diff --git a/internal/net/dialer/dialer_darwin.go b/internal/net/dialer/dialer_darwin.go
index bb32b7f9..38ec4051 100644
--- a/internal/net/dialer/dialer_darwin.go
+++ b/internal/net/dialer/dialer_darwin.go
@@ -35,3 +35,8 @@ func bindDevice(network, address string, fd uintptr, ifceName string) error {
 func setMark(fd uintptr, mark int) error {
 	return nil
 }
+
+// switchNetns is a no-op stub — network namespace switching is a Linux-only feature.
+func switchNetns(name string) (restore func(), err error) {
+	return nil, nil
+}
diff --git a/internal/net/dialer/dialer_freebsd.go b/internal/net/dialer/dialer_freebsd.go
index 7b9a1467..ae0b6463 100644
--- a/internal/net/dialer/dialer_freebsd.go
+++ b/internal/net/dialer/dialer_freebsd.go
@@ -14,3 +14,8 @@ func setMark(fd uintptr, mark int) error {
 	}
 	return unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, unix.SO_USER_COOKIE, mark)
 }
+
+// switchNetns is a no-op stub — network namespace switching is a Linux-only feature.
+func switchNetns(name string) (restore func(), err error) {
+	return nil, nil
+}
diff --git a/internal/net/dialer/dialer_openbsd.go b/internal/net/dialer/dialer_openbsd.go
index ada42152..044f05e3 100644
--- a/internal/net/dialer/dialer_openbsd.go
+++ b/internal/net/dialer/dialer_openbsd.go
@@ -14,3 +14,8 @@ func setMark(fd uintptr, mark int) error {
 	}
 	return unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, unix.SO_RTABLE, mark)
 }
+
+// switchNetns is a no-op stub — network namespace switching is a Linux-only feature.
+func switchNetns(name string) (restore func(), err error) {
+	return nil, nil
+}
diff --git a/internal/net/dialer/dialer_other.go b/internal/net/dialer/dialer_other.go
index 3c35b6f1..0562e928 100644
--- a/internal/net/dialer/dialer_other.go
+++ b/internal/net/dialer/dialer_other.go
@@ -9,3 +9,8 @@ func bindDevice(network, address string, fd uintptr, ifceName string) error {
 func setMark(fd uintptr, mark int) error {
 	return nil
 }
+
+// switchNetns is a no-op stub — network namespace switching is a Linux-only feature.
+func switchNetns(name string) (restore func(), err error) {
+	return nil, nil
+}
diff --git a/internal/net/dialer/dialer_windows.go b/internal/net/dialer/dialer_windows.go
index da6c5a95..096f7058 100644
--- a/internal/net/dialer/dialer_windows.go
+++ b/internal/net/dialer/dialer_windows.go
@@ -49,6 +49,11 @@ func setMark(fd uintptr, mark int) error {
 	return nil
 }
 
+// switchNetns is a no-op stub — network namespace switching is a Linux-only feature.
+func switchNetns(name string) (restore func(), err error) {
+	return nil, nil
+}
+
 func bindSocketToInterface4(handle windows.Handle, index uint32) error {
 	// For IPv4, this parameter must be an interface index in network byte order.
 	// Ref: https://learn.microsoft.com/en-us/windows/win32/winsock/ipproto-ip-socket-options