diff --git a/crates/ptth_quic/src/executable_relay_server.rs b/crates/ptth_quic/src/executable_relay_server.rs
index d5cf41d..5840612 100644
--- a/crates/ptth_quic/src/executable_relay_server.rs
+++ b/crates/ptth_quic/src/executable_relay_server.rs
@@ -40,12 +40,15 @@ pub (crate) struct Metrics {
 
 impl App {
 	pub async fn new (opt: Opt) -> anyhow::Result <Self> {
+		let config = load_config ().await.ok ();
+		
 		let listen_addr = opt.listen_addr.unwrap_or_else (|| String::from ("0.0.0.0:30380")).parse ()?;
 		let (endpoint, server_cert) = make_server_endpoint (listen_addr)?;
 		
 		let listen_addr = endpoint.local_addr ()?;
+		let tcp_port = opt.tcp_listen_port.or (config.map (|cfg| cfg.tcp_listen_port).flatten ());
 		
-		let tcp_listener = if let Some (tcp_port) = opt.tcp_listen_port {
+		let tcp_listener = if