diff --git a/client/android/preferences.go b/client/android/preferences.go
index 5ce31026c..3623de23f 100644
--- a/client/android/preferences.go
+++ b/client/android/preferences.go
@@ -46,7 +46,7 @@ func (p *Preferences) GetManagementURL() (string, error) {
 		return p.configInput.ManagementURL, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return "", err
 	}
@@ -64,7 +64,7 @@ func (p *Preferences) GetAdminURL() (string, error) {
 		return p.configInput.AdminURL, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return "", err
 	}
@@ -86,7 +86,7 @@ func (p *Preferences) HasPreSharedKey() (bool, error) {
 		return *p.configInput.PreSharedKey != "", nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return false, err
 	}
@@ -112,7 +112,7 @@ func (p *Preferences) GetRosenpassEnabled() (bool, error) {
 		return *p.configInput.RosenpassEnabled, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return false, err
 	}
@@ -133,7 +133,7 @@ func (p *Preferences) GetRosenpassPermissive() (bool, error) {
 		return *p.configInput.RosenpassPermissive, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return false, err
 	}
@@ -149,7 +149,7 @@ func (p *Preferences) GetDisableClientRoutes() (bool, error) {
 		return *p.configInput.DisableClientRoutes, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return false, err
 	}
@@ -170,7 +170,7 @@ func (p *Preferences) GetDisableServerRoutes() (bool, error) {
 		return *p.configInput.DisableServerRoutes, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return false, err
 	}
@@ -188,7 +188,7 @@ func (p *Preferences) GetDisableDNS() (bool, error) {
 		return *p.configInput.DisableDNS, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return false, err
 	}
@@ -206,7 +206,7 @@ func (p *Preferences) GetDisableFirewall() (bool, error) {
 		return *p.configInput.DisableFirewall, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return false, err
 	}
@@ -227,7 +227,7 @@ func (p *Preferences) GetServerSSHAllowed() (bool, error) {
 		return *p.configInput.ServerSSHAllowed, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return false, err
 	}
@@ -249,7 +249,7 @@ func (p *Preferences) GetEnableSSHRoot() (bool, error) {
 		return *p.configInput.EnableSSHRoot, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return false, err
 	}
@@ -271,7 +271,7 @@ func (p *Preferences) GetEnableSSHSFTP() (bool, error) {
 		return *p.configInput.EnableSSHSFTP, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return false, err
 	}
@@ -293,7 +293,7 @@ func (p *Preferences) GetEnableSSHLocalPortForwarding() (bool, error) {
 		return *p.configInput.EnableSSHLocalPortForwarding, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return false, err
 	}
@@ -315,7 +315,7 @@ func (p *Preferences) GetEnableSSHRemotePortForwarding() (bool, error) {
 		return *p.configInput.EnableSSHRemotePortForwarding, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return false, err
 	}
@@ -340,7 +340,7 @@ func (p *Preferences) GetBlockInbound() (bool, error) {
 		return *p.configInput.BlockInbound, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return false, err
 	}
@@ -358,7 +358,7 @@ func (p *Preferences) GetDisableIPv6() (bool, error) {
 		return *p.configInput.DisableIPv6, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return false, err
 	}
@@ -377,7 +377,7 @@ func (p *Preferences) GetRemoteJobsAllowed() (bool, error) {
 		return *p.configInput.RemoteJobsAllowed, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return false, err
 	}
diff --git a/client/cmd/login.go b/client/cmd/login.go
index 11867be09..1dc2d0d09 100644
--- a/client/cmd/login.go
+++ b/client/cmd/login.go
@@ -9,8 +9,6 @@ import (
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 	"golang.org/x/term"
-	"google.golang.org/grpc/codes"
-	gstatus "google.golang.org/grpc/status"
 
 	"github.com/netbirdio/netbird/client/internal"
 	"github.com/netbirdio/netbird/client/internal/auth"
@@ -145,10 +143,7 @@ func doDaemonLogin(ctx context.Context, cmd *cobra.Command, providedSetupKey str
 	err = WithBackOff(func() error {
 		var backOffErr error
 		loginResp, backOffErr = client.Login(ctx, &loginRequest)
-		if s, ok := gstatus.FromError(backOffErr); ok && (s.Code() == codes.InvalidArgument ||
-			s.Code() == codes.PermissionDenied ||
-			s.Code() == codes.NotFound ||
-			s.Code() == codes.Unimplemented) {
+		if terminalLoginError(backOffErr) {
 			loginErr = backOffErr
 			return nil
 		}
@@ -327,10 +322,28 @@ func doForegroundLogin(ctx context.Context, cmd *cobra.Command, setupKey string,
 
 	}
 
-	config, err := profilemanager.ReadConfig(configFilePath)
+	config, err := profilemanager.ReadConfigOrDefault(configFilePath)
 	if err != nil {
 		return fmt.Errorf("read config file %s: %v", configFilePath, err)
 	}
+	// Reading a config does not provision one: this login is about to dial
+	// management with the profile's identity, so mint the keys if the profile
+	// has none yet and put them on disk — a key that stayed in memory would
+	// come back different on the next run and register a second peer.
+	//
+	// Before the MDM overlay below, on purpose: the file must keep the
+	// profile's own values. The overlay is runtime-only and re-derived on
+	// every load, so persisting it would turn an enforced management URL or
+	// pre-shared key into one the user appears to own once the policy is
+	// withdrawn.
+	if generated, err := config.EnsureIdentity(); err != nil {
+		return fmt.Errorf("ensure profile identity: %v", err)
+	} else if generated {
+		if err := profilemanager.WriteOutConfig(configFilePath, config); err != nil {
+			return fmt.Errorf("write out config file %s: %v", configFilePath, err)
+		}
+	}
+
 	// CLI standalone login: profilemanager no longer auto-applies MDM,
 	// so layer in the OS-native policy here. Desktop builds construct
 	// a Loader with no fetcher — the build-tagged loadPlatform reads
diff --git a/client/cmd/root.go b/client/cmd/root.go
index be6479440..2ca14c39c 100644
--- a/client/cmd/root.go
+++ b/client/cmd/root.go
@@ -20,6 +20,8 @@ import (
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	gstatus "google.golang.org/grpc/status"
 
 	"github.com/netbirdio/netbird/client/anonymize"
 	daddr "github.com/netbirdio/netbird/client/internal/daemonaddr"
@@ -285,6 +287,43 @@ func DialClientGRPCServer(ctx context.Context, addr string) (*grpc.ClientConn, e
 	return grpc.DialContext(ctx, target, opts...)
 }
 
+// terminalLoginError reports whether a Login failure is final, so the backoff
+// cycle stops and the caller is told what the daemon said instead of "login
+// backoff cycle failed" thirty seconds later. Retrying cannot change any of
+// these answers: the request is malformed, the caller is not allowed, the
+// target does not exist, a precondition on the daemon refuses it (the
+// update-settings kill switch, an MDM-managed field), or the method is not
+// implemented.
+//
+// Both `netbird up` and `netbird login` run Login through the backoff, and
+// they each carried their own copy of this list — which is how one of them
+// ended up retrying a refusal the other treated as final.
+func terminalLoginError(err error) bool {
+	// A successful Login reaches here with a nil error, and that is not a
+	// terminal failure. Handled explicitly rather than left to
+	// gstatus.FromError, which answers (nil, true) for a nil error and leans on
+	// Status.Code tolerating a nil receiver to come back as codes.OK.
+	if err == nil {
+		return false
+	}
+
+	s, ok := gstatus.FromError(err)
+	if !ok {
+		return false
+	}
+
+	switch s.Code() {
+	case codes.InvalidArgument,
+		codes.PermissionDenied,
+		codes.NotFound,
+		codes.FailedPrecondition,
+		codes.Unimplemented:
+		return true
+	default:
+		return false
+	}
+}
+
 // WithBackOff execute function in backoff cycle.
 func WithBackOff(bf func() error) error {
 	return backoff.RetryNotify(bf, CLIBackOffSettings, func(err error, duration time.Duration) {
diff --git a/client/cmd/up.go b/client/cmd/up.go
index f5fac9749..120a25595 100644
--- a/client/cmd/up.go
+++ b/client/cmd/up.go
@@ -357,9 +357,17 @@ func runInDaemonMode(ctx context.Context, cmd *cobra.Command, pm *profilemanager
 	// set the new config
 	req := setupSetConfigReq(customDNSAddressConverted, cmd, activeProf.ID.String(), username.Username)
 	if _, err := client.SetConfig(ctx, req); err != nil {
-		if st, ok := gstatus.FromError(err); ok && st.Code() == codes.Unavailable {
-			log.Warnf("setConfig method is not available in the daemon: %s", st.Message())
-		} else {
+		switch reason, refused := refusedSettingsUpdate(err); {
+		case refused:
+			// Failing here is the point: carrying on would connect while
+			// silently dropping the settings the caller asked for, since
+			// nothing further down the line applies them.
+			return fmt.Errorf("the daemon refused the settings update: %s", reason)
+		case gstatus.Code(err) == codes.Unavailable:
+			// The daemon cannot serve the method at all, which is what this
+			// code means; an older daemon without it lands here.
+			log.Warnf("the daemon did not apply the settings update: %s", gstatus.Convert(err).Message())
+		default:
 			return daemonCallError("call service setConfig method", err)
 		}
 	}
@@ -400,10 +408,7 @@ func doDaemonUp(ctx context.Context, cmd *cobra.Command, client proto.DaemonServ
 	err = WithBackOff(func() error {
 		var backOffErr error
 		loginResp, backOffErr = client.Login(ctx, loginRequest)
-		if s, ok := gstatus.FromError(backOffErr); ok && (s.Code() == codes.InvalidArgument ||
-			s.Code() == codes.PermissionDenied ||
-			s.Code() == codes.NotFound ||
-			s.Code() == codes.Unimplemented) {
+		if terminalLoginError(backOffErr) {
 			loginErr = backOffErr
 			return nil
 		}
@@ -472,6 +477,22 @@ func setSSHSetConfigFields(req *proto.SetConfigRequest, cmd *cobra.Command) {
 	}
 }
 
+// refusedSettingsUpdate reports whether err is the daemon refusing the settings
+// a request carried — the update-settings kill switch, or a field an MDM policy
+// manages — and returns the reason it gave.
+//
+// The distinction that matters is against codes.Unavailable, which means the
+// daemon cannot serve the call: that one is worth a warning, because an older
+// daemon without the method lands there and the rest of `netbird up` still
+// works. A refusal is not, because the settings would be silently dropped.
+func refusedSettingsUpdate(err error) (string, bool) {
+	st, ok := gstatus.FromError(err)
+	if !ok || st.Code() != codes.FailedPrecondition {
+		return "", false
+	}
+	return st.Message(), true
+}
+
 func setupSetConfigReq(customDNSAddressConverted []byte, cmd *cobra.Command, profileName, username string) *proto.SetConfigRequest {
 	var req proto.SetConfigRequest
 	req.ProfileName = profileName
diff --git a/client/cmd/up_setconfig_refusal_test.go b/client/cmd/up_setconfig_refusal_test.go
new file mode 100644
index 000000000..fdf580102
--- /dev/null
+++ b/client/cmd/up_setconfig_refusal_test.go
@@ -0,0 +1,85 @@
+package cmd
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"google.golang.org/grpc/codes"
+	gstatus "google.golang.org/grpc/status"
+)
+
+// A refused settings update has to fail `netbird up`, or a caller that asked
+// for a setting the daemon will not apply connects as if it had been applied.
+// The daemon being unable to serve the call is the case that stays a warning.
+func TestRefusedSettingsUpdate(t *testing.T) {
+	tests := []struct {
+		name        string
+		err         error
+		wantRefused bool
+	}{
+		{
+			name:        "the kill switch refused the change",
+			err:         gstatus.Errorf(codes.FailedPrecondition, "update settings are disabled, you cannot use this feature without update settings enabled"),
+			wantRefused: true,
+		},
+		{
+			name:        "an MDM policy manages the field",
+			err:         gstatus.Errorf(codes.FailedPrecondition, "fields managed by MDM policy: managementURL"),
+			wantRefused: true,
+		},
+		{
+			name:        "the daemon cannot serve the call",
+			err:         gstatus.Errorf(codes.Unavailable, "connection refused"),
+			wantRefused: false,
+		},
+		{
+			name:        "any other RPC failure",
+			err:         gstatus.Errorf(codes.Internal, "boom"),
+			wantRefused: false,
+		},
+		{
+			name:        "not a status error at all",
+			err:         errors.New("boom"),
+			wantRefused: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			reason, refused := refusedSettingsUpdate(tt.err)
+			require.Equal(t, tt.wantRefused, refused)
+			if tt.wantRefused {
+				require.Equal(t, gstatus.Convert(tt.err).Message(), reason, "the daemon's reason must reach the caller")
+			}
+		})
+	}
+}
+
+// Both `netbird up` and `netbird login` drive Login through the backoff cycle,
+// and a final answer has to stop it: retrying a refusal only replaces the
+// daemon's reason with "login backoff cycle failed" thirty seconds later.
+func TestTerminalLoginError(t *testing.T) {
+	tests := []struct {
+		name         string
+		err          error
+		wantTerminal bool
+	}{
+		{name: "settings refused by the kill switch", err: gstatus.Errorf(codes.FailedPrecondition, "update settings are disabled"), wantTerminal: true},
+		{name: "field managed by MDM", err: gstatus.Errorf(codes.FailedPrecondition, "fields managed by MDM policy: managementURL"), wantTerminal: true},
+		{name: "caller not allowed", err: gstatus.Errorf(codes.PermissionDenied, "nope"), wantTerminal: true},
+		{name: "malformed request", err: gstatus.Errorf(codes.InvalidArgument, "nope"), wantTerminal: true},
+		{name: "profile not found", err: gstatus.Errorf(codes.NotFound, "nope"), wantTerminal: true},
+		{name: "method missing on an older daemon", err: gstatus.Errorf(codes.Unimplemented, "nope"), wantTerminal: true},
+		{name: "daemon unreachable, worth retrying", err: gstatus.Errorf(codes.Unavailable, "connection refused"), wantTerminal: false},
+		{name: "transient internal failure", err: gstatus.Errorf(codes.Internal, "boom"), wantTerminal: false},
+		{name: "not a status error", err: errors.New("boom"), wantTerminal: false},
+		{name: "no error at all, the login succeeded", err: nil, wantTerminal: false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			require.Equal(t, tt.wantTerminal, terminalLoginError(tt.err))
+		})
+	}
+}
diff --git a/client/internal/debug/debug_test.go b/client/internal/debug/debug_test.go
index 6a810bccc..0f74490f2 100644
--- a/client/internal/debug/debug_test.go
+++ b/client/internal/debug/debug_test.go
@@ -846,6 +846,7 @@ func TestAddConfig_AllFieldsCovered(t *testing.T) {
 		"ClientCertKeyPair":    "non-config: parsed cert pair, not serialized",
 		"Name":                 "non-config: profile name is not needed for debug purposes",
 		"policy":               "non-config: in-memory MDM policy snapshot, surfaced via Config.Policy() / GetConfigResponse.MDMManagedFields",
+		"probing":              "non-config: marks a throwaway copy built to be diffed against; never set on a config anyone runs with",
 		"DebugBundleUploadURL": "sensitive: MDM-provided upload URL may carry credentials or query tokens; kept out of the shared bundle",
 	}
 
diff --git a/client/internal/profilemanager/config.go b/client/internal/profilemanager/config.go
index 412f81b5c..ac1b90a62 100644
--- a/client/internal/profilemanager/config.go
+++ b/client/internal/profilemanager/config.go
@@ -10,7 +10,6 @@ import (
 	"os"
 	"os/user"
 	"path/filepath"
-	"reflect"
 	"runtime"
 	"slices"
 	"strings"
@@ -198,6 +197,11 @@ type Config struct {
 
 	MTU uint16
 
+	// probing marks a config that exists only to be compared against and then
+	// thrown away, so apply() can skip the work that feeds no verdict.
+	// Unexported, so it never reaches the JSON.
+	probing bool
+
 	// policy is the MDM policy that produced the currently-set values
 	// for any MDM-enforced fields. Set by ApplyMDMPolicy on every
 	// invocation. Never persisted to disk. Callers query enforcement
@@ -300,9 +304,11 @@ func fileExists(path string) (bool, error) {
 	return false, err
 }
 
-// createNewConfig creates a new config generating a new Wireguard key and saving to file
-func createNewConfig(input ConfigInput) (*Config, error) {
-	config := &Config{
+// newConfigSkeleton returns the field values a brand-new profile config starts
+// from, before apply() fills in the rest. Shared with the dry-run baseline so
+// the two cannot disagree about what "a new config" means.
+func newConfigSkeleton() *Config {
+	return &Config{
 		// defaults to false only for new (post 0.26) configurations
 		ServerSSHAllowed: util.False(),
 		// Remote jobs are an explicit opt-in and default off, including for
@@ -310,6 +316,91 @@ func createNewConfig(input ConfigInput) (*Config, error) {
 		RemoteJobsAllowed: util.False(),
 		WgPort:            iface.DefaultWgPort,
 	}
+}
+
+// resolveUnsetDefaults is the single place where an optional field that carries
+// no value gets one, and the only place that states what each of those defaults
+// is. apply() runs it before it compares anything, and that ordering is the
+// point: with the values named, every comparison below it diffs values instead
+// of presence.
+//
+// Presence-based comparison is what broke `netbird up` for a client configured
+// through the environment. These fields mean "the effective default" when they
+// hold nothing — every consumer already reads a nil as the value resolved here,
+// the SSH toggles in engine_ssh.go and the network monitor in
+// createEngineConfig — so naming them changes nothing about what runs. But
+// while they stayed nil, an input restating the default read as a change, and
+// since the CLI sends every flag whose value came from an environment variable
+// on each `netbird up`, a client with NB_ENABLE_SSH_ROOT=false restated it
+// every time and the update-settings gate refused it.
+//
+// Filling a field in is not a settings change, so a caller measuring change
+// must not read the returned bool as one: see WouldChange, which runs a pass
+// for this and discards its verdict.
+//
+// ServerSSHAllowed is the one field whose default depends on the config's age.
+// A brand-new profile gets false from newConfigSkeleton, which runs before
+// this, so what is resolved here is only the legacy case: a config written by a
+// version that had no such field keeps SSH on, for backwards compatibility.
+func (config *Config) resolveUnsetDefaults() (updated bool) {
+	// Fields that default to false on every platform.
+	for _, field := range []**bool{
+		&config.EnableSSHRoot,
+		&config.EnableSSHSFTP,
+		&config.EnableSSHLocalPortForwarding,
+		&config.EnableSSHRemotePortForwarding,
+		&config.DisableSSHAuth,
+		// Remote jobs are an explicit opt-in: unlike SSH, a pre-existing config
+		// with no value defaults to disabled rather than being turned on.
+		&config.RemoteJobsAllowed,
+	} {
+		if *field == nil {
+			*field = util.False()
+			updated = true
+		}
+	}
+
+	if config.DisableNotifications == nil {
+		log.Infof("setting notifications to disabled by default")
+		config.DisableNotifications = util.True()
+		updated = true
+	}
+
+	if config.SSHJWTCacheTTL == nil {
+		// A zero TTL disables the JWT cache, which is what no value meant.
+		config.SSHJWTCacheTTL = new(int)
+		updated = true
+	}
+
+	if config.NetworkMonitor == nil {
+		// network monitoring is on by default on windows and darwin clients
+		enabled := runtime.GOOS == "windows" || runtime.GOOS == "darwin"
+		config.NetworkMonitor = &enabled
+		updated = true
+	}
+
+	if config.ServerSSHAllowed == nil {
+		if runtime.GOOS == "android" {
+			// default to disabled SSH on Android for security
+			log.Infof("setting SSH server to false by default on Android")
+			config.ServerSSHAllowed = util.False()
+		} else {
+			// enables SSH for configs from old versions to preserve backwards compatibility
+			log.Infof("falling back to enabled SSH server for pre-existing configuration")
+			config.ServerSSHAllowed = util.True()
+		}
+		updated = true
+	}
+
+	return updated
+}
+
+// createNewConfig resolves a new config in memory, with no identity: whoever
+// needs the peer's keys calls EnsureIdentity and persists the result, so a read
+// that lands on a missing file cannot hand back a config carrying keys that
+// nothing will ever write down.
+func createNewConfig(input ConfigInput) (*Config, error) {
+	config := newConfigSkeleton()
 
 	if _, err := config.apply(input); err != nil {
 		return nil, err
@@ -318,6 +409,52 @@ func createNewConfig(input ConfigInput) (*Config, error) {
 	return config, nil
 }
 
