Merge pull request #125 from fosrl/dev

1.6.0

.github/CODEOWNERS

@@ -0,0 +1 @@
+* @oschwartz10612 @miloschwartz

.github/ISSUE_TEMPLATE/1.bug_report.yml

@@ -14,12 +14,13 @@ body:
           label: Environment
           description: Please fill out the relevant details below for your environment.
           value: |
-              - OS Type & Version: (e.g., Ubuntu 22.04)
+              - OS Type & Version:
               - Pangolin Version:
+              - Edition (Community or Enterprise):
               - Gerbil Version:
               - Traefik Version:
               - Newt Version:
-              - Olm Version: (if applicable)
+              - Client Version:
       validations:
           required: true
 

README.md

@@ -1,4 +1,5 @@
 # Olm
+Olm is being phased out in favor of the [Pangolin CLI](https://github.com/fosrl/cli) and is only meant for advanced use cases.
 
 Olm is a [WireGuard](https://www.wireguard.com/) tunnel client designed to securely connect your computer to Newt sites running on remote networks.
 

dns/override/dns_override_android.go

@@ -13,4 +13,16 @@ func SetupDNSOverride(interfaceName string, proxyIp netip.Addr) error {
 // RestoreDNSOverride is a no-op on Android
 func RestoreDNSOverride() error {
 	return nil
-}
+}
+
+// CleanupStaleState is a no-op on Android as DNS configuration is handled by the VpnService API
+func CleanupStaleState(interfaceName string) error {
+	_ = interfaceName
+	return nil
+}
+
+// ForceResetDNS is a no-op on Android.
+func ForceResetDNS(interfaceName string) error {
+	_ = interfaceName
+	return nil
+}

dns/override/dns_override_darwin.go

@@ -15,6 +15,13 @@ var configurator platform.DNSConfigurator
 // SetupDNSOverride configures the system DNS to use the DNS proxy on macOS
 // Uses scutil for DNS configuration
 func SetupDNSOverride(interfaceName string, proxyIp netip.Addr) error {
+	// Defensively clear any stale DNS state from a previous unclean shutdown
+	// before installing the new override. This makes a second tunnel start
+	// safe even if the previous client crashed without restoring DNS.
+	if err := CleanupStaleState(interfaceName); err != nil {
+		logger.Warn("Pre-setup stale DNS cleanup failed (continuing): %v", err)
+	}
+
 	var err error
 	configurator, err = platform.NewDarwinDNSConfigurator()
 	if err != nil {
@@ -61,3 +68,48 @@ func RestoreDNSOverride() error {
 	logger.Info("DNS configuration restored successfully")
 	return nil
 }
+
+// CleanupStaleState removes any stale DNS configuration left over from a previous
+// unclean shutdown (e.g., system crash, power loss while tunnel was active).
+// This function should be called early during startup, before any network operations,
+// to ensure DNS is working properly.
+//
+// On macOS, this cleans up any scutil DNS keys that were created but not removed.
+func CleanupStaleState(interfaceName string) error {
+	_ = interfaceName
+	if err := platform.CleanupStaleDarwinDNS(); err != nil {
+		logger.Warn("Failed to cleanup stale Darwin DNS config: %v", err)
+		return fmt.Errorf("Darwin DNS cleanup: %w", err)
+	}
+
+	logger.Info("Stale DNS state cleanup completed successfully")
+	return nil
+}
+
+// ForceResetDNS forcibly clears any DNS override state, whether or not the
+// current process installed it. This is intended for the "reset-dns" CLI
+// command and for the watchdog process to recover from a stuck override
+// left behind by a crashed client.
+func ForceResetDNS(interfaceName string) error {
+	logger.Info("Forcing DNS reset on Darwin (interface=%s)", interfaceName)
+
+	// First clean up any persisted state from a previous session.
+	cleanupErr := CleanupStaleState(interfaceName)
+
+	// Then, if the current process happens to hold a live configurator,
+	// instruct it to restore DNS as well so in-memory state is consistent.
+	if configurator != nil {
+		if err := configurator.RestoreDNS(); err != nil {
+			logger.Warn("ForceResetDNS: in-memory restore failed: %v", err)
+		}
+		configurator = nil
+	}
+
+	// As a last-resort defense, sweep any scutil keys matching our naming
+	// convention even if no state file exists.
+	if err := platform.SweepOlmScutilKeys(); err != nil {
+		logger.Warn("ForceResetDNS: scutil sweep failed: %v", err)
+	}
+
+	return cleanupErr
+}

dns/override/dns_override_ios.go

@@ -12,4 +12,16 @@ func SetupDNSOverride(interfaceName string, proxyIp netip.Addr) error {
 // RestoreDNSOverride is a no-op on iOS as DNS configuration is handled by the system
 func RestoreDNSOverride() error {
 	return nil
-}
+}
+
+// CleanupStaleState is a no-op on iOS as DNS configuration is handled by the system
+func CleanupStaleState(interfaceName string) error {
+	_ = interfaceName
+	return nil
+}
+
+// ForceResetDNS is a no-op on iOS.
+func ForceResetDNS(interfaceName string) error {
+	_ = interfaceName
+	return nil
+}

dns/override/dns_override_unix.go

@@ -15,6 +15,13 @@ var configurator platform.DNSConfigurator
 // SetupDNSOverride configures the system DNS to use the DNS proxy on Linux/FreeBSD
 // Detects the DNS manager by reading /etc/resolv.conf and verifying runtime availability
 func SetupDNSOverride(interfaceName string, proxyIp netip.Addr) error {
+	// Defensively clear any stale DNS state from a previous unclean shutdown
+	// before installing the new override. This makes a second tunnel start
+	// safe even if the previous client crashed without restoring DNS.
+	if err := CleanupStaleState(interfaceName); err != nil {
+		logger.Warn("Pre-setup stale DNS cleanup failed (continuing): %v", err)
+	}
+
 	var err error
 
 	// Detect which DNS manager is in use by checking /etc/resolv.conf and runtime availability
@@ -98,3 +105,71 @@ func RestoreDNSOverride() error {
 	logger.Info("DNS configuration restored successfully")
 	return nil
 }
+
+// CleanupStaleState removes any stale DNS configuration left over from a previous
+// unclean shutdown (e.g., system crash, power loss while tunnel was active).
+// This function should be called early during startup, before any network operations,
+// to ensure DNS is working properly.
+//
+// It checks and cleans up stale state from all supported DNS managers:
+// - NetworkManager: removes /etc/NetworkManager/conf.d/olm-dns.conf
+// - resolvconf: removes entry for the provided interface
+// - File-based: restores /etc/resolv.conf from backup if it exists
+//
+// This is safe to call even if no stale state exists.
+func CleanupStaleState(interfaceName string) error {
+	var errs []error
+
+	// Clean up NetworkManager stale config
+	if err := platform.CleanupStaleNetworkManagerDNS(); err != nil {
+		logger.Warn("Failed to cleanup stale NetworkManager DNS config: %v", err)
+		errs = append(errs, fmt.Errorf("NetworkManager cleanup: %w", err))
+	} else {
+		logger.Debug("NetworkManager DNS cleanup completed")
+	}
+
+	// Clean up resolvconf stale entries for the provided interface
+	if err := platform.CleanupStaleResolvconfDNS(interfaceName); err != nil {
+		logger.Warn("Failed to cleanup stale resolvconf DNS config: %v", err)
+		errs = append(errs, fmt.Errorf("resolvconf cleanup: %w", err))
+	} else {
+		logger.Debug("resolvconf DNS cleanup completed")
+	}
+
+	// Clean up file-based stale backup
+	if err := platform.CleanupStaleFileDNS(); err != nil {
+		logger.Warn("Failed to cleanup stale file-based DNS config: %v", err)
+		errs = append(errs, fmt.Errorf("file DNS cleanup: %w", err))
+	} else {
+		logger.Debug("File-based DNS cleanup completed")
+	}
+
+	if len(errs) > 0 {
+		return fmt.Errorf("some DNS cleanup operations failed: %v", errs)
+	}
+
+	logger.Info("Stale DNS state cleanup completed successfully")
+	return nil
+}
+
+// ForceResetDNS forcibly clears any DNS override state, whether or not the
+// current process installed it. This is intended for the "reset-dns" CLI
+// command and for the watchdog process to recover from a stuck override
+// left behind by a crashed client.
+func ForceResetDNS(interfaceName string) error {
+	logger.Info("Forcing DNS reset on Linux/FreeBSD (interface=%s)", interfaceName)
+
+	// First clean up any persisted state from a previous session.
+	cleanupErr := CleanupStaleState(interfaceName)
+
+	// Then, if the current process happens to hold a live configurator,
+	// instruct it to restore DNS as well so in-memory state is consistent.
+	if configurator != nil {
+		if err := configurator.RestoreDNS(); err != nil {
+			logger.Warn("ForceResetDNS: in-memory restore failed: %v", err)
+		}
+		configurator = nil
+	}
+
+	return cleanupErr
+}

dns/override/dns_override_windows.go

@@ -15,6 +15,12 @@ var configurator platform.DNSConfigurator
 // SetupDNSOverride configures the system DNS to use the DNS proxy on Windows
 // Uses registry-based configuration (automatically extracts interface GUID)
 func SetupDNSOverride(interfaceName string, proxyIp netip.Addr) error {
+	// Defensively clear any stale DNS state from a previous unclean shutdown
+	// before installing the new override.
+	if err := CleanupStaleState(interfaceName); err != nil {
+		logger.Warn("Pre-setup stale DNS cleanup failed (continuing): %v", err)
+	}
+
 	var err error
 	configurator, err = platform.NewWindowsDNSConfigurator(interfaceName)
 	if err != nil {
@@ -61,3 +67,33 @@ func RestoreDNSOverride() error {
 	logger.Info("DNS configuration restored successfully")
 	return nil
 }
+
+// CleanupStaleState removes any stale DNS configuration left over from a previous
+// unclean shutdown (e.g., system crash, power loss while tunnel was active).
+// This function should be called early during startup, before any network operations,
+// to ensure DNS is working properly.
+//
+// On Windows, DNS configuration is tied to the interface GUID. When the WireGuard
+// interface is recreated, it gets a new GUID, so there's no stale state to clean up.
+func CleanupStaleState(interfaceName string) error {
+	// Windows DNS configuration via registry is interface-specific.
+	// When the WireGuard interface is recreated, it gets a new GUID,
+	// so there's no leftover state to clean up from previous sessions.
+	_ = interfaceName
+	logger.Debug("Windows DNS cleanup: no stale state to clean (interface-specific)")
+	return nil
+}
+
+// ForceResetDNS forcibly clears any DNS override state. On Windows this is
+// largely a no-op because the registry override is tied to the interface
+// GUID and is reclaimed when the interface is torn down.
+func ForceResetDNS(interfaceName string) error {
+	logger.Info("Forcing DNS reset on Windows (interface=%s)", interfaceName)
+	if configurator != nil {
+		if err := configurator.RestoreDNS(); err != nil {
+			logger.Warn("ForceResetDNS: in-memory restore failed: %v", err)
+		}
+		configurator = nil
+	}
+	return CleanupStaleState(interfaceName)
+}

