[client] Fix backoff.Ticker goroutine leak in reconnect guard

* routemanager: enforce a single selected exit node

Backport of the exit-node exclusivity reconcile from the 0.75.0 line
(upstream commit 966fbec11) onto v0.74.0. Exit nodes are mutually
exclusive, but the RouteSelector stores routes with default-on semantics,
so every available exit node reported as selected at once.

Reconcile exit-node selection on each network map: keep at most one
selected -- the user's persisted pick, else whatever management marks for
auto-apply (SkipAutoApply=false), else none. Never auto-activate an exit
node the map does not request.

Carries over only the manager/routeselector logic and its test; the
desktop-only client/server changes and the BumpNetworksRevision UI-push
feature from the original commit are intentionally excluded.

* routeselector: make exit-node reconciliation atomic

enforceSingleExitNode took the RouteSelector lock three separate times
(IsDeselectAll, then DeselectRoutes, then SelectRoutes), so a concurrent
DeselectAllRoutes could interleave and be silently undone: SelectRoutes on
its deselectAll branch clears the flag and re-selects the preferred exit
node, overriding the user's "all off".

Move the whole reconciliation into a single locked RouteSelector method
(SetExclusiveExitNode) that checks deselectAll inside the critical section,
so a deselect-all either fully precedes the reconcile (left untouched) or
fully follows it (honoured). No interleaving is possible.

.github/workflows/release.yml

@@ -293,8 +293,11 @@ jobs:
           ${{ steps.goreleaser.outputs.artifacts }}
           JSON
 
+          # dockers_v2 artifacts have no top-level goarch field, so match the
+          # per-platform -amd64 tag suffix instead; it works for both the old
+          # dockers and the new dockers_v2 image naming.
           mapfile -t src_images < <(
-            jq -r '.[] | select(.type == "Docker Image") | select(.goarch == "amd64") | .name | select(startswith("ghcr.io/"))' /tmp/goreleaser-artifacts.json
+            jq -r '.[] | select(.type == "Docker Image") | .name | select(startswith("ghcr.io/") and endswith("-amd64"))' /tmp/goreleaser-artifacts.json
           )
 
           for src in "${src_images[@]}"; do

.gitignore

@@ -1,3 +1,4 @@
+.claude
 .idea
 .run
 *.iml

client/iface/configurer/kernel_unix.go

@@ -17,12 +17,15 @@ import (
 
 type KernelConfigurer struct {
 	deviceName string
+	statsCache *statsCache
 }
 
 func NewKernelConfigurer(deviceName string) *KernelConfigurer {
-	return &KernelConfigurer{
+	c := &KernelConfigurer{
 		deviceName: deviceName,
 	}
+	c.statsCache = newStatsCache(statsCacheTTL, c.fetchStats)
+	return c
 }
 
 func (c *KernelConfigurer) ConfigureInterface(privateKey string, port int) error {
@@ -246,12 +249,6 @@ func (c *KernelConfigurer) configure(config wgtypes.Config) error {
 		}
 	}()
 
-	// validate if device with name exists
-	_, err = wg.Device(c.deviceName)
-	if err != nil {
-		return err
-	}
-
 	return wg.ConfigureDevice(c.deviceName, config)
 }
 
@@ -300,6 +297,14 @@ func (c *KernelConfigurer) FullStats() (*Stats, error) {
 }
 
 func (c *KernelConfigurer) GetStats() (map[string]WGStats, error) {
+	return c.statsCache.get()
+}
+
+func (c *KernelConfigurer) LastActivities() map[string]monotime.Time {
+	return nil
+}
+
+func (c *KernelConfigurer) fetchStats() (map[string]WGStats, error) {
 	stats := make(map[string]WGStats)
 	wg, err := wgctrl.New()
 	if err != nil {
@@ -326,7 +331,3 @@ func (c *KernelConfigurer) GetStats() (map[string]WGStats, error) {
 	}
 	return stats, nil
 }
-
-func (c *KernelConfigurer) LastActivities() map[string]monotime.Time {
-	return nil
-}

client/iface/configurer/stats_cache.go

@@ -0,0 +1,52 @@
+package configurer
+
+import (
+	"sync"
+	"time"
+
+	"golang.org/x/sync/singleflight"
+)
+
+const statsCacheTTL = 1 * time.Second
+
+type statsCache struct {
+	ttl   time.Duration
+	fetch func() (map[string]WGStats, error)
+
+	mu       sync.RWMutex
+	value    map[string]WGStats
+	expireAt time.Time
+
+	sf singleflight.Group
+}
+
+func newStatsCache(ttl time.Duration, fetch func() (map[string]WGStats, error)) *statsCache {
+	return &statsCache{ttl: ttl, fetch: fetch}
+}
+
+func (c *statsCache) get() (map[string]WGStats, error) {
+	c.mu.RLock()
+	if c.value != nil && time.Now().Before(c.expireAt) {
+		value := c.value
+		c.mu.RUnlock()
+		return value, nil
+	}
+	c.mu.RUnlock()
+
+	value, err, _ := c.sf.Do("stats", func() (interface{}, error) {
+		res, err := c.fetch()
+		if err != nil {
+			return nil, err
+		}
+
+		c.mu.Lock()
+		c.value = res
+		c.expireAt = time.Now().Add(c.ttl)
+		c.mu.Unlock()
+		return res, nil
+	})
+	if err != nil {
+		return nil, err
+	}
+	return value.(map[string]WGStats), nil
+}

client/iface/configurer/stats_cache_test.go

@@ -0,0 +1,70 @@
+package configurer
+
+import (
+	"errors"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestStatsCache_CachesWithinTTL(t *testing.T) {
+	var calls atomic.Int64
+	c := newStatsCache(50*time.Millisecond, func() (map[string]WGStats, error) {
+		calls.Add(1)
+		return map[string]WGStats{"p": {}}, nil
+	})
+
+	for i := 0; i < 10; i++ {
+		_, err := c.get()
+		require.NoError(t, err)
+	}
+	require.Equal(t, int64(1), calls.Load(), "within TTL only one underlying fetch")
+
+	time.Sleep(60 * time.Millisecond)
+	_, err := c.get()
+	require.NoError(t, err)
+	require.Equal(t, int64(2), calls.Load(), "after TTL expiry a fresh fetch happens")
+}
+
+func TestStatsCache_SingleFlight(t *testing.T) {
+	var calls atomic.Int64
+	release := make(chan struct{})
+	c := newStatsCache(time.Minute, func() (map[string]WGStats, error) {
+		calls.Add(1)
+		<-release
+		return map[string]WGStats{}, nil
+	})
+
+	const n = 50
+	var wg sync.WaitGroup
+	wg.Add(n)
+	for i := 0; i < n; i++ {
+		go func() {
+			defer wg.Done()
+			_, _ = c.get()
+		}()
+	}
+	time.Sleep(20 * time.Millisecond)
+	close(release)
+	wg.Wait()
+
+	require.Equal(t, int64(1), calls.Load(), "concurrent misses collapse into one fetch")
+}
+
+func TestStatsCache_ErrorNotCached(t *testing.T) {
+	var calls atomic.Int64
+	wantErr := errors.New("dump failed")
+	c := newStatsCache(time.Minute, func() (map[string]WGStats, error) {
+		calls.Add(1)
+		return nil, wantErr
+	})
+
+	_, err := c.get()
+	require.ErrorIs(t, err, wantErr)
+	_, err = c.get()
+	require.ErrorIs(t, err, wantErr)
+	require.Equal(t, int64(2), calls.Load(), "errors are not cached; each call retries")
+}