+// createProvisionedConfig is createNewConfig plus the peer's identity, for the
+// callers that go on to persist the config or to connect with it.
+func createProvisionedConfig(input ConfigInput) (*Config, error) {
+	config, err := createNewConfig(input)
+	if err != nil {
+		return nil, err
+	}
+
+	if _, err := config.EnsureIdentity(); err != nil {
+		return nil, err
+	}
+
+	return config, nil
+}
+
+// EnsureIdentity generates the keys that identify this peer if the config does
+// not carry them yet, reporting whether it had to generate any.
+//
+// It is deliberately not part of apply(). Everything apply() fills in is a
+// default it can recompute on the next read, but a generated key is not: it
+// has to be persisted, or the peer comes back with a different WireGuard
+// identity and re-registers. Having apply() generate keys is what forced every
+// read of a config to write it back — so identity provisioning is its own step
+// now, and the callers that perform it write the result out explicitly.
+func (config *Config) EnsureIdentity() (bool, error) {
+	generated := false
+
+	if config.PrivateKey == "" {
+		log.Infof("generated new Wireguard key")
+		config.PrivateKey = generateKey()
+		generated = true
+	}
+
+	if config.SSHKey == "" {
+		log.Infof("generated new SSH key")
+		pem, err := ssh.GeneratePrivateKey(ssh.ED25519)
+		if err != nil {
+			return generated, err
+		}
+		config.SSHKey = string(pem)
+		generated = true
+	}
+
+	return generated, nil
+}
+
 func (config *Config) apply(input ConfigInput) (updated bool, err error) {
 	if config.Name != "" {
 		sanitized, err := sanitizeDisplayName(config.Name)
@@ -329,6 +466,13 @@ func (config *Config) apply(input ConfigInput) (updated bool, err error) {
 			updated = true
 		}
 	}
+
+	// Every optional field gets its value here, before anything below compares
+	// one. See resolveUnsetDefaults for why that ordering is the point.
+	if config.resolveUnsetDefaults() {
+		updated = true
+	}
+
 	if config.ManagementURL == nil {
 		log.Infof("using default Management URL %s", DefaultManagementURL)
 		config.ManagementURL, err = parseURL("Management URL", DefaultManagementURL)
@@ -336,20 +480,21 @@ func (config *Config) apply(input ConfigInput) (updated bool, err error) {
 			return false, err
 		}
 	}
-	if input.ManagementURL != "" && input.ManagementURL != config.ManagementURL.String() {
-		log.Infof("new Management URL provided, updated to %#v (old value %#v)",
-			input.ManagementURL, config.ManagementURL.String())
+	// The comparison is on the endpoint the URL addresses, not on its
+	// spelling: the same endpoint can be written several ways (an implicit
+	// :443, a trailing slash, a different host case), and treating an
+	// equivalent URL as new would rewrite the config and report a settings
+	// change where the configuration does not actually change.
+	if input.ManagementURL != "" {
 		URL, err := parseURL("Management URL", input.ManagementURL)
 		if err != nil {
 			return false, err
 		}
-		config.ManagementURL = URL
-		updated = true
-	} else if config.ManagementURL == nil {
-		log.Infof("using default Management URL %s", DefaultManagementURL)
-		config.ManagementURL, err = parseURL("Management URL", DefaultManagementURL)
-		if err != nil {
-			return false, err
+		if !SameServiceURL(URL, config.ManagementURL) {
+			log.Infof("new Management URL provided, updated to %#v (old value %#v)",
+				URL.String(), config.ManagementURL.String())
+			config.ManagementURL = URL
+			updated = true
 		}
 	}
 
@@ -360,31 +505,20 @@ func (config *Config) apply(input ConfigInput) (updated bool, err error) {
 			return false, err
 		}
 	}
-	if input.AdminURL != "" && input.AdminURL != config.AdminURL.String() {
-		log.Infof("new Admin Panel URL provided, updated to %#v (old value %#v)",
-			input.AdminURL, config.AdminURL.String())
+	// The admin panel is opened, not dialed, so unlike the Management URL its
+	// path is part of what identifies it: a panel served under /netbird is not
+	// the one served at the root.
+	if input.AdminURL != "" {
 		newURL, err := parseURL("Admin Panel URL", input.AdminURL)
 		if err != nil {
 			return updated, err
 		}
-		config.AdminURL = newURL
-		updated = true
-	}
-
-	if config.PrivateKey == "" {
-		log.Infof("generated new Wireguard key")
-		config.PrivateKey = generateKey()
-		updated = true
-	}
-
-	if config.SSHKey == "" {
-		log.Infof("generated new SSH key")
-		pem, err := ssh.GeneratePrivateKey(ssh.ED25519)
-		if err != nil {
-			return false, err
+		if !SameServiceURLIncludingPath(newURL, config.AdminURL) {
+			log.Infof("new Admin Panel URL provided, updated to %#v (old value %#v)",
+				newURL.String(), config.AdminURL.String())
+			config.AdminURL = newURL
+			updated = true
 		}
-		config.SSHKey = string(pem)
-		updated = true
 	}
 
 	if input.WireguardPort != nil && *input.WireguardPort != config.WgPort {
@@ -405,7 +539,14 @@ func (config *Config) apply(input ConfigInput) (updated bool, err error) {
 		updated = true
 	}
 
-	if input.NATExternalIPs != nil && !reflect.DeepEqual(config.NATExternalIPs, input.NATExternalIPs) {
+	// slices.Equal, not reflect.DeepEqual, and for the same reason the DNS
+	// labels below use it: DeepEqual calls a nil slice and an empty one
+	// different, while both mean "no NAT mappings". A profile stores the
+	// absent list as JSON null and reads it back nil, and `netbird up` sends
+	// CleanNATExternalIPs — an empty list — whenever NB_EXTERNAL_IP_MAP is set
+	// to nothing, so the two met on every start and the gate read a no-op as a
+	// settings change.
+	if input.NATExternalIPs != nil && !slices.Equal(config.NATExternalIPs, input.NATExternalIPs) {
 		log.Infof("updating NAT External IP [ %s ] (old value: [ %s ])",
 			strings.Join(input.NATExternalIPs, " "),
 			strings.Join(config.NATExternalIPs, " "))
@@ -443,21 +584,12 @@ func (config *Config) apply(input ConfigInput) (updated bool, err error) {
 		updated = true
 	}
 
-	if input.NetworkMonitor != nil && (config.NetworkMonitor == nil || *input.NetworkMonitor != *config.NetworkMonitor) {
+	if input.NetworkMonitor != nil && *input.NetworkMonitor != *config.NetworkMonitor {
 		log.Infof("switching Network Monitor to %t", *input.NetworkMonitor)
 		config.NetworkMonitor = input.NetworkMonitor
 		updated = true
 	}
 
-	if config.NetworkMonitor == nil {
-		// enable network monitoring by default on windows and darwin clients
-		if runtime.GOOS == "windows" || runtime.GOOS == "darwin" {
-			enabled := true
-			config.NetworkMonitor = &enabled
-			updated = true
-		}
-	}
-
 	if input.CustomDNSAddress != nil && string(input.CustomDNSAddress) != config.CustomDNSAddress {
 		log.Infof("updating custom DNS address %#v (old value %#v)",
 			string(input.CustomDNSAddress), config.CustomDNSAddress)
@@ -490,7 +622,7 @@ func (config *Config) apply(input ConfigInput) (updated bool, err error) {
 		updated = true
 	}
 
-	if input.ServerSSHAllowed != nil && (config.ServerSSHAllowed == nil || *input.ServerSSHAllowed != *config.ServerSSHAllowed) {
+	if input.ServerSSHAllowed != nil && *input.ServerSSHAllowed != *config.ServerSSHAllowed {
 		if *input.ServerSSHAllowed {
 			log.Infof("enabling SSH server")
 		} else {
@@ -498,20 +630,9 @@ func (config *Config) apply(input ConfigInput) (updated bool, err error) {
 		}
 		config.ServerSSHAllowed = input.ServerSSHAllowed
 		updated = true
-	} else if config.ServerSSHAllowed == nil {
-		if runtime.GOOS == "android" {
-			// default to disabled SSH on Android for security
-			log.Infof("setting SSH server to false by default on Android")
-			config.ServerSSHAllowed = util.False()
-		} else {
-			// enables SSH for configs from old versions to preserve backwards compatibility
-			log.Infof("falling back to enabled SSH server for pre-existing configuration")
-			config.ServerSSHAllowed = util.True()
-		}
-		updated = true
 	}
 
-	if input.RemoteJobsAllowed != nil && (config.RemoteJobsAllowed == nil || *input.RemoteJobsAllowed != *config.RemoteJobsAllowed) {
+	if input.RemoteJobsAllowed != nil && *input.RemoteJobsAllowed != *config.RemoteJobsAllowed {
 		if *input.RemoteJobsAllowed {
 			log.Infof("enabling remote jobs")
 		} else {
@@ -519,14 +640,9 @@ func (config *Config) apply(input ConfigInput) (updated bool, err error) {
 		}
 		config.RemoteJobsAllowed = input.RemoteJobsAllowed
 		updated = true
-	} else if config.RemoteJobsAllowed == nil {
-		// Remote jobs are an explicit opt-in: unlike SSH, a pre-existing config
-		// with no value defaults to disabled rather than being turned on.
-		config.RemoteJobsAllowed = util.False()
-		updated = true
 	}
 
-	if input.EnableSSHRoot != nil && (config.EnableSSHRoot == nil || *input.EnableSSHRoot != *config.EnableSSHRoot) {
+	if input.EnableSSHRoot != nil && *input.EnableSSHRoot != *config.EnableSSHRoot {
 		if *input.EnableSSHRoot {
 			log.Infof("enabling SSH root login")
 		} else {
@@ -536,7 +652,7 @@ func (config *Config) apply(input ConfigInput) (updated bool, err error) {
 		updated = true
 	}
 
-	if input.EnableSSHSFTP != nil && (config.EnableSSHSFTP == nil || *input.EnableSSHSFTP != *config.EnableSSHSFTP) {
+	if input.EnableSSHSFTP != nil && *input.EnableSSHSFTP != *config.EnableSSHSFTP {
 		if *input.EnableSSHSFTP {
 			log.Infof("enabling SSH SFTP subsystem")
 		} else {
@@ -546,7 +662,7 @@ func (config *Config) apply(input ConfigInput) (updated bool, err error) {
 		updated = true
 	}
 
-	if input.EnableSSHLocalPortForwarding != nil && (config.EnableSSHLocalPortForwarding == nil || *input.EnableSSHLocalPortForwarding != *config.EnableSSHLocalPortForwarding) {
+	if input.EnableSSHLocalPortForwarding != nil && *input.EnableSSHLocalPortForwarding != *config.EnableSSHLocalPortForwarding {
 		if *input.EnableSSHLocalPortForwarding {
 			log.Infof("enabling SSH local port forwarding")
 		} else {
@@ -556,7 +672,7 @@ func (config *Config) apply(input ConfigInput) (updated bool, err error) {
 		updated = true
 	}
 
-	if input.EnableSSHRemotePortForwarding != nil && (config.EnableSSHRemotePortForwarding == nil || *input.EnableSSHRemotePortForwarding != *config.EnableSSHRemotePortForwarding) {
+	if input.EnableSSHRemotePortForwarding != nil && *input.EnableSSHRemotePortForwarding != *config.EnableSSHRemotePortForwarding {
 		if *input.EnableSSHRemotePortForwarding {
 			log.Infof("enabling SSH remote port forwarding")
 		} else {
@@ -566,7 +682,7 @@ func (config *Config) apply(input ConfigInput) (updated bool, err error) {
 		updated = true
 	}
 
-	if input.DisableSSHAuth != nil && (config.DisableSSHAuth == nil || *input.DisableSSHAuth != *config.DisableSSHAuth) {
+	if input.DisableSSHAuth != nil && *input.DisableSSHAuth != *config.DisableSSHAuth {
 		if *input.DisableSSHAuth {
 			log.Infof("disabling SSH authentication")
 		} else {
@@ -576,7 +692,7 @@ func (config *Config) apply(input ConfigInput) (updated bool, err error) {
 		updated = true
 	}
 
-	if input.SSHJWTCacheTTL != nil && (config.SSHJWTCacheTTL == nil || *input.SSHJWTCacheTTL != *config.SSHJWTCacheTTL) {
+	if input.SSHJWTCacheTTL != nil && *input.SSHJWTCacheTTL != *config.SSHJWTCacheTTL {
 		log.Infof("updating SSH JWT cache TTL to %d seconds", *input.SSHJWTCacheTTL)
 		config.SSHJWTCacheTTL = input.SSHJWTCacheTTL
 		updated = true
@@ -659,13 +775,16 @@ func (config *Config) apply(input ConfigInput) (updated bool, err error) {
 		updated = true
 	}
 
-	if input.SyncMessageVersion != nil && *input.SyncMessageVersion != *config.SyncMessageVersion {
+	// Assigning the pointer, not writing through it: a config that carries no
+	// version yet would otherwise be a nil dereference, and a panic inside a
+	// request handler is not a way to fail.
+	if input.SyncMessageVersion != nil && (config.SyncMessageVersion == nil || *input.SyncMessageVersion != *config.SyncMessageVersion) {
 		log.Infof("setting SyncMessageVersion to %v", *input.SyncMessageVersion)
-		*config.SyncMessageVersion = *input.SyncMessageVersion
+		config.SyncMessageVersion = input.SyncMessageVersion
 		updated = true
 	}
 
-	if input.DisableNotifications != nil && (config.DisableNotifications == nil || *input.DisableNotifications != *config.DisableNotifications) {
+	if input.DisableNotifications != nil && *input.DisableNotifications != *config.DisableNotifications {
 		if *input.DisableNotifications {
 			log.Infof("disabling notifications")
 		} else {
@@ -675,24 +794,24 @@ func (config *Config) apply(input ConfigInput) (updated bool, err error) {
 		updated = true
 	}
 
-	if config.DisableNotifications == nil {
-		disabled := true
-		config.DisableNotifications = &disabled
-		log.Infof("setting notifications to disabled by default")
-		updated = true
-	}
-
-	if input.ClientCertKeyPath != "" {
+	// Compared, not just assigned: restating the path a config already holds
+	// changes nothing, and reporting it as an update makes a caller that
+	// re-sends its own configuration look like one asking to change it.
+	if input.ClientCertKeyPath != "" && input.ClientCertKeyPath != config.ClientCertKeyPath {
 		config.ClientCertKeyPath = input.ClientCertKeyPath
 		updated = true
 	}
 
-	if input.ClientCertPath != "" {
+	if input.ClientCertPath != "" && input.ClientCertPath != config.ClientCertPath {
 		config.ClientCertPath = input.ClientCertPath
 		updated = true
 	}
 
-	if config.ClientCertPath != "" && config.ClientCertKeyPath != "" {
+	// Not on a probe: the loaded pair feeds the connection, never the
+	// comparison, and this would otherwise run on every gated SetConfig and
+	// Login — twice per request — including those that are refused or change
+	// nothing, logging an error per request when the files are missing.
+	if !config.probing && config.ClientCertPath != "" && config.ClientCertKeyPath != "" {
 		cert, err := tls.LoadX509KeyPair(config.ClientCertPath, config.ClientCertKeyPath)
 		if err != nil {
 			log.Error("Failed to load mTLS cert/key pair: ", err)
@@ -886,6 +1005,49 @@ func ParseServiceURL(serviceName, serviceURL string) (*url.URL, error) {
 	return parseURL(serviceName, serviceURL)
 }
 
+// SameServiceURL reports whether two service URLs address the same endpoint:
+// same scheme, same host compared case-insensitively as DNS names are, and
+// same effective port, where an absent port means the scheme's default.
+//
+// This is the one comparison every caller deciding "did this URL change?" must
+// use. A string comparison answers a different question: "https://host",
+// "https://host/" and "https://HOST:443" are one endpoint written three ways,
+// and reading them as three values makes a client that restates its own
+// management URL look like a client asking to be repointed. A nil operand
+// matches only another nil one.
+//
+// The path plays no part: a management URL is dialed, and only its host and
+// port are. util.SameServiceURL is this comparison plus the path, which is
+// what SameServiceURLIncludingPath needs and delegates to.
+func SameServiceURL(a, b *url.URL) bool {
+	if a == nil || b == nil {
+		return a == b
+	}
+
+	return strings.EqualFold(a.Scheme, b.Scheme) &&
+		strings.EqualFold(a.Hostname(), b.Hostname()) &&
+		util.ServiceURLPort(a) == util.ServiceURLPort(b)
+}
+
+// SameServiceURLIncludingPath is SameServiceURL plus everything a URL carries
+// past its endpoint: path, query, fragment and userinfo.
+//
+// Use it for a URL that gets opened rather than dialed. The admin panel can
+// live under a path, so two URLs with the same endpoint and different paths are
+// two different panels — where for a URL the client dials over gRPC only the
+// endpoint is ever used. Equivalent spellings still compare equal: a missing
+// path and "/" are the same root, and so is a trailing slash on any path.
+func SameServiceURLIncludingPath(a, b *url.URL) bool {
+	if a == nil || b == nil {
+		return a == b
+	}
+
+	return util.SameServiceURL(a, b) &&
+		a.RawQuery == b.RawQuery &&
+		a.Fragment == b.Fragment &&
+		a.User.String() == b.User.String()
+}
+
 func parseURL(serviceName, serviceURL string) (*url.URL, error) {
 	parsedMgmtURL, err := url.ParseRequestURI(serviceURL)
 	if err != nil {
@@ -930,6 +1092,84 @@ func isPreSharedKeyHidden(preSharedKey *string) bool {
 	return false
 }
 