dns/override/watchdog.go

@@ -0,0 +1,136 @@
+package olm
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/fosrl/newt/logger"
+)
+
+// WatchdogConfig configures the DNS override watchdog. The watchdog runs as
+// an external process (spawned via SpawnWatchdog) and monitors a parent olm
+// process. When the parent appears to have died without restoring DNS, the
+// watchdog forcibly resets the system DNS configuration.
+type WatchdogConfig struct {
+	// ParentPID is the PID of the olm process that installed the DNS
+	// override. The watchdog exits when this PID is no longer alive.
+	ParentPID int
+
+	// SocketPath is the path to the olm Unix domain socket (or named pipe
+	// on Windows). The watchdog uses it as a secondary liveness signal.
+	// May be empty if no socket-based API is enabled.
+	SocketPath string
+
+	// InterfaceName is the name of the WireGuard interface whose DNS
+	// override should be reset on parent death.
+	InterfaceName string
+
+	// CheckInterval is how often to poll the parent's liveness.
+	// Defaults to 5 seconds when zero.
+	CheckInterval time.Duration
+
+	// FailureThreshold is the number of consecutive failed liveness checks
+	// before the watchdog declares the parent dead and resets DNS.
+	// Defaults to 3 when zero.
+	FailureThreshold int
+}
+
+// RunWatchdog runs the watchdog loop in the current process until either
+// (a) the parent dies and DNS is reset, or (b) ctx is cancelled.
+func RunWatchdog(ctx context.Context, cfg WatchdogConfig) error {
+	if cfg.ParentPID <= 0 {
+		return fmt.Errorf("watchdog: invalid parent PID %d", cfg.ParentPID)
+	}
+	if cfg.CheckInterval <= 0 {
+		cfg.CheckInterval = 5 * time.Second
+	}
+	if cfg.FailureThreshold <= 0 {
+		cfg.FailureThreshold = 3
+	}
+
+	logger.Info("DNS watchdog started: parent=%d interval=%s threshold=%d socket=%q interface=%q",
+		cfg.ParentPID, cfg.CheckInterval, cfg.FailureThreshold, cfg.SocketPath, cfg.InterfaceName)
+
+	ticker := time.NewTicker(cfg.CheckInterval)
+	defer ticker.Stop()
+
+	consecutiveFailures := 0
+
+	for {
+		select {
+		case <-ctx.Done():
+			logger.Info("DNS watchdog context cancelled, exiting cleanly")
+			return ctx.Err()
+		case <-ticker.C:
+		}
+
+		alive := isParentAlive(cfg.ParentPID, cfg.SocketPath)
+		if alive {
+			if consecutiveFailures > 0 {
+				logger.Debug("DNS watchdog: parent recovered after %d failures", consecutiveFailures)
+			}
+			consecutiveFailures = 0
+			continue
+		}
+
+		consecutiveFailures++
+		logger.Warn("DNS watchdog: parent liveness check failed (%d/%d)",
+			consecutiveFailures, cfg.FailureThreshold)
+
+		if consecutiveFailures >= cfg.FailureThreshold {
+			logger.Warn("DNS watchdog: parent declared dead, forcing DNS reset")
+			if err := ForceResetDNS(cfg.InterfaceName); err != nil {
+				logger.Error("DNS watchdog: ForceResetDNS failed: %v", err)
+				return err
+			}
+			logger.Info("DNS watchdog: DNS reset complete, exiting")
+			return nil
+		}
+	}
+}
+
+// isParentAlive returns true if the parent process appears to be alive. It
+// considers the parent alive if EITHER the PID is still running OR the
+// socket-based health endpoint responds. This dual check avoids false
+// positives where one signal is flaky (e.g., socket blocked but process
+// still recovering).
+func isParentAlive(pid int, socketPath string) bool {
+	if pidAlive(pid) {
+		return true
+	}
+	// Process is gone; double-check via socket to avoid races where PID
+	// recycling or signal-0 quirks lie to us. Socket should already be
+	// gone too.
+	if socketPath != "" && socketHealthy(socketPath) {
+		return true
+	}
+	return false
+}
+
+// socketHealthy attempts a fast /health request over the unix socket.
+func socketHealthy(socketPath string) bool {
+	if _, err := os.Stat(socketPath); err != nil {
+		return false
+	}
+
+	client := &http.Client{
+		Timeout: 2 * time.Second,
+		Transport: &http.Transport{
+			DialContext: func(ctx context.Context, _, _ string) (net.Conn, error) {
+				d := net.Dialer{Timeout: 2 * time.Second}
+				return d.DialContext(ctx, "unix", socketPath)
+			},
+		},
+	}
+
+	resp, err := client.Get("http://localhost/health")
+	if err != nil {
+		return false
+	}
+	defer resp.Body.Close()
+	return resp.StatusCode == http.StatusOK
+}

dns/override/watchdog_spawn_unix.go

@@ -0,0 +1,119 @@
+//go:build !windows
+
+package olm
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"strconv"
+	"syscall"
+
+	"github.com/fosrl/newt/logger"
+)
+
+// SpawnWatchdogConfig captures the inputs needed to launch the external
+// watchdog subprocess that monitors the calling olm process and forces a
+// DNS reset if the parent dies before restoring DNS.
+type SpawnWatchdogConfig struct {
+	// Executable is the path to the binary that will host the watchdog
+	// (typically os.Executable()). The binary must understand the
+	// watchdog subcommand layout described below.
+	Executable string
+
+	// Subcommand is the argv prefix the binary uses to enter watchdog
+	// mode (e.g., []string{"watchdog"} or []string{"dns", "watchdog"}).
+	Subcommand []string
+
+	// InterfaceName is the WireGuard interface whose DNS override should
+	// be reset if the parent dies.
+	InterfaceName string
+
+	// SocketPath is the parent's olm API socket path (may be empty).
+	SocketPath string
+
+	// LogFile, if non-empty, is the path the watchdog writes its stdout
+	// and stderr to. If empty, /dev/null is used.
+	LogFile string
+}
+
+// SpawnWatchdog launches the watchdog subprocess in a detached process group
+// so that it survives the death of the parent. The returned *exec.Cmd is the
+// handle the parent should call StopWatchdog on during clean shutdown.
+//
+// The spawned process is invoked as:
+//
+//	<Executable> <Subcommand...> --parent-pid=<ppid> \
+//	    --interface=<InterfaceName> [--socket=<SocketPath>]
+//
+// Both pangolin (cli) and olm should map their watchdog subcommand to
+// RunWatchdog.
+func SpawnWatchdog(cfg SpawnWatchdogConfig) (*exec.Cmd, error) {
+	if cfg.Executable == "" {
+		return nil, fmt.Errorf("watchdog: executable is required")
+	}
+	if len(cfg.Subcommand) == 0 {
+		return nil, fmt.Errorf("watchdog: subcommand is required")
+	}
+
+	args := append([]string{}, cfg.Subcommand...)
+	args = append(args,
+		"--parent-pid="+strconv.Itoa(os.Getpid()),
+		"--interface="+cfg.InterfaceName,
+	)
+	if cfg.SocketPath != "" {
+		args = append(args, "--socket="+cfg.SocketPath)
+	}
+
+	cmd := exec.Command(cfg.Executable, args...)
+
+	// Detach: new session so the watchdog is not killed by a signal
+	// delivered to the parent's process group.
+	cmd.SysProcAttr = &syscall.SysProcAttr{
+		Setsid: true,
+	}
+
+	// Direct watchdog output to a log file or /dev/null so it doesn't
+	// share file descriptors with the parent's TTY.
+	logTarget := cfg.LogFile
+	if logTarget == "" {
+		logTarget = os.DevNull
+	}
+	logFile, err := os.OpenFile(logTarget, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0o644)
+	if err != nil {
+		return nil, fmt.Errorf("watchdog: open log file: %w", err)
+	}
+	cmd.Stdin = nil
+	cmd.Stdout = logFile
+	cmd.Stderr = logFile
+
+	if err := cmd.Start(); err != nil {
+		_ = logFile.Close()
+		return nil, fmt.Errorf("watchdog: start: %w", err)
+	}
+
+	// We don't need our handle on the log file after the subprocess
+	// inherits it.
+	_ = logFile.Close()
+
+	logger.Info("DNS watchdog spawned (pid=%d, exe=%s)", cmd.Process.Pid, cfg.Executable)
+	return cmd, nil
+}
+
+// StopWatchdog asks the watchdog to exit cleanly via SIGTERM and reaps it.
+// Safe to call with a nil cmd.
+func StopWatchdog(cmd *exec.Cmd) {
+	if cmd == nil || cmd.Process == nil {
+		return
+	}
+	pid := cmd.Process.Pid
+	if err := cmd.Process.Signal(syscall.SIGTERM); err != nil {
+		logger.Debug("DNS watchdog stop signal failed (pid=%d): %v", pid, err)
+	}
+	// Reap in the background; we don't want to block shutdown if the
+	// watchdog is wedged.
+	go func() {
+		_ = cmd.Wait()
+		logger.Debug("DNS watchdog (pid=%d) reaped", pid)
+	}()
+}

dns/override/watchdog_spawn_windows.go

@@ -0,0 +1,29 @@
+//go:build windows
+
+package olm
+
+import (
+	"os/exec"
+)
+
+// SpawnWatchdogConfig is provided on Windows for API symmetry but the
+// watchdog itself is effectively a no-op there (see watchdog_windows.go).
+type SpawnWatchdogConfig struct {
+	Executable    string
+	Subcommand    []string
+	InterfaceName string
+	SocketPath    string
+	LogFile       string
+}
+
+// SpawnWatchdog is a no-op on Windows; DNS overrides are interface-GUID
+// scoped and reclaimed when the interface is removed.
+func SpawnWatchdog(cfg SpawnWatchdogConfig) (*exec.Cmd, error) {
+	_ = cfg
+	return nil, nil
+}
+
+// StopWatchdog is a no-op on Windows.
+func StopWatchdog(cmd *exec.Cmd) {
+	_ = cmd
+}

dns/override/watchdog_unix.go

@@ -0,0 +1,25 @@
+//go:build !windows
+
+package olm
+
+import (
+	"os"
+	"syscall"
+)
+
+// pidAlive returns true if the process with the given PID is still alive.
+// On Unix-like systems we use signal 0, which performs error checking but
+// does not deliver an actual signal.
+func pidAlive(pid int) bool {
+	if pid <= 0 {
+		return false
+	}
+	proc, err := os.FindProcess(pid)
+	if err != nil {
+		return false
+	}
+	if err := proc.Signal(syscall.Signal(0)); err != nil {
+		return false
+	}
+	return true
+}