client/iface/configurer/usp.go

@@ -40,6 +40,7 @@ type WGUSPConfigurer struct {
 	device           *device.Device
 	deviceName       string
 	activityRecorder *bind.ActivityRecorder
+	statsCache       *statsCache
 
 	uapiListener net.Listener
 }
@@ -50,16 +51,19 @@ func NewUSPConfigurer(device *device.Device, deviceName string, activityRecorder
 		deviceName:       deviceName,
 		activityRecorder: activityRecorder,
 	}
+	wgCfg.statsCache = newStatsCache(statsCacheTTL, wgCfg.fetchStats)
 	wgCfg.startUAPI()
 	return wgCfg
 }
 
 func NewUSPConfigurerNoUAPI(device *device.Device, deviceName string, activityRecorder *bind.ActivityRecorder) *WGUSPConfigurer {
-	return &WGUSPConfigurer{
+	wgCfg := &WGUSPConfigurer{
 		device:           device,
 		deviceName:       deviceName,
 		activityRecorder: activityRecorder,
 	}
+	wgCfg.statsCache = newStatsCache(statsCacheTTL, wgCfg.fetchStats)
+	return wgCfg
 }
 
 func (c *WGUSPConfigurer) ConfigureInterface(privateKey string, port int) error {
@@ -348,6 +352,10 @@ func (t *WGUSPConfigurer) Close() {
 }
 
 func (t *WGUSPConfigurer) GetStats() (map[string]WGStats, error) {
+	return t.statsCache.get()
+}
+
+func (t *WGUSPConfigurer) fetchStats() (map[string]WGStats, error) {
 	ipc, err := t.device.IpcGet()
 	if err != nil {
 		return nil, fmt.Errorf("ipc get: %w", err)

client/internal/peer/guard/guard.go

@@ -85,7 +85,11 @@ func (g *Guard) reconnectLoopWithRetry(ctx context.Context, callback func()) {
 	defer g.srWatcher.RemoveListener(srReconnectedChan)
 
 	ticker := g.initialTicker(ctx)
-	defer ticker.Stop()
+	defer func() {
+		// If backoff.Ticker.send is blocked, context.Done will not close the Ticker goroutine.
+		// We have to explicitly call Stop, even if we use backoff.WithContext.
+		ticker.Stop()
+	}()
 
 	tickerChannel := ticker.C
 

client/internal/peer/guard/guard_leak_test.go

@@ -0,0 +1,92 @@
+package guard
+
+import (
+	"context"
+	"runtime"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+
+	"github.com/netbirdio/netbird/client/internal/peer/ice"
+)
+
+func newTestGuard(status connStatusFunc) *Guard {
+	srw := NewSRWatcher(nil, nil, nil, ice.Config{})
+	return NewGuard(log.WithField("test", "guard"), status, 50*time.Millisecond, srw)
+}
+
+// countBackoffTickerGoroutines returns how many goroutines are currently sitting
+// in backoff/v4.(*Ticker).run (a ticker goroutine that has not exited).
+func countBackoffTickerGoroutines() int {
+	buf := make([]byte, 1<<25) // 32MB
+	n := runtime.Stack(buf, true)
+	return strings.Count(string(buf[:n]), "backoff/v4.(*Ticker).run")
+}
+
+// TestGuard_ReconnectTicker_NoGoroutineLeakOnShutdown reproduces a observed
+// leak: after a shutdown burst, ticker run/send goroutines stay parked
+// forever even though every reconnect loop has exited.
+func TestGuard_ReconnectTicker_NoGoroutineLeakOnShutdown(t *testing.T) {
+	before := countBackoffTickerGoroutines()
+
+	const peers = 6000
+	cancels := make([]context.CancelFunc, 0, peers)
+	var wg sync.WaitGroup
+
+	// A status check slower than the tick cadence. This models the real
+	// isConnectedOnAllWay/callback doing work: while the loop is busy in the
+	// handler, the ticker fires the next tick and parks in send(), because
+	// send() never selects on ctx.
+	slowStatus := func() ConnStatus {
+		time.Sleep(70 * time.Millisecond)
+		return ConnStatusConnected
+	}
+
+	for range peers {
+		g := newTestGuard(slowStatus)
+		ctx, cancel := context.WithCancel(context.Background())
+		cancels = append(cancels, cancel)
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			g.Start(ctx, func() {})
+		}()
+		// Force the live ticker to be a newReconnectTicker.
+		g.SetRelayedConnDisconnected()
+	}
+
+	// Let the replacement tickers get past their 800ms initial interval, so
+	// many are parked in send() waiting on the (slow) consumer when we tear
+	// everything down.
+	time.Sleep(1500 * time.Millisecond)
+
+	// Shutdown burst: cancel every peer at once, like engine teardown.
+	for _, c := range cancels {
+		c()
+	}
+
+	// Every reconnect loop must return
+	waitCh := make(chan struct{})
+	go func() { wg.Wait(); close(waitCh) }()
+	select {
+	case <-waitCh:
+	case <-time.After(30 * time.Second):
+		t.Fatal("not all reconnect loops returned after ctx cancel")
+	}
+
+	// Give any correctly-stopped ticker goroutines time to unwind.
+	for range 50 {
+		runtime.Gosched()
+		time.Sleep(10 * time.Millisecond)
+	}
+
+	leaked := countBackoffTickerGoroutines() - before
+	t.Logf("backoff Ticker.run goroutines still parked after teardown of %d peers: %d", peers, leaked)
+	if leaked > 0 {
+		t.Errorf("LEAK: %d backoff ticker goroutines parked after all reconnect loops exited "+
+			"(defer ticker.Stop() stops the initial ticker, not the live replacement)", leaked)
+	}
+}