+// WouldChange reports whether applying input would modify any field the
+// config persists, leaving the receiver untouched. It is the dry-run half of
+// UpdateConfig and reuses the very same diff logic (Config.apply), so a
+// caller asking "is this a settings change?" cannot drift from what an
+// actual update would do, nor go stale when a new field is added.
+//
+// A redacted pre-shared key is collapsed to "unset" exactly as
+// UpdateOrCreateConfig does, so a UI that round-trips the mask is not read as
+// a request for a new key.
+//
+// A nil receiver means the profile holds no config yet, so the baseline is the
+// config the daemon would create for it: input values matching those defaults
+// change nothing, anything else does.
+func (config *Config) WouldChange(input ConfigInput) (bool, error) {
+	probe := config.clone()
+	if probe == nil {
+		baseline, err := newDryRunBaseline(input.ConfigPath)
+		if err != nil {
+			return true, fmt.Errorf("build default config baseline: %w", err)
+		}
+		probe = baseline
+	}
+	probe.probing = true
+
+	// Normalize before measuring. apply() reports two different things through
+	// one bool: an input that changed a value, and a field it had to fill in
+	// because the config carried none. Only the first is a settings change, so
+	// the filling-in gets a pass of its own whose verdict is discarded, and the
+	// pass that answers the caller runs against a config with nothing left to
+	// fill in.
+	//
+	// Readers already hand out normalized configs — readConfig applies an empty
+	// input for this very reason — so this is normally a no-op. But a gate that
+	// refuses a request must not depend on where its caller got the config
+	// from, and it must not start reading "this profile predates a field" as
+	// "the caller asked for a change" the day someone adds one.
+	if _, err := probe.apply(ConfigInput{ConfigPath: input.ConfigPath}); err != nil {
+		return true, fmt.Errorf("normalize the config to diff against: %w", err)
+	}
+
+	if isPreSharedKeyHidden(input.PreSharedKey) {
+		input.PreSharedKey = nil
+	}
+
+	return probe.apply(input)
+}
+
+// newDryRunBaseline builds the config a brand-new profile would start from, for
+// a dry run to compare an input against. It is createNewConfig without the
+// identity: this config exists only to be compared against and thrown away, and
+// no ConfigInput field maps to either key.
+func newDryRunBaseline(configPath string) (*Config, error) {
+	baseline := newConfigSkeleton()
+
+	if _, err := baseline.apply(ConfigInput{ConfigPath: configPath}); err != nil {
+		return nil, err
+	}
+
+	return baseline, nil
+}
+
+// clone returns a copy of the config that apply can be run against without the
+// original observing the writes, or nil for a nil receiver. Only what apply
+// mutates in place needs detaching, which is the slices it replaces or appends
+// to: every pointer field it touches is reassigned rather than written through,
+// and ClientCertKeyPair is only overwritten.
+func (config *Config) clone() *Config {
+	if config == nil {
+		return nil
+	}
+
+	probe := *config
+	probe.IFaceBlackList = slices.Clone(config.IFaceBlackList)
+	probe.NATExternalIPs = slices.Clone(config.NATExternalIPs)
+	probe.DNSLabels = slices.Clone(config.DNSLabels)
+	return &probe
+}
+
 // UpdateConfig update existing configuration according to input configuration and return with the configuration
 func UpdateConfig(input ConfigInput) (*Config, error) {
 	configExists, err := fileExists(input.ConfigPath)
@@ -940,6 +1180,14 @@ func UpdateConfig(input ConfigInput) (*Config, error) {
 		return nil, fmt.Errorf("config file %s does not exist", input.ConfigPath)
 	}
 
+	// A UI that round-trips the mask GetConfig hands it back is asking to keep
+	// the stored key, not to set the mask as the new one. UpdateOrCreateConfig
+	// and DirectUpdateOrCreateConfig already collapse it; this one did not, so
+	// the same round-trip through SetConfig replaced the key with asterisks.
+	if isPreSharedKeyHidden(input.PreSharedKey) {
+		input.PreSharedKey = nil
+	}
+
 	return update(input)
 }
 
@@ -951,7 +1199,7 @@ func UpdateOrCreateConfig(input ConfigInput) (*Config, error) {
 	}
 	if !configExists {
 		log.Infof("generating new config %s", input.ConfigPath)
-		cfg, err := createNewConfig(input)
+		cfg, err := createProvisionedConfig(input)
 		if err != nil {
 			return nil, err
 		}
@@ -976,12 +1224,20 @@ func update(input ConfigInput) (*Config, error) {
 		return nil, err
 	}
 
+	// A write path is a provisioning point: a stored profile can legitimately
+	// carry no identity (a mobile logout clears the keys in place), and the
+	// next config write is what has to mint a new one. Reads leave that alone.
+	identityGenerated, err := config.EnsureIdentity()
+	if err != nil {
+		return nil, err
+	}
+
 	updated, err := config.apply(input)
 	if err != nil {
 		return nil, err
 	}
 
-	if updated {
+	if updated || identityGenerated {
 		if err := util.WriteJson(context.Background(), input.ConfigPath, config); err != nil {
 			return nil, err
 		}
@@ -990,8 +1246,8 @@ func update(input ConfigInput) (*Config, error) {
 	return config, nil
 }
 
-// GetConfig read config file and return with Config and if it was created. Errors out if it does not exist
-func GetConfig(configPath string) (*Config, error) {
+// GetExistingConfig reads and returns the config if it exists on disk. Fails otherwise.
+func GetExistingConfig(configPath string) (*Config, error) {
 	return readConfig(configPath, false)
 }
 
@@ -1074,17 +1330,27 @@ func UpdateOldManagementURL(ctx context.Context, config *Config, configPath stri
 	return newConfig, nil
 }
 
-// CreateInMemoryConfig generate a new config but do not write out it to the store
+// CreateInMemoryConfig generate a new config but do not write out it to the store.
+// It carries an identity: callers connect with what they get back.
 func CreateInMemoryConfig(input ConfigInput) (*Config, error) {
-	return createNewConfig(input)
+	return createProvisionedConfig(input)
 }
 
-// ReadConfig read config file and return with Config. If it is not exists create a new with default values
-func ReadConfig(configPath string) (*Config, error) {
+// ReadConfigOrDefault reads the profile config at configPath, or resolves the
+// default config in memory when the file does not exist. It never writes, and
+// never mints an identity — EnsureIdentity is where that happens, so the
+// caller that provisions is also the one that persists.
+func ReadConfigOrDefault(configPath string) (*Config, error) {
 	return readConfig(configPath, true)
 }
 
-// ReadConfig read config file and return with Config. If it is not exists create a new with default values
+// readConfig reads the profile config at configPath. createIfMissing resolves a
+// default config in memory when the file is absent, rather than erroring.
+//
+// Reads are pure. This used to write the config back whenever apply() had to
+// fill in a default the file was missing, which quietly made every reader a
+// writer: a gate deciding whether to refuse a request, a UI listing profiles,
+// a mobile getter reading a single preference.
 func readConfig(configPath string, createIfMissing bool) (*Config, error) {
 	configExists, err := fileExists(configPath)
 	if err != nil {
@@ -1102,12 +1368,8 @@ func readConfig(configPath string, createIfMissing bool) (*Config, error) {
 			return nil, err
 		}
 		// initialize through apply() without changes
-		if changed, err := config.apply(ConfigInput{}); err != nil {
+		if _, err := config.apply(ConfigInput{}); err != nil {
 			return nil, err
-		} else if changed {
-			if err = WriteOutConfig(configPath, config); err != nil {
-				return nil, err
-			}
 		}
 
 		return config, nil
@@ -1115,13 +1377,7 @@ func readConfig(configPath string, createIfMissing bool) (*Config, error) {
 		return nil, fmt.Errorf("config file %s does not exist", configPath)
 	}
 
-	cfg, err := createNewConfig(ConfigInput{ConfigPath: configPath})
-	if err != nil {
-		return nil, err
-	}
-
-	err = WriteOutConfig(configPath, cfg)
-	return cfg, err
+	return createNewConfig(ConfigInput{ConfigPath: configPath})
 }
 
 // WriteOutConfig write put the prepared config to the given path
@@ -1144,7 +1400,7 @@ func DirectUpdateOrCreateConfig(input ConfigInput) (*Config, error) {
 	}
 	if !configExists {
 		log.Infof("generating new config %s", input.ConfigPath)
-		cfg, err := createNewConfig(input)
+		cfg, err := createProvisionedConfig(input)
 		if err != nil {
 			return nil, err
 		}
@@ -1171,12 +1427,18 @@ func directUpdate(input ConfigInput) (*Config, error) {
 		return nil, err
 	}
 
+	// Same provisioning point as update(); see the note there.
+	identityGenerated, err := config.EnsureIdentity()
+	if err != nil {
+		return nil, err
+	}
+
 	updated, err := config.apply(input)
 	if err != nil {
 		return nil, err
 	}
 
-	if updated {
+	if updated || identityGenerated {
 		if err := util.DirectWriteJson(context.Background(), input.ConfigPath, config); err != nil {
 			return nil, err
 		}
@@ -1198,7 +1460,16 @@ func ConfigToJSON(config *Config) (string, error) {
 
 // ConfigFromJSON deserializes a JSON string to a Config struct.
 // This is useful for restoring config from alternative storage mechanisms.
-// After unmarshaling, defaults are applied to ensure the config is fully initialized.
+// After unmarshaling, defaults are applied to ensure the config is fully
+// initialized.
+//
+// The peer identity is deliberately none of its business, in either direction.
+// It does not generate one: a read cannot hand back keys that nothing will
+// write down (see ReadConfigOrDefault). Nor does it refuse a document that
+// carries none, because a config legitimately has no identity between a logout
+// and the next login — mobile logout clears both keys in place — and this is
+// also the deserializer the iOS SDK copies a config through. Whoever goes on
+// to connect is where an absent identity has to be answered.
 func ConfigFromJSON(jsonStr string) (*Config, error) {
 	config := &Config{}
 	err := json.Unmarshal([]byte(jsonStr), config)
diff --git a/client/internal/profilemanager/config_json_test.go b/client/internal/profilemanager/config_json_test.go
new file mode 100644
index 000000000..9a6d820c4
--- /dev/null
+++ b/client/internal/profilemanager/config_json_test.go
@@ -0,0 +1,44 @@
+package profilemanager
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+// The serialized form is how the tvOS SDK stores a profile and how the iOS SDK
+// copies one in memory, so it must round-trip whatever a profile legitimately
+// holds — including no identity at all, which is the state mobile logout leaves
+// behind when it clears both keys in place. Refusing that document here broke
+// logout, profile switching and the login that follows them.
+func TestConfigFromJSONRoundTripsALoggedOutProfile(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "exported.json")
+	stored, err := UpdateOrCreateConfig(ConfigInput{ConfigPath: path, ManagementURL: DefaultManagementURL})
+	require.NoError(t, err)
+	require.NotEmpty(t, stored.PrivateKey, "a provisioned config is the fixture this test starts from")
+	require.NotEmpty(t, stored.SSHKey)
+
+	exported, err := ConfigToJSON(stored)
+	require.NoError(t, err)
+
+	restored, err := ConfigFromJSON(exported)
+	require.NoError(t, err, "a config exported after a login must load")
+	require.Equal(t, stored.PrivateKey, restored.PrivateKey, "the restored peer is not the stored one")
+	require.Equal(t, stored.SSHKey, restored.SSHKey)
+
+	// What mobile logout leaves on disk.
+	loggedOut := stored.clone()
+	loggedOut.PrivateKey = ""
+	loggedOut.SSHKey = ""
+
+	document, err := ConfigToJSON(loggedOut)
+	require.NoError(t, err)
+
+	reloaded, err := ConfigFromJSON(document)
+	require.NoError(t, err, "a logged-out profile must still load")
+	require.Empty(t, reloaded.PrivateKey, "loading must not mint a key nothing will write down")
+	require.Empty(t, reloaded.SSHKey)
+	require.Equal(t, stored.ManagementURL.String(), reloaded.ManagementURL.String(),
+		"the rest of the profile survives the logout")
+}
diff --git a/client/internal/profilemanager/config_optional_fields_test.go b/client/internal/profilemanager/config_optional_fields_test.go
new file mode 100644
index 000000000..9b74e2217
--- /dev/null
+++ b/client/internal/profilemanager/config_optional_fields_test.go
@@ -0,0 +1,131 @@
+package profilemanager
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"reflect"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+// optionalBoolFields lists the *bool fields of Config by name, derived from the
+// type so a field added later is covered without touching these tests.
+func optionalBoolFields() []string {
+	pointerToBool := reflect.TypeOf((*bool)(nil))
+
+	var fields []string
+	configType := reflect.TypeOf(Config{})
+	for i := range configType.NumField() {
+		field := configType.Field(i)
+		if field.Type == pointerToBool && field.Tag.Get("json") != "-" {
+			fields = append(fields, field.Name)
+		}
+	}
+	return fields
+}
+
+func requireNoUnsetOptionalBool(t *testing.T, config *Config, context string) {
+	t.Helper()
+
+	value := reflect.ValueOf(*config)
+	for _, name := range optionalBoolFields() {
+		require.False(t, value.FieldByName(name).IsNil(),
+			"%s left %s unset, so its readers have to invent a default and a diff of it compares presence instead of value", context, name)
+	}
+}
+
+// An optional bool must not be tristate. While one can be nil, true or false,
+// every reader has to invent the meaning of nil, and — the reason this test
+// exists — a diff of the config ends up comparing presence rather than value:
+// that is what made the update-settings gate refuse `netbird up` for a client
+// restating its own defaults. apply() is where a config becomes complete, so
+// the invariant belongs to it: no *bool may come out of apply() unset.
+func TestApplyLeavesNoOptionalBoolUnset(t *testing.T) {
+	require.NotEmpty(t, optionalBoolFields(), "the invariant is only meaningful while Config has optional bools")
+
+	t.Run("a config built from scratch", func(t *testing.T) {
+		config := newConfigSkeleton()
+		_, err := config.apply(ConfigInput{})
+		require.NoError(t, err)
+
+		requireNoUnsetOptionalBool(t, config, "apply on a new config")
+	})
+
+	t.Run("a config file that predates every optional field", func(t *testing.T) {
+		path := filepath.Join(t.TempDir(), "legacy.json")
+		require.NoError(t, os.WriteFile(path, []byte(`{"WgIface":"wt0"}`), 0o600))
+
+		config, err := GetExistingConfig(path)
+		require.NoError(t, err)
+
+		requireNoUnsetOptionalBool(t, config, "a read of a legacy config")
+	})
+
+	t.Run("a config file that stores them as null", func(t *testing.T) {
+		path := filepath.Join(t.TempDir(), "null.json")
+		_, err := UpdateOrCreateConfig(ConfigInput{ConfigPath: path})
+		require.NoError(t, err)
+		unsetOnDisk(t, path, optionalBoolFields()...)
+
+		config, err := GetExistingConfig(path)
+		require.NoError(t, err)
+
+		requireNoUnsetOptionalBool(t, config, "a read of a config storing nulls")
+	})
+}
+
+// The same invariant on disk: what a write leaves in the file is what the next
+// client to read it starts from, so no write may store a null.
+func TestNoWriteStoresAnUnsetOptionalBool(t *testing.T) {
+	requireNoNullOnDisk := func(t *testing.T, path string, context string) {
+		t.Helper()
+
+		raw, err := os.ReadFile(path)
+		require.NoError(t, err)
+
+		var stored map[string]json.RawMessage
+		require.NoError(t, json.Unmarshal(raw, &stored))
+
+		for _, name := range optionalBoolFields() {
+			value, present := stored[name]
+			require.True(t, present, "%s did not store %s at all", context, name)
+			require.NotEqual(t, "null", string(value), "%s stored %s as null", context, name)
+		}
+	}
+
+	t.Run("UpdateOrCreateConfig", func(t *testing.T) {
+		path := filepath.Join(t.TempDir(), "created.json")
+		_, err := UpdateOrCreateConfig(ConfigInput{ConfigPath: path, ManagementURL: DefaultManagementURL})
+		require.NoError(t, err)
+
+		requireNoNullOnDisk(t, path, "UpdateOrCreateConfig")
+	})
+
+	t.Run("UpdateConfig over a config storing nulls", func(t *testing.T) {
+		path := filepath.Join(t.TempDir(), "stored.json")
+		_, err := UpdateOrCreateConfig(ConfigInput{ConfigPath: path})
+		require.NoError(t, err)
+		unsetOnDisk(t, path, optionalBoolFields()...)
+
+		_, err = UpdateConfig(ConfigInput{ConfigPath: path, ManagementURL: "https://mgmt.example.com"})
+		require.NoError(t, err)
+
+		requireNoNullOnDisk(t, path, "UpdateConfig")
+	})
+
+	// Renaming used to copy the file back through a bare Unmarshal, which
+	// preserved the nulls a pre-fix client had written.
+	t.Run("RenameProfile", func(t *testing.T) {
+		withTestSM(t, func(sm *ServiceManager, username string) {
+			created, err := sm.AddProfile("work", username)
+			require.NoError(t, err)
+			unsetOnDisk(t, created.Path, optionalBoolFields()...)
+
+			require.NoError(t, sm.RenameProfile(created.ID, username, "office"))
+
+			requireNoNullOnDisk(t, created.Path, "RenameProfile")
+		})
+	})
+}
diff --git a/client/internal/profilemanager/config_probe_test.go b/client/internal/profilemanager/config_probe_test.go
new file mode 100644
index 000000000..35a179a84
--- /dev/null
+++ b/client/internal/profilemanager/config_probe_test.go
@@ -0,0 +1,96 @@
+package profilemanager
+
+import (
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/pem"
+	"math/big"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+// writeCertPair writes a throwaway certificate and key, so apply() has
+// something real to load rather than a missing file it would only log about.
+func writeCertPair(t *testing.T) (certPath, keyPath string) {
+	t.Helper()
+
+	key, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	require.NoError(t, err)
+
+	template := x509.Certificate{
+		SerialNumber: big.NewInt(1),
+		Subject:      pkix.Name{CommonName: "probe-test"},
+		NotBefore:    time.Now().Add(-time.Hour),
+		NotAfter:     time.Now().Add(time.Hour),
+	}
+	der, err := x509.CreateCertificate(rand.Reader, &template, &template, &key.PublicKey, key)
+	require.NoError(t, err)
+
+	keyDER, err := x509.MarshalECPrivateKey(key)
+	require.NoError(t, err)
+
+	dir := t.TempDir()
+	certPath = filepath.Join(dir, "client.crt")
+	keyPath = filepath.Join(dir, "client.key")
+	require.NoError(t, os.WriteFile(certPath, pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: der}), 0o600))
+	require.NoError(t, os.WriteFile(keyPath, pem.EncodeToMemory(&pem.Block{Type: "EC PRIVATE KEY", Bytes: keyDER}), 0o600))
+	return certPath, keyPath
+}
+
+// The dry run behind the update-settings gate must not read the mTLS pair off
+// disk. The loaded pair feeds the connection, never the comparison, and the
+// gate runs it on every SetConfig and Login — twice per request — including the
+// ones it refuses.
+func TestProbeDoesNotLoadTheCertificatePair(t *testing.T) {
+	certPath, keyPath := writeCertPair(t)
+
+	t.Run("a real apply loads it", func(t *testing.T) {
+		config := newConfigSkeleton()
+		config.ClientCertPath, config.ClientCertKeyPath = certPath, keyPath
+
+		_, err := config.apply(ConfigInput{})
+		require.NoError(t, err)
+		require.NotNil(t, config.ClientCertKeyPair, "the connection would have no client certificate")
+	})
+
+	t.Run("a probe does not", func(t *testing.T) {
+		config := newConfigSkeleton()
+		config.ClientCertPath, config.ClientCertKeyPath = certPath, keyPath
+		config.probing = true
+
+		_, err := config.apply(ConfigInput{})
+		require.NoError(t, err)
+		require.Nil(t, config.ClientCertKeyPair, "the dry run read the certificate off disk")
+	})
+
+	// And the verdict is the same either way, which is the only thing the gate
+	// asks of the probe.
+	t.Run("the verdict is unaffected", func(t *testing.T) {
+		path := filepath.Join(t.TempDir(), "mtls.json")
+		_, err := UpdateOrCreateConfig(ConfigInput{
+			ConfigPath:        path,
+			ManagementURL:     DefaultManagementURL,
+			ClientCertPath:    certPath,
+			ClientCertKeyPath: keyPath,
+		})
+		require.NoError(t, err)
+
+		stored, err := GetExistingConfig(path)
+		require.NoError(t, err)
+
+		changed, err := stored.WouldChange(ConfigInput{ClientCertPath: certPath, ClientCertKeyPath: keyPath})
+		require.NoError(t, err)
+		require.False(t, changed, "restating the stored certificate paths is not a change")
+
+		changed, err = stored.WouldChange(ConfigInput{ClientCertPath: filepath.Join(t.TempDir(), "other.crt")})
+		require.NoError(t, err)
+		require.True(t, changed, "a different certificate path is a change")
+	})
+}
diff --git a/client/internal/profilemanager/config_test.go b/client/internal/profilemanager/config_test.go
index 248920b5e..a461aa71f 100644
--- a/client/internal/profilemanager/config_test.go
+++ b/client/internal/profilemanager/config_test.go
@@ -196,7 +196,7 @@ func TestWireguardPortZeroExplicit(t *testing.T) {
 	assert.Equal(t, 0, config.WgPort, "WgPort should be 0 when explicitly set by user")
 