dns/override/watchdog_windows.go

@@ -0,0 +1,15 @@
+//go:build windows
+
+package olm
+
+// pidAlive on Windows. Reliable PID probing on Windows requires syscall
+// OpenProcess with PROCESS_QUERY_LIMITED_INFORMATION followed by
+// GetExitCodeProcess, which is non-trivial. Since DNS override on Windows
+// is interface-GUID-scoped and is naturally cleaned up when the WireGuard
+// interface goes away, the watchdog is effectively a no-op on Windows.
+// We always report the parent as alive so the watchdog never tears down
+// DNS based on PID checks.
+func pidAlive(pid int) bool {
+	_ = pid
+	return true
+}

dns/platform/darwin.go

@@ -417,3 +417,126 @@ func (d *DarwinDNSConfigurator) clearState() error {
 	logger.Debug("Cleared DNS state file")
 	return nil
 }
+
+// CleanupStaleDarwinDNS removes any stale DNS configuration left by the Darwin
+// configurator from a previous unclean shutdown. This is a static function that can be
+// called without creating a configurator instance, useful for cleanup before network operations.
+func CleanupStaleDarwinDNS() error {
+	// Always sweep orphaned Olm scutil keys regardless of whether a state
+	// file exists. This protects against cases where the state file was
+	// lost (e.g., user home wiped, write failed) but DNS keys are still
+	// installed in the running scutil session.
+	defer func() {
+		_ = SweepOlmScutilKeys()
+		// Flush DNS cache after any sweep so changes take effect.
+		_ = exec.Command(dscacheutilPath, "-flushcache").Run()
+		_ = exec.Command("killall", "-HUP", "mDNSResponder").Run()
+	}()
+
+	stateFilePath := getDNSStateFilePath()
+
+	// Check if state file exists
+	data, err := os.ReadFile(stateFilePath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			// No state file, nothing to clean up
+			return nil
+		}
+		return fmt.Errorf("read state file: %w", err)
+	}
+
+	var state DNSPersistentState
+	if err := json.Unmarshal(data, &state); err != nil {
+		// Invalid state file, remove it
+		os.Remove(stateFilePath)
+		return nil
+	}
+
+	if len(state.CreatedKeys) == 0 {
+		// No keys to clean up
+		return nil
+	}
+
+	logger.Info("Found DNS state from previous session, cleaning up %d keys", len(state.CreatedKeys))
+
+	// Remove all keys from previous session using scutil directly
+	for _, key := range state.CreatedKeys {
+		logger.Debug("Removing leftover DNS key: %s", key)
+		cmd := fmt.Sprintf("open\nremove %s\nquit\n", key)
+		scutilCmd := exec.Command(scutilPath)
+		scutilCmd.Stdin = strings.NewReader(cmd)
+		if err := scutilCmd.Run(); err != nil {
+			logger.Warn("Failed to remove DNS key %s: %v", key, err)
+		}
+	}
+
+	// Clear state file
+	if err := os.Remove(stateFilePath); err != nil && !os.IsNotExist(err) {
+		logger.Warn("Failed to clear DNS state file: %v", err)
+	}
+
+	// Flush DNS cache after cleanup
+	cacheCmd := exec.Command(dscacheutilPath, "-flushcache")
+	_ = cacheCmd.Run()
+
+	killCmd := exec.Command("killall", "-HUP", "mDNSResponder")
+	_ = killCmd.Run()
+
+	return nil
+}
+
+// SweepOlmScutilKeys enumerates scutil State:/Network/Service/Olm-* keys and
+// removes any that are present. This is a best-effort safety net used when
+// state files have been lost or never written.
+func SweepOlmScutilKeys() error {
+	// list scutil keys matching our naming convention
+	listOutput, err := runScutilOnce("list State:/Network/Service/Olm-.*/DNS\n")
+	if err != nil {
+		return fmt.Errorf("scutil list: %w", err)
+	}
+
+	var keys []string
+	scanner := bufio.NewScanner(bytes.NewReader(listOutput))
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		// scutil output format: subKey [0] = State:/Network/Service/Olm-Override/DNS
+		idx := strings.Index(line, "State:/Network/Service/Olm-")
+		if idx < 0 {
+			continue
+		}
+		key := strings.TrimSpace(line[idx:])
+		if key != "" {
+			keys = append(keys, key)
+		}
+	}
+
+	if len(keys) == 0 {
+		return nil
+	}
+
+	logger.Info("Sweeping %d orphaned Olm scutil DNS keys", len(keys))
+
+	var commands strings.Builder
+	for _, key := range keys {
+		commands.WriteString(fmt.Sprintf("remove %s\n", key))
+	}
+
+	if _, err := runScutilOnce(commands.String()); err != nil {
+		return fmt.Errorf("scutil sweep remove: %w", err)
+	}
+
+	return nil
+}
+
+// runScutilOnce runs a one-shot scutil command sequence wrapped with open/quit
+// without requiring a configurator instance.
+func runScutilOnce(commands string) ([]byte, error) {
+	wrapped := fmt.Sprintf("open\n%squit\n", commands)
+	cmd := exec.Command(scutilPath)
+	cmd.Stdin = strings.NewReader(wrapped)
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		return nil, fmt.Errorf("scutil command failed: %w, output: %s", err, output)
+	}
+	return output, nil
+}

dns/platform/file.go

@@ -218,3 +218,27 @@ func copyFile(src, dst string) error {
 
 	return nil
 }
+
+// CleanupStaleFileDNS removes any stale DNS configuration left by the file-based
+// configurator from a previous unclean shutdown. This is a static function that can be
+// called without creating a configurator instance, useful for cleanup before network operations.
+func CleanupStaleFileDNS() error {
+	// Check if backup file exists from a previous session
+	if _, err := os.Stat(resolvConfBackupPath); os.IsNotExist(err) {
+		// No backup file, nothing to clean up
+		return nil
+	}
+
+	// A backup exists, which means we crashed while DNS was configured
+	// Restore the original resolv.conf
+	if err := copyFile(resolvConfBackupPath, resolvConfPath); err != nil {
+		return fmt.Errorf("restore from backup during cleanup: %w", err)
+	}
+
+	// Remove backup file
+	if err := os.Remove(resolvConfBackupPath); err != nil {
+		return fmt.Errorf("remove backup file during cleanup: %w", err)
+	}
+
+	return nil
+}

dns/platform/network_manager.go

@@ -323,3 +323,41 @@ func GetNetworkManagerVersion() (string, error) {
 
 	return version, nil
 }
+
+// CleanupStaleNetworkManagerDNS removes any stale DNS configuration left by NetworkManager
+// configurator from a previous unclean shutdown. This is a static function that can be called
+// without creating a configurator instance, useful for cleanup before network operations.
+func CleanupStaleNetworkManagerDNS() error {
+	confPath := networkManagerConfDir + "/" + networkManagerDNSConfFile
+
+	// Check if our config file exists from a previous session
+	if _, err := os.Stat(confPath); os.IsNotExist(err) {
+		// No config file, nothing to clean up
+		return nil
+	}
+
+	// Remove the stale configuration file
+	if err := os.Remove(confPath); err != nil && !os.IsNotExist(err) {
+		return fmt.Errorf("remove stale DNS config file: %w", err)
+	}
+
+	// Try to reload NetworkManager if it's available
+	if IsNetworkManagerAvailable() {
+		conn, err := dbus.SystemBus()
+		if err != nil {
+			return fmt.Errorf("connect to system bus for reload: %w", err)
+		}
+		defer conn.Close()
+
+		obj := conn.Object(networkManagerDest, networkManagerDbusObjectNode)
+
+		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+		defer cancel()
+
+		if err := obj.CallWithContext(ctx, networkManagerDest+".Reload", 0, uint32(0)).Store(); err != nil {
+			return fmt.Errorf("reload NetworkManager after cleanup: %w", err)
+		}
+	}
+
+	return nil
+}

dns/platform/resolvconf.go

@@ -219,3 +219,37 @@ func IsResolvconfAvailable() bool {
 	cmd := exec.Command(resolvconfCommand, "--version")
 	return cmd.Run() == nil
 }
+
+// CleanupStaleResolvconfDNS removes any stale DNS configuration left by the resolvconf
+// configurator from a previous unclean shutdown. This is a static function that can be
+// called without creating a configurator instance, useful for cleanup before network operations.
+// The interfaceName parameter specifies which interface entry to clean up (typically "olm").
+func CleanupStaleResolvconfDNS(interfaceName string) error {
+	if !IsResolvconfAvailable() {
+		// resolvconf not available, nothing to clean up
+		return nil
+	}
+
+	// Detect resolvconf implementation type
+	implType, err := detectResolvconfType()
+	if err != nil {
+		// Can't detect type, try default
+		implType = "resolvconf"
+	}
+
+	// Try to delete any existing entry for this interface
+	// This is idempotent - if no entry exists, resolvconf will just return success
+	var cmd *exec.Cmd
+
+	switch implType {
+	case "openresolv":
+		cmd = exec.Command(resolvconfCommand, "-f", "-d", interfaceName)
+	default:
+		cmd = exec.Command(resolvconfCommand, "-d", interfaceName)
+	}
+
+	// Ignore errors - the entry may not exist, which is fine
+	_ = cmd.Run()
+
+	return nil
+}

dns_commands.go

@@ -0,0 +1,68 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"time"
+
+	"github.com/fosrl/newt/logger"
+	dnsOverride "github.com/fosrl/olm/dns/override"
+)
+
+const (
+	defaultWatchdogInterval  = 5 * time.Second
+	defaultWatchdogThreshold = 3
+)
+
+// runDNSWatchdogCommand handles the `olm watchdog` subcommand. The watchdog
+// is meant to be spawned by an olm process after it installs a DNS
+// override, and forcibly resets the system DNS if that parent dies before
+// restoring it.
+func runDNSWatchdogCommand(ctx context.Context, args []string) error {
+	fs := flag.NewFlagSet("watchdog", flag.ContinueOnError)
+	parentPID := fs.Int("parent-pid", 0, "PID of the olm process to monitor")
+	socketPath := fs.String("socket", "", "Path to the olm API unix socket (optional)")
+	interfaceName := fs.String("interface", "", "WireGuard interface name (used for cleanup)")
+	interval := fs.Duration("interval", defaultWatchdogInterval, "Liveness check interval")
+	threshold := fs.Int("threshold", defaultWatchdogThreshold, "Consecutive failures before DNS reset")
+
+	if err := fs.Parse(args); err != nil {
+		return err
+	}
+
+	if *parentPID <= 0 {
+		return fmt.Errorf("--parent-pid is required and must be positive")
+	}
+
+	// Ensure logger is initialised for the watchdog process.
+	logger.Init(nil)
+
+	return dnsOverride.RunWatchdog(ctx, dnsOverride.WatchdogConfig{
+		ParentPID:        *parentPID,
+		SocketPath:       *socketPath,
+		InterfaceName:    *interfaceName,
+		CheckInterval:    *interval,
+		FailureThreshold: *threshold,
+	})
+}
+
+// runResetDNSCommand handles the `olm reset-dns` subcommand. It forcibly
+// removes any DNS override state left behind on the system.
+func runResetDNSCommand(args []string) error {
+	fs := flag.NewFlagSet("reset-dns", flag.ContinueOnError)
+	interfaceName := fs.String("interface", "olm", "WireGuard interface name")
+
+	if err := fs.Parse(args); err != nil {
+		return err
+	}
+
+	logger.Init(nil)
+
+	if err := dnsOverride.ForceResetDNS(*interfaceName); err != nil {
+		return err
+	}
+
+	fmt.Println("DNS reset complete")
+	return nil
+}