client/internal/routemanager/exit_node_selection_test.go

@@ -0,0 +1,191 @@
+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 newExitNodeTestManager() *DefaultManager {
+	return &DefaultManager{routeSelector: routeselector.NewRouteSelector()}
+}
+
+func exitRoute(netID, peer string, skipAutoApply bool) *route.Route {
+	return &route.Route{
+		NetID:         route.NetID(netID),
+		Network:       netip.MustParsePrefix("0.0.0.0/0"),
+		Peer:          peer,
+		SkipAutoApply: skipAutoApply,
+	}
+}
+
+func TestPickPreferredExitNode(t *testing.T) {
+	tests := []struct {
+		name string
+		info exitNodeInfo
+		want route.NetID
+	}{
+		{
+			name: "persisted user selection wins over management",
+			info: exitNodeInfo{
+				allIDs:               []route.NetID{"a", "b", "c"},
+				userSelected:         []route.NetID{"b"},
+				selectedByManagement: []route.NetID{"a"},
+			},
+			want: "b",
+		},
+		{
+			name: "multiple user-selected self-heal to deterministic min",
+			info: exitNodeInfo{
+				allIDs:       []route.NetID{"a", "b", "c"},
+				userSelected: []route.NetID{"c", "a"},
+			},
+			want: "a",
+		},
+		{
+			name: "explicit opt-out keeps none",
+			info: exitNodeInfo{
+				allIDs:         []route.NetID{"a", "b"},
+				userDeselected: []route.NetID{"a", "b"},
+			},
+			want: "",
+		},
+		{
+			name: "fresh defaults to management auto-apply pick",
+			info: exitNodeInfo{
+				allIDs:               []route.NetID{"a", "b", "c"},
+				selectedByManagement: []route.NetID{"b"},
+			},
+			want: "b",
+		},
+		{
+			name: "no user pick and no management auto-apply selects none",
+			info: exitNodeInfo{
+				allIDs: []route.NetID{"c", "a", "b"},
+			},
+			want: "",
+		},
+		{
+			name: "user-deselect does not block a management auto-apply sibling",
+			info: exitNodeInfo{
+				allIDs:               []route.NetID{"a", "b"},
+				userDeselected:       []route.NetID{"a"},
+				selectedByManagement: []route.NetID{"b"},
+			},
+			want: "b",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.want, pickPreferredExitNode(tt.info), "preferred exit node")
+		})
+	}
+}
+
+func TestEnforceSingleExitNode(t *testing.T) {
+	m := newExitNodeTestManager()
+	all := []route.NetID{"a", "b", "c"}
+
+	m.enforceSingleExitNode("b", all)
+	assert.False(t, m.routeSelector.IsSelected("a"), "a should be deselected")
+	assert.True(t, m.routeSelector.IsSelected("b"), "b should be the only selected exit node")
+	assert.False(t, m.routeSelector.IsSelected("c"), "c should be deselected")
+
+	// Switching the preferred node moves the single selection.
+	m.enforceSingleExitNode("c", all)
+	assert.False(t, m.routeSelector.IsSelected("a"), "a stays deselected")
+	assert.False(t, m.routeSelector.IsSelected("b"), "b should now be deselected")
+	assert.True(t, m.routeSelector.IsSelected("c"), "c should now be selected")
+
+	// Empty preferred turns every exit node off.
+	m.enforceSingleExitNode("", all)
+	for _, id := range all {
+		assert.False(t, m.routeSelector.IsSelected(id), "no exit node should be selected")
+	}
+}
+
+func TestEnforceSingleExitNode_RespectsDeselectAll(t *testing.T) {
+	m := newExitNodeTestManager()
+	m.routeSelector.DeselectAllRoutes()
+
+	m.enforceSingleExitNode("b", []route.NetID{"a", "b"})
+
+	assert.True(t, m.routeSelector.IsDeselectAll(), "global deselect-all must stay in effect")
+	assert.False(t, m.routeSelector.IsSelected("b"), "no exit node should be forced on while deselect-all is set")
+}
+
+func TestUpdateRouteSelectorFromManagement_FreshSelectsOne(t *testing.T) {
+	m := newExitNodeTestManager()
+	routes := 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"}},
+		"exitC|0.0.0.0/0":    {exitRoute("exitC", "p4", false)},
+	}
+
+	m.updateRouteSelectorFromManagement(routes)
+
+	// Exactly one exit node (the deterministic first) is selected.
+	assert.True(t, m.routeSelector.IsSelected("exitA"), "exitA is the deterministic default")
+	assert.False(t, m.routeSelector.IsSelected("exitB"), "exitB must not also be selected")
+	assert.False(t, m.routeSelector.IsSelected("exitC"), "exitC must not also be selected")
+	// Non-exit routes are left at their default-on state.
+	assert.True(t, m.routeSelector.IsSelected("lan"), "non-exit route selection is untouched")
+}
+
+func TestUpdateRouteSelectorFromManagement_HonorsPersistedPick(t *testing.T) {
+	m := newExitNodeTestManager()
+	routes := route.HAMap{
+		"exitA|0.0.0.0/0": {exitRoute("exitA", "p1", false)},
+		"exitB|0.0.0.0/0": {exitRoute("exitB", "p2", false)},
+	}
+	all := []route.NetID{"exitA", "exitB"}
+
+	// Simulate the state the runtime select path leaves behind: exactly one
+	// exit node explicitly selected, its sibling deselected.
+	require.NoError(t, m.routeSelector.SelectRoutes([]route.NetID{"exitB"}, true, all))
+	require.NoError(t, m.routeSelector.DeselectRoutes([]route.NetID{"exitA"}, all))
+
+	m.updateRouteSelectorFromManagement(routes)
+
+	assert.True(t, m.routeSelector.IsSelected("exitB"), "persisted pick must stay selected")
+	assert.False(t, m.routeSelector.IsSelected("exitA"), "the other exit node stays deselected")
+}
+
+func TestUpdateRouteSelectorFromManagement_OptOutKeepsNone(t *testing.T) {
+	m := newExitNodeTestManager()
+	routes := route.HAMap{
+		"exitA|0.0.0.0/0": {exitRoute("exitA", "p1", false)},
+		"exitB|0.0.0.0/0": {exitRoute("exitB", "p2", false)},
+	}
+	all := []route.NetID{"exitA", "exitB"}
+
+	// User deselected exit nodes and selected none.
+	require.NoError(t, m.routeSelector.DeselectRoutes(all, all))
+
+	m.updateRouteSelectorFromManagement(routes)
+
+	assert.False(t, m.routeSelector.IsSelected("exitA"), "opt-out keeps exitA off")
+	assert.False(t, m.routeSelector.IsSelected("exitB"), "opt-out keeps exitB off")
+}
+
+func TestUpdateRouteSelectorFromManagement_NoAutoApplySelectsNone(t *testing.T) {
+	m := newExitNodeTestManager()
+	// SkipAutoApply=true: management offers the exit nodes but doesn't request
+	// auto-activation, so none should be selected until the user picks one.
+	routes := route.HAMap{
+		"exitA|0.0.0.0/0": {exitRoute("exitA", "p1", true)},
+		"exitB|0.0.0.0/0": {exitRoute("exitB", "p2", true)},
+	}
+
+	m.updateRouteSelectorFromManagement(routes)
+
+	assert.False(t, m.routeSelector.IsSelected("exitA"), "no auto-apply keeps exitA off")
+	assert.False(t, m.routeSelector.IsSelected("exitB"), "no auto-apply keeps exitB off")
+}

