diff --git a/cmd/tailscale/backend.go b/cmd/tailscale/backend.go
index a5f52dd..9142f62 100644
--- a/cmd/tailscale/backend.go
+++ b/cmd/tailscale/backend.go
@@ -122,6 +122,7 @@ func (b *backend) setCfg(cfg *router.Config) error {
 }
 
 func (b *backend) updateTUN(service jni.Object, cfg *router.Config) error {
+	b.CloseTUNs()
 	if reflect.DeepEqual(cfg, b.lastCfg) {
 		return nil
 	}