go.mod

@@ -4,11 +4,11 @@ go 1.25.0
 
 require (
 	github.com/Microsoft/go-winio v0.6.2
-	github.com/fosrl/newt v1.10.3
+	github.com/fosrl/newt v1.12.0
 	github.com/godbus/dbus/v5 v5.2.2
 	github.com/gorilla/websocket v1.5.3
 	github.com/miekg/dns v1.1.70
-	golang.org/x/sys v0.41.0
+	golang.org/x/sys v0.42.0
 	golang.zx2c4.com/wireguard v0.0.0-20250521234502-f333402bd9cb
 	golang.zx2c4.com/wireguard/wgctrl v0.0.0-20241231184526-a9ab2273dd10
 	gvisor.dev/gvisor v0.0.0-20250503011706-39ed1f5ac29c
@@ -20,13 +20,13 @@ require (
 	github.com/google/go-cmp v0.7.0 // indirect
 	github.com/vishvananda/netlink v1.3.1 // indirect
 	github.com/vishvananda/netns v0.0.5 // indirect
-	golang.org/x/crypto v0.48.0 // indirect
+	golang.org/x/crypto v0.49.0 // indirect
 	golang.org/x/exp v0.0.0-20251113190631-e25ba8c21ef6 // indirect
-	golang.org/x/mod v0.32.0 // indirect
-	golang.org/x/net v0.51.0 // indirect
-	golang.org/x/sync v0.19.0 // indirect
+	golang.org/x/mod v0.33.0 // indirect
+	golang.org/x/net v0.52.0 // indirect
+	golang.org/x/sync v0.20.0 // indirect
 	golang.org/x/time v0.12.0 // indirect
-	golang.org/x/tools v0.41.0 // indirect
+	golang.org/x/tools v0.42.0 // indirect
 	golang.zx2c4.com/wintun v0.0.0-20230126152724-0fa3db229ce2 // indirect
 	golang.zx2c4.com/wireguard/windows v0.5.3 // indirect
 )

go.sum

@@ -1,7 +1,7 @@
 github.com/Microsoft/go-winio v0.6.2 h1:F2VQgta7ecxGYO8k3ZZz3RS8fVIXVxONVUPlNERoyfY=
 github.com/Microsoft/go-winio v0.6.2/go.mod h1:yd8OoFMLzJbo9gZq8j5qaps8bJ9aShtEA8Ipt1oGCvU=
-github.com/fosrl/newt v1.10.3 h1:JO9gFK9LP/w2EeDIn4wU+jKggAFPo06hX5hxFSETqcw=
-github.com/fosrl/newt v1.10.3/go.mod h1:iYuuCAG7iabheiogMOX87r61uQN31S39nKxMKRuLS+s=
+github.com/fosrl/newt v1.12.0 h1:IodzVlsprOYkHvKrXwDfDTh2ZMtXV6IG1rhUj6Jhd44=
+github.com/fosrl/newt v1.12.0/go.mod h1:IJW2sZ4WKKLRuxMz6oBm8PMyAEVkOxZk6d1OUV5/LPM=
 github.com/godbus/dbus/v5 v5.2.2 h1:TUR3TgtSVDmjiXOgAAyaZbYmIeP3DPkld3jgKGV8mXQ=
 github.com/godbus/dbus/v5 v5.2.2/go.mod h1:3AAv2+hPq5rdnr5txxxRwiGjPXamgoIHgz9FPBfOp3c=
 github.com/google/btree v1.1.3 h1:CVpQJjYgC4VbzxeGVHfvZrv1ctoYCAI8vbl07Fcxlyg=
@@ -16,24 +16,24 @@ github.com/vishvananda/netlink v1.3.1 h1:3AEMt62VKqz90r0tmNhog0r/PpWKmrEShJU0wJW
 github.com/vishvananda/netlink v1.3.1/go.mod h1:ARtKouGSTGchR8aMwmkzC0qiNPrrWO5JS/XMVl45+b4=
 github.com/vishvananda/netns v0.0.5 h1:DfiHV+j8bA32MFM7bfEunvT8IAqQ/NzSJHtcmW5zdEY=
 github.com/vishvananda/netns v0.0.5/go.mod h1:SpkAiCQRtJ6TvvxPnOSyH3BMl6unz3xZlaprSwhNNJM=
-golang.org/x/crypto v0.48.0 h1:/VRzVqiRSggnhY7gNRxPauEQ5Drw9haKdM0jqfcCFts=
-golang.org/x/crypto v0.48.0/go.mod h1:r0kV5h3qnFPlQnBSrULhlsRfryS2pmewsg+XfMgkVos=
+golang.org/x/crypto v0.49.0 h1:+Ng2ULVvLHnJ/ZFEq4KdcDd/cfjrrjjNSXNzxg0Y4U4=
+golang.org/x/crypto v0.49.0/go.mod h1:ErX4dUh2UM+CFYiXZRTcMpEcN8b/1gxEuv3nODoYtCA=
 golang.org/x/exp v0.0.0-20251113190631-e25ba8c21ef6 h1:zfMcR1Cs4KNuomFFgGefv5N0czO2XZpUbxGUy8i8ug0=
 golang.org/x/exp v0.0.0-20251113190631-e25ba8c21ef6/go.mod h1:46edojNIoXTNOhySWIWdix628clX9ODXwPsQuG6hsK0=
-golang.org/x/mod v0.32.0 h1:9F4d3PHLljb6x//jOyokMv3eX+YDeepZSEo3mFJy93c=
-golang.org/x/mod v0.32.0/go.mod h1:SgipZ/3h2Ci89DlEtEXWUk/HteuRin+HHhN+WbNhguU=
-golang.org/x/net v0.51.0 h1:94R/GTO7mt3/4wIKpcR5gkGmRLOuE/2hNGeWq/GBIFo=
-golang.org/x/net v0.51.0/go.mod h1:aamm+2QF5ogm02fjy5Bb7CQ0WMt1/WVM7FtyaTLlA9Y=
-golang.org/x/sync v0.19.0 h1:vV+1eWNmZ5geRlYjzm2adRgW2/mcpevXNg50YZtPCE4=
-golang.org/x/sync v0.19.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
+golang.org/x/mod v0.33.0 h1:tHFzIWbBifEmbwtGz65eaWyGiGZatSrT9prnU8DbVL8=
+golang.org/x/mod v0.33.0/go.mod h1:swjeQEj+6r7fODbD2cqrnje9PnziFuw4bmLbBZFrQ5w=
+golang.org/x/net v0.52.0 h1:He/TN1l0e4mmR3QqHMT2Xab3Aj3L9qjbhRm78/6jrW0=
+golang.org/x/net v0.52.0/go.mod h1:R1MAz7uMZxVMualyPXb+VaqGSa3LIaUqk0eEt3w36Sw=
+golang.org/x/sync v0.20.0 h1:e0PTpb7pjO8GAtTs2dQ6jYa5BWYlMuX047Dco/pItO4=
+golang.org/x/sync v0.20.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
 golang.org/x/sys v0.2.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.10.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.41.0 h1:Ivj+2Cp/ylzLiEU89QhWblYnOE9zerudt9Ftecq2C6k=
-golang.org/x/sys v0.41.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+golang.org/x/sys v0.42.0 h1:omrd2nAlyT5ESRdCLYdm3+fMfNFE/+Rf4bDIQImRJeo=
+golang.org/x/sys v0.42.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
 golang.org/x/time v0.12.0 h1:ScB/8o8olJvc+CQPWrK3fPZNfh7qgwCrY0zJmoEQLSE=
 golang.org/x/time v0.12.0/go.mod h1:CDIdPxbZBQxdj6cxyCIdrNogrJKMJ7pr37NYpMcMDSg=
-golang.org/x/tools v0.41.0 h1:a9b8iMweWG+S0OBnlU36rzLp20z1Rp10w+IY2czHTQc=
-golang.org/x/tools v0.41.0/go.mod h1:XSY6eDqxVNiYgezAVqqCeihT4j1U2CCsqvH3WhQpnlg=
+golang.org/x/tools v0.42.0 h1:uNgphsn75Tdz5Ji2q36v/nsFSfR/9BRFvqhGBaJGd5k=
+golang.org/x/tools v0.42.0/go.mod h1:Ma6lCIwGZvHK6XtgbswSoWroEkhugApmsXyrUmBhfr0=
 golang.zx2c4.com/wintun v0.0.0-20230126152724-0fa3db229ce2 h1:B82qJJgjvYKsXS9jeunTOisW56dUokqW/FOteYJJ/yg=
 golang.zx2c4.com/wintun v0.0.0-20230126152724-0fa3db229ce2/go.mod h1:deeaetjYA+DHMHg+sMSMI58GrEteJUUzzw7en6TJQcI=
 golang.zx2c4.com/wireguard v0.0.0-20250521234502-f333402bd9cb h1:whnFRlWMcXI9d+ZbWg+4sHnLp52d5yiIPUxMBSt4X9A=

main.go

@@ -164,6 +164,26 @@ func main() {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
+	// Internal DNS subcommands. These are handled before normal flag
+	// parsing because they have their own argument layouts and need to
+	// run without setting up the full olm runtime.
+	if len(os.Args) > 1 {
+		switch os.Args[1] {
+		case "watchdog", "dns-watchdog":
+			if err := runDNSWatchdogCommand(signalCtx, os.Args[2:]); err != nil {
+				fmt.Fprintf(os.Stderr, "watchdog failed: %v\n", err)
+				os.Exit(1)
+			}
+			return
+		case "reset-dns":
+			if err := runResetDNSCommand(os.Args[2:]); err != nil {
+				fmt.Fprintf(os.Stderr, "reset-dns failed: %v\n", err)
+				os.Exit(1)
+			}
+			return
+		}
+	}
+
 	// Run in console mode
 	runOlmMainWithArgs(ctx, cancel, signalCtx, os.Args[1:])
 }
@@ -221,6 +241,8 @@ func runOlmMainWithArgs(ctx context.Context, cancel context.CancelFunc, signalCt
 		OnExit:       cancel, // Pass cancel function directly to trigger shutdown
 		OnTerminated: cancel,
 		PprofAddr:    ":4444", // TODO: REMOVE OR MAKE CONFIGURABLE
+		// Re-invoke this binary in watchdog mode to clean up DNS if we die.
+		WatchdogSubcommand: []string{"watchdog"},
 	}
 
 	olm, err := olmpkg.Init(ctx, olmConfig)

olm/connect.go

@@ -205,12 +205,13 @@ func (o *Olm) handleConnect(msg websocket.WSMessage) {
 	// Register JIT handler: when the DNS proxy resolves a local record, check whether
 	// the owning site is already connected and, if not, initiate a JIT connection.
 	o.dnsProxy.SetJITHandler(func(siteId int) {
-		if o.peerManager == nil || o.websocket == nil {
+		pm := o.getPeerManager()
+		if pm == nil || o.websocket == nil {
 			return
 		}
 