client/internal/routemanager/manager.go

@@ -701,7 +701,13 @@ func resolveURLsToIPs(urls []string) []net.IP {
 	return ips
 }
 
-// updateRouteSelectorFromManagement updates the route selector based on the isSelected status from the management server
+// updateRouteSelectorFromManagement reconciles exit-node selection on every
+// network map: it keeps at most one exit node selected — the user's persisted
+// pick, else whatever management marks for auto-apply (SkipAutoApply=false),
+// else none. We never auto-activate an exit node the map doesn't request; it
+// stays off until the user picks it. Exit nodes are mutually exclusive, but the
+// RouteSelector stores routes with default-on semantics, so without this every
+// available exit node would report selected at once.
 func (m *DefaultManager) updateRouteSelectorFromManagement(clientRoutes route.HAMap) {
 	m.mirrorV6ExitPairSelections(clientRoutes)
 
@@ -712,13 +718,14 @@ func (m *DefaultManager) updateRouteSelectorFromManagement(clientRoutes route.HA
 		return
 	}
 
-	exitNodeInfo := m.collectExitNodeInfo(clientRoutes)
-	if len(exitNodeInfo.allIDs) == 0 {
+	info := m.collectExitNodeInfo(clientRoutes)
+	if len(info.allIDs) == 0 {
 		return
 	}
 
-	m.updateExitNodeSelections(exitNodeInfo)
-	m.logExitNodeUpdate(exitNodeInfo)
+	preferred := pickPreferredExitNode(info)
+	m.enforceSingleExitNode(preferred, info.allIDs)
+	m.logExitNodeUpdate(info, preferred)
 }
 
 // mirrorV6ExitPairSelections keeps every synthesized "-v6" exit route's selection
@@ -746,6 +753,10 @@ type exitNodeInfo struct {
 	userDeselected       []route.NetID
 }
 
+// collectExitNodeInfo categorises the available exit nodes by their persisted
+// selection state. It keys on the base (v4) NetID and skips the synthesized
+// "-v6" partner, which inherits its base's selection through the RouteSelector
+// — counting it separately would double-count the pair.
 func (m *DefaultManager) collectExitNodeInfo(clientRoutes route.HAMap) exitNodeInfo {
 	var info exitNodeInfo
 
@@ -755,6 +766,9 @@ func (m *DefaultManager) collectExitNodeInfo(clientRoutes route.HAMap) exitNodeI
 		}
 
 		netID := haID.NetID()
+		if strings.HasSuffix(string(netID), route.V6ExitSuffix) {
+			continue
+		}
 		info.allIDs = append(info.allIDs, netID)
 
 		if m.routeSelector.HasUserSelectionForRoute(netID) {
@@ -791,45 +805,52 @@ func (m *DefaultManager) checkManagementSelection(routes []*route.Route, netID r
 	}
 }
 
-func (m *DefaultManager) updateExitNodeSelections(info exitNodeInfo) {
-	routesToDeselect := m.getRoutesToDeselect(info.allIDs)
-	m.deselectExitNodes(routesToDeselect)
-	m.selectExitNodesByManagement(info.selectedByManagement, info.allIDs)
+// pickPreferredExitNode chooses the single exit node to keep selected. In order:
+//   - a persisted user selection wins (deterministic if several survive from
+//     legacy state, so the set self-heals down to one);
+//   - otherwise activate only what management marks for auto-apply
+//     (SkipAutoApply=false); the lexicographically first if it marks several.
+//
+// Returns "" when neither holds — we never force an arbitrary exit node on. A
+// route the map doesn't auto-apply stays off until the user selects it.
+// info.userDeselected is informational only: an explicit deselect simply keeps
+// that route out of both lists above, so it can't be picked.
+func pickPreferredExitNode(info exitNodeInfo) route.NetID {
+	if len(info.userSelected) > 0 {
+		return minNetID(info.userSelected)
+	}
+	if len(info.selectedByManagement) > 0 {
+		return minNetID(info.selectedByManagement)
+	}
+	return ""
 }
 
-func (m *DefaultManager) getRoutesToDeselect(allIDs []route.NetID) []route.NetID {
-	var routesToDeselect []route.NetID
-	for _, netID := range allIDs {
-		if !m.routeSelector.HasUserSelectionForRoute(netID) {
-			routesToDeselect = append(routesToDeselect, netID)
+// enforceSingleExitNode makes preferred the only selected exit node: every other
+// available exit node is deselected and preferred (if any) is selected, without
+// disturbing non-exit route selections. The whole reconciliation runs under a
+// single RouteSelector lock (SetExclusiveExitNode) so a concurrent deselect-all
+// cannot interleave and get undone; a global deselect-all is left untouched so
+// the user's "all off" stays in effect.
+func (m *DefaultManager) enforceSingleExitNode(preferred route.NetID, allIDs []route.NetID) {
+	m.routeSelector.SetExclusiveExitNode(preferred, allIDs)
+}
+
+func (m *DefaultManager) logExitNodeUpdate(info exitNodeInfo, preferred route.NetID) {
+	log.Debugf("Exit node selection: %d available, preferred=%q (%d user-selected, %d user-deselected, %d management-selected)",
+		len(info.allIDs), preferred, len(info.userSelected), len(info.userDeselected), len(info.selectedByManagement))
+}
+
+// minNetID returns the lexicographically smallest NetID, for a deterministic
+// default pick that stays stable across restarts.
+func minNetID(ids []route.NetID) route.NetID {
+	if len(ids) == 0 {
+		return ""
+	}
+	best := ids[0]
+	for _, id := range ids[1:] {
+		if id < best {
+			best = id
 		}
 	}
-	return routesToDeselect
-}
-
-func (m *DefaultManager) deselectExitNodes(routesToDeselect []route.NetID) {
-	if len(routesToDeselect) == 0 {
-		return
-	}
-
-	err := m.routeSelector.DeselectRoutes(routesToDeselect, routesToDeselect)
-	if err != nil {
-		log.Warnf("Failed to deselect exit nodes: %v", err)
-	}
-}
-
-func (m *DefaultManager) selectExitNodesByManagement(selectedByManagement []route.NetID, allIDs []route.NetID) {
-	if len(selectedByManagement) == 0 {
-		return
-	}
-
-	err := m.routeSelector.SelectRoutes(selectedByManagement, true, allIDs)
-	if err != nil {
-		log.Warnf("Failed to select exit nodes: %v", err)
-	}
-}
-
-func (m *DefaultManager) logExitNodeUpdate(info exitNodeInfo) {
-	log.Debugf("Updated route selector: %d exit nodes available, %d selected by management, %d user-selected, %d user-deselected",
-		len(info.allIDs), len(info.selectedByManagement), len(info.userSelected), len(info.userDeselected))
+	return best
 }

