type service interface {
+	Listen() error
+	Stop()
+	RegisterMux(domain string, handler dns.Handler)
+	DeregisterMux(key string)
+	RuntimePort() int
+	RuntimeIP() string
+}

client/internal/dns/service_listener.go

@@ -0,0 +1,145 @@
+package dns
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"net/netip"
+	"runtime"
+	"sync"
+	"time"
+
+	"github.com/miekg/dns"
+	log "github.com/sirupsen/logrus"
+)
+
+const (
+	customPort = 5053
+	defaultIP  = "127.0.0.1"
+	customIP   = "127.0.0.153"
+)
+
+type serviceViaListener struct {
+	wgInterface       WGIface
+	dnsMux            *dns.ServeMux
+	customAddr        *netip.AddrPort
+	server            *dns.Server
+	runtimeIP         string
+	runtimePort       int
+	listenerIsRunning bool
+	listenerFlagLock  sync.Mutex
+}
+
+func newServiceViaListener(wgIface WGIface, customAddr *netip.AddrPort) *serviceViaListener {
+	mux := dns.NewServeMux()
+
+	s := &serviceViaListener{
+		wgInterface: wgIface,
+		dnsMux:      mux,
+		customAddr:  customAddr,
+		server: &dns.Server{
+			Net:     "udp",
+			Handler: mux,
+			UDPSize: 65535,
+		},
+	}
+	return s
+}
+
+func (s *serviceViaListener) Listen() error {
+	s.listenerFlagLock.Lock()
+	defer s.listenerFlagLock.Unlock()
+
+	if s.listenerIsRunning {
+		return nil
+	}
+
+	var err error
+	s.runtimeIP, s.runtimePort, err = s.evalRuntimeAddress()
+	if err != nil {
+		log.Errorf("failed to eval runtime address: %s", err)
+		return err
+	}
+	s.server.Addr = fmt.Sprintf("%s:%d", s.runtimeIP, s.runtimePort)
+
+	log.Debugf("starting dns on %s", s.server.Addr)
+	go func() {
+		s.setListenerStatus(true)
+		defer s.setListenerStatus(false)
+
+		err := s.server.ListenAndServe()
+		if err != nil {
+			log.Errorf("dns server running with %d port returned an error: %v. Will not retry", s.runtimePort, err)
+		}
+	}()
+	return nil
+}
+
+func (s *serviceViaListener) Stop() {
+	s.listenerFlagLock.Lock()
+	defer s.listenerFlagLock.Unlock()
+
+	if !s.listenerIsRunning {
+		return
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	err := s.server.ShutdownContext(ctx)
+	if err != nil {
+		log.Errorf("stopping dns server listener returned an error: %v", err)
+	}
+}
+
+func (s *serviceViaListener) RegisterMux(pattern string, handler dns.Handler) {
+	s.dnsMux.Handle(pattern, handler)
+}
+
+func (s *serviceViaListener) DeregisterMux(pattern string) {
+	s.dnsMux.HandleRemove(pattern)
+}
+
+func (s *serviceViaListener) RuntimePort() int {
+	return s.runtimePort
+}
+
+func (s *serviceViaListener) RuntimeIP() string {
+	return s.runtimeIP
+}
+
+func (s *serviceViaListener) setListenerStatus(running bool) {
+	s.listenerIsRunning = running
+}
+
+func (s *serviceViaListener) getFirstListenerAvailable() (string, int, error) {
+	ips := []string{defaultIP, customIP}
+	if runtime.GOOS != "darwin" {
+		ips = append([]string{s.wgInterface.Address().IP.String()}, ips...)
+	}
+	ports := []int{defaultPort, customPort}
+	for _, port := range ports {
+		for _, ip := range ips {
+			addrString := fmt.Sprintf("%s:%d", ip, port)
+			udpAddr := net.UDPAddrFromAddrPort(netip.MustParseAddrPort(addrString))
+			probeListener, err := net.ListenUDP("udp", udpAddr)
+			if err == nil {
+				err = probeListener.Close()
+				if err != nil {
+					log.Errorf("got an error closing the probe listener, error: %s", err)
+				}
+				return ip, port, nil
+			}
+			log.Warnf("binding dns on %s is not available, error: %s", addrString, err)
+		}
+	}
+	return "", 0, fmt.Errorf("unable to find an unused ip and port combination. IPs tested: %v and ports %v", ips, ports)
+}
+
+func (s *serviceViaListener) evalRuntimeAddress() (string, int, error) {
+	if s.customAddr != nil {
+		return s.customAddr.Addr().String(), int(s.customAddr.Port()), nil
+	}
+
+	return s.getFirstListenerAvailable()
+}