 		// Site already has an active peer connection - nothing to do.
-		if _, exists := o.peerManager.GetPeer(siteId); exists {
+		if _, exists := pm.GetPeer(siteId); exists {
 			return
 		}
 
@@ -239,6 +240,12 @@ func (o *Olm) handleConnect(msg websocket.WSMessage) {
 			return
 		}
 
+		// Start the external watchdog (if configured). The watchdog will
+		// reset DNS if this process dies before it can call
+		// RestoreDNSOverride. This is a no-op when no watchdog
+		// subcommand has been configured on the OlmConfig.
+		o.startDNSWatchdog(o.tunnelConfig.InterfaceName)
+
 		network.SetDNSServers([]string{o.dnsProxy.GetProxyIP().String()})
 	}
 

olm/data.go

@@ -32,21 +32,27 @@ func (o *Olm) handleWgPeerAddData(msg websocket.WSMessage) {
 		return
 	}
 
-	if _, exists := o.peerManager.GetPeer(addSubnetsData.SiteId); !exists {
+	pm := o.getPeerManager()
+	if pm == nil {
+		logger.Debug("Ignoring add-remote-subnets-aliases message: peerManager is nil (shutdown in progress)")
+		return
+	}
+
+	if _, exists := pm.GetPeer(addSubnetsData.SiteId); !exists {
 		logger.Debug("Peer %d not found for removing remote subnets and aliases", addSubnetsData.SiteId)
 		return
 	}
 
 	// Add new subnets
 	for _, subnet := range addSubnetsData.RemoteSubnets {
-		if err := o.peerManager.AddRemoteSubnet(addSubnetsData.SiteId, subnet); err != nil {
+		if err := pm.AddRemoteSubnet(addSubnetsData.SiteId, subnet); err != nil {
 			logger.Error("Failed to add allowed IP %s: %v", subnet, err)
 		}
 	}
 
 	// Add new aliases
 	for _, alias := range addSubnetsData.Aliases {
-		if err := o.peerManager.AddAlias(addSubnetsData.SiteId, alias); err != nil {
+		if err := pm.AddAlias(addSubnetsData.SiteId, alias); err != nil {
 			logger.Error("Failed to add alias %s: %v", alias.Alias, err)
 		}
 	}
@@ -73,21 +79,27 @@ func (o *Olm) handleWgPeerRemoveData(msg websocket.WSMessage) {
 		return
 	}
 
-	if _, exists := o.peerManager.GetPeer(removeSubnetsData.SiteId); !exists {
+	pm := o.getPeerManager()
+	if pm == nil {
+		logger.Debug("Ignoring remove-remote-subnets-aliases message: peerManager is nil (shutdown in progress)")
+		return
+	}
+
+	if _, exists := pm.GetPeer(removeSubnetsData.SiteId); !exists {
 		logger.Debug("Peer %d not found for removing remote subnets and aliases", removeSubnetsData.SiteId)
 		return
 	}
 
 	// Remove subnets
 	for _, subnet := range removeSubnetsData.RemoteSubnets {
-		if err := o.peerManager.RemoveRemoteSubnet(removeSubnetsData.SiteId, subnet); err != nil {
+		if err := pm.RemoveRemoteSubnet(removeSubnetsData.SiteId, subnet); err != nil {
 			logger.Error("Failed to remove allowed IP %s: %v", subnet, err)
 		}
 	}
 
 	// Remove aliases
 	for _, alias := range removeSubnetsData.Aliases {
-		if err := o.peerManager.RemoveAlias(removeSubnetsData.SiteId, alias.Alias); err != nil {
+		if err := pm.RemoveAlias(removeSubnetsData.SiteId, alias.Alias); err != nil {
 			logger.Error("Failed to remove alias %s: %v", alias.Alias, err)
 		}
 	}
@@ -114,7 +126,13 @@ func (o *Olm) handleWgPeerUpdateData(msg websocket.WSMessage) {
 		return
 	}
 
-	if _, exists := o.peerManager.GetPeer(updateSubnetsData.SiteId); !exists {
+	pm := o.getPeerManager()
+	if pm == nil {
+		logger.Debug("Ignoring update-remote-subnets-aliases message: peerManager is nil (shutdown in progress)")
+		return
+	}
+
+	if _, exists := pm.GetPeer(updateSubnetsData.SiteId); !exists {
 		logger.Debug("Peer %d not found for updating remote subnets and aliases", updateSubnetsData.SiteId)
 		return
 	}
@@ -123,14 +141,14 @@ func (o *Olm) handleWgPeerUpdateData(msg websocket.WSMessage) {
 	// This ensures that if an old and new subnet are the same on different peers,
 	// the route won't be temporarily removed
 	for _, subnet := range updateSubnetsData.NewRemoteSubnets {
-		if err := o.peerManager.AddRemoteSubnet(updateSubnetsData.SiteId, subnet); err != nil {
+		if err := pm.AddRemoteSubnet(updateSubnetsData.SiteId, subnet); err != nil {
 			logger.Error("Failed to add allowed IP %s: %v", subnet, err)
 		}
 	}
 
 	// Remove old subnets after new ones are added
 	for _, subnet := range updateSubnetsData.OldRemoteSubnets {
-		if err := o.peerManager.RemoveRemoteSubnet(updateSubnetsData.SiteId, subnet); err != nil {
+		if err := pm.RemoveRemoteSubnet(updateSubnetsData.SiteId, subnet); err != nil {
 			logger.Error("Failed to remove allowed IP %s: %v", subnet, err)
 		}
 	}
@@ -139,14 +157,14 @@ func (o *Olm) handleWgPeerUpdateData(msg websocket.WSMessage) {
 	// This ensures that if an old and new alias share the same IP, the IP won't be
 	// temporarily removed from the allowed IPs list
 	for _, alias := range updateSubnetsData.NewAliases {
-		if err := o.peerManager.AddAlias(updateSubnetsData.SiteId, alias); err != nil {
+		if err := pm.AddAlias(updateSubnetsData.SiteId, alias); err != nil {
 			logger.Error("Failed to add alias %s: %v", alias.Alias, err)
 		}
 	}
 
 	// Remove old aliases after new ones are added
 	for _, alias := range updateSubnetsData.OldAliases {
-		if err := o.peerManager.RemoveAlias(updateSubnetsData.SiteId, alias.Alias); err != nil {
+		if err := pm.RemoveAlias(updateSubnetsData.SiteId, alias.Alias); err != nil {
 			logger.Error("Failed to remove alias %s: %v", alias.Alias, err)
 		}
 	}
@@ -163,7 +181,8 @@ func (o *Olm) handleSync(msg websocket.WSMessage) {
 		return
 	}
 
-	if o.peerManager == nil {
+	pm := o.getPeerManager()
+	if pm == nil {
 		logger.Warn("Peer manager not initialized, ignoring sync request")
 		return
 	}
@@ -190,7 +209,7 @@ func (o *Olm) handleSync(msg websocket.WSMessage) {
 	}
 
 	// Get all current peers
-	currentPeers := o.peerManager.GetAllPeers()
+	currentPeers := pm.GetAllPeers()
 	currentPeerMap := make(map[int]peers.SiteConfig)
 	for _, peer := range currentPeers {
 		currentPeerMap[peer.SiteId] = peer
@@ -200,7 +219,7 @@ func (o *Olm) handleSync(msg websocket.WSMessage) {
 	for siteId := range currentPeerMap {
 		if _, exists := expectedPeers[siteId]; !exists {
 			logger.Info("Sync: Removing peer for site %d (no longer in expected config)", siteId)
-			if err := o.peerManager.RemovePeer(siteId); err != nil {
+			if err := pm.RemovePeer(siteId); err != nil {
 				logger.Error("Sync: Failed to remove peer %d: %v", siteId, err)
 			} else {
 				// Remove any exit nodes associated with this peer from hole punching
@@ -217,19 +236,22 @@ func (o *Olm) handleSync(msg websocket.WSMessage) {
 	// Find peers to add (in expected but not in current) and peers to update
 	for siteId, expectedSite := range expectedPeers {
 		if _, exists := currentPeerMap[siteId]; !exists {
+			// Only trigger add if this is NOT a JIT-only config (i.e., has more than just siteId and aliases)
+			jitOnly := expectedSite.PublicKey == ""
+			if jitOnly {
+				logger.Debug("Sync: Registering aliases for JIT-only site %d", siteId)
+				if err := pm.AddPeer(expectedSite); err != nil {
+					logger.Error("Sync: Failed to register aliases for JIT site %d: %v", siteId, err)
+				}
+				continue
+			}
+
 			// New peer - add it using the add flow (with holepunch)
 			logger.Info("Sync: Adding new peer for site %d", siteId)
 
 			o.holePunchManager.TriggerHolePunch()
 			o.holePunchManager.ResetServerHolepunchInterval() // start sending immediately again so we fill in the endpoint on the cloud
 
-			// // TODO: do we need to send the message to the cloud to add the peer that way?
-			// if err := o.peerManager.AddPeer(expectedSite); err != nil {
-			// 	logger.Error("Sync: Failed to add peer %d: %v", siteId, err)
-			// } else {
-			// 	logger.Info("Sync: Successfully added peer for site %d", siteId)
-			// }
-
 			// add the peer via the server
 			// this is important because newt needs to get triggered as well to add the peer once the hp is complete
 			chainId := fmt.Sprintf("sync-%d", expectedSite.SiteId)
@@ -301,7 +323,7 @@ func (o *Olm) handleSync(msg websocket.WSMessage) {
 					siteConfig.Aliases = expectedSite.Aliases
 				}
 
-				if err := o.peerManager.UpdatePeer(siteConfig); err != nil {
+				if err := pm.UpdatePeer(siteConfig); err != nil {
 					logger.Error("Sync: Failed to update peer %d: %v", siteId, err)
 				} else {
 					// If the endpoint changed, trigger holepunch to refresh NAT mappings

olm/olm.go

@@ -9,6 +9,7 @@ import (
 	"net/http"
 	_ "net/http/pprof"
 	"os"
+	"os/exec"
 	"sync"
 	"time"
 