client/internal/routeselector/routeselector.go

@@ -115,7 +115,38 @@ func (rs *RouteSelector) DeselectAllRoutes() {
 	clear(rs.selectedRoutes)
 }
 
-// IsDeselectAll reports whether the user has explicitly deselected all routes.
+// SetExclusiveExitNode atomically makes preferred the only selected exit node
+// among exitIDs: every other ID in exitIDs is deselected and preferred (when
+// non-empty) is selected, all under a single lock. Holding the lock across the
+// whole reconciliation prevents a concurrent DeselectAllRoutes from interleaving
+// between the deselect and select steps and being silently undone. A global
+// deselect-all is left untouched so the user's "all off" stays in effect;
+// non-exit routes are never referenced, so their selection is preserved.
+func (rs *RouteSelector) SetExclusiveExitNode(preferred route.NetID, exitIDs []route.NetID) {
+	rs.mu.Lock()
+	defer rs.mu.Unlock()
+
+	if rs.deselectAll {
+		return
+	}
+
+	for _, id := range exitIDs {
+		if id == preferred {
+			continue
+		}
+		rs.deselectedRoutes[id] = struct{}{}
+		delete(rs.selectedRoutes, id)
+	}
+
+	if preferred != "" {
+		delete(rs.deselectedRoutes, preferred)
+		rs.selectedRoutes[preferred] = struct{}{}
+	}
+}
+
+// IsDeselectAll reports whether the global "deselect all" flag is set, i.e. the
+// user explicitly disabled every route. Callers enforcing per-route invariants
+// (e.g. single exit node) should leave the selection untouched when it is.
 func (rs *RouteSelector) IsDeselectAll() bool {
 	rs.mu.RLock()
 	defer rs.mu.RUnlock()