client/internal/dns/service_memory.go

@@ -0,0 +1,139 @@
+package dns
+
+import (
+	"fmt"
+	"math/big"
+	"net"
+	"sync"
+
+	"github.com/google/gopacket"
+	"github.com/google/gopacket/layers"
+	"github.com/miekg/dns"
+	log "github.com/sirupsen/logrus"
+)
+
+type serviceViaMemory struct {
+	wgInterface       WGIface
+	dnsMux            *dns.ServeMux
+	runtimeIP         string
+	runtimePort       int
+	udpFilterHookID   string
+	listenerIsRunning bool
+	listenerFlagLock  sync.Mutex
+}
+
+func newServiceViaMemory(wgIface WGIface) *serviceViaMemory {
+	s := &serviceViaMemory{
+		wgInterface: wgIface,
+		dnsMux:      dns.NewServeMux(),
+
+		runtimeIP:   getLastIPFromNetwork(wgIface.Address().Network, 1),
+		runtimePort: defaultPort,
+	}
+	return s
+}
+
+func (s *serviceViaMemory) Listen() error {
+	s.listenerFlagLock.Lock()
+	defer s.listenerFlagLock.Unlock()
+
+	if s.listenerIsRunning {
+		return nil
+	}
+
+	var err error
+	s.udpFilterHookID, err = s.filterDNSTraffic()
+	if err != nil {
+		return err
+	}
+	s.listenerIsRunning = true
+
+	log.Debugf("dns service listening on: %s", s.RuntimeIP())
+	return nil
+}
+
+func (s *serviceViaMemory) Stop() {
+	s.listenerFlagLock.Lock()
+	defer s.listenerFlagLock.Unlock()
+
+	if !s.listenerIsRunning {
+		return
+	}
+
+	if err := s.wgInterface.GetFilter().RemovePacketHook(s.udpFilterHookID); err != nil {
+		log.Errorf("unable to remove DNS packet hook: %s", err)
+	}
+
+	s.listenerIsRunning = false
+}
+
+func (s *serviceViaMemory) RegisterMux(pattern string, handler dns.Handler) {
+	s.dnsMux.Handle(pattern, handler)
+}
+
+func (s *serviceViaMemory) DeregisterMux(pattern string) {
+	s.dnsMux.HandleRemove(pattern)
+}
+
+func (s *serviceViaMemory) RuntimePort() int {
+	return s.runtimePort
+}
+
+func (s *serviceViaMemory) RuntimeIP() string {
+	return s.runtimeIP
+}
+
+func (s *serviceViaMemory) filterDNSTraffic() (string, error) {
+	filter := s.wgInterface.GetFilter()
+	if filter == nil {
+		return "", fmt.Errorf("can't set DNS filter, filter not initialized")
+	}
+
+	firstLayerDecoder := layers.LayerTypeIPv4
+	if s.wgInterface.Address().Network.IP.To4() == nil {
+		firstLayerDecoder = layers.LayerTypeIPv6
+	}
+
+	hook := func(packetData []byte) bool {
+		// Decode the packet
+		packet := gopacket.NewPacket(packetData, firstLayerDecoder, gopacket.Default)
+
+		// Get the UDP layer
+		udpLayer := packet.Layer(layers.LayerTypeUDP)
+		udp := udpLayer.(*layers.UDP)
+
+		msg := new(dns.Msg)
+		if err := msg.Unpack(udp.Payload); err != nil {
+			log.Tracef("parse DNS request: %v", err)
+			return true
+		}
+
+		writer := responseWriter{
+			packet: packet,
+			device: s.wgInterface.GetDevice().Device,
+		}
+		go s.dnsMux.ServeDNS(&writer, msg)
+		return true
+	}
+
+	return filter.AddUDPPacketHook(false, net.ParseIP(s.runtimeIP), uint16(s.runtimePort), hook), nil
+}
+
+func getLastIPFromNetwork(network *net.IPNet, fromEnd int) string {
+	// Calculate the last IP in the CIDR range
+	var endIP net.IP
+	for i := 0; i < len(network.IP); i++ {
+		endIP = append(endIP, network.IP[i]|^network.Mask[i])
+	}
+
+	// convert to big.Int
+	endInt := big.NewInt(0)
+	endInt.SetBytes(endIP)
+
+	// subtract fromEnd from the last ip
+	fromEndBig := big.NewInt(int64(fromEnd))
+	resultInt := big.NewInt(0)
+	resultInt.Sub(endInt, fromEndBig)
+
+	return net.IP(resultInt.Bytes()).String()
+}