 	// Verify it persists
-	readConfig, err := GetConfig(configPath)
+	readConfig, err := GetExistingConfig(configPath)
 	require.NoError(t, err)
 	assert.Equal(t, 0, readConfig.WgPort, "WgPort should remain 0 after reading from file")
 }
diff --git a/client/internal/profilemanager/config_would_change_test.go b/client/internal/profilemanager/config_would_change_test.go
new file mode 100644
index 000000000..6b140030f
--- /dev/null
+++ b/client/internal/profilemanager/config_would_change_test.go
@@ -0,0 +1,529 @@
+package profilemanager
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"runtime"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/netbirdio/netbird/client/iface"
+	"github.com/netbirdio/netbird/shared/management/domain"
+)
+
+func seededConfig(t *testing.T) *Config {
+	t.Helper()
+
+	path := filepath.Join(t.TempDir(), "seeded.json")
+	cfg, err := UpdateOrCreateConfig(ConfigInput{
+		ConfigPath:    path,
+		ManagementURL: "https://api.netbird.io:443",
+		PreSharedKey:  strPointer("stored-key"),
+	})
+	require.NoError(t, err)
+	return cfg
+}
+
+func strPointer(s string) *string { return &s }
+
+func intPtr(i int) *int { return &i }
+
+func TestWouldChange(t *testing.T) {
+	tests := []struct {
+		name  string
+		input ConfigInput
+		want  bool
+	}{
+		{name: "empty input", input: ConfigInput{}, want: false},
+		{name: "same management URL", input: ConfigInput{ManagementURL: "https://api.netbird.io:443"}, want: false},
+		{name: "management URL without its default port", input: ConfigInput{ManagementURL: "https://api.netbird.io"}, want: false},
+		{name: "different management URL", input: ConfigInput{ManagementURL: "https://other.example:443"}, want: true},
+		{name: "same pre-shared key", input: ConfigInput{PreSharedKey: strPointer("stored-key")}, want: false},
+		{name: "redacted pre-shared key", input: ConfigInput{PreSharedKey: strPointer("**********")}, want: false},
+		{name: "different pre-shared key", input: ConfigInput{PreSharedKey: strPointer("other-key")}, want: true},
+		{name: "new interface blacklist entry", input: ConfigInput{ExtraIFaceBlackList: []string{"nb-probe0"}}, want: true},
+		{name: "blacklist entry already present", input: ConfigInput{ExtraIFaceBlackList: []string{"lo"}}, want: false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			cfg := seededConfig(t)
+
+			changed, err := cfg.WouldChange(tt.input)
+			require.NoError(t, err)
+			require.Equal(t, tt.want, changed)
+		})
+	}
+}
+
+// The dry run must not be observable on the config it is run against: it
+// decides whether a write is allowed, it does not perform one.
+func TestWouldChangeLeavesTheConfigAlone(t *testing.T) {
+	cfg := seededConfig(t)
+	blacklist := len(cfg.IFaceBlackList)
+
+	changed, err := cfg.WouldChange(ConfigInput{
+		ManagementURL:       "https://other.example:443",
+		PreSharedKey:        strPointer("other-key"),
+		ExtraIFaceBlackList: []string{"nb-probe0"},
+		DNSLabels:           domain.FromPunycodeList([]string{"probe"}),
+		NATExternalIPs:      []string{"1.2.3.4"},
+	})
+	require.NoError(t, err)
+	require.True(t, changed)
+
+	require.Equal(t, "https://api.netbird.io:443", cfg.ManagementURL.String())
+	require.Equal(t, "stored-key", cfg.PreSharedKey)
+	require.Len(t, cfg.IFaceBlackList, blacklist)
+	require.Empty(t, cfg.DNSLabels)
+	require.Empty(t, cfg.NATExternalIPs)
+}
+
+// A nil config means the profile holds nothing yet, so the baseline is what
+// the daemon would create for it.
+func TestWouldChangeWithoutAStoredConfig(t *testing.T) {
+	var cfg *Config
+
+	changed, err := cfg.WouldChange(ConfigInput{})
+	require.NoError(t, err)
+	require.False(t, changed, "a request carrying nothing cannot change anything")
+
+	changed, err = cfg.WouldChange(ConfigInput{ManagementURL: DefaultManagementURL})
+	require.NoError(t, err)
+	require.False(t, changed, "the default management URL is what would be written anyway")
+
+	changed, err = cfg.WouldChange(ConfigInput{ManagementURL: "https://other.example:443"})
+	require.NoError(t, err)
+	require.True(t, changed)
+}
+
+func TestWouldChangeReportsAnInvalidInput(t *testing.T) {
+	cfg := seededConfig(t)
+
+	_, err := cfg.WouldChange(ConfigInput{ManagementURL: "not-a-url"})
+	require.Error(t, err)
+}
+
+// Reads must not write. A config file missing a field apply() fills in (MTU,
+// here) is what used to trigger the write-back.
+func TestReadsDoNotWriteTheConfigBack(t *testing.T) {
+	denormalized := []byte(`{"WgIface":"wt0"}`)
+
+	for name, read := range map[string]func(string) (*Config, error){
+		"GetExistingConfig":   GetExistingConfig,
+		"ReadConfigOrDefault": ReadConfigOrDefault,
+	} {
+		t.Run(name, func(t *testing.T) {
+			path := filepath.Join(t.TempDir(), "profile.json")
+			require.NoError(t, os.WriteFile(path, denormalized, 0o600))
+
+			cfg, err := read(path)
+			require.NoError(t, err)
+			require.Equal(t, uint16(iface.DefaultMTU), cfg.MTU, "the returned config is still normalized in memory")
+			require.Empty(t, cfg.PrivateKey, "a read must not mint an identity either")
+
+			after, err := os.ReadFile(path)
+			require.NoError(t, err)
+			require.Equal(t, string(denormalized), string(after), "%s rewrote the config file", name)
+		})
+	}
+}
+
+// ReadConfigOrDefault resolves a default config for a profile that has no file
+// yet, and that must not create the file either.
+func TestReadConfigDoesNotCreateTheFile(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "absent.json")
+
+	cfg, err := ReadConfigOrDefault(path)
+	require.NoError(t, err)
+	require.Equal(t, DefaultManagementURL, cfg.ManagementURL.String())
+
+	_, err = os.Stat(path)
+	require.True(t, os.IsNotExist(err), "ReadConfigOrDefault created the config file")
+}
+
+// The identity is the one thing a read cannot recompute, so it is provisioned
+// on request and its caller persists it.
+func TestEnsureIdentity(t *testing.T) {
+	cfg := newConfigSkeleton()
+
+	generated, err := cfg.EnsureIdentity()
+	require.NoError(t, err)
+	require.True(t, generated)
+	require.NotEmpty(t, cfg.PrivateKey)
+	require.NotEmpty(t, cfg.SSHKey)
+
+	key := cfg.PrivateKey
+	generated, err = cfg.EnsureIdentity()
+	require.NoError(t, err)
+	require.False(t, generated, "a config that already has an identity keeps it")
+	require.Equal(t, key, cfg.PrivateKey)
+}
+
+// One endpoint written several ways is one endpoint. A gate that compared
+// spellings refused a client restating its own management URL with a trailing
+// slash, which is a normal way to write it.
+func TestSameServiceURL(t *testing.T) {
+	tests := []struct {
+		a, b string
+		want bool
+	}{
+		{a: "https://mgmt.example.com", b: "https://mgmt.example.com:443", want: true},
+		{a: "https://mgmt.example.com", b: "https://mgmt.example.com/", want: true},
+		{a: "https://mgmt.example.com/", b: "https://mgmt.example.com:443/", want: true},
+		{a: "https://MGMT.example.com", b: "https://mgmt.example.com", want: true},
+		{a: "http://mgmt.example.com", b: "http://mgmt.example.com:80", want: true},
+		{a: "https://mgmt.example.com", b: "http://mgmt.example.com", want: false},
+		{a: "https://mgmt.example.com", b: "https://mgmt.example.com:8443", want: false},
+		{a: "https://mgmt.example.com", b: "https://other.example.com", want: false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.a+" vs "+tt.b, func(t *testing.T) {
+			a, err := ParseServiceURL("a", tt.a)
+			require.NoError(t, err)
+			b, err := ParseServiceURL("b", tt.b)
+			require.NoError(t, err)
+
+			require.Equal(t, tt.want, SameServiceURL(a, b))
+			require.Equal(t, tt.want, SameServiceURL(b, a), "the comparison must be symmetric")
+		})
+	}
+}
+
+// The same spellings, through the dry run the update-settings gate uses.
+func TestWouldChangeIgnoresURLSpelling(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "seeded.json")
+	_, err := UpdateOrCreateConfig(ConfigInput{
+		ConfigPath:    path,
+		ManagementURL: "https://mgmt.example.com",
+	})
+	require.NoError(t, err)
+
+	cfg, err := GetExistingConfig(path)
+	require.NoError(t, err)
+
+	for _, spelling := range []string{
+		"https://mgmt.example.com",
+		"https://mgmt.example.com/",
+		"https://mgmt.example.com:443",
+		"https://mgmt.example.com:443/",
+		"https://MGMT.example.com",
+	} {
+		changed, err := cfg.WouldChange(ConfigInput{ManagementURL: spelling})
+		require.NoError(t, err)
+		require.False(t, changed, "%q is the stored endpoint written differently", spelling)
+	}
+
+	changed, err := cfg.WouldChange(ConfigInput{ManagementURL: "https://mgmt.example.com:8443"})
+	require.NoError(t, err)
+	require.True(t, changed, "a different port is a different endpoint")
+}
+
+// The dry-run baseline exists to be compared against and discarded, so it must
+// not mint keys — the CLI's login backoff loop would otherwise log a fresh
+// "generated new Wireguard key" on every attempt.
+func TestDryRunBaselineDoesNotGenerateKeys(t *testing.T) {
+	baseline, err := newDryRunBaseline(filepath.Join(t.TempDir(), "absent.json"))
+	require.NoError(t, err)
+
+	require.Empty(t, baseline.PrivateKey, "generated a WireGuard key for a throwaway config")
+	require.Empty(t, baseline.SSHKey, "generated an SSH key for a throwaway config")
+
+	// Everything the comparison actually looks at is still the default config.
+	require.Equal(t, DefaultManagementURL, baseline.ManagementURL.String())
+	require.Equal(t, uint16(iface.DefaultMTU), baseline.MTU)
+	require.Equal(t, iface.DefaultWgPort, baseline.WgPort)
+}
+
+// A stored profile can carry no identity — a mobile logout clears the keys in
+// place — so the next config write has to mint one, which is what keeps the
+// following login from dialing management with an empty key.
+func TestUpdateConfigProvisionsAMissingIdentity(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "logged-out.json")
+	_, err := UpdateOrCreateConfig(ConfigInput{
+		ConfigPath:    path,
+		ManagementURL: "https://api.netbird.io:443",
+	})
+	require.NoError(t, err)
+
+	// Stand in for the logout, which zeroes the keys and writes the config out.
+	loggedOut, err := GetExistingConfig(path)
+	require.NoError(t, err)
+	loggedOut.PrivateKey = ""
+	loggedOut.SSHKey = ""
+	require.NoError(t, WriteOutConfig(path, loggedOut))
+
+	cfg, err := UpdateOrCreateConfig(ConfigInput{ConfigPath: path})
+	require.NoError(t, err)
+	require.NotEmpty(t, cfg.PrivateKey, "the write path did not provision an identity")
+	require.NotEmpty(t, cfg.SSHKey)
+
+	persisted, err := GetExistingConfig(path)
+	require.NoError(t, err)
+	require.Equal(t, cfg.PrivateKey, persisted.PrivateKey, "the provisioned identity was not persisted")
+}
+
+// A config that carries no sync message version must not make the dry run
+// panic: the gate runs inside a request handler, where failing closed is the
+// worst acceptable outcome.
+func TestWouldChangeWithoutAStoredSyncMessageVersion(t *testing.T) {
+	cfg := seededConfig(t)
+	require.Nil(t, cfg.SyncMessageVersion, "the fixture is only useful while the field starts out unset")
+
+	version := 2
+	changed, err := cfg.WouldChange(ConfigInput{SyncMessageVersion: &version})
+	require.NoError(t, err)
+	require.True(t, changed)
+	require.Nil(t, cfg.SyncMessageVersion, "the dry run set the version on the stored config")
+}
+
+// Restating the certificate paths a config already holds is not a change, for
+// the same reason restating any other value is not.
+func TestWouldChangeIgnoresRestatedCertificatePaths(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "mtls.json")
+	_, err := UpdateOrCreateConfig(ConfigInput{
+		ConfigPath:        path,
+		ManagementURL:     "https://api.netbird.io:443",
+		ClientCertPath:    "/etc/netbird/client.crt",
+		ClientCertKeyPath: "/etc/netbird/client.key",
+	})
+	require.NoError(t, err)
+
+	cfg, err := GetExistingConfig(path)
+	require.NoError(t, err)
+
+	changed, err := cfg.WouldChange(ConfigInput{
+		ClientCertPath:    "/etc/netbird/client.crt",
+		ClientCertKeyPath: "/etc/netbird/client.key",
+	})
+	require.NoError(t, err)
+	require.False(t, changed, "the stored certificate paths were restated")
+
+	changed, err = cfg.WouldChange(ConfigInput{ClientCertPath: "/etc/netbird/other.crt"})
+	require.NoError(t, err)
+	require.True(t, changed, "a different certificate path is a change")
+}
+
+// A read that lands on a missing file must not hand back keys: nothing would
+// write them down, so the caller would connect with an identity that changes on
+// the next run and registers a second peer.
+func TestReadConfigOrDefaultCarriesNoIdentity(t *testing.T) {
+	cfg, err := ReadConfigOrDefault(filepath.Join(t.TempDir(), "absent.json"))
+	require.NoError(t, err)
+
+	require.Empty(t, cfg.PrivateKey, "a read minted a WireGuard key")
+	require.Empty(t, cfg.SSHKey, "a read minted an SSH key")
+
+	// So the caller's own EnsureIdentity is the one that reports the work, and
+	// therefore the one that triggers the write.
+	generated, err := cfg.EnsureIdentity()
+	require.NoError(t, err)
+	require.True(t, generated, "the provisioning caller could not tell it had to persist the identity")
+}
+
+// CreateInMemoryConfig is the opposite contract: its callers connect with what
+// they get back, so it does carry an identity.
+func TestCreateInMemoryConfigCarriesAnIdentity(t *testing.T) {
+	cfg, err := CreateInMemoryConfig(ConfigInput{ManagementURL: "https://api.netbird.io:443"})
+	require.NoError(t, err)
+
+	require.NotEmpty(t, cfg.PrivateKey)
+	require.NotEmpty(t, cfg.SSHKey)
+}
+
+// The admin panel is opened, not dialed, so its path identifies it. Comparing
+// it as a bare endpoint left a custom panel URL unable to change.
+func TestAdminURLPathIsPartOfTheIdentity(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "panel.json")
+	_, err := UpdateOrCreateConfig(ConfigInput{
+		ConfigPath: path,
+		AdminURL:   "https://app.example.com/netbird",
+	})
+	require.NoError(t, err)
+
+	cfg, err := GetExistingConfig(path)
+	require.NoError(t, err)
+	require.Equal(t, "https://app.example.com:443/netbird", cfg.AdminURL.String())
+
+	// Equivalent spellings of the same panel are still not a change.
+	for _, same := range []string{
+		"https://app.example.com/netbird",
+		"https://app.example.com:443/netbird",
+		"https://app.example.com/netbird/",
+		"https://APP.example.com/netbird",
+	} {
+		changed, err := cfg.WouldChange(ConfigInput{AdminURL: same})
+		require.NoError(t, err)
+		require.False(t, changed, "%q is the stored panel written differently", same)
+	}
+
+	// A different path is a different panel, and it must be persisted.
+	changed, err := cfg.WouldChange(ConfigInput{AdminURL: "https://app.example.com/other"})
+	require.NoError(t, err)
+	require.True(t, changed, "a different panel path is a change")
+
+	updated, err := UpdateConfig(ConfigInput{ConfigPath: path, AdminURL: "https://app.example.com/other"})
+	require.NoError(t, err)
+	require.Equal(t, "https://app.example.com:443/other", updated.AdminURL.String(), "the new panel path was not persisted")
+}
+
+// unsetOnDisk rewrites the stored config so the named fields carry a JSON null,
+// which is how a profile written before apply() resolved them looks on disk.
+// It synthesizes that state: no write produces it any more.
+func unsetOnDisk(t *testing.T, path string, fields ...string) {
+	t.Helper()
+
+	raw, err := os.ReadFile(path)
+	require.NoError(t, err)
+
+	var stored map[string]json.RawMessage
+	require.NoError(t, json.Unmarshal(raw, &stored))
+
+	for _, field := range fields {
+		_, present := stored[field]
+		require.True(t, present, "%s is not a field of the stored config", field)
+		stored[field] = json.RawMessage("null")
+	}
+
+	rewritten, err := json.Marshal(stored)
+	require.NoError(t, err)
+	require.NoError(t, os.WriteFile(path, rewritten, 0600))
+}
+
+// Seven fields mean "the effective default" when they hold no value, and every
+// profile written before apply() resolved them holds them as null. Restating
+// that default is asking for no change — and the CLI restates it on every
+// `netbird up`, because a flag set through an environment variable is a flag
+// pflag reports as Changed. Judging those restatements as changes made the
+// update-settings gate refuse `netbird up` outright for a client configured
+// through the environment, which is the shape of a Kubernetes deployment.
+//
+// A login now writes those fields set, so the fixture puts the null state back
+// on disk with unsetOnDisk instead of getting it from a login.
+func TestWouldChangeIgnoresRestatedDefaultsOfUnsetFields(t *testing.T) {
+	networkMonitorDefault := runtime.GOOS == "windows" || runtime.GOOS == "darwin"
+
+	tests := []struct {
+		field       string
+		theDefault  ConfigInput
+		theOtherWay ConfigInput
+	}{
+		{"EnableSSHRoot",
+			ConfigInput{EnableSSHRoot: boolPtr(false)}, ConfigInput{EnableSSHRoot: boolPtr(true)}},
+		{"EnableSSHSFTP",
+			ConfigInput{EnableSSHSFTP: boolPtr(false)}, ConfigInput{EnableSSHSFTP: boolPtr(true)}},
+		{"EnableSSHLocalPortForwarding",
+			ConfigInput{EnableSSHLocalPortForwarding: boolPtr(false)}, ConfigInput{EnableSSHLocalPortForwarding: boolPtr(true)}},
+		{"EnableSSHRemotePortForwarding",
+			ConfigInput{EnableSSHRemotePortForwarding: boolPtr(false)}, ConfigInput{EnableSSHRemotePortForwarding: boolPtr(true)}},
+		{"DisableSSHAuth",
+			ConfigInput{DisableSSHAuth: boolPtr(false)}, ConfigInput{DisableSSHAuth: boolPtr(true)}},
+		{"SSHJWTCacheTTL",
+			ConfigInput{SSHJWTCacheTTL: intPtr(0)}, ConfigInput{SSHJWTCacheTTL: intPtr(300)}},
+		{"NetworkMonitor",
+			ConfigInput{NetworkMonitor: boolPtr(networkMonitorDefault)}, ConfigInput{NetworkMonitor: boolPtr(!networkMonitorDefault)}},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.field, func(t *testing.T) {
+			path := filepath.Join(t.TempDir(), "unset.json")
+			_, err := UpdateOrCreateConfig(ConfigInput{
+				ConfigPath:    path,
+				ManagementURL: "https://api.netbird.io:443",
+			})
+			require.NoError(t, err)
+			unsetOnDisk(t, path, tt.field)
+
+			cfg, err := GetExistingConfig(path)
+			require.NoError(t, err)
+
+			changed, err := cfg.WouldChange(tt.theDefault)
+			require.NoError(t, err)
+			require.False(t, changed, "restating the default of an unset %s was judged a change", tt.field)
+
+			// The gate still has to refuse a request that does ask for something.
+			changed, err = cfg.WouldChange(tt.theOtherWay)
+			require.NoError(t, err)
+			require.True(t, changed, "asking for a non-default %s is a change", tt.field)
+		})
+	}
+}
+
+// The verdict must not depend on where the caller got the config from. Readers
+// normalize what they hand out, but apply() signals "I filled in a default"
+// through the same bool as "the input changed something", so a config that
+// never passed through a read would otherwise report a change for an input
+// that asks for nothing.
+func TestWouldChangeNormalizesBeforeMeasuring(t *testing.T) {
+	rawConfig := func(t *testing.T) *Config {
+		t.Helper()
+
+		cfg := &Config{WgIface: iface.WgInterfaceDefault}
+		require.Nil(t, cfg.ServerSSHAllowed, "the fixture is only useful while the config is not normalized")
+		require.Nil(t, cfg.EnableSSHRoot)
+		require.Empty(t, cfg.IFaceBlackList)
+		return cfg
+	}
+
+	changed, err := rawConfig(t).WouldChange(ConfigInput{})
+	require.NoError(t, err)
+	require.False(t, changed, "an input carrying nothing cannot change anything")
+
+	changed, err = rawConfig(t).WouldChange(ConfigInput{EnableSSHRoot: boolPtr(false)})
+	require.NoError(t, err)
+	require.False(t, changed, "the default of a field the config never held is not a change")
+
+	changed, err = rawConfig(t).WouldChange(ConfigInput{EnableSSHRoot: boolPtr(true)})
+	require.NoError(t, err)
+	require.True(t, changed, "a non-default value is still a change")
+}
+
+// A zero-padded port addresses the same port. The normalization itself belongs
+// to util.ServiceURLPort and is tested there; this asserts that the comparison
+// this package hands its callers inherits it.
+func TestServiceURLPortIsNormalizedNumerically(t *testing.T) {
+	padded, err := ParseServiceURL("padded", "https://mgmt.example.com:0443")
+	require.NoError(t, err)
+	plain, err := ParseServiceURL("plain", "https://mgmt.example.com:443")
+	require.NoError(t, err)
+
+	require.True(t, SameServiceURL(padded, plain))
+}
+
+// A list the profile does not have and a list the request empties are the same
+// thing: no NAT mappings, no DNS labels. The profile stores an absent list as
+// JSON null and reads it back as a nil slice, while `netbird up` sends the
+// emptied list — CleanNATExternalIPs / CleanDNSLabels — whenever the matching
+// environment variable is set to nothing, which a deployment template does by
+// default. Judging nil and empty as different made the gate refuse that start,
+// which is the very deadlock this branch exists to remove, on another field.
+func TestWouldChangeIgnoresAnEmptiedListThatWasAlreadyAbsent(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "lists.json")
+	_, err := UpdateOrCreateConfig(ConfigInput{ConfigPath: path, ManagementURL: DefaultManagementURL})
+	require.NoError(t, err)
+
+	stored, err := GetExistingConfig(path)
+	require.NoError(t, err)
+	require.Nil(t, stored.NATExternalIPs, "the fixture is only useful while the stored list is absent")
+	require.Nil(t, stored.DNSLabels)
+
+	changed, err := stored.WouldChange(ConfigInput{NATExternalIPs: make([]string, 0)})
+	require.NoError(t, err)
+	require.False(t, changed, "emptying a NAT list the profile never had is not a change")
+
+	changed, err = stored.WouldChange(ConfigInput{DNSLabels: domain.List{}})
+	require.NoError(t, err)
+	require.False(t, changed, "emptying a DNS label list the profile never had is not a change")
+
+	// A list that does hold something still moves when the request empties it.
+	withEntries, err := UpdateConfig(ConfigInput{ConfigPath: path, NATExternalIPs: []string{"1.2.3.4"}})
+	require.NoError(t, err)
+	require.Equal(t, []string{"1.2.3.4"}, withEntries.NATExternalIPs)
+
+	changed, err = withEntries.WouldChange(ConfigInput{NATExternalIPs: make([]string, 0)})
+	require.NoError(t, err)
+	require.True(t, changed, "clearing a NAT list that had an entry is a change")
+}
diff --git a/client/internal/profilemanager/service.go b/client/internal/profilemanager/service.go
index ec287f01a..e58f421fd 100644
--- a/client/internal/profilemanager/service.go
+++ b/client/internal/profilemanager/service.go
@@ -313,7 +313,11 @@ func (s *ServiceManager) AddProfile(displayName, username string) (*Profile, err
 	}
 