e2e/agentnetwork/vllm_test.go

@@ -0,0 +1,171 @@
+//go:build e2e
+
+package agentnetwork
+
+import (
+	"context"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/netbirdio/netbird/e2e/harness"
+	"github.com/netbirdio/netbird/shared/management/http/api"
+)
+
+// TestVLLMProvider proves the proxy supports a self-hosted vLLM backend. vLLM is
+// OpenAI-compatible, so it uses the "vllm" catalog entry (KindCustom) and is
+// reached over plain HTTP — no TLS anywhere on the path:
+//
+//	client --tunnel--> netbird proxy --http--> vllm (:8000, OpenAI-compatible)
+//
+// The mock vLLM server answers /v1/chat/completions with an OpenAI-shaped
+// completion carrying a non-zero usage block. The test asserts the chat returns
+// 200 with the completion, that the request is recorded in the access log by its
+// session id, and that vLLM's usage block is metered into a consumption row —
+// which together prove request routing, response parsing, and token accounting
+// all work for a self-hosted OpenAI-compatible provider.
+//
+// It needs no external credentials (the mock ignores auth), so it always runs.
+func TestVLLMProvider(t *testing.T) {
+	ctx, cancel := context.WithTimeout(context.Background(), 15*time.Minute)
+	defer cancel()
+
+	vllm, err := harness.StartVLLM(ctx, srv)
+	require.NoError(t, err, "start mock vLLM server")
+	t.Cleanup(func() { _ = vllm.Terminate(context.Background()) })
+
+	grp, err := srv.API().Groups.Create(ctx, api.PostApiGroupsJSONRequestBody{Name: "e2e-vllm"})
+	require.NoError(t, err, "create group")
+	t.Cleanup(func() { _ = srv.API().Groups.Delete(context.Background(), grp.Id) })
+
+	ephemeral := false
+	sk, err := srv.API().SetupKeys.Create(ctx, api.PostApiSetupKeysJSONRequestBody{
+		Name:       "e2e-vllm-client",
+		Type:       "reusable",
+		ExpiresIn:  86400,
+		UsageLimit: 0,
+		AutoGroups: []string{grp.Id},
+		Ephemeral:  &ephemeral,
+	})
+	require.NoError(t, err, "mint setup key")
+	require.NotEmpty(t, sk.Key, "setup key plaintext")
+
+	// vLLM provider pointed at the mock over plain HTTP. The mock ignores auth,
+	// so a dummy key satisfies the "Bearer ${API_KEY}" template. The served model
+	// is enumerated so the router dispatches this model string to this provider.
+	dummyKey := "sk-vllm-e2e"
+	prov, err := srv.CreateProvider(ctx, api.AgentNetworkProviderRequest{
+		Name:             "vllm",
+		ProviderId:       "vllm",
+		UpstreamUrl:      vllm.URL,
+		ApiKey:           &dummyKey,
+		Enabled:          ptr(true),
+		BootstrapCluster: ptr(harness.AgentNetworkCluster),
+		Models: &[]api.AgentNetworkProviderModel{
+			{Id: harness.VLLMModel, InputPer1k: 0.001, OutputPer1k: 0.002},
+		},
+	})
+	require.NoError(t, err, "create vllm provider")
+	t.Cleanup(func() { _ = srv.DeleteProvider(context.Background(), prov.Id) })
+
+	// Token limit far above the handful of tokens this test drives, so it never
+	// blocks but switches on usage metering — the switch that makes consumption
+	// rows get recorded.
+	enabled := true
+	pol, err := srv.CreatePolicy(ctx, api.AgentNetworkPolicyRequest{
+		Name:                   "e2e-vllm-allow",
+		Enabled:                &enabled,
+		SourceGroups:           []string{grp.Id},
+		DestinationProviderIds: []string{prov.Id},
+		Limits: &api.AgentNetworkPolicyLimits{
+			TokenLimit: api.AgentNetworkPolicyTokenLimit{
+				Enabled:       true,
+				GroupCap:      10_000_000,
+				UserCap:       10_000_000,
+				WindowSeconds: 60,
+			},
+		},
+	})
+	require.NoError(t, err, "create policy")
+	t.Cleanup(func() { _ = srv.DeletePolicy(context.Background(), pol.Id) })
+
+	settings, err := srv.GetSettings(ctx)
+	require.NoError(t, err, "read settings")
+	require.NotEmpty(t, settings.Endpoint, "endpoint must be assigned")
+
+	proxyToken, err := srv.CreateProxyTokenCLI(ctx, "e2e-vllm-proxy")
+	require.NoError(t, err, "mint proxy token")
+	px, err := harness.StartProxy(ctx, srv, proxyToken)
+	require.NoError(t, err, "start proxy")
+	t.Cleanup(func() { _ = px.Terminate(context.Background()) })
+
+	cl, err := harness.StartClient(ctx, srv, sk.Key)
+	require.NoError(t, err, "start client")
+	t.Cleanup(func() { _ = cl.Terminate(context.Background()) })
+
+	require.NoError(t, cl.WaitConnected(ctx, 90*time.Second), "client must connect to management")
+	if err := cl.WaitProxyPeer(ctx, 180*time.Second); err != nil {
+		t.Fatalf("client did not see the proxy peer: %v\n=== proxy logs ===\n%s", err, px.Logs(context.Background()))
+	}
+	proxyIP, err := cl.ResolveProxyIP(ctx, settings.Endpoint)
+	require.NoError(t, err, "resolve endpoint to proxy IP")
+
+	before, _ := srv.ListAccessLogs(ctx)
+	sessionID := "e2e-session-vllm"
+
+	// Retry to absorb tunnel/DNS jitter on the first call.
+	var code int
+	var body string
+	deadline := time.Now().Add(90 * time.Second)
+	for time.Now().Before(deadline) {
+		c, b, cerr := cl.Chat(ctx, settings.Endpoint, proxyIP, harness.WireChat, harness.VLLMModel, "Reply with exactly: pong", sessionID)
+		if cerr == nil {
+			code, body = c, b
+			if code == 200 {
+				break
+			}
+		}
+		time.Sleep(5 * time.Second)
+	}
+	require.Equal(t, 200, code,
+		"chat through the vLLM provider must return 200; body: %s\n=== vllm logs ===\n%s\n=== proxy logs ===\n%s",
+		body, vllm.Logs(context.Background()), px.Logs(context.Background()))
+	require.True(t, strings.Contains(body, "chat.completion"),
+		"body should be an OpenAI-compatible chat completion; got: %s", body)
+
+	// The request must surface as an access-log row carrying our session id.
+	require.Eventually(t, func() bool {
+		logs, lerr := srv.ListAccessLogs(ctx)
+		return lerr == nil && logs.TotalRecords > before.TotalRecords
+	}, 30*time.Second, 2*time.Second, "an access-log row should be ingested for the vLLM provider")
+
+	require.Eventually(t, func() bool {
+		logs, lerr := srv.ListAccessLogs(ctx)
+		if lerr != nil {
+			return false
+		}
+		for _, r := range logs.Data {
+			if r.SessionId != nil && *r.SessionId == sessionID {
+				return true
+			}
+		}
+		return false
+	}, 30*time.Second, 2*time.Second, "session id %q must be recorded in an access-log row", sessionID)
+
+	// vLLM's usage block (prompt_tokens=11, completion_tokens=2) must be parsed
+	// and metered into a consumption row with positive token counts.
+	require.Eventually(t, func() bool {
+		rows, lerr := srv.ListConsumption(ctx)
+		if lerr != nil {
+			return false
+		}
+		for _, r := range rows {
+			if r.TokensInput > 0 && r.TokensOutput > 0 {
+				return true
+			}
+		}
+		return false
+	}, 60*time.Second, 3*time.Second, "vLLM usage must be metered into a consumption row")
+}

e2e/harness/vllm.go

@@ -0,0 +1,113 @@
+//go:build e2e
+
+package harness
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/docker/docker/api/types/container"
+	"github.com/testcontainers/testcontainers-go"
+	"github.com/testcontainers/testcontainers-go/wait"
+)
+
+const (
+	vllmImage = "nginx:alpine"
+	vllmAlias = "vllm"
+	vllmPort  = "8000/tcp"
+	// VLLMModel is the served model id the mock advertises and echoes back. It
+	// matches a real small model commonly served by vLLM so the provider's
+	// enumerated model and the client's request line up.
+	VLLMModel = "Qwen/Qwen2.5-0.5B-Instruct"
+)
+
+// vllmNginxConf emulates a vLLM OpenAI-compatible server over plain HTTP (vLLM's
+// default: no TLS, port 8000). It answers /v1/models with a one-model list and
+// any chat/completions path with a canned OpenAI-shaped chat completion carrying
+// a non-zero usage block, so the proxy's OpenAI parser records real token
+// consumption. Running actual vLLM in CI is infeasible (GPU + multi-GB model
+// download), so this stands in for the wire contract the proxy depends on.
+const vllmNginxConf = `pid /tmp/nginx.pid;
+events {}
+http {
+  server {
+    listen 8000;
+    location = /v1/models {
+      default_type application/json;
+      return 200 '{"object":"list","data":[{"id":"Qwen/Qwen2.5-0.5B-Instruct","object":"model","owned_by":"vllm"}]}';
+    }
+    location / {
+      default_type application/json;
+      return 200 '{"id":"chatcmpl-e2e-vllm","object":"chat.completion","created":1700000000,"model":"Qwen/Qwen2.5-0.5B-Instruct","choices":[{"index":0,"message":{"role":"assistant","content":"pong"},"finish_reason":"stop"}],"usage":{"prompt_tokens":11,"completion_tokens":2,"total_tokens":13}}';
+    }
+  }
+}
+`
+
+// VLLM is a mock vLLM OpenAI-compatible server on the combined server's network,
+// reachable at http://vllm:8000. A "vllm" provider points at it to exercise the
+// proxy's support for self-hosted OpenAI-compatible backends.
+type VLLM struct {
+	container testcontainers.Container
+	workDir   string
+	// URL is the upstream URL the vllm provider points at (http://<alias>:8000).
+	URL string
+}
+
+// StartVLLM runs the mock vLLM server on the shared network over plain HTTP.
+func StartVLLM(ctx context.Context, c *Combined) (*VLLM, error) {
+	workDir, err := os.MkdirTemp("/tmp", "nb-e2e-vllm-*")
+	if err != nil {
+		return nil, fmt.Errorf("create vllm work dir: %w", err)
+	}
+	// Widen so the (non-root worker) nginx container can traverse the bind mount.
+	if err := os.Chmod(workDir, 0o755); err != nil { //nolint:gosec // throwaway e2e config dir
+		return nil, fmt.Errorf("chmod vllm dir: %w", err)
+	}
+	if err := os.WriteFile(filepath.Join(workDir, "nginx.conf"), []byte(vllmNginxConf), 0o644); err != nil { //nolint:gosec // non-secret e2e config
+		return nil, fmt.Errorf("write nginx conf: %w", err)
+	}
+
+	req := testcontainers.ContainerRequest{
+		Image:          vllmImage,
+		ExposedPorts:   []string{vllmPort},
+		Networks:       []string{c.network.Name},
+		NetworkAliases: map[string][]string{c.network.Name: {vllmAlias}},
+		Cmd:            []string{"nginx", "-c", "/conf/nginx.conf", "-g", "daemon off;"},
+		HostConfigModifier: func(hc *container.HostConfig) {
+			hc.Binds = append(hc.Binds, workDir+":/conf:ro")
+		},
+		WaitingFor: wait.ForListeningPort(vllmPort).WithStartupTimeout(60 * time.Second),
+	}
+
+	ctr, err := testcontainers.GenericContainer(ctx, testcontainers.GenericContainerRequest{
+		ContainerRequest: req,
+		Started:          true,
+	})
+	if err != nil {
+		_ = os.RemoveAll(workDir)
+		return nil, fmt.Errorf("start vllm container: %w", err)
+	}
+
+	return &VLLM{container: ctr, workDir: workDir, URL: "http://" + vllmAlias + ":8000"}, nil
+}
+
+// Logs returns the vLLM container logs, for diagnostics on failure.
+func (v *VLLM) Logs(ctx context.Context) string {
+	return containerLogs(ctx, v.container)
+}
+
+// Terminate stops the vLLM container and cleans its work dir.
+func (v *VLLM) Terminate(ctx context.Context) error {
+	var err error
+	if v.container != nil {
+		err = v.container.Terminate(ctx)
+	}
+	if v.workDir != "" {
+		_ = os.RemoveAll(v.workDir)
+	}
+	return err
+}