client/internal/dns/service_memory_test.go

@@ -0,0 +1,31 @@
+package dns
+
+import (
+	"net"
+	"testing"
+)
+
+func TestGetLastIPFromNetwork(t *testing.T) {
+	tests := []struct {
+		addr string
+		ip   string
+	}{
+		{"2001:db8::/32", "2001:db8:ffff:ffff:ffff:ffff:ffff:fffe"},
+		{"192.168.0.0/30", "192.168.0.2"},
+		{"192.168.0.0/16", "192.168.255.254"},
+		{"192.168.0.0/24", "192.168.0.254"},
+	}
+
+	for _, tt := range tests {
+		_, ipnet, err := net.ParseCIDR(tt.addr)
+		if err != nil {
+			t.Errorf("Error parsing CIDR: %v", err)
+			return
+		}
+
+		lastIP := getLastIPFromNetwork(ipnet, 1)
+		if lastIP != tt.ip {
+			t.Errorf("wrong IP address, expected %s: got %s", tt.ip, lastIP)
+		}
+	}
+}

client/internal/dns/systemd_linux.go

@@ -15,7 +15,6 @@ import (
 	"golang.org/x/sys/unix"
 
 	nbdns "github.com/netbirdio/netbird/dns"
-	"github.com/netbirdio/netbird/iface"
 )
 
 const (
@@ -53,7 +52,7 @@ type systemdDbusLinkDomainsInput struct {
 	MatchOnly bool
 }
 
-func newSystemdDbusConfigurator(wgInterface *iface.WGIface) (hostManager, error) {
+func newSystemdDbusConfigurator(wgInterface WGIface) (hostManager, error) {
 	iface, err := net.InterfaceByName(wgInterface.Name())
 	if err != nil {
 		return nil, err

client/internal/dns/wgiface.go

@@ -0,0 +1,14 @@
+//go:build !windows
+
+package dns
+
+import "github.com/netbirdio/netbird/iface"
+
+// WGIface defines subset methods of interface required for manager
+type WGIface interface {
+	Name() string
+	Address() iface.WGAddress
+	IsUserspaceBind() bool
+	GetFilter() iface.PacketFilter
+	GetDevice() *iface.DeviceWrapper
+}

client/internal/dns/wgiface_windows.go

@@ -0,0 +1,13 @@
+package dns
+
+import "github.com/netbirdio/netbird/iface"
+
+// WGIface defines subset methods of interface required for manager
+type WGIface interface {
+	Name() string
+	Address() iface.WGAddress
+	IsUserspaceBind() bool
+	GetFilter() iface.PacketFilter
+	GetDevice() *iface.DeviceWrapper
+	GetInterfaceGUIDString() (string, error)
+}

client/internal/engine.go

@@ -190,23 +190,25 @@ func (e *Engine) Start() error {
 	}
 
 	var routes []*route.Route
-	var dnsCfg *nbdns.Config
 
 	if runtime.GOOS == "android" {
-		routes, dnsCfg, err = e.readInitialSettings()
+		routes, err = e.readInitialSettings()
 		if err != nil {
 			return err
 		}
-	}
-
 		if e.dnsServer == nil {
+			e.dnsServer = dns.NewDefaultServerPermanentUpstream(e.ctx, e.wgInterface, e.mobileDep.HostDNSAddresses)
+			go e.mobileDep.DnsReadyListener.OnReady()
+		}
+	} else {
 		// todo fix custom address
-		dnsServer, err := dns.NewDefaultServer(e.ctx, e.wgInterface, e.config.CustomDNSAddress, dnsCfg)
+		if e.dnsServer == nil {
+			e.dnsServer, err = dns.NewDefaultServer(e.ctx, e.wgInterface, e.config.CustomDNSAddress)
 			if err != nil {
 				e.close()
 				return err
 			}
-		e.dnsServer = dnsServer
+		}
 	}
 
 	e.routeManager = routemanager.NewManager(e.ctx, e.config.WgPrivateKey.PublicKey().String(), e.wgInterface, e.statusRecorder, routes)
@@ -1045,14 +1047,13 @@ func (e *Engine) close() {
 	}
 }
 