@@ -47,6 +48,7 @@ type Olm struct {
 	websocket        *websocket.Client
 	holePunchManager *holepunch.Manager
 	peerManager      *peers.PeerManager
+	peerManagerMu    sync.RWMutex
 	// Power mode management
 	currentPowerMode string
 	powerModeMu      sync.Mutex
@@ -67,13 +69,26 @@ type Olm struct {
 	stopRegister   func()
 	updateRegister func(newData any)
 
-	stopPeerSends  map[string]func()
-	stopPeerInits  map[string]func()
+	stopPeerSends   map[string]func()
+	stopPeerInits   map[string]func()
 	jitPendingSites map[int]string // siteId -> chainId for in-flight JIT requests
-	peerSendMu    sync.Mutex
+	peerSendMu      sync.Mutex
 
 	// WaitGroup to track tunnel lifecycle
 	tunnelWg sync.WaitGroup
+
+	// External DNS watchdog process (spawned after DNS override is installed).
+	// nil when no watchdog is running.
+	dnsWatchdogCmd *exec.Cmd
+}
+
+// getPeerManager safely returns the current peerManager under a read-lock.
+// Callers must check the returned value for nil before using it.
+func (o *Olm) getPeerManager() *peers.PeerManager {
+	o.peerManagerMu.RLock()
+	pm := o.peerManager
+	o.peerManagerMu.RUnlock()
+	return pm
 }
 
 // initTunnelInfo creates the shared UDP socket and holepunch manager.
@@ -178,10 +193,10 @@ func Init(ctx context.Context, config OlmConfig) (*Olm, error) {
 	apiServer.SetAgent(config.Agent)
 
 	newOlm := &Olm{
-		logFile:       logFile,
-		olmCtx:        ctx,
-		apiServer:     apiServer,
-		olmConfig:     config,
+		logFile:         logFile,
+		olmCtx:          ctx,
+		apiServer:       apiServer,
+		olmConfig:       config,
 		stopPeerSends:   make(map[string]func()),
 		stopPeerInits:   make(map[string]func()),
 		jitPendingSites: make(map[int]string),
@@ -317,6 +332,54 @@ func (o *Olm) registerAPICallbacks() {
 	)
 }
 
+// startDNSWatchdog launches an external watchdog process that will reset
+// system DNS if this olm process dies before it can call
+// RestoreDNSOverride. It is a no-op when the OlmConfig has no
+// WatchdogSubcommand configured, or when the watchdog has already been
+// started for this Olm instance.
+func (o *Olm) startDNSWatchdog(interfaceName string) {
+	if o.dnsWatchdogCmd != nil {
+		return
+	}
+	if len(o.olmConfig.WatchdogSubcommand) == 0 {
+		logger.Debug("DNS watchdog disabled (no WatchdogSubcommand configured)")
+		return
+	}
+
+	executable := o.olmConfig.WatchdogExecutable
+	if executable == "" {
+		exe, err := os.Executable()
+		if err != nil {
+			logger.Warn("DNS watchdog: failed to resolve executable: %v", err)
+			return
+		}
+		executable = exe
+	}
+
+	cmd, err := dnsOverride.SpawnWatchdog(dnsOverride.SpawnWatchdogConfig{
+		Executable:    executable,
+		Subcommand:    o.olmConfig.WatchdogSubcommand,
+		InterfaceName: interfaceName,
+		SocketPath:    o.olmConfig.SocketPath,
+		LogFile:       o.olmConfig.WatchdogLogFile,
+	})
+	if err != nil {
+		logger.Warn("DNS watchdog: spawn failed: %v", err)
+		return
+	}
+	o.dnsWatchdogCmd = cmd
+}
+
+// stopDNSWatchdog stops any previously spawned DNS watchdog process.
+// Safe to call when no watchdog was started.
+func (o *Olm) stopDNSWatchdog() {
+	if o.dnsWatchdogCmd == nil {
+		return
+	}
+	dnsOverride.StopWatchdog(o.dnsWatchdogCmd)
+	o.dnsWatchdogCmd = nil
+}
+
 func (o *Olm) StartTunnel(config TunnelConfig) {
 	if o.tunnelRunning {
 		logger.Info("Tunnel already running")
@@ -457,7 +520,8 @@ func (o *Olm) StartTunnel(config TunnelConfig) {
 				"userToken":   userToken,
 				"fingerprint": o.fingerprint,
 				"postures":    o.postures,
-			}, 2*time.Second, 10)
+				"chainId":     generateChainId(), // use a random chainId for registration updates - it won't be used for cancellation since registration is a one-time message but for tracking the session
+			}, 2*time.Second, 20) // after 18 tries on the server side we send the error so dont change this without changing that
 
 			// Invoke onRegistered callback if configured
 			if o.olmConfig.OnRegistered != nil {
@@ -585,16 +649,23 @@ func (o *Olm) Close() {
 		logger.Error("Failed to restore DNS: %v", err)
 	}
 
+	// Stop the watchdog *after* a successful DNS restore so that if we
+	// somehow crash mid-restore the watchdog still has a chance to clean
+	// up. The watchdog itself is a no-op if it was never spawned.
+	o.stopDNSWatchdog()
+
 	if o.holePunchManager != nil {
 		o.holePunchManager.Stop()
 		o.holePunchManager = nil
 	}
 
 	// Close() also calls Stop() internally
+	o.peerManagerMu.Lock()
 	if o.peerManager != nil {
 		o.peerManager.Close()
 		o.peerManager = nil
 	}
+	o.peerManagerMu.Unlock()
 
 	if o.uapiListener != nil {
 		_ = o.uapiListener.Close()
@@ -806,14 +877,14 @@ func (o *Olm) SetPowerMode(mode string) error {
 
 		lowPowerInterval := 10 * time.Minute
 
-		if o.peerManager != nil {
-			peerMonitor := o.peerManager.GetPeerMonitor()
+		if pm := o.getPeerManager(); pm != nil {
+			peerMonitor := pm.GetPeerMonitor()
 			if peerMonitor != nil {
 				peerMonitor.SetPeerInterval(lowPowerInterval, lowPowerInterval)
 				peerMonitor.SetPeerHolepunchInterval(lowPowerInterval, lowPowerInterval)
 				logger.Info("Set monitoring intervals to 10 minutes for low power mode")
 			}
-			o.peerManager.UpdateAllPeersPersistentKeepalive(0) // disable
+			pm.UpdateAllPeersPersistentKeepalive(0) // disable
 		}
 
 		if o.holePunchManager != nil {
@@ -858,14 +929,14 @@ func (o *Olm) SetPowerMode(mode string) error {
 			}
 
 			// Restore intervals and reconnect websocket
-			if o.peerManager != nil {
-				peerMonitor := o.peerManager.GetPeerMonitor()
+			if pm := o.getPeerManager(); pm != nil {
+				peerMonitor := pm.GetPeerMonitor()
 				if peerMonitor != nil {
 					peerMonitor.ResetPeerHolepunchInterval()
 					peerMonitor.ResetPeerInterval()
 				}
 
-				o.peerManager.UpdateAllPeersPersistentKeepalive(5)
+				pm.UpdateAllPeersPersistentKeepalive(5)
 			}
 
 			if o.holePunchManager != nil {

olm/peer.go

@@ -20,7 +20,14 @@ func (o *Olm) handleWgPeerAdd(msg websocket.WSMessage) {
 		return
 	}
 
-	if o.peerManager == nil {
+	// Check if connection setup is complete
+	if !o.registered {
+		logger.Warn("Not connected, ignoring add-peer message")
+		return
+	}
+
+	pm := o.getPeerManager()
+	if pm == nil {
 		logger.Debug("Ignoring add-peer message: peerManager is nil (shutdown in progress)")
 		return
 	}
@@ -64,7 +71,7 @@ func (o *Olm) handleWgPeerAdd(msg websocket.WSMessage) {
 
 	_ = o.holePunchManager.TriggerHolePunch() // Trigger immediate hole punch attempt so that if the peer decides to relay we have already punched close to when we need it
 
-	if err := o.peerManager.AddPeer(siteConfigMsg.SiteConfig); err != nil {
+	if err := pm.AddPeer(siteConfigMsg.SiteConfig); err != nil {
 		logger.Error("Failed to add peer: %v", err)
 		return
 	}
@@ -81,7 +88,14 @@ func (o *Olm) handleWgPeerRemove(msg websocket.WSMessage) {
 		return
 	}
 
-	if o.peerManager == nil {
+	// Check if connection setup is complete
+	if !o.registered {
+		logger.Warn("Not connected, ignoring remove-peer message")
+		return
+	}
+
+	pm := o.getPeerManager()
+	if pm == nil {
 		logger.Debug("Ignoring remove-peer message: peerManager is nil (shutdown in progress)")
 		return
 	}
@@ -98,7 +112,7 @@ func (o *Olm) handleWgPeerRemove(msg websocket.WSMessage) {
 		return
 	}
 
-	if err := o.peerManager.RemovePeer(removeData.SiteId); err != nil {
+	if err := pm.RemovePeer(removeData.SiteId); err != nil {
 		logger.Error("Failed to remove peer: %v", err)
 		return
 	}
@@ -123,7 +137,14 @@ func (o *Olm) handleWgPeerUpdate(msg websocket.WSMessage) {
 		return
 	}
 
-	if o.peerManager == nil {
+	// Check if connection setup is complete
+	if !o.registered {
+		logger.Warn("Not connected, ignoring update-peer message")
+		return
+	}
+
+	pm := o.getPeerManager()
+	if pm == nil {
 		logger.Debug("Ignoring update-peer message: peerManager is nil (shutdown in progress)")
 		return
 	}
@@ -141,7 +162,7 @@ func (o *Olm) handleWgPeerUpdate(msg websocket.WSMessage) {
 	}
 
 	// Get existing peer from PeerManager
-	existingPeer, exists := o.peerManager.GetPeer(updateData.SiteId)
+	existingPeer, exists := pm.GetPeer(updateData.SiteId)
 	if !exists {
 		logger.Warn("Peer with site ID %d not found", updateData.SiteId)
 		return
@@ -168,8 +189,11 @@ func (o *Olm) handleWgPeerUpdate(msg websocket.WSMessage) {
 	if updateData.RemoteSubnets != nil {
 		siteConfig.RemoteSubnets = updateData.RemoteSubnets
 	}
+	if updateData.Aliases != nil {
+		siteConfig.Aliases = updateData.Aliases
+	}
 