infrastructure_files/getting-started.sh

@@ -351,11 +351,6 @@ initialize_default_values() {
   NETBIRD_STUN_PORT=3478
 
   # Docker images
-  # Record whether the operator explicitly pinned the server/proxy images via
-  # env vars, so the agent-network preset can pick its own defaults without
-  # clobbering an explicit override.
-  NETBIRD_SERVER_IMAGE_EXPLICIT=${NETBIRD_SERVER_IMAGE:+true}
-  NETBIRD_PROXY_IMAGE_EXPLICIT=${NETBIRD_PROXY_IMAGE:+true}
   DASHBOARD_IMAGE=${DASHBOARD_IMAGE:-"netbirdio/dashboard:latest"}
   # Combined server replaces separate signal, relay, and management containers
   NETBIRD_SERVER_IMAGE=${NETBIRD_SERVER_IMAGE:-"netbirdio/netbird-server:latest"}
@@ -415,15 +410,6 @@ apply_agent_network_preset() {
   ENABLE_PROXY="true"
   ENABLE_CROWDSEC="false"
 
-  # Agent-network ships dedicated server/proxy images. Honor an explicit
-  # env override; otherwise pin the agent-network builds.
-  if [[ "${NETBIRD_SERVER_IMAGE_EXPLICIT}" != "true" ]]; then
-    NETBIRD_SERVER_IMAGE="netbirdio/netbird-server:0.74.0-rc.2"
-  fi
-  if [[ "${NETBIRD_PROXY_IMAGE_EXPLICIT}" != "true" ]]; then
-    NETBIRD_PROXY_IMAGE="netbirdio/reverse-proxy:0.74.0-rc.2"
-  fi
-
   if [[ -n "${NETBIRD_LETSENCRYPT_EMAIL}" ]]; then
     TRAEFIK_ACME_EMAIL="${NETBIRD_LETSENCRYPT_EMAIL}"
   else

management/internals/modules/agentnetwork/catalog/catalog.go

@@ -627,6 +627,21 @@ var providers = []Provider{
 		},
 		Models: []Model{},
 	},
+	{
+		// vLLM is an OpenAI-compatible self-hosted server. It behaves like
+		// the generic custom entry; it gets its own catalog id purely so it
+		// surfaces as a named "vLLM" choice in the provider picker.
+		ID:                 "vllm",
+		Kind:               KindCustom,
+		Name:               "vLLM",
+		Description:        "Self-hosted vLLM (OpenAI-compatible)",
+		DefaultHost:        "",
+		AuthHeaderName:     "Authorization",
+		AuthHeaderTemplate: "Bearer ${API_KEY}",
+		DefaultContentType: "application/json",
+		BrandColor:         "#30A2FF",
+		Models:             []Model{},
+	},
 	{
 		ID:                 "custom",
 		Kind:               KindCustom,

management/internals/shared/grpc/conversion.go

@@ -47,16 +47,13 @@ func init() {
 	precomputedDeprecatedRemotePeersConstraint = constraint
 }
 
+// toNetbirdConfig converts the server configuration to the wire representation. It returns
+// nil when no server config is set (the fan-out network-map path) because clients treat any
+// non-nil config as authoritative: a config without a relay section is interpreted as relay
+// disabled and wipes the clients' relay URLs.
 func toNetbirdConfig(config *nbconfig.Config, turnCredentials *Token, relayToken *Token, extraSettings *types.ExtraSettings, settings *types.Settings) *proto.NetbirdConfig {
 	if config == nil {
-		if settings == nil {
-			return nil
-		}
-		return &proto.NetbirdConfig{
-			Metrics: &proto.MetricsConfig{
-				Enabled: settings.MetricsPushEnabled,
-			},
-		}
+		return nil
 	}
 
 	var stuns []*proto.HostConfig

management/internals/shared/grpc/conversion_test.go

@@ -8,11 +8,13 @@ import (
 	"time"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 
 	nbdns "github.com/netbirdio/netbird/dns"
 	"github.com/netbirdio/netbird/management/internals/controllers/network_map"
 	"github.com/netbirdio/netbird/management/internals/controllers/network_map/controller/cache"
 	nbconfig "github.com/netbirdio/netbird/management/internals/server/config"
+	"github.com/netbirdio/netbird/management/server/types"
 )
 