 	profPath := filepath.Join(configDir, id.String()+".json")
-	cfg, err := createNewConfig(ConfigInput{ConfigPath: profPath})
+	// Provisioned, not bare: this config goes straight to disk, and a profile
+	// file with no identity is one whose first reader has to mint the keys and
+	// remember to write them back. Before identity generation moved out of
+	// apply() into EnsureIdentity, createNewConfig produced them here too.
+	cfg, err := createProvisionedConfig(ConfigInput{ConfigPath: profPath})
 	if err != nil {
 		return nil, fmt.Errorf("failed to create new config: %w", err)
 	}
@@ -330,6 +334,19 @@ func (s *ServiceManager) AddProfile(displayName, username string) (*Profile, err
 	}, nil
 }
 
+// RenameProfile changes a profile's display name. It rewrites the whole
+// profile file, not just the name: the config is read through the normalizing
+// reader, so apply()'s resolved values — the optional booleans, the interface
+// blacklist, the DNS route interval — are persisted along with the new name.
+//
+// That is deliberate. A write that skipped apply() is what left profiles on
+// disk carrying null where a value was meant, and made a diff of the config
+// compare presence instead of value. Two consequences worth knowing: the
+// platform-dependent defaults resolved here are the renaming host's
+// (ServerSSHAllowed and the network monitor differ per OS), and a profile
+// whose stored name does not survive sanitizeDisplayName now fails to rename
+// rather than being rewritten — though apply() rejects such a profile on every
+// other read too, so it was already unusable.
 func (s *ServiceManager) RenameProfile(id ID, username string, newName string) error {
 	displayName, err := sanitizeDisplayName(newName)
 	if err != nil {
@@ -356,17 +373,17 @@ func (s *ServiceManager) RenameProfile(id ID, username string, newName string) e
 		return ErrProfileNotFound
 	}
 
-	data, err := os.ReadFile(target.Path)
+	// Through the reader, not a bare Unmarshal: this was the one write that
+	// skipped apply(), so it copied back whatever the file held — including an
+	// optional field left unset, which every other write resolves to its
+	// default. Renaming a profile is a poor place to leave that behind.
+	cfg, err := GetExistingConfig(target.Path)
 	if err != nil {
-		return err
-	}
-	var cfg Config
-	if err := json.Unmarshal(data, &cfg); err != nil {
-		return err
+		return fmt.Errorf("read profile config: %w", err)
 	}
 	cfg.Name = displayName
 
-	if err := util.WriteJson(context.Background(), target.Path, cfg); err != nil {
+	if err := WriteOutConfig(target.Path, cfg); err != nil {
 		return fmt.Errorf("failed to write profile name: %w", err)
 	}
 	return nil
diff --git a/client/internal/profilemanager/service_test.go b/client/internal/profilemanager/service_test.go
index 5e051b15d..d26ce746a 100644
--- a/client/internal/profilemanager/service_test.go
+++ b/client/internal/profilemanager/service_test.go
@@ -228,3 +228,27 @@ func TestRemoveProfile_DeletesStateFile(t *testing.T) {
 		assert.True(t, errors.Is(err, os.ErrNotExist), "state file should be removed")
 	})
 }
+
+// A profile file is written here and read back by whoever connects with it, so
+// it has to carry the peer's identity. While AddProfile used the bare
+// constructor, it wrote a config with no keys: the first reader had to mint
+// them, and the paths that read without writing — a gate deciding whether to
+// refuse a request, the mobile SDKs loading a stored profile — got a config
+// that cannot connect.
+func TestAddProfileWritesAnIdentity(t *testing.T) {
+	withTestSM(t, func(sm *ServiceManager, username string) {
+		created, err := sm.AddProfile("work", username)
+		require.NoError(t, err)
+
+		stored, err := GetExistingConfig(created.Path)
+		require.NoError(t, err)
+
+		require.NotEmpty(t, stored.PrivateKey, "the profile was written without a WireGuard key")
+		require.NotEmpty(t, stored.SSHKey, "the profile was written without an SSH key")
+
+		// And the identity is the one on disk, not one minted per read.
+		reread, err := GetExistingConfig(created.Path)
+		require.NoError(t, err)
+		require.Equal(t, stored.PrivateKey, reread.PrivateKey)
+	})
+}
diff --git a/client/ios/NetBirdSDK/client.go b/client/ios/NetBirdSDK/client.go
index 96c747ae4..a6315a4ab 100644
--- a/client/ios/NetBirdSDK/client.go
+++ b/client/ios/NetBirdSDK/client.go
@@ -130,6 +130,10 @@ func NewClient(cfgFile, stateFile, cacheDir, logFilePath, deviceName string, osV
 
 // SetConfigFromJSON stores the JSON config that later loads resolve instead of the config file (tvOS).
 func (c *Client) SetConfigFromJSON(jsonStr string) error {
+	// Parsed only to reject an unreadable document early; the JSON itself is
+	// what is stored, and every load re-parses it. A document carrying no peer
+	// identity is readable and accepted: that is a logged-out profile, and the
+	// login that follows provisions the keys.
 	if _, err := profilemanager.ConfigFromJSON(jsonStr); err != nil {
 		log.Errorf("SetConfigFromJSON: failed to parse config JSON: %v", err)
 		return err
diff --git a/client/ios/NetBirdSDK/login.go b/client/ios/NetBirdSDK/login.go
index 0dfff620e..6a9a6d3d0 100644
--- a/client/ios/NetBirdSDK/login.go
+++ b/client/ios/NetBirdSDK/login.go
@@ -379,6 +379,35 @@ func (a *Auth) SetConfigFromJSON(jsonStr string) error {
 }
 
 func (a *Auth) setBaseConfig(base *profilemanager.Config) error {
+	// A logged-out profile carries no keys: the mobile logout clears them in
+	// place so the next login registers a new peer instead of resurrecting the
+	// old one. This is that login, and auth.NewAuth parses the WireGuard key
+	// before the SSO flow even starts, so an absent identity fails the login on
+	// key size rather than asking the user to sign in.
+	//
+	// Minted on the base config, which is the one GetConfigJSON hands back for
+	// the caller to store — the overlaid copy below is runtime-only.
+	generated, err := base.EnsureIdentity()
+	if err != nil {
+		return fmt.Errorf("ensure profile identity: %w", err)
+	}
+	if generated {
+		if a.cfgPath != "" {
+			// Non-atomic, like NewAuth's own write: the tvOS App Group sandbox
+			// blocks the temp-file-and-rename an atomic write needs.
+			if err := profilemanager.DirectWriteOutConfig(a.cfgPath, base); err != nil {
+				return fmt.Errorf("write out profile config: %w", err)
+			}
+		} else {
+			// No file to write to — this is the tvOS path, where the profile
+			// lives in the caller's own store. It persists the new identity by
+			// calling GetConfigJSON once the login completes; until then the
+			// keys exist only here, and a login that never completes leaves
+			// nothing behind.
+			log.Infof("provisioned a peer identity for a config with no file on disk")
+		}
+	}
+
 	overlaid, err := copyConfig(base)
 	if err != nil {
 		return err
diff --git a/client/ios/NetBirdSDK/preferences.go b/client/ios/NetBirdSDK/preferences.go
index 5297920a3..642f9e160 100644
--- a/client/ios/NetBirdSDK/preferences.go
+++ b/client/ios/NetBirdSDK/preferences.go
@@ -49,7 +49,7 @@ func (p *Preferences) GetManagementURL() (string, error) {
 		return p.configInput.ManagementURL, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return "", err
 	}
@@ -67,7 +67,7 @@ func (p *Preferences) GetAdminURL() (string, error) {
 		return p.configInput.AdminURL, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return "", err
 	}
@@ -89,7 +89,7 @@ func (p *Preferences) HasPreSharedKey() (bool, error) {
 		return *p.configInput.PreSharedKey != "", nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return false, err
 	}
@@ -115,7 +115,7 @@ func (p *Preferences) GetRosenpassEnabled() (bool, error) {
 		return *p.configInput.RosenpassEnabled, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return false, err
 	}
@@ -136,7 +136,7 @@ func (p *Preferences) GetRosenpassPermissive() (bool, error) {
 		return *p.configInput.RosenpassPermissive, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return false, err
 	}
@@ -149,7 +149,7 @@ func (p *Preferences) GetDisableIPv6() (bool, error) {
 		return *p.configInput.DisableIPv6, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return false, err
 	}
@@ -168,7 +168,7 @@ func (p *Preferences) GetRemoteJobsAllowed() (bool, error) {
 		return *p.configInput.RemoteJobsAllowed, nil
 	}
 
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
+	cfg, err := profilemanager.ReadConfigOrDefault(p.configInput.ConfigPath)
 	if err != nil {
 		return false, err
 	}
diff --git a/client/mobile/profile_lifecycle_test.go b/client/mobile/profile_lifecycle_test.go
new file mode 100644
index 000000000..9612f550d
--- /dev/null
+++ b/client/mobile/profile_lifecycle_test.go
@@ -0,0 +1,97 @@
+package mobile
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/netbirdio/netbird/client/internal/profilemanager"
+)
+
+// loadAsTheMobileSDKsDo replays what the iOS SDK does with a stored profile:
+// read the config, serialize it, and load it back. Client.SetConfigFromJSON
+// stores that document for tvOS, Auth.SetConfigFromJSON authenticates with it,
+// and copyConfig round-trips a Config through the same pair to take an
+// in-memory copy before applying the MDM overlay.
+func loadAsTheMobileSDKsDo(t *testing.T, configPath string) *profilemanager.Config {
+	t.Helper()
+
+	stored, err := profilemanager.GetExistingConfig(configPath)
+	require.NoError(t, err, "read the stored profile")
+
+	document, err := profilemanager.ConfigToJSON(stored)
+	require.NoError(t, err, "serialize the stored profile")
+
+	reloaded, err := profilemanager.ConfigFromJSON(document)
+	require.NoError(t, err, "load the profile back")
+	return reloaded
+}
+
+// A profile survives the whole round its user puts it through: created, logged
+// out, loaded again, and switched away from and back.
+//
+// Logout is the step that makes this worth asserting. It clears the peer's
+// keys in place so the next login registers a new peer rather than bringing
+// the old one back, which leaves a profile that legitimately carries no
+// identity — and both mobile SDKs go on loading that profile through the
+// serialized form. A load that refused it, or a creation that never wrote an
+// identity in the first place, breaks logout and profile switching on iOS and
+// Android without any of it being visible from the desktop client.
+func TestProfileSurvivesLogoutAndReload(t *testing.T) {
+	pm := newTestProfileManager(t)
+
+	created, err := pm.AddProfile("work")
+	require.NoError(t, err)
+	require.NoError(t, pm.SwitchProfile(profilemanager.DefaultProfileName))
+
+	// Created: the profile carries the identity it will connect with.
+	require.NotEmpty(t, privateKeyOf(t, pm, created.ID), "a new profile was written with no identity")
+
+	configPath, err := pm.GetConfigPath(created.ID)
+	require.NoError(t, err)
+
+	before := loadAsTheMobileSDKsDo(t, configPath)
+	require.NotEmpty(t, before.PrivateKey)
+	managementURL := before.ManagementURL.String()
+
+	// Logged out: the identity is gone, on purpose.
+	require.NoError(t, pm.LogoutProfile(created.ID))
+	require.Empty(t, privateKeyOf(t, pm, created.ID), "logout left the peer's key behind")
+
+	// Loaded again: the profile is still readable, and loading it neither
+	// fails nor mints a key that nothing would write down.
+	after := loadAsTheMobileSDKsDo(t, configPath)
+	assert.Empty(t, after.PrivateKey, "loading a logged-out profile minted a key nothing will persist")
+	assert.Empty(t, after.SSHKey, "loading a logged-out profile minted an SSH key")
+	assert.Equal(t, managementURL, after.ManagementURL.String(), "the rest of the profile did not survive the logout")
+
+	// Switched away from and back: still the same profile, still loadable.
+	require.NoError(t, pm.SwitchProfile(created.ID))
+	require.NoError(t, pm.SwitchProfile(profilemanager.DefaultProfileName))
+	require.NoError(t, pm.SwitchProfile(created.ID))
+
+	active, err := pm.GetActiveProfile()
+	require.NoError(t, err)
+	assert.Equal(t, created.ID, active.ID, "the profile switched to is not the active one")
+
+	assert.Equal(t, managementURL, loadAsTheMobileSDKsDo(t, configPath).ManagementURL.String(),
+		"the profile did not survive the round of switches")
+}
+
+// The profile the SDKs fall back to gets the same treatment, since it is the
+// one a mobile client without an explicit profile runs on.
+func TestDefaultProfileSurvivesLogoutAndReload(t *testing.T) {
+	pm := newTestProfileManager(t)
+	require.NoError(t, pm.SwitchProfile(profilemanager.DefaultProfileName))
+
+	configPath, err := pm.GetConfigPath(profilemanager.DefaultProfileName)
+	require.NoError(t, err)
+	require.NotEmpty(t, loadAsTheMobileSDKsDo(t, configPath).PrivateKey)
+
+	require.NoError(t, pm.LogoutProfile(profilemanager.DefaultProfileName))
+
+	reloaded := loadAsTheMobileSDKsDo(t, configPath)
+	assert.Empty(t, reloaded.PrivateKey, "loading the logged-out default profile minted a key")
+	assert.NotNil(t, reloaded.ManagementURL, "the profile lost its management URL")
+}
diff --git a/client/mobile/profile_manager.go b/client/mobile/profile_manager.go
index 348b7253b..ad79d80c0 100644
--- a/client/mobile/profile_manager.go
+++ b/client/mobile/profile_manager.go
@@ -192,7 +192,10 @@ func (pm *ProfileManager) LogoutProfile(id string) error {
 		return fmt.Errorf("profile %q does not exist", id)
 	}
 
-	config, err := profilemanager.ReadConfig(configPath)
+	// The existing-file reader, not the generating one: the check above is not
+	// atomic with this read, so a profile removed in between would otherwise be
+	// resolved from the defaults here and recreated by the write below.
+	config, err := profilemanager.GetExistingConfig(configPath)
 	if err != nil {
 		return fmt.Errorf("read profile config: %w", err)
 	}
diff --git a/client/server/login_gate_test.go b/client/server/login_gate_test.go
index de62a8180..17ae3ecad 100644
--- a/client/server/login_gate_test.go
+++ b/client/server/login_gate_test.go
@@ -93,7 +93,7 @@ func TestLogin_ChangeThatBecomesPrivilegedMidRequestHasNoSideEffects(t *testing.
 	require.NoError(t, err)
 	require.Equal(t, profilemanager.ID(activeProfile), active.ID, "the refused login switched the active profile anyway")
 