-	if err := o.peerManager.UpdatePeer(siteConfig); err != nil {
+	if err := pm.UpdatePeer(siteConfig); err != nil {
 		logger.Error("Failed to update peer: %v", err)
 		return
 	}
@@ -177,8 +201,10 @@ func (o *Olm) handleWgPeerUpdate(msg websocket.WSMessage) {
 	// If the endpoint changed, trigger holepunch to refresh NAT mappings
 	if updateData.Endpoint != "" && updateData.Endpoint != existingPeer.Endpoint {
 		logger.Info("Endpoint changed for site %d, triggering holepunch to refresh NAT mappings", updateData.SiteId)
-		_ = o.holePunchManager.TriggerHolePunch()
-		o.holePunchManager.ResetServerHolepunchInterval()
+		if o.holePunchManager != nil {
+			_ = o.holePunchManager.TriggerHolePunch()
+			o.holePunchManager.ResetServerHolepunchInterval()
+		}
 	}
 
 	logger.Info("Successfully updated peer for site %d", updateData.SiteId)
@@ -188,7 +214,8 @@ func (o *Olm) handleWgPeerRelay(msg websocket.WSMessage) {
 	logger.Debug("Received relay-peer message: %v", msg.Data)
 
 	// Check if peerManager is still valid (may be nil during shutdown)
-	if o.peerManager == nil {
+	pm := o.getPeerManager()
+	if pm == nil {
 		logger.Debug("Ignoring relay message: peerManager is nil (shutdown in progress)")
 		return
 	}
@@ -208,7 +235,7 @@ func (o *Olm) handleWgPeerRelay(msg websocket.WSMessage) {
 		return
 	}
 
-	if monitor := o.peerManager.GetPeerMonitor(); monitor != nil {
+	if monitor := pm.GetPeerMonitor(); monitor != nil {
 		monitor.CancelRelaySend(relayData.ChainId)
 	}
 
@@ -222,14 +249,15 @@ func (o *Olm) handleWgPeerRelay(msg websocket.WSMessage) {
 	// Update HTTP server to mark this peer as using relay
 	o.apiServer.UpdatePeerRelayStatus(relayData.SiteId, relayData.RelayEndpoint, true)
 
-	o.peerManager.RelayPeer(relayData.SiteId, primaryRelay, relayData.RelayPort)
+	pm.RelayPeer(relayData.SiteId, primaryRelay, relayData.RelayPort)
 }
 
 func (o *Olm) handleWgPeerUnrelay(msg websocket.WSMessage) {
 	logger.Debug("Received unrelay-peer message: %v", msg.Data)
 
 	// Check if peerManager is still valid (may be nil during shutdown)
-	if o.peerManager == nil {
+	pm := o.getPeerManager()
+	if pm == nil {
 		logger.Debug("Ignoring unrelay message: peerManager is nil (shutdown in progress)")
 		return
 	}
@@ -249,7 +277,7 @@ func (o *Olm) handleWgPeerUnrelay(msg websocket.WSMessage) {
 		return
 	}
 
-	if monitor := o.peerManager.GetPeerMonitor(); monitor != nil {
+	if monitor := pm.GetPeerMonitor(); monitor != nil {
 		monitor.CancelRelaySend(relayData.ChainId)
 	}
 
@@ -262,7 +290,7 @@ func (o *Olm) handleWgPeerUnrelay(msg websocket.WSMessage) {
 	// Update HTTP server to mark this peer as using relay
 	o.apiServer.UpdatePeerRelayStatus(relayData.SiteId, relayData.Endpoint, false)
 
-	o.peerManager.UnRelayPeer(relayData.SiteId, primaryRelay)
+	pm.UnRelayPeer(relayData.SiteId, primaryRelay)
 }
 
 func (o *Olm) handleWgPeerHolepunchAddSite(msg websocket.WSMessage) {
@@ -317,7 +345,12 @@ func (o *Olm) handleWgPeerHolepunchAddSite(msg websocket.WSMessage) {
 	}
 
 	// Get existing peer from PeerManager
-	_, exists := o.peerManager.GetPeer(handshakeData.SiteId)
+	pm := o.getPeerManager()
+	if pm == nil {
+		logger.Debug("Ignoring peer-handshake message: peerManager is nil (shutdown in progress)")
+		return
+	}
+	_, exists := pm.GetPeer(handshakeData.SiteId)
 	if exists {
 		logger.Warn("Peer with site ID %d already added", handshakeData.SiteId)
 		return

olm/types.go

@@ -48,6 +48,21 @@ type OlmConfig struct {
 	OnAuthError  func(statusCode int, message string) // Called when auth fails (401/403)
 	OnOlmError   func(code string, message string)    // Called when registration fails
 	OnExit       func()                               // Called when exit is requested via API
+
+	// DNS watchdog (optional). When WatchdogSubcommand is non-empty, the
+	// olm package will spawn an external watchdog subprocess after a DNS
+	// override is installed. The watchdog will reset the system DNS if
+	// this process dies before it can call RestoreDNSOverride.
+	//
+	// The watchdog is launched as:
+	//   <WatchdogExecutable> <WatchdogSubcommand...> \
+	//       --parent-pid=<pid> --interface=<name> [--socket=<path>]
+	//
+	// When WatchdogExecutable is empty, os.Executable() of the calling
+	// process is used. WatchdogLogFile defaults to /dev/null.
+	WatchdogExecutable string
+	WatchdogSubcommand []string
+	WatchdogLogFile    string
 }
 
 type TunnelConfig struct {
@@ -61,7 +76,7 @@ type TunnelConfig struct {
 	MTU           int
 	DNS           string
 	UpstreamDNS   []string
-	PublicDNS   []string
+	PublicDNS     []string
 	InterfaceName string
 
 	// Advanced

peers/manager.go

@@ -6,6 +6,7 @@ import (
 	"strconv"
 	"strings"
 	"sync"
+	"time"
 
 	"github.com/fosrl/newt/bind"
 	"github.com/fosrl/newt/logger"
@@ -32,7 +33,7 @@ type PeerManagerConfig struct {
 	SharedBind *bind.SharedBind
 	// WSClient is optional - if nil, relay messages won't be sent
 	WSClient  *websocket.Client
-	APIServer   *api.API
+	APIServer *api.API
 	PublicDNS []string
 }
 
@@ -51,9 +52,12 @@ type PeerManager struct {
 	// key is the CIDR string, value is a set of siteIds that want this IP
 	allowedIPClaims map[string]map[int]bool
 	APIServer       *api.API
-	publicDNS     []string
+	publicDNS       []string
 
 	PersistentKeepalive int
+
+	routeOptimizerStop chan struct{}
+	optimizerTrigger   chan struct{}
 }
 
 // NewPeerManager creates a new PeerManager with an internal PeerMonitor
@@ -67,7 +71,7 @@ func NewPeerManager(config PeerManagerConfig) *PeerManager {
 		allowedIPOwners: make(map[string]int),
 		allowedIPClaims: make(map[string]map[int]bool),
 		APIServer:       config.APIServer,
-		publicDNS:     config.PublicDNS,
+		publicDNS:       config.PublicDNS,
 	}
 
 	// Create the peer monitor
@@ -80,6 +84,8 @@ func NewPeerManager(config PeerManagerConfig) *PeerManager {
 		config.PublicDNS,
 	)
 
+	pm.optimizerTrigger = make(chan struct{}, 1)
+
 	return pm
 }
 
@@ -110,7 +116,7 @@ func (pm *PeerManager) GetAllPeers() []SiteConfig {
 func (pm *PeerManager) AddPeer(siteConfig SiteConfig) error {
 	pm.mu.Lock()
 	defer pm.mu.Unlock()
-	
+
 	for _, alias := range siteConfig.Aliases {
 		address := net.ParseIP(alias.AliasAddress)
 		if address == nil {
@@ -118,7 +124,7 @@ func (pm *PeerManager) AddPeer(siteConfig SiteConfig) error {
 		}
 		pm.dnsProxy.AddDNSRecord(alias.Alias, address, siteConfig.SiteId)
 	}
-	
+
 	if siteConfig.PublicKey == "" {
 		logger.Debug("Skip adding site %d because no pub key", siteConfig.SiteId)
 		return nil
@@ -156,7 +162,7 @@ func (pm *PeerManager) AddPeer(siteConfig SiteConfig) error {
 	if err := network.AddRoutes(siteConfig.RemoteSubnets, pm.interfaceName); err != nil {
 		logger.Error("Failed to add routes for remote subnets: %v", err)
 	}
-	
+
 	monitorAddress := strings.Split(siteConfig.ServerIP, "/")[0]
 	monitorPeer := net.JoinHostPort(monitorAddress, strconv.Itoa(int(siteConfig.ServerPort+1))) // +1 for the monitor port
 
@@ -183,7 +189,7 @@ func (pm *PeerManager) AddPeer(siteConfig SiteConfig) error {
 func (pm *PeerManager) UpdateAllPeersPersistentKeepalive(interval int) map[int]error {
 	pm.mu.RLock()
 	defer pm.mu.RUnlock()
-	
+
 	pm.PersistentKeepalive = interval
 
 	errors := make(map[int]error)
@@ -305,6 +311,29 @@ func (pm *PeerManager) UpdatePeer(siteConfig SiteConfig) error {
 		return fmt.Errorf("peer with site ID %d not found", siteConfig.SiteId)
 	}
 
+	// Update aliases
+	// Remove old aliases
+	for _, alias := range oldPeer.Aliases {
+		address := net.ParseIP(alias.AliasAddress)
+		if address == nil {
+			continue
+		}
+		pm.dnsProxy.RemoveDNSRecord(alias.Alias, address)
+	}
+	// Add new aliases
+	for _, alias := range siteConfig.Aliases {
+		address := net.ParseIP(alias.AliasAddress)
+		if address == nil {
+			continue
+		}
+		pm.dnsProxy.AddDNSRecord(alias.Alias, address, siteConfig.SiteId)
+	}
+
+	if siteConfig.PublicKey == "" {
+		logger.Debug("Skip updating site %d because no pub key", siteConfig.SiteId)
+		return nil
+	}
+
 	// If public key changed, remove old peer first
 	if siteConfig.PublicKey != oldPeer.PublicKey {
 		if err := RemovePeer(pm.device, siteConfig.SiteId, oldPeer.PublicKey); err != nil {
@@ -428,24 +457,6 @@ func (pm *PeerManager) UpdatePeer(siteConfig SiteConfig) error {
 		}
 	}
 
-	// Update aliases
-	// Remove old aliases
-	for _, alias := range oldPeer.Aliases {
-		address := net.ParseIP(alias.AliasAddress)
-		if address == nil {
-			continue
-		}
-		pm.dnsProxy.RemoveDNSRecord(alias.Alias, address)
-	}
-	// Add new aliases
-	for _, alias := range siteConfig.Aliases {
-		address := net.ParseIP(alias.AliasAddress)
-		if address == nil {
-			continue
-		}
-		pm.dnsProxy.AddDNSRecord(alias.Alias, address, siteConfig.SiteId)
-	}
-
 	pm.peerMonitor.UpdateHolepunchEndpoint(siteConfig.SiteId, siteConfig.Endpoint)
 
 	monitorAddress := strings.Split(siteConfig.ServerIP, "/")[0]
@@ -856,10 +867,12 @@ func (pm *PeerManager) Start() {
 	if pm.peerMonitor != nil {
 		pm.peerMonitor.Start()
 	}
+	pm.startRouteOptimizer()
 }
 