 func TestToProtocolDNSConfigWithCache(t *testing.T) {
@@ -263,3 +265,39 @@ func TestEncodeSessionExpiresAt(t *testing.T) {
 		assert.True(t, got.AsTime().Equal(deadline))
 	})
 }
+
+// TestToNetbirdConfig_RelayInvariant guards against the v0.74.0 relay-wipe regression.
+// Clients treat any non-nil NetbirdConfig as authoritative and interpret a missing relay
+// section as relay disabled, wiping their relay URLs. toNetbirdConfig must therefore
+// return nil when no server config is set (the fan-out network-map path) instead of a
+// partial config, and a result built from a relay-enabled config must carry the relay
+// section.
+func TestToNetbirdConfig_RelayInvariant(t *testing.T) {
+	settings := &types.Settings{MetricsPushEnabled: true}
+
+	t.Run("nil server config returns nil config", func(t *testing.T) {
+		nbCfg := toNetbirdConfig(nil, nil, nil, nil, settings)
+		assert.Nil(t, nbCfg, "fan-out updates must not carry a partial NetbirdConfig even when settings are present")
+	})
+
+	t.Run("relay-enabled config carries relay section", func(t *testing.T) {
+		cfg := &nbconfig.Config{
+			Stuns: []*nbconfig.Host{{Proto: nbconfig.UDP, URI: "stun:stun.example.com:3478"}},
+			TURNConfig: &nbconfig.TURNConfig{
+				Turns: []*nbconfig.Host{{Proto: nbconfig.UDP, URI: "turn:turn.example.com:3478", Username: "user", Password: "pass"}},
+			},
+			Relay:  &nbconfig.Relay{Addresses: []string{"rels://relay.example.com:443"}},
+			Signal: &nbconfig.Host{Proto: nbconfig.HTTP, URI: "signal.example.com:10000"},
+		}
+		relayToken := &Token{Payload: "token-payload", Signature: "token-signature"}
+
+		nbCfg := toNetbirdConfig(cfg, nil, relayToken, nil, settings)
+		require.NotNil(t, nbCfg)
+		require.NotNil(t, nbCfg.Relay, "non-nil NetbirdConfig must include the relay section")
+		assert.Equal(t, cfg.Relay.Addresses, nbCfg.Relay.Urls, "relay URLs should match the server config")
+		assert.Equal(t, relayToken.Payload, nbCfg.Relay.TokenPayload, "relay token payload should be set")
+		assert.Equal(t, relayToken.Signature, nbCfg.Relay.TokenSignature, "relay token signature should be set")
+		require.NotNil(t, nbCfg.Metrics)
+		assert.True(t, nbCfg.Metrics.Enabled, "metrics flag should carry the settings value")
+	})
+}

management/server/peer_test.go

@@ -1048,11 +1048,7 @@ func testUpdateAccountPeers(t *testing.T) {
 
 			for _, channel := range peerChannels {
 				update := <-channel
-				assert.NotNil(t, update.Update.NetbirdConfig)
-				assert.Nil(t, update.Update.NetbirdConfig.Stuns)
-				assert.Nil(t, update.Update.NetbirdConfig.Turns)
-				assert.Nil(t, update.Update.NetbirdConfig.Signal)
-				assert.Nil(t, update.Update.NetbirdConfig.Relay)
+				assert.Nil(t, update.Update.NetbirdConfig, "fan-out updates must not carry a NetbirdConfig; clients treat a config without relay as relay disabled and wipe their relay URLs")
 				assert.Equal(t, tc.peers, len(update.Update.NetworkMap.RemotePeers))
 				assert.Equal(t, tc.peers*2, len(update.Update.NetworkMap.FirewallRules))
 			}

shared/management/client/grpc.go

@@ -33,10 +33,15 @@ const ConnectTimeout = 10 * time.Second
 const healthCheckTimeout = 5 * time.Second
 
 const (
-	// EnvMaxRecvMsgSize overrides the default gRPC max receive message size (4 MB)
+	// EnvMaxRecvMsgSize overrides the default gRPC max receive message size
 	// for the management client connection. Value is in bytes.
 	EnvMaxRecvMsgSize = "NB_MANAGEMENT_GRPC_MAX_MSG_SIZE"
 
+	// defaultMaxRecvMsgSize is the max gRPC receive message size used for the
+	// management client connection when EnvMaxRecvMsgSize is unset or invalid.
+	// It overrides the gRPC library default of 4 MB.
+	defaultMaxRecvMsgSize = 1024 * 1024 * 16
+
 	errMsgMgmtPublicKey    = "failed getting Management Service public key: %s"
 	errMsgNoMgmtConnection = "no connection to management"
 )
@@ -84,22 +89,22 @@ type ExposeResponse struct {
 }
 
 // MaxRecvMsgSize returns the configured max gRPC receive message size from
-// the environment, or 0 if unset (which uses the gRPC default of 4 MB).
+// the environment, or defaultMaxRecvMsgSize (16 MB) if unset or invalid.
 func MaxRecvMsgSize() int {
 	val := os.Getenv(EnvMaxRecvMsgSize)
 	if val == "" {
-		return 0
+		return defaultMaxRecvMsgSize
 	}
 
 	size, err := strconv.Atoi(val)
 	if err != nil {
 		log.Warnf("invalid %s value %q, using default: %v", EnvMaxRecvMsgSize, val, err)
-		return 0
+		return defaultMaxRecvMsgSize
 	}
 
 	if size <= 0 {
 		log.Warnf("invalid %s value %d, must be positive, using default", EnvMaxRecvMsgSize, size)
-		return 0
+		return defaultMaxRecvMsgSize
 	}
 
 	return size

shared/management/client/grpc_test.go

@@ -21,11 +21,11 @@ func TestMaxRecvMsgSize(t *testing.T) {
 		envValue string
 		expected int
 	}{
-		{name: "unset returns 0", envValue: "", expected: 0},
+		{name: "unset returns default", envValue: "", expected: defaultMaxRecvMsgSize},
 		{name: "valid value", envValue: "10485760", expected: 10485760},
-		{name: "non-numeric returns 0", envValue: "abc", expected: 0},
-		{name: "negative returns 0", envValue: "-1", expected: 0},
-		{name: "zero returns 0", envValue: "0", expected: 0},
+		{name: "non-numeric returns default", envValue: "abc", expected: defaultMaxRecvMsgSize},
+		{name: "negative returns default", envValue: "-1", expected: defaultMaxRecvMsgSize},
+		{name: "zero returns default", envValue: "0", expected: defaultMaxRecvMsgSize},
 	}
 
 	for _, tt := range tests {