-	stored, err := profilemanager.ReadConfig(targetPath)
+	stored, err := profilemanager.GetExistingConfig(targetPath)
 	require.NoError(t, err)
 	require.Equal(t, "https://api.netbird.io:443", stored.ManagementURL.String(), "the refused login moved the management URL")
 }
diff --git a/client/server/login_overrides_test.go b/client/server/login_overrides_test.go
index 5a2298764..f858c6059 100644
--- a/client/server/login_overrides_test.go
+++ b/client/server/login_overrides_test.go
@@ -7,6 +7,7 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"github.com/netbirdio/netbird/client/internal/profilemanager"
+	"github.com/netbirdio/netbird/client/proto"
 )
 
 func TestPersistLoginOverrides(t *testing.T) {
@@ -80,10 +81,13 @@ func TestPersistLoginOverrides(t *testing.T) {
 			require.NoError(t, err, "seed config")
 
 			activeProf := &profilemanager.ActiveProfileState{ID: "default"}
-			err = persistLoginOverrides(activeProf, tt.newMgmtURL, tt.newPSK)
+			err = persistLoginOverrides(activeProf, &proto.LoginRequest{
+				ManagementUrl:        tt.newMgmtURL,
+				OptionalPreSharedKey: tt.newPSK,
+			})
 			require.NoError(t, err, "persistLoginOverrides")
 
-			cfg, err := profilemanager.ReadConfig(profilemanager.DefaultConfigPath)
+			cfg, err := profilemanager.ReadConfigOrDefault(profilemanager.DefaultConfigPath)
 			require.NoError(t, err, "read back config")
 
 			require.Equal(t, tt.wantMgmtURL, cfg.ManagementURL.String(), "management URL")
diff --git a/client/server/logout_gate_test.go b/client/server/logout_gate_test.go
index 2d84d1b6a..d88801959 100644
--- a/client/server/logout_gate_test.go
+++ b/client/server/logout_gate_test.go
@@ -129,7 +129,7 @@ func TestLogout_ForeignUserProfileDoesNotUseTheRunningConfig(t *testing.T) {
 	// refused with PermissionDenied. The namesake profile does not, so the
 	// correct path gets as far as dialing its own unreachable management URL.
 	enableSSHOnProfile(t, cfgPath)
-	running, err := profilemanager.GetConfig(cfgPath)
+	running, err := profilemanager.GetExistingConfig(cfgPath)
 	require.NoError(t, err)
 	s.config = running
 	s.connectClient = newDummyConnectClient(context.Background())
diff --git a/client/server/mdm.go b/client/server/mdm.go
index 7a47b2a57..b22c3b0a3 100644
--- a/client/server/mdm.go
+++ b/client/server/mdm.go
@@ -180,92 +180,6 @@ func mdmManagedFieldConflicts(msg *proto.SetConfigRequest, policy *mdm.Policy) [
 	})
 }
 
-// setConfigRequestHasConfigOverrides reports whether the SetConfigRequest
-// carries ANY field that would actually mutate the persisted config.
-// The CLI builds a SetConfigRequest unconditionally on every
-// `netbird up` (see setupSetConfigReq in cmd/up.go) — a plain
-// `netbird up` produces a request with every field at its zero value;
-// the gate must skip such no-op invocations or it would always fire
-// even when the user did not pass any --flag. Returns false on a nil
-// msg; true when any management/admin URL, PSK, DNS/NAT list+clean
-// flag, interface/port/MTU, or any optional bool/duration field is set.
-func setConfigRequestHasConfigOverrides(msg *proto.SetConfigRequest) bool {
-	if msg == nil {
-		return false
-	}
-	return msg.ManagementUrl != "" ||
-		msg.AdminURL != "" ||
-		msg.OptionalPreSharedKey != nil ||
-		len(msg.CustomDNSAddress) > 0 ||
-		len(msg.NatExternalIPs) > 0 || msg.CleanNATExternalIPs ||
-		len(msg.ExtraIFaceBlacklist) > 0 ||
-		len(msg.DnsLabels) > 0 || msg.CleanDNSLabels ||
-		msg.DnsRouteInterval != nil ||
-		msg.RosenpassEnabled != nil ||
-		msg.RosenpassPermissive != nil ||
-		msg.InterfaceName != nil ||
-		msg.WireguardPort != nil ||
-		msg.Mtu != nil ||
-		msg.DisableAutoConnect != nil ||
-		msg.ServerSSHAllowed != nil ||
-		msg.RemoteJobsAllowed != nil ||
-		msg.NetworkMonitor != nil ||
-		msg.DisableClientRoutes != nil ||
-		msg.DisableServerRoutes != nil ||
-		msg.DisableDns != nil ||
-		msg.DisableFirewall != nil ||
-		msg.BlockLanAccess != nil ||
-		msg.DisableNotifications != nil ||
-		msg.BlockInbound != nil ||
-		msg.DisableIpv6 != nil ||
-		msg.EnableSSHRoot != nil ||
-		msg.EnableSSHSFTP != nil ||
-		msg.EnableSSHLocalPortForwarding != nil ||
-		msg.EnableSSHRemotePortForwarding != nil ||
-		msg.DisableSSHAuth != nil ||
-		msg.SshJWTCacheTTL != nil ||
-		msg.EnableLocalMetrics != nil ||
-		msg.LocalMetricsAddress != nil
-}
-
-// loginRequestHasConfigOverrides reports whether the LoginRequest
-// carries ANY field that would mutate persisted daemon configuration
-// (as opposed to pure-auth fields like setupKey, hostname, hint,
-// profileName, username). Used by the Login handler to decide whether
-// the `--disable-update-settings` / MDM gates must run: a re-auth that
-// changes nothing about the configuration is always allowed.
-func loginRequestHasConfigOverrides(msg *proto.LoginRequest) bool {
-	if msg == nil {
-		return false
-	}
-	return msg.ManagementUrl != "" ||
-		msg.AdminURL != "" ||
-		msg.PreSharedKey != "" || //nolint:staticcheck // SA1019: legacy proto field still accepted by Login
-		msg.OptionalPreSharedKey != nil ||
-		len(msg.CustomDNSAddress) > 0 ||
-		len(msg.NatExternalIPs) > 0 || msg.CleanNATExternalIPs ||
-		msg.RosenpassEnabled != nil ||
-		msg.InterfaceName != nil ||
-		msg.WireguardPort != nil ||
-		msg.DisableAutoConnect != nil ||
-		msg.ServerSSHAllowed != nil ||
-		msg.RemoteJobsAllowed != nil ||
-		msg.RosenpassPermissive != nil ||
-		len(msg.ExtraIFaceBlacklist) > 0 ||
-		msg.NetworkMonitor != nil ||
-		msg.DnsRouteInterval != nil ||
-		msg.DisableClientRoutes != nil ||
-		msg.DisableServerRoutes != nil ||
-		msg.DisableDns != nil ||
-		msg.DisableFirewall != nil ||
-		msg.BlockLanAccess != nil ||
-		msg.DisableNotifications != nil ||
-		len(msg.DnsLabels) > 0 || msg.CleanDNSLabels ||
-		msg.BlockInbound != nil ||
-		msg.EnableLocalMetrics != nil ||
-		msg.LocalMetricsAddress != nil
-}
-
 // loginRequestMDMConflicts mirrors mdmManagedFieldConflicts but for the
 // LoginRequest surface. Same value-aware semantics: a field set to the
 // MDM-enforced value is a no-op echo, not a conflict; only a divergent
diff --git a/client/server/provision_identity_test.go b/client/server/provision_identity_test.go
new file mode 100644
index 000000000..c944cdb1a
--- /dev/null
+++ b/client/server/provision_identity_test.go
@@ -0,0 +1,59 @@
+package server
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/netbirdio/netbird/client/internal/profilemanager"
+)
+
+// The daemon provisions the peer's identity and persists it, because a key that
+// stayed in memory would come back different on the next start and register a
+// second peer. Provisioning is idempotent: a profile that already has an
+// identity keeps the one on disk.
+func TestProvisionProfileIdentity(t *testing.T) {
+	origDir := profilemanager.DefaultConfigPathDir
+	origPath := profilemanager.DefaultConfigPath
+	t.Cleanup(func() {
+		profilemanager.DefaultConfigPathDir = origDir
+		profilemanager.DefaultConfigPath = origPath
+	})
+
+	dir := t.TempDir()
+	profilemanager.DefaultConfigPathDir = dir
+	profilemanager.DefaultConfigPath = filepath.Join(dir, "default.json")
+
+	activeProf := &profilemanager.ActiveProfileState{ID: "default"}
+
+	t.Run("a profile with no file is provisioned and written", func(t *testing.T) {
+		_, err := os.Stat(profilemanager.DefaultConfigPath)
+		require.True(t, os.IsNotExist(err), "the fixture starts without a config file")
+
+		config, existed, err := provisionProfileIdentity(activeProf)
+		require.NoError(t, err)
+		require.False(t, existed, "the file was reported as pre-existing")
+		require.NotEmpty(t, config.PrivateKey)
+
+		stored, err := profilemanager.GetExistingConfig(profilemanager.DefaultConfigPath)
+		require.NoError(t, err, "provisioning did not write the config out")
+		require.Equal(t, config.PrivateKey, stored.PrivateKey, "the persisted identity is not the one returned")
+		require.NotEmpty(t, stored.SSHKey)
+	})
+
+	t.Run("a second call keeps the identity on disk", func(t *testing.T) {
+		before, err := profilemanager.GetExistingConfig(profilemanager.DefaultConfigPath)
+		require.NoError(t, err)
+
+		config, existed, err := provisionProfileIdentity(activeProf)
+		require.NoError(t, err)
+		require.True(t, existed)
+		require.Equal(t, before.PrivateKey, config.PrivateKey, "provisioning minted a second identity")
+
+		after, err := profilemanager.GetExistingConfig(profilemanager.DefaultConfigPath)
+		require.NoError(t, err)
+		require.Equal(t, before.PrivateKey, after.PrivateKey, "provisioning rewrote the stored identity")
+	})
+}
diff --git a/client/server/server.go b/client/server/server.go
index 108aa8a41..f7f81b688 100644
--- a/client/server/server.go
+++ b/client/server/server.go
@@ -58,8 +58,13 @@ const (
 	// JWT token cache TTL for the client daemon (disabled by default)
 	defaultJWTCacheTTL = 0
 
-	errRestoreResidualState   = "failed to restore residual state: %v"
-	errProfilesDisabled       = "profiles are disabled, you cannot use this feature without profiles enabled"
+	errRestoreResidualState = "failed to restore residual state: %v"
+	errProfilesDisabled     = "profiles are disabled, you cannot use this feature without profiles enabled"
+	// errUpdateSettingsDisabled is returned with codes.FailedPrecondition, not
+	// codes.Unavailable: the daemon answered, and it refused. Unavailable means
+	// "the daemon cannot serve this", which is why the CLI downgrades it to a
+	// warning and the GUI reads it as an unreachable daemon — both wrong for a
+	// refusal the caller has to act on.
 	errUpdateSettingsDisabled = "update settings are disabled, you cannot use this feature without update settings enabled"
 	errNetworksDisabled       = "network selection is disabled by the administrator"
 )
@@ -492,16 +497,27 @@ func (s *Server) SetConfig(callerCtx context.Context, msg *proto.SetConfigReques
 	s.mutex.Lock()
 	defer s.mutex.Unlock()
 
-	// Skip the update-settings gate when the request carries no actual
-	// overrides: the CLI builds a SetConfigRequest unconditionally on
-	// every `netbird up` (setupSetConfigReq in cmd/up.go), so a plain
-	// `netbird up` would otherwise always trip the gate and surface a
-	// misleading "setConfig method is not available" warning, even when
-	// the user did not pass any config flag.
-	if setConfigRequestHasConfigOverrides(msg) {
-		if s.checkUpdateSettingsDisabled() {
-			return nil, gstatus.Errorf(codes.Unavailable, errUpdateSettingsDisabled)
-		}
+	stored, err := s.storedProfileConfig(msg.ProfileName, msg.Username)
+	if err != nil {
+		return nil, err
+	}
+
+	config, err := s.setConfigInputFromRequest(msg)
+	if err != nil {
+		return nil, err
+	}
+
+	// Update-settings gate: refuse the request only when it would actually
+	// change a persisted setting. The CLI builds a SetConfigRequest
+	// unconditionally on every `netbird up` (setupSetConfigReq in
+	// cmd/up.go) and fills it from its flags and environment, so a service
+	// or container that restates the configuration it already runs with
+	// must pass the gate. Deciding this on field presence alone refused
+	// those callers, and — through the identical gate in Login — refused
+	// their login too, which left a client configured by environment
+	// (NB_MANAGEMENT_URL and friends) unable to come up at all.
+	if s.checkUpdateSettingsDisabled() && configChangeRequested(stored, config) {
+		return nil, gstatus.Errorf(codes.FailedPrecondition, errUpdateSettingsDisabled)
 	}
 
 	// MDM gate: refuse the whole request if any of its fields is enforced
@@ -513,19 +529,10 @@ func (s *Server) SetConfig(callerCtx context.Context, msg *proto.SetConfigReques
 		return nil, err
 	}
 
-	stored, err := s.storedProfileConfig(msg.ProfileName, msg.Username)
-	if err != nil {
-		return nil, err
-	}
 	if err := requirePrivilegeForConfigChange(callerCtx, stored, privilegedChangeFromSetConfig(msg)); err != nil {
 		return nil, err
 	}
 
-	config, err := s.setConfigInputFromRequest(msg)
-	if err != nil {
-		return nil, err
-	}
-
 	updatedConf, err := profilemanager.UpdateConfig(config)
 	if err != nil {
 		log.Errorf("failed to update profile config: %v", err)
@@ -641,37 +648,45 @@ func (s *Server) setConfigInputFromRequest(msg *proto.SetConfigRequest) (profile
 
 // Login uses setup key to prepare configuration for the daemon.
 func (s *Server) Login(callerCtx context.Context, msg *proto.LoginRequest) (*proto.LoginResponse, error) {
+	activeProf, err := s.profileManager.GetActiveProfileState()
+	if err != nil {
+		return nil, fmt.Errorf("failed to get active profile state: %w", err)
+	}
+
+	// The stored config of the profile this request targets backs all three
+	// gates below. It is read before anything changes daemon state, so a
+	// refused login neither switches the profile nor cancels a login already
+	// in progress, and it is the profile the switch further down would
+	// activate.
+	stored, err := s.storedLoginConfig(activeProf, msg)
+	if err != nil {
+		return nil, err
+	}
+
 	// Config-override gates. LoginRequest carries the same surface as
 	// SetConfigRequest (managementUrl, PSK, ssh/rosenpass/port toggles,
 	// ...), so the same protections must apply. Without these the CLI
 	// command `netbird up --management-url=X` (which falls through to
 	// Login when SetConfig is rejected — see cmd/up.go) would silently
 	// bypass `--disable-update-settings` and any MDM policy.
-	if loginRequestHasConfigOverrides(msg) {
-		if s.checkUpdateSettingsDisabled() {
-			return nil, gstatus.Errorf(codes.Unavailable, errUpdateSettingsDisabled)
-		}
-		policy := s.mdmLoader.Load()
-		if err := rejectMDMManagedFieldConflicts(loginRequestMDMConflicts(msg, policy)); err != nil {
-			return nil, err
-		}
+	//
+	// The update-settings gate is value-aware, as in SetConfig: it looks at
+	// what a login would actually persist (loginOverridesInput) and refuses
+	// only a real divergence from the stored config. A login that restates
+	// the values already on disk changes nothing, so it must go through —
+	// that is what keeps a re-login, or a container restart carrying
+	// NB_MANAGEMENT_URL, working with the kill switch on.
+	if s.checkUpdateSettingsDisabled() && configChangeRequested(stored, loginOverridesInput(msg)) {
+		return nil, gstatus.Errorf(codes.FailedPrecondition, errUpdateSettingsDisabled)
 	}
 
-	activeProf, err := s.profileManager.GetActiveProfileState()
-	if err != nil {
-		log.Errorf("failed to get active profile state: %v", err)
-		return nil, fmt.Errorf("failed to get active profile state: %w", err)
+	policy := s.mdmLoader.Load()
+	if err := rejectMDMManagedFieldConflicts(loginRequestMDMConflicts(msg, policy)); err != nil {
+		return nil, err
 	}
 
 	// Privilege gate: same restrictions as SetConfig, since LoginRequest can carry
-	// the same fields. It runs before anything here changes daemon state, so a
-	// refused login neither switches the profile nor cancels a login already in
-	// progress, and it reads the profile the request targets, which is the one the
-	// switch below would activate.
-	stored, err := s.storedLoginConfig(activeProf, msg)
-	if err != nil {
-		return nil, err
-	}
+	// the same fields.
 	if err := requirePrivilegeForConfigChange(callerCtx, stored, privilegedChangeFromLogin(msg)); err != nil {
 		return nil, err
 	}
@@ -1174,6 +1189,10 @@ func (s *Server) storedLoginConfig(activeProf *profilemanager.ActiveProfileState
 
 // storedConfigAtPath reads a profile config file, yielding nil when it does not
 // exist yet.
+//
+// Reading it has no side effect: profilemanager.GetExistingConfig does not
+// write, so a request that the gates go on to refuse leaves the profile file as
+// it found it.
 func (s *Server) storedConfigAtPath(path string) (*profilemanager.Config, error) {
 	if _, err := os.Stat(path); err != nil {
 		if os.IsNotExist(err) {
@@ -1182,7 +1201,7 @@ func (s *Server) storedConfigAtPath(path string) (*profilemanager.Config, error)
 		return nil, fmt.Errorf("stat profile config: %w", err)
 	}
 
-	cfg, err := profilemanager.GetConfig(path)
+	cfg, err := profilemanager.GetExistingConfig(path)
 	if err != nil {
 		return nil, fmt.Errorf("read profile config: %w", err)
 	}
@@ -1485,8 +1504,16 @@ func (s *Server) handleActiveProfileLogout(ctx context.Context) (*proto.LogoutRe
 	return &proto.LogoutResponse{}, nil
 }
 
-// getConfig reads config file and returns Config and whether the config file already existed. Errors out if it does not exist
-func (s *Server) getConfig(activeProf *profilemanager.ActiveProfileState) (*profilemanager.Config, bool, error) {
+// provisionProfileIdentity resolves the active profile's config and puts the
+// keys that identify the peer on disk, reporting whether the config file
+// already existed.
+//
+// This is the daemon's provisioning point: the config resolved here is the one
+// the peer runs with, so it needs its identity, and that has to reach disk — a
+// key that stays in memory would come back different on the next start and
+// re-register the peer. Reads themselves are pure, so the write is here, in
+// the open, instead of hiding inside the reader.
+func provisionProfileIdentity(activeProf *profilemanager.ActiveProfileState) (*profilemanager.Config, bool, error) {
 	cfgPath, err := activeProf.FilePath()
 	if err != nil {
 		return nil, false, fmt.Errorf("failed to get active profile file path: %w", err)
@@ -1497,15 +1524,38 @@ func (s *Server) getConfig(activeProf *profilemanager.ActiveProfileState) (*prof
 
 	log.Infof("active profile config existed: %t, err %v", configExisted, err)
 
-	config, err := profilemanager.ReadConfig(cfgPath)
+	config, err := profilemanager.ReadConfigOrDefault(cfgPath)
 	if err != nil {
 		return nil, false, fmt.Errorf("failed to get config: %w", err)
 	}
 