-func (e *Engine) readInitialSettings() ([]*route.Route, *nbdns.Config, error) {
+func (e *Engine) readInitialSettings() ([]*route.Route, error) {
 	netMap, err := e.mgmClient.GetNetworkMap()
 	if err != nil {
-		return nil, nil, err
+		return nil, err
 	}
 	routes := toRoutes(netMap.GetRoutes())
-	dnsCfg := toDNSConfig(netMap.GetDNSConfig())
+	return routes, nil
-	return routes, &dnsCfg, nil
 }
 
 func findIPFromInterfaceName(ifaceName string) (net.IP, error) {

client/internal/mobile_dependency.go

@@ -1,6 +1,7 @@
 package internal
 
 import (
+	"github.com/netbirdio/netbird/client/internal/dns"
 	"github.com/netbirdio/netbird/client/internal/routemanager"
 	"github.com/netbirdio/netbird/client/internal/stdnet"
 	"github.com/netbirdio/netbird/iface"
@@ -11,4 +12,6 @@ type MobileDependency struct {
 	TunAdapter       iface.TunAdapter
 	IFaceDiscover    stdnet.ExternalIFaceDiscover
 	RouteListener    routemanager.RouteListener
+	HostDNSAddresses []string
+	DnsReadyListener dns.ReadyListener
 }

client/server/server.go

@@ -102,7 +102,7 @@ func (s *Server) Start() error {
 	}
 
 	go func() {
-		if err := internal.RunClient(ctx, config, s.statusRecorder, nil, nil, nil); err != nil {
+		if err := internal.RunClient(ctx, config, s.statusRecorder); err != nil {
 			log.Errorf("init connections: %v", err)
 		}
 	}()
@@ -391,7 +391,7 @@ func (s *Server) Up(callerCtx context.Context, _ *proto.UpRequest) (*proto.UpRes
 	}
 
 	go func() {
-		if err := internal.RunClient(ctx, s.config, s.statusRecorder, nil, nil, nil); err != nil {
+		if err := internal.RunClient(ctx, s.config, s.statusRecorder); err != nil {
 			log.Errorf("run client connection: %v", err)
 			return
 		}

iface/iface_android.go

@@ -5,7 +5,6 @@ import (
 	"sync"
 
 	"github.com/pion/transport/v2"
-	log "github.com/sirupsen/logrus"
 )
 
 // NewWGIFace Creates a new WireGuard interface instance
@@ -34,7 +33,6 @@ func NewWGIFace(ifaceName string, address string, mtu int, tunAdapter TunAdapter
 func (w *WGIface) CreateOnMobile(mIFaceArgs MobileIFaceArguments) error {
 	w.mu.Lock()
 	defer w.mu.Unlock()
-	log.Debugf("create WireGuard interface %s", w.tun.DeviceName())
 	return w.tun.Create(mIFaceArgs)
 }
 

iface/iface_nonandroid.go

@@ -7,7 +7,6 @@ import (
 	"sync"
 
 	"github.com/pion/transport/v2"
-	log "github.com/sirupsen/logrus"
 )
 
 // NewWGIFace Creates a new WireGuard interface instance
@@ -38,6 +37,5 @@ func (w *WGIface) CreateOnMobile(mIFaceArgs MobileIFaceArguments) error {
 func (w *WGIface) Create() error {
 	w.mu.Lock()
 	defer w.mu.Unlock()
-	log.Debugf("create WireGuard interface %s", w.tun.DeviceName())
 	return w.tun.Create()
 }

iface/tun_android.go

@@ -34,6 +34,7 @@ func newTunDevice(address WGAddress, mtu int, tunAdapter TunAdapter, transportNe
 }
 
 func (t *tunDevice) Create(mIFaceArgs MobileIFaceArguments) error {
+	log.Info("create tun interface")
 	var err error
 	routesString := t.routesToString(mIFaceArgs.Routes)
 	t.fd, err = t.tunAdapter.ConfigureInterface(t.address.String(), t.mtu, mIFaceArgs.Dns, routesString)

iface/tun_linux.go

@@ -12,14 +12,14 @@ import (
 
 func (c *tunDevice) Create() error {
 	if WireGuardModuleIsLoaded() {
-		log.Info("using kernel WireGuard")
+		log.Infof("create tun interface with kernel WireGuard support: %s", c.DeviceName())
 		return c.createWithKernel()
 	}
 
 	if !tunModuleIsLoaded() {
 		return fmt.Errorf("couldn't check or load tun module")
 	}
-	log.Info("using userspace WireGuard")
+	log.Infof("create tun interface with userspace WireGuard support: %s", c.DeviceName())
 	var err error
 	c.netInterface, err = c.createWithUserspace()
 	if err != nil {