 // Stop stops the peer monitor
 func (pm *PeerManager) Stop() {
+	pm.stopRouteOptimizer()
 	if pm.peerMonitor != nil {
 		pm.peerMonitor.Stop()
 	}
@@ -867,6 +880,7 @@ func (pm *PeerManager) Stop() {
 
 // Close stops the peer monitor and cleans up resources
 func (pm *PeerManager) Close() {
+	pm.stopRouteOptimizer()
 	if pm.peerMonitor != nil {
 		pm.peerMonitor.Close()
 		pm.peerMonitor = nil
@@ -928,3 +942,166 @@ endpoint=%s`, util.FixKey(peer.PublicKey), endpoint)
 	logger.Info("Switched peer %d back to direct connection at %s", siteId, endpoint)
 	return nil
 }
+
+// isBetterConnection returns true if connection quality (a) is better than (b).
+// Priority: connected > disconnected, then direct > relayed, then lower RTT.
+func isBetterConnection(aConn bool, aRelay bool, aRTT time.Duration,
+	bConn bool, bRelay bool, bRTT time.Duration) bool {
+	if aConn != bConn {
+		return aConn // connected beats disconnected
+	}
+	if !aConn {
+		return false // both offline, no preference
+	}
+	if aRelay != bRelay {
+		return !aRelay // direct beats relayed
+	}
+	// Same connectivity class: prefer lower RTT
+	if aRTT == 0 {
+		return false // unknown RTT, don't displace
+	}
+	if bRTT == 0 {
+		return true // current has no RTT data, prefer known
+	}
+	return aRTT < bRTT
+}
+
+// selectBestOwner returns the siteId of the best site to own the given IP,
+// based on connection quality. Must be called with pm.mu held.
+func (pm *PeerManager) selectBestOwner(claims map[int]bool) int {
+	bestSiteId := -1
+	var bestConn, bestRelay bool
+	var bestRTT time.Duration
+
+	for siteId := range claims {
+		conn, relay, rtt := pm.peerMonitor.GetConnectionQuality(siteId)
+		if bestSiteId < 0 || isBetterConnection(conn, relay, rtt, bestConn, bestRelay, bestRTT) {
+			bestSiteId = siteId
+			bestConn = conn
+			bestRelay = relay
+			bestRTT = rtt
+		}
+	}
+	return bestSiteId
+}
+
+// getWireGuardAllowedIPs returns the full set of IPs that should be in WireGuard
+// for a peer: server IP /32 plus all shared IPs it currently owns.
+// Must be called with pm.mu held.
+func (pm *PeerManager) getWireGuardAllowedIPs(siteId int) []string {
+	peer, exists := pm.peers[siteId]
+	if !exists {
+		return nil
+	}
+	serverIP := strings.Split(peer.ServerIP, "/")[0] + "/32"
+	ips := []string{serverIP}
+	for cidr, owner := range pm.allowedIPOwners {
+		if owner == siteId {
+			ips = append(ips, cidr)
+		}
+	}
+	return ips
+}
+
+// transferOwnership moves WireGuard ownership of cidr from fromSiteId to toSiteId.
+// Must be called with pm.mu held.
+func (pm *PeerManager) transferOwnership(cidr string, fromSiteId int, toSiteId int) error {
+	// Update owner map first
+	pm.allowedIPOwners[cidr] = toSiteId
+
+	// Remove cidr from old owner's WireGuard allowed IPs
+	if fromPeer, exists := pm.peers[fromSiteId]; exists {
+		remaining := pm.getWireGuardAllowedIPs(fromSiteId) // cidr is no longer in owners, so it won't appear here
+		if err := RemoveAllowedIP(pm.device, fromPeer.PublicKey, remaining); err != nil {
+			// Revert
+			pm.allowedIPOwners[cidr] = fromSiteId
+			return fmt.Errorf("remove IP %s from site %d: %v", cidr, fromSiteId, err)
+		}
+	}
+
+	// Add cidr to new owner's WireGuard allowed IPs
+	if toPeer, exists := pm.peers[toSiteId]; exists {
+		if err := AddAllowedIP(pm.device, toPeer.PublicKey, cidr); err != nil {
+			return fmt.Errorf("add IP %s to site %d: %v", cidr, toSiteId, err)
+		}
+	}
+
+	return nil
+}
+
+// optimizeRoutes evaluates all shared IPs and reassigns ownership to the best site.
+func (pm *PeerManager) optimizeRoutes() {
+	pm.mu.Lock()
+	defer pm.mu.Unlock()
+
+	for cidr, claims := range pm.allowedIPClaims {
+		if len(claims) <= 1 {
+			continue // No competition, nothing to optimize
+		}
+
+		currentOwner, hasOwner := pm.allowedIPOwners[cidr]
+		bestOwner := pm.selectBestOwner(claims)
+
+		if bestOwner < 0 {
+			continue
+		}
+		if hasOwner && currentOwner == bestOwner {
+			continue // Already on the best site
+		}
+
+		if !hasOwner {
+			// No current owner, just assign
+			pm.allowedIPOwners[cidr] = bestOwner
+			if toPeer, exists := pm.peers[bestOwner]; exists {
+				if err := AddAllowedIP(pm.device, toPeer.PublicKey, cidr); err != nil {
+					logger.Error("Failed to assign IP %s to site %d: %v", cidr, bestOwner, err)
+				}
+			}
+			continue
+		}
+
+		logger.Info("Route optimizer: moving %s from site %d to site %d", cidr, currentOwner, bestOwner)
+		if err := pm.transferOwnership(cidr, currentOwner, bestOwner); err != nil {
+			logger.Error("Failed to transfer ownership of %s from site %d to site %d: %v",
+				cidr, currentOwner, bestOwner, err)
+		}
+	}
+}
+
+// startRouteOptimizer registers the status-change callback and launches the optimizer goroutine.
+func (pm *PeerManager) startRouteOptimizer() {
+	pm.routeOptimizerStop = make(chan struct{})
+
+	// Trigger optimization whenever any peer's connection status changes
+	if pm.peerMonitor != nil {
+		pm.peerMonitor.SetStatusChangeCallback(func(_ int) {
+			select {
+			case pm.optimizerTrigger <- struct{}{}:
+			default:
+			}
+		})
+	}
+
+	go func() {
+		ticker := time.NewTicker(5 * time.Second)
+		defer ticker.Stop()
+		for {
+			select {
+			case <-pm.routeOptimizerStop:
+				return
+			case <-pm.optimizerTrigger:
+				pm.optimizeRoutes()
+			case <-ticker.C:
+				pm.optimizeRoutes()
+			}
+		}
+	}()
+}
+
+// stopRouteOptimizer stops the route optimizer goroutine if it is running.
+func (pm *PeerManager) stopRouteOptimizer() {
+	if pm.routeOptimizerStop != nil {
+		close(pm.routeOptimizerStop)
+		pm.routeOptimizerStop = nil
+	}
+}

peers/monitor/monitor.go

@@ -85,7 +85,9 @@ type PeerMonitor struct {
 	apiServer *api.API
 
 	// WG connection status tracking
-	wgConnectionStatus map[int]bool // siteID -> WG connected status
+	wgConnectionStatus  map[int]bool          // siteID -> WG connected status
+	wgConnectionRTT     map[int]time.Duration // siteID -> last known RTT
+	statusChangeCallback func(siteId int)      // called when any peer's connection status changes
 }
 
 // NewPeerMonitor creates a new peer monitor with the given callback
@@ -122,6 +124,7 @@ func NewPeerMonitor(wsClient *websocket.Client, middleDev *middleDevice.MiddleDe
 		rapidTestMaxAttempts: 5,                      // 5 attempts = ~1-1.5 seconds total
 		apiServer:            apiServer,
 		wgConnectionStatus:   make(map[int]bool),
+		wgConnectionRTT:      make(map[int]time.Duration),
 		// Exponential backoff settings for holepunch monitor
 		defaultHolepunchMinInterval: 2 * time.Second,
 		defaultHolepunchMaxInterval: 30 * time.Second,
@@ -392,6 +395,9 @@ func (pm *PeerMonitor) handleConnectionStatusChange(siteID int, status Connectio
 	pm.mutex.Lock()
 	previousStatus, exists := pm.wgConnectionStatus[siteID]
 	pm.wgConnectionStatus[siteID] = status.Connected
+	if status.Connected && status.RTT > 0 {
+		pm.wgConnectionRTT[siteID] = status.RTT
+	}
 	isRelayed := pm.relayedPeers[siteID]
 	endpoint := pm.holepunchEndpoints[siteID]
 	pm.mutex.Unlock()
@@ -409,6 +415,11 @@ func (pm *PeerMonitor) handleConnectionStatusChange(siteID int, status Connectio
 	if pm.apiServer != nil {
 		pm.apiServer.UpdatePeerStatus(siteID, status.Connected, status.RTT, endpoint, isRelayed)
 	}
+
+	// Notify route optimizer of status change
+	if pm.statusChangeCallback != nil {
+		pm.statusChangeCallback(siteID)
+	}
 }
 
 // sendRelay sends a relay message to the server with retry, keyed by chainId
@@ -521,6 +532,25 @@ func (pm *PeerMonitor) IsPeerRelayed(siteID int) bool {
 	return pm.relayedPeers[siteID]
 }
 
+// SetStatusChangeCallback registers a callback that is invoked whenever a peer's
+// WireGuard connection status changes (connected/disconnected). The callback must
+// be non-blocking (e.g., send to a buffered channel).
+func (pm *PeerMonitor) SetStatusChangeCallback(cb func(siteId int)) {
+	pm.mutex.Lock()
+	defer pm.mutex.Unlock()
+	pm.statusChangeCallback = cb
+}
+
+// GetConnectionQuality returns the current connection quality metrics for a peer.
+func (pm *PeerMonitor) GetConnectionQuality(siteId int) (connected bool, relayed bool, rtt time.Duration) {
+	pm.mutex.Lock()
+	defer pm.mutex.Unlock()
+	connected = pm.wgConnectionStatus[siteId]
+	relayed = pm.relayedPeers[siteId]
+	rtt = pm.wgConnectionRTT[siteId]
+	return
+}
+
 // startHolepunchMonitor starts the holepunch connection monitoring
 // Note: This function assumes the mutex is already held by the caller (called from Start())
 func (pm *PeerMonitor) startHolepunchMonitor() error {