-	// Apply the daemon-owned MDM policy on top of the just-resolved
-	// Config. profilemanager's apply() initialises the policy to
-	// empty — the Loader lives outside Config, so this overlay step
-	// is driven externally here.
+	generated, err := config.EnsureIdentity()
+	if err != nil {
+		return nil, false, fmt.Errorf("ensure profile identity: %w", err)
+	}
+
+	if generated || !configExisted {
+		if err := profilemanager.WriteOutConfig(cfgPath, config); err != nil {
+			return nil, false, fmt.Errorf("write out profile config: %w", err)
+		}
+	}
+
+	return config, configExisted, nil
+}
+
+// getConfig resolves the active profile's config, provisions its identity and
+// reports whether the config file already existed.
+func (s *Server) getConfig(activeProf *profilemanager.ActiveProfileState) (*profilemanager.Config, bool, error) {
+	config, configExisted, err := provisionProfileIdentity(activeProf)
+	if err != nil {
+		return nil, false, err
+	}
+
+	// Apply the daemon-owned MDM policy on top of the just-resolved Config.
+	// profilemanager's apply() initialises the policy to empty — the Loader
+	// lives outside Config, so this overlay step is driven externally here.
+	// After the write above, on purpose: the overlay is runtime-only and
+	// re-derived on every load, so the file keeps the profile's own values.
 	config.ApplyMDMPolicy(s.mdmLoader.Load())
 
 	return config, configExisted, nil
@@ -1560,7 +1610,7 @@ func (s *Server) logoutFromProfile(ctx context.Context, profile *profilemanager.
 		cfgPath = profilemanager.DefaultConfigPath
 	}
 
-	config, err := profilemanager.GetConfig(cfgPath)
+	config, err := profilemanager.GetExistingConfig(cfgPath)
 	if err != nil {
 		return fmt.Errorf("profile '%s' not found", profile.ID)
 	}
@@ -1579,6 +1629,19 @@ func (s *Server) sendLogoutRequestWithConfig(ctx context.Context, config *profil
 	// Privilege gate: deregistering frees this machine's key to be registered
 	// against another management server, which is only restricted while the SSH
 	// server makes that a privilege handover.
+	// Ahead of the privilege gate on purpose. A profile with no identity was
+	// never registered — a logout clears the keys in place, so logging the same
+	// profile out twice lands here — so there is nothing to deregister and
+	// nothing for the gate to protect: what it guards against is handing this
+	// machine's registered key to another management server. Behind the gate,
+	// an unprivileged caller would be refused instead, and for a profile whose
+	// ServerSSHAllowed is unset that is every caller, since an absent value
+	// counts as SSH enabled.
+	if config.PrivateKey == "" {
+		log.Infof("profile carries no identity, nothing to deregister")
+		return nil
+	}
+
 	if err := requirePrivilegeForDeregistration(ctx, config); err != nil {
 		return err
 	}
@@ -2196,7 +2259,7 @@ func (s *Server) GetConfig(ctx context.Context, req *proto.GetConfigRequest) (*p
 		cfgPath = profilemanager.DefaultConfigPath
 	}
 
-	cfg, err := profilemanager.GetConfig(cfgPath)
+	cfg, err := profilemanager.GetExistingConfig(cfgPath)
 	if err != nil {
 		log.Errorf("failed to get active profile config: %v", err)
 		return nil, fmt.Errorf("failed to get active profile config: %w", err)
@@ -2659,8 +2722,6 @@ func sendTerminalNotification() error {
 	return wallCmd.Wait()
 }
 
-// persistLoginOverrides writes management URL and pre-shared key from a LoginRequest to the
-// active profile config so that subsequent reads pick them up. Empty/nil values are ignored.
 // afterLoginPreCheck is a seam for tests to run a concurrent config change
 // between Login's first privilege check and the authoritative one.
 var afterLoginPreCheck func()
@@ -2691,6 +2752,15 @@ func (s *Server) authorizeAndPrepareLogin(callerCtx context.Context, msg *proto.
 		return nil, nil, err
 	}
 
+	// The update-settings decision is re-taken here for the same reason as the
+	// privilege one: Login's earlier check ran outside this lock, so the stored
+	// config it compared against could have moved since. This one is the
+	// authoritative check, and it is the last read before persistLoginOverrides
+	// writes.
+	if s.checkUpdateSettingsDisabled() && configChangeRequested(stored, loginOverridesInput(msg)) {
+		return nil, nil, gstatus.Errorf(codes.FailedPrecondition, errUpdateSettingsDisabled)
+	}
+
 	s.mutex.Lock()
 	if s.actCancel != nil {
 		s.actCancel()
@@ -2717,18 +2787,28 @@ func (s *Server) authorizeAndPrepareLogin(callerCtx context.Context, msg *proto.
 		return nil, nil, fmt.Errorf("active profile state: %w", err)
 	}
 
-	if err := persistLoginOverrides(activeProf, msg.ManagementUrl, msg.OptionalPreSharedKey); err != nil {
+	if err := persistLoginOverrides(activeProf, msg); err != nil {
 		return nil, nil, fmt.Errorf("persist login overrides: %w", err)
 	}
 
+	// Provisioning under the same lock as the decision above, and next to the
+	// write it guards. getConfig would otherwise mint the identity and persist
+	// it once this returns: between its read and its write, a SetConfig that
+	// had already answered its caller would be overwritten by the config this
+	// login read before it landed.
+	if _, _, err := provisionProfileIdentity(activeProf); err != nil {
+		return nil, nil, err
+	}
+
 	return ctx, activeProf, nil
 }
 
-func persistLoginOverrides(activeProf *profilemanager.ActiveProfileState, managementURL string, preSharedKey *string) error {
-	if preSharedKey != nil && *preSharedKey == "" {
-		preSharedKey = nil
-	}
-	if managementURL == "" && preSharedKey == nil {
+// persistLoginOverrides writes the config fields a login request is allowed to
+// carry into the active profile. It shares its input builder with the
+// update-settings gate, so the gate judges exactly the fields this writes.
+func persistLoginOverrides(activeProf *profilemanager.ActiveProfileState, msg *proto.LoginRequest) error {
+	input := loginOverridesInput(msg)
+	if input.ManagementURL == "" && input.PreSharedKey == nil {
 		return nil
 	}
 
@@ -2737,11 +2817,7 @@ func persistLoginOverrides(activeProf *profilemanager.ActiveProfileState, manage
 		return fmt.Errorf("active profile file path: %w", err)
 	}
 
-	input := profilemanager.ConfigInput{
-		ConfigPath:    cfgPath,
-		ManagementURL: managementURL,
-		PreSharedKey:  preSharedKey,
-	}
+	input.ConfigPath = cfgPath
 	if _, err := profilemanager.UpdateOrCreateConfig(input); err != nil {
 		return fmt.Errorf("update config: %w", err)
 	}
diff --git a/client/server/setconfig_mdm_test.go b/client/server/setconfig_mdm_test.go
index a392af6d3..d174dc47b 100644
--- a/client/server/setconfig_mdm_test.go
+++ b/client/server/setconfig_mdm_test.go
@@ -290,7 +290,7 @@ func TestSetConfig_MDMReject_AllOrNothing(t *testing.T) {
 
 	// Confirm RosenpassEnabled was NOT applied even though it was not
 	// in the conflict list: the request was rejected as a whole.
-	reloaded, err := profilemanager.GetConfig(cfgPath)
+	reloaded, err := profilemanager.GetExistingConfig(cfgPath)
 	require.NoError(t, err)
 	assert.False(t, reloaded.RosenpassEnabled, "non-conflicting field must not be applied when request is rejected")
 }
diff --git a/client/server/setconfig_test.go b/client/server/setconfig_test.go
index 7442b718e..d7f7b2bd5 100644
--- a/client/server/setconfig_test.go
+++ b/client/server/setconfig_test.go
@@ -125,7 +125,7 @@ func TestSetConfig_AllFieldsSaved(t *testing.T) {
 	cfgPath, err := profState.FilePath()
 	require.NoError(t, err)
 
-	cfg, err := profilemanager.GetConfig(cfgPath)
+	cfg, err := profilemanager.GetExistingConfig(cfgPath)
 	require.NoError(t, err)
 
 	require.Equal(t, "https://new-api.netbird.io:443", cfg.ManagementURL.String())
diff --git a/client/server/ssh_gate.go b/client/server/ssh_gate.go
index 01d24687e..40d66b7a5 100644
--- a/client/server/ssh_gate.go
+++ b/client/server/ssh_gate.go
@@ -331,21 +331,5 @@ func sameManagementURL(stored *url.URL, requested string) bool {
 		return false
 	}
 
-	return stored.Scheme == parsed.Scheme &&
-		stored.Hostname() == parsed.Hostname() &&
-		effectivePort(stored) == effectivePort(parsed)
-}
-
-func effectivePort(u *url.URL) string {
-	if port := u.Port(); port != "" {
-		return port
-	}
-	switch u.Scheme {
-	case "https":
-		return "443"
-	case "http":
-		return "80"
-	default:
-		return ""
-	}
+	return profilemanager.SameServiceURL(stored, parsed)
 }
diff --git a/client/server/update_settings_gate.go b/client/server/update_settings_gate.go
new file mode 100644
index 000000000..b4d32754f
--- /dev/null
+++ b/client/server/update_settings_gate.go
@@ -0,0 +1,55 @@
+package server
+
+import (
+	log "github.com/sirupsen/logrus"
+
+	"github.com/netbirdio/netbird/client/internal/profilemanager"
+	"github.com/netbirdio/netbird/client/proto"
+)
+
+// configChangeRequested reports whether applying input would move the target
+// profile away from the configuration it already persists. It is the decision
+// procedure of the update-settings kill switch (--disable-update-settings /
+// NB_DISABLE_UPDATE_SETTINGS / the MDM DisableUpdateSettings key): that switch
+// forbids *changing* settings, so a request that restates the stored values is
+// not a change and must not be refused.
+//
+// This has to be judged on values, not on field presence. `netbird up` rebuilds
+// the whole config surface of SetConfigRequest and LoginRequest from its flags
+// and environment on every invocation, so a service or container configured by
+// environment restates its own configuration on every start. A presence-based
+// gate refused those requests, and because Login carries the same fields it
+// refused the login too — leaving such a client unable to come up at all.
+//
+// A dry run that cannot be evaluated fails closed: the request counts as a
+// change, so a malformed field can never open the gate. The error itself is
+// reported to the caller by the real update path.
+func configChangeRequested(stored *profilemanager.Config, input profilemanager.ConfigInput) bool {
+	changed, err := stored.WouldChange(input)
+	if err != nil {
+		log.Warnf("cannot evaluate the requested config change, treating it as a change: %v", err)
+		return true
+	}
+	return changed
+}
+
+// loginOverridesInput builds the ConfigInput a login request persists. The
+// management URL and the pre-shared key are the only config fields the daemon
+// applies from a LoginRequest; everything else on that message is either pure
+// auth or ignored. An empty pre-shared key is dropped rather than written, so
+// a login cannot clear the stored key by omission.
+//
+// Both the write (persistLoginOverrides) and the update-settings gate go
+// through this builder, so the gate can neither refuse a field the write
+// ignores nor miss one it applies.
+func loginOverridesInput(msg *proto.LoginRequest) profilemanager.ConfigInput {
+	preSharedKey := msg.OptionalPreSharedKey
+	if preSharedKey != nil && *preSharedKey == "" {
+		preSharedKey = nil
+	}
+
+	return profilemanager.ConfigInput{
+		ManagementURL: msg.ManagementUrl,
+		PreSharedKey:  preSharedKey,
+	}
+}
diff --git a/client/server/update_settings_gate_test.go b/client/server/update_settings_gate_test.go
new file mode 100644
index 000000000..0d2cd8810
--- /dev/null
+++ b/client/server/update_settings_gate_test.go
@@ -0,0 +1,390 @@
+package server
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"google.golang.org/grpc/codes"
+	gstatus "google.golang.org/grpc/status"
+
+	"github.com/netbirdio/netbird/client/internal"
+	"github.com/netbirdio/netbird/client/internal/profilemanager"
+	"github.com/netbirdio/netbird/client/mdm"
+	"github.com/netbirdio/netbird/client/proto"
+)
+
+// The seeded profile of setupServerWithProfile is created with this management
+// URL, so a request carrying it restates what the profile already holds.
+const storedManagementURL = "https://api.netbird.io:443"
+
+// A client configured by environment re-sends its whole configuration on every
+// `netbird up`: the CLI fills the request from its flags and env regardless of
+// what changed. With the update-settings kill switch on, such a request must
+// pass — nothing about the configuration moves.
+func TestSetConfig_RestatingTheStoredConfigPassesTheGate(t *testing.T) {
+	s, ctx, profName, username, _ := setupServerWithProfile(t)
+	s.updateSettingsDisabled = true
+
+	_, err := s.SetConfig(ctx, &proto.SetConfigRequest{
+		ProfileName:   profName,
+		Username:      username,
+		ManagementUrl: storedManagementURL,
+	})
+	require.NoError(t, err, "restating the stored management URL is not a settings change")
+}
+
+// The same endpoint written without its default port is the same endpoint. A
+// gate that compared raw strings refused NB_MANAGEMENT_URL=https://host, which
+// is how the URL is normally spelled.
+func TestSetConfig_EquivalentManagementURLPassesTheGate(t *testing.T) {
+	s, ctx, profName, username, _ := setupServerWithProfile(t)
+	s.updateSettingsDisabled = true
+
+	_, err := s.SetConfig(ctx, &proto.SetConfigRequest{
+		ProfileName:   profName,
+		Username:      username,
+		ManagementUrl: "https://api.netbird.io",
+	})
+	require.NoError(t, err, "an implicit :443 is the same management URL")
+}
+
+// The kill switch still has to do its job: a request that moves a setting is
+// refused, and the profile keeps the value it had.
+func TestSetConfig_ChangingASettingIsRefused(t *testing.T) {
+	s, ctx, profName, username, cfgPath := setupServerWithProfile(t)
+	s.updateSettingsDisabled = true
+
+	_, err := s.SetConfig(ctx, &proto.SetConfigRequest{
+		ProfileName:   profName,
+		Username:      username,
+		ManagementUrl: "https://mgmt.elsewhere.example:443",
+	})
+	require.Error(t, err, "moving the management URL is a settings change")
+	require.Equal(t, codes.FailedPrecondition, gstatus.Code(err), "want the update-settings refusal, got %v", err)
+
+	cfg, err := profilemanager.GetExistingConfig(cfgPath)
+	require.NoError(t, err)
+	require.Equal(t, storedManagementURL, cfg.ManagementURL.String(), "the refused request changed the config anyway")
+}
+
+// A field whose requested value differs from the stored one is a change even
+// when the rest of the request restates the configuration.
+func TestSetConfig_SingleDivergingFieldIsRefused(t *testing.T) {
+	s, ctx, profName, username, _ := setupServerWithProfile(t)
+	s.updateSettingsDisabled = true
+
+	rosenpass := true
+	_, err := s.SetConfig(ctx, &proto.SetConfigRequest{
+		ProfileName:      profName,
+		Username:         username,
+		ManagementUrl:    storedManagementURL,
+		RosenpassEnabled: &rosenpass,
+	})
+	require.Error(t, err, "enabling Rosenpass is a settings change")
+	require.Equal(t, codes.FailedPrecondition, gstatus.Code(err), "want the update-settings refusal, got %v", err)
+}
+
+// With the switch off, the same diverging request goes through: the gate must
+// not leak into a daemon that never enabled it.
+func TestSetConfig_ChangeAllowedWhenTheSwitchIsOff(t *testing.T) {
+	s, ctx, profName, username, cfgPath := setupServerWithProfile(t)
+
+	_, err := s.SetConfig(ctx, &proto.SetConfigRequest{
+		ProfileName:   profName,
+		Username:      username,
+		ManagementUrl: "https://mgmt.elsewhere.example:443",
+	})
+	require.NoError(t, err)
+
+	cfg, err := profilemanager.GetExistingConfig(cfgPath)
+	require.NoError(t, err)
+	require.Equal(t, "https://mgmt.elsewhere.example:443", cfg.ManagementURL.String())
+}
+
+// Login carries the same config surface as SetConfig, so it is gated the same
+// way: a login that would move a protected setting is refused before it can
+// touch daemon state.
+func TestLogin_ChangingTheManagementURLIsRefused(t *testing.T) {
+	s, _, profName, username, cfgPath := setupServerWithProfile(t)
+	s.updateSettingsDisabled = true
+	s.rootCtx = internal.CtxInitState(context.Background())
+
+	cancelled := false
+	s.actCancel = func() { cancelled = true }
+
+	_, err := s.Login(userCtx(), &proto.LoginRequest{
+		Username:      &username,
+		ManagementUrl: "https://mgmt.elsewhere.example:443",
+	})
+	require.Error(t, err, "moving the management URL through Login is a settings change")
+	require.Equal(t, codes.FailedPrecondition, gstatus.Code(err), "want the update-settings refusal, got %v", err)
+
+	// "Refused before it can touch daemon state" is the contract, so check the
+	// state as well as the error.
+	cfg, err := profilemanager.GetExistingConfig(cfgPath)
+	require.NoError(t, err)
+	require.Equal(t, storedManagementURL, cfg.ManagementURL.String(), "the refused login moved the management URL")
+	require.False(t, cancelled, "the refused login cancelled the login already in progress")
+
+	active, err := s.profileManager.GetActiveProfileState()
+	require.NoError(t, err)
+	require.Equal(t, profilemanager.ID(profName), active.ID, "the refused login switched the active profile")
+}
+
+// seedProfileConfig writes a profile config carrying the given management URL
+// and pre-shared key into a temp dir, and returns its path.
+func seedProfileConfig(t *testing.T, managementURL, preSharedKey string) string {
+	t.Helper()
+
+	path := filepath.Join(t.TempDir(), "seeded.json")
+	_, err := profilemanager.UpdateOrCreateConfig(profilemanager.ConfigInput{
+		ConfigPath:    path,
+		ManagementURL: managementURL,
+		PreSharedKey:  &preSharedKey,
+	})
+	require.NoError(t, err, "seed profile config")
+	return path
+}
+
+// The decision procedure itself, over the fields a login actually persists.
+// A login that restates the stored values must not be refused: that is what
+// keeps a re-login, or a container restart carrying NB_MANAGEMENT_URL, working
+// with the kill switch on.
+func TestLoginGateDecision(t *testing.T) {
+	stored, err := profilemanager.GetExistingConfig(seedProfileConfig(t, storedManagementURL, "stored-key"))
+	require.NoError(t, err)
+
+	redacted := mdm.PreSharedKeyRedactedSentinel
+	empty := ""
+	sameKey := "stored-key"
+	otherKey := "other-key"
+
+	tests := []struct {
+		name        string
+		msg         *proto.LoginRequest
+		wantChanged bool
+	}{
+		{
+			name:        "pure auth carries no config",
+			msg:         &proto.LoginRequest{SetupKey: "ABC"},
+			wantChanged: false,
+		},
+		{
+			name:        "stored management URL restated",
+			msg:         &proto.LoginRequest{ManagementUrl: storedManagementURL},
+			wantChanged: false,
+		},
+		{
+			name:        "stored management URL without its default port",
+			msg:         &proto.LoginRequest{ManagementUrl: "https://api.netbird.io"},
+			wantChanged: false,
+		},
+		{
+			name:        "different management URL",
+			msg:         &proto.LoginRequest{ManagementUrl: "https://mgmt.elsewhere.example:443"},
+			wantChanged: true,
+		},
+		{
+			name:        "stored pre-shared key restated",
+			msg:         &proto.LoginRequest{OptionalPreSharedKey: &sameKey},
+			wantChanged: false,
+		},
+		{
+			name:        "redacted pre-shared key echoed back",
+			msg:         &proto.LoginRequest{OptionalPreSharedKey: &redacted},
+			wantChanged: false,
+		},
+		{
+			name:        "empty pre-shared key is not a request to clear it",
+			msg:         &proto.LoginRequest{OptionalPreSharedKey: &empty},
+			wantChanged: false,
+		},
+		{
+			name:        "different pre-shared key",
+			msg:         &proto.LoginRequest{OptionalPreSharedKey: &otherKey},
+			wantChanged: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			require.Equal(t, tt.wantChanged, configChangeRequested(stored, loginOverridesInput(tt.msg)))
+		})
+	}
+}
+
+// A profile with no config on disk yet is judged against the config the daemon
+// would create for it, so a first login that asks for the defaults is not a
+// change while one that asks for a different management URL is.
+func TestGateDecisionWithoutStoredConfig(t *testing.T) {
+	require.False(t, configChangeRequested(nil, profilemanager.ConfigInput{}),
+		"a request carrying nothing cannot change anything")
+	require.False(t, configChangeRequested(nil, profilemanager.ConfigInput{ManagementURL: profilemanager.DefaultManagementURL}),
+		"asking for the default management URL is what the daemon would write anyway")
+	require.True(t, configChangeRequested(nil, profilemanager.ConfigInput{ManagementURL: "https://mgmt.elsewhere.example:443"}),
+		"asking for a non-default management URL is a change")
+}
+
+// A dry run that cannot be evaluated must fail closed, or a malformed field
+// would open the gate.
+func TestGateDecisionFailsClosedOnAnInvalidRequest(t *testing.T) {
+	require.True(t, configChangeRequested(nil, profilemanager.ConfigInput{ManagementURL: "not-a-url"}),
+		"an unevaluable request must count as a change")
+}
+
+// The gate reads the stored config to decide, and reading it must not write it:
+// a refused request has to leave the profile file byte-for-byte as it was.
+// A config file missing a field the config layer fills in (MTU, here) is what
+// makes the normalization write fire.
+func TestSetConfig_RefusedRequestLeavesTheConfigFileUntouched(t *testing.T) {
+	s, ctx, profName, username, cfgPath := setupServerWithProfile(t)
+	s.updateSettingsDisabled = true
+
+	require.NoError(t, os.WriteFile(cfgPath, []byte(`{"WgIface":"wt0"}`), 0o600))
+	before, err := os.ReadFile(cfgPath)
+	require.NoError(t, err)
+
+	_, err = s.SetConfig(ctx, &proto.SetConfigRequest{
+		ProfileName:   profName,
+		Username:      username,
+		ManagementUrl: "https://mgmt.elsewhere.example:443",
+	})
+	require.Error(t, err)
+	require.Equal(t, codes.FailedPrecondition, gstatus.Code(err), "want the update-settings refusal, got %v", err)
+
+	after, err := os.ReadFile(cfgPath)
+	require.NoError(t, err)
+	require.Equal(t, string(before), string(after), "the refused request rewrote the profile config")
+}
+
+// The container case that the string comparison still broke: the management URL
+// supplied through the environment is the stored one, written with a trailing
+// slash.
+func TestSetConfig_ManagementURLSpellingsPassTheGate(t *testing.T) {
+	for _, spelling := range []string{
+		"https://api.netbird.io",
+		"https://api.netbird.io/",
+		"https://api.netbird.io:443/",
+		"https://API.netbird.io:443",
+	} {
+		t.Run(spelling, func(t *testing.T) {
+			s, ctx, profName, username, _ := setupServerWithProfile(t)
+			s.updateSettingsDisabled = true
+
+			_, err := s.SetConfig(ctx, &proto.SetConfigRequest{
+				ProfileName:   profName,
+				Username:      username,
+				ManagementUrl: spelling,
+			})
+			require.NoError(t, err, "%q is the stored management URL written differently", spelling)
+		})
+	}
+}
+
+// The RPC the whole fix hangs on. Login is retried by the CLI in a backoff
+// loop, so a login that restates the stored configuration — which is what a
+// container configured by environment sends on every start — must get past the
+// gate, or the client never comes up at all.
+//
+// Past the gate the handler goes on to do real work this test does not stand
+// up, so the assertion is only that the refusal did not happen.
+func TestLogin_RestatingTheStoredConfigPassesTheGate(t *testing.T) {
+	s, _, _, username, _ := setupServerWithProfile(t)
+	s.updateSettingsDisabled = true
+	s.rootCtx = internal.CtxInitState(context.Background())
+
+	// Stand in for the management round trip the handler makes once the gate
+	// lets it through, so this test exercises the gate and not the network:
+	// without it the profile's management URL is dialed for real.
+	s.isLoginRequiredFn = func(context.Context) (bool, error) { return false, nil }
+
+	_, err := s.Login(userCtx(), &proto.LoginRequest{
+		Username:      &username,
+		ManagementUrl: storedManagementURL,
+	})
+	if err != nil {
+		require.NotEqual(t, codes.FailedPrecondition, gstatus.Code(err),
+			"the gate refused a login that changes nothing: %v", err)
+		require.NotContains(t, err.Error(), "update settings are disabled",
+			"the gate refused a login that changes nothing: %v", err)
+	}
+}
+
+// The value-aware decision has the same synchronization problem as the
+// privileged-change one: Login's first check runs outside guardedConfigMu, so
+// the stored config it compared against can move before the write. A login that
+// was a no-op when it was checked must not be written once it has become a
+// change.
+func TestLogin_ChangeThatAppearsMidRequestIsRefused(t *testing.T) {
+	s, _, _, username, _ := setupServerWithProfile(t)
+	s.updateSettingsDisabled = true
+	s.rootCtx = internal.CtxInitState(context.Background())
+
+	target := "moved-under-us"
+	targetPath := filepath.Join(profilemanager.DefaultConfigPathDir, target+".json")
+	_, err := profilemanager.UpdateOrCreateConfig(profilemanager.ConfigInput{
+		ConfigPath:    targetPath,
+		ManagementURL: storedManagementURL,
+	})
+	require.NoError(t, err)
+
+	cancelled := false
+	s.actCancel = func() { cancelled = true }
+
+	// Stand in for a concurrent writer that repoints the profile between the two
+	// checks, which is the interleaving the lock has to make safe. The login
+	// restates the URL the profile held when it was checked, so the first check
+	// sees a no-op and lets it through.
+	afterLoginPreCheck = func() {
+		_, err := profilemanager.UpdateOrCreateConfig(profilemanager.ConfigInput{
+			ConfigPath:    targetPath,
+			ManagementURL: "https://mgmt.elsewhere.example:443",
+		})
+		require.NoError(t, err)
+	}
+	t.Cleanup(func() { afterLoginPreCheck = nil })
+
+	_, err = s.Login(userCtx(), &proto.LoginRequest{
+		ProfileName:   &target,
+		Username:      &username,
+		ManagementUrl: storedManagementURL,
+	})
+	require.Error(t, err, "the login became a settings change before it was written")
+	require.Equal(t, codes.FailedPrecondition, gstatus.Code(err), "want the update-settings refusal, got %v", err)
+	require.False(t, cancelled, "the refused login cancelled the login already in progress")
+
+	stored, err := profilemanager.GetExistingConfig(targetPath)
+	require.NoError(t, err)
+	require.Equal(t, "https://mgmt.elsewhere.example:443", stored.ManagementURL.String(),
+		"the refused login wrote the management URL it was asked for")
+}
+
+// Logging out a profile that was already logged out must not fail: the logout
+// clears the keys in place, so the second attempt finds a profile with no
+// identity, which was never registered and has nothing to deregister.
+func TestLogout_ProfileWithoutAnIdentityIsANoOp(t *testing.T) {
+	s, _, _, _, cfgPath := setupServerWithProfile(t)
+
+	loggedOut, err := profilemanager.GetExistingConfig(cfgPath)
+	require.NoError(t, err)
+	loggedOut.PrivateKey = ""
+	loggedOut.SSHKey = ""
+	require.NoError(t, profilemanager.WriteOutConfig(cfgPath, loggedOut))
+
+	stored, err := profilemanager.GetExistingConfig(cfgPath)
+	require.NoError(t, err)
+	require.NoError(t, s.sendLogoutRequestWithConfig(privilegedTestCtx(), stored),
+		"logging out an identity-less profile must not fail")
+
+	// And for an unprivileged caller too: the deregistration privilege gate
+	// guards the handover of a registered key, so with no key there is nothing
+	// to guard. An unset SSH setting is what arms that gate — sshServerEnabled
+	// reads an absent value as enabled — so this stands in for every legacy
+	// profile, where behind the gate the caller would be refused.
+	stored.ServerSSHAllowed = nil
+	require.NoError(t, s.sendLogoutRequestWithConfig(userCtx(), stored),
+		"an unprivileged caller could not log out a profile with nothing to deregister")
+}
diff --git a/client/ui/i18n/locales/de/common.json b/client/ui/i18n/locales/de/common.json
index c39584992..dcce2f908 100644
--- a/client/ui/i18n/locales/de/common.json
+++ b/client/ui/i18n/locales/de/common.json
@@ -1363,6 +1363,12 @@
     "error.daemon_unreachable": {
         "message": "Der NetBird-Dienst antwortet nicht. Bitte prüfen Sie, ob der Dienst läuft."
     },
+    "error.settings_locked": {
+        "message": "Die Einstellungen können auf diesem Gerät nicht geändert werden: Ein Administrator hat sie gesperrt."
+    },
+    "error.settings_managed_by_mdm": {
+        "message": "Diese Einstellung wird von Ihrer Organisation verwaltet und kann nicht geändert werden."
+    },
     "error.unknown": {
         "message": "Vorgang fehlgeschlagen."
     },
diff --git a/client/ui/i18n/locales/en/common.json b/client/ui/i18n/locales/en/common.json
index e9ee26de4..94d741b3e 100644
--- a/client/ui/i18n/locales/en/common.json
+++ b/client/ui/i18n/locales/en/common.json
@@ -1815,6 +1815,14 @@
         "message": "The NetBird daemon is not responding. Please check that the service is running.",
         "description": "Error: the NetBird background service isn't responding. 'daemon' = the background service."
     },
+    "error.settings_locked": {
+        "message": "Settings cannot be changed on this device: an administrator has locked them.",
+        "description": "Error: the local daemon was started with update-settings disabled, so it refuses configuration changes."
+    },
+    "error.settings_managed_by_mdm": {
+        "message": "This setting is managed by your organization and cannot be changed.",
+        "description": "Error: the setting is enforced by an MDM policy. 'MDM' = mobile device management, the organization's device-management system."
+    },
     "error.unknown": {
         "message": "Operation failed.",
         "description": "Generic fallback error message used when no specific error applies."
diff --git a/client/ui/i18n/locales/es/common.json b/client/ui/i18n/locales/es/common.json
index 245b5aa5f..979879680 100644
--- a/client/ui/i18n/locales/es/common.json
+++ b/client/ui/i18n/locales/es/common.json
@@ -1363,6 +1363,12 @@
     "error.daemon_unreachable": {
         "message": "El daemon de NetBird no responde. Compruebe que el servicio esté en ejecución."
     },
+    "error.settings_locked": {
+        "message": "La configuración no se puede cambiar en este dispositivo: un administrador la ha bloqueado."
+    },
+    "error.settings_managed_by_mdm": {
+        "message": "Esta configuración está gestionada por su organización y no se puede cambiar."
+    },
     "error.unknown": {
         "message": "La operación falló."
     },
diff --git a/client/ui/i18n/locales/fr/common.json b/client/ui/i18n/locales/fr/common.json
index 6da66a643..f9961d864 100644
--- a/client/ui/i18n/locales/fr/common.json
+++ b/client/ui/i18n/locales/fr/common.json
@@ -1363,6 +1363,12 @@
     "error.daemon_unreachable": {
         "message": "Le daemon NetBird ne répond pas. Veuillez vérifier que le service est en cours d’exécution."
     },
+    "error.settings_locked": {
+        "message": "Les paramètres ne peuvent pas être modifiés sur cet appareil : un administrateur les a verrouillés."
+    },
+    "error.settings_managed_by_mdm": {
+        "message": "Ce paramètre est géré par votre organisation et ne peut pas être modifié."
+    },
     "error.unknown": {
         "message": "L’opération a échoué."
     },
diff --git a/client/ui/i18n/locales/hu/common.json b/client/ui/i18n/locales/hu/common.json
index 1b4d2fb9d..94dcb578c 100644
--- a/client/ui/i18n/locales/hu/common.json
+++ b/client/ui/i18n/locales/hu/common.json
@@ -1363,6 +1363,12 @@
     "error.daemon_unreachable": {
         "message": "A NetBird szolgáltatás nem válaszol. Kérjük, ellenőrizze, hogy fut-e a szolgáltatás."
     },
+    "error.settings_locked": {
+        "message": "A beállítások ezen az eszközön nem módosíthatók: egy rendszergazda zárolta őket."
+    },
+    "error.settings_managed_by_mdm": {
+        "message": "Ezt a beállítást a szervezete kezeli, ezért nem módosítható."
+    },
     "error.unknown": {
         "message": "A művelet meghiúsult."
     },
diff --git a/client/ui/i18n/locales/it/common.json b/client/ui/i18n/locales/it/common.json
index 4cee0f842..8c1312535 100644
--- a/client/ui/i18n/locales/it/common.json
+++ b/client/ui/i18n/locales/it/common.json
@@ -1363,6 +1363,12 @@
     "error.daemon_unreachable": {
         "message": "Il daemon NetBird non risponde. Verifichi che il servizio sia in esecuzione."
     },
+    "error.settings_locked": {
+        "message": "Le impostazioni non possono essere modificate su questo dispositivo: un amministratore le ha bloccate."
+    },
+    "error.settings_managed_by_mdm": {
+        "message": "Questa impostazione è gestita dalla sua organizzazione e non può essere modificata."
+    },
     "error.unknown": {
         "message": "Operazione non riuscita."
     },
diff --git a/client/ui/i18n/locales/ja/common.json b/client/ui/i18n/locales/ja/common.json
index 4fc81d283..a3138de6c 100644
--- a/client/ui/i18n/locales/ja/common.json
+++ b/client/ui/i18n/locales/ja/common.json
@@ -1363,6 +1363,12 @@
     "error.daemon_unreachable": {
         "message": "NetBird デーモンが応答していません。サービスが実行されているか確認してください。"
     },
+    "error.settings_locked": {
+        "message": "この端末では設定を変更できません。管理者によってロックされています。"
+    },
+    "error.settings_managed_by_mdm": {
+        "message": "この設定は組織によって管理されているため、変更できません。"
+    },
     "error.unknown": {
         "message": "操作に失敗しました。"
     },
diff --git a/client/ui/i18n/locales/pt/common.json b/client/ui/i18n/locales/pt/common.json
index cb4a542d0..a75ae3dfc 100644
--- a/client/ui/i18n/locales/pt/common.json
+++ b/client/ui/i18n/locales/pt/common.json
@@ -1363,6 +1363,12 @@
     "error.daemon_unreachable": {
         "message": "O daemon do NetBird não está respondendo. Verifique se o serviço está em execução."
     },
+    "error.settings_locked": {
+        "message": "As configurações não podem ser alteradas neste dispositivo: um administrador bloqueou-as."
+    },
+    "error.settings_managed_by_mdm": {
+        "message": "Esta configuração é gerida pela sua organização e não pode ser alterada."
+    },
     "error.unknown": {
         "message": "A operação falhou."
     },
diff --git a/client/ui/i18n/locales/ru/common.json b/client/ui/i18n/locales/ru/common.json
index 61ece03b8..e11ed26a4 100644
--- a/client/ui/i18n/locales/ru/common.json
+++ b/client/ui/i18n/locales/ru/common.json
@@ -1363,6 +1363,12 @@
     "error.daemon_unreachable": {
         "message": "Демон NetBird не отвечает. Проверьте, запущена ли служба."
     },
+    "error.settings_locked": {
+        "message": "Настройки на этом устройстве изменить нельзя: администратор заблокировал их."
+    },
+    "error.settings_managed_by_mdm": {
+        "message": "Эта настройка управляется вашей организацией и не может быть изменена."
+    },
     "error.unknown": {
         "message": "Не удалось выполнить операцию."
     },
diff --git a/client/ui/i18n/locales/uk/common.json b/client/ui/i18n/locales/uk/common.json
index f8fe71562..01d2f4452 100644
--- a/client/ui/i18n/locales/uk/common.json
+++ b/client/ui/i18n/locales/uk/common.json
@@ -1361,6 +1361,12 @@
     "error.daemon_unreachable": {
         "message": "Служба NetBird не відповідає. Будь ласка, перевірте, чи запущена служба."
     },
+    "error.settings_locked": {
+        "message": "Налаштування на цьому пристрої змінити неможливо: адміністратор їх заблокував."
+    },
+    "error.settings_managed_by_mdm": {
+        "message": "Це налаштування керується вашою організацією і не може бути змінене."
+    },
     "error.unknown": {
         "message": "Помилка операції."
     },
diff --git a/client/ui/i18n/locales/zh-CN/common.json b/client/ui/i18n/locales/zh-CN/common.json
index 126b11851..64725a69f 100644
--- a/client/ui/i18n/locales/zh-CN/common.json
+++ b/client/ui/i18n/locales/zh-CN/common.json
@@ -1363,6 +1363,12 @@
     "error.daemon_unreachable": {
         "message": "NetBird 守护进程无响应。请检查服务是否正在运行。"
     },
+    "error.settings_locked": {
+        "message": "此设备上的设置无法更改：管理员已将其锁定。"
+    },
+    "error.settings_managed_by_mdm": {
+        "message": "此设置由您的组织管理，无法更改。"
+    },
     "error.unknown": {
         "message": "操作失败。"
     },
diff --git a/client/ui/services/errors.go b/client/ui/services/errors.go
index 0c6f2f20f..d193e9f02 100644
--- a/client/ui/services/errors.go
+++ b/client/ui/services/errors.go
@@ -134,8 +134,19 @@ func (c errorClassifier) classify(err error) *ClientError {
 		strings.Contains(lower, "connection refused"),
 		strings.Contains(lower, "context deadline exceeded"):
 		code = "daemon_unreachable"
+	case strings.Contains(lower, "update settings are disabled"):
+		code = "settings_locked"
+	case strings.Contains(lower, "managed by mdm"):
+		code = "settings_managed_by_mdm"
 	}
 
+	// Deliberately no blanket mapping for FailedPrecondition below: the daemon
+	// returns it for two dozen states that are not settings refusals at all —
+	// "not logged in", "client is not running", "session can no longer be
+	// extended" — and this classifier is shared with the session and connection
+	// services. Only the two refusals the daemon composes are named, by their
+	// message.
+
 	// Fall back to the gRPC status code when the message didn't match a known
 	// substring — the daemon now forwards the innermost code with a clean desc
 	// that no longer contains the English marker text.
diff --git a/client/ui/services/errors_test.go b/client/ui/services/errors_test.go
index 2f8f3d039..c2a10442f 100644
--- a/client/ui/services/errors_test.go
+++ b/client/ui/services/errors_test.go
@@ -34,6 +34,29 @@ func TestErrorClassifier_Classify(t *testing.T) {
 		require.Equal(t, "session_expired", ce.Code)
 	})
 
+	t.Run("the update-settings kill switch is a refusal, not a failure", func(t *testing.T) {
+		err := gstatus.Error(gcodes.FailedPrecondition,
+			"update settings are disabled, you cannot use this feature without update settings enabled")
+
+		ce := c.classify(err)
+		require.NotNil(t, ce)
+		require.Equal(t, "settings_locked", ce.Code)
+	})
+
+	t.Run("an MDM-managed field is named as such", func(t *testing.T) {
+		err := gstatus.Error(gcodes.FailedPrecondition,
+			"fields managed by MDM cannot be modified: [managementURL]")
+
+		require.Equal(t, "settings_managed_by_mdm", c.classify(err).Code)
+	})
+
+	t.Run("an unrelated FailedPrecondition is not called a refusal", func(t *testing.T) {
+		// The daemon uses this code for states that are not settings refusals,
+		// and this classifier is shared with the session and connection
+		// services, so only the two refusals it composes are named.
+		require.Equal(t, "unknown", c.classify(gstatus.Error(gcodes.FailedPrecondition, "not logged in")).Code)
+	})
+
 	t.Run("unavailable code maps to daemon_unreachable", func(t *testing.T) {
 		ce := c.classify(gstatus.Error(gcodes.Unavailable, "transport closing"))
 		require.Equal(t, "daemon_unreachable", ce.Code)