diff --git a/shadowsocks/local.py b/shadowsocks/local.py
index 232df99..37d39ac 100755
--- a/shadowsocks/local.py
+++ b/shadowsocks/local.py
@@ -52,6 +52,7 @@ def main():
     tcp_server.add_to_loop(loop)
     udp_server.add_to_loop(loop)
     has_tunnel = False
+    # if tunnel_service is True then run tunnel_udp_server
     if config["tunnel_service"]:
         tunnel_udp_server = get_tunnel_udp_server(config.copy(), dns_resolver)
         tunnel_udp_server.add_to_loop(loop)
diff --git a/shadowsocks/tunnel.py b/shadowsocks/tunnel.py
index 38fd2ef..c62b4c5 100644
--- a/shadowsocks/tunnel.py
+++ b/shadowsocks/tunnel.py
@@ -55,6 +55,8 @@ def main():
     config = shell.get_config(True)
     daemon.daemon_exec(config)
     dns_resolver = asyncdns.DNSResolver()
+    # if running tunnel then update tunnel_service to True
+    config["tunnel_service"] = True
     tunnel_udp_server = get_tunnel_udp_server(config, dns_resolver)
     loop = eventloop.EventLoop()
     dns_resolver.add_to_loop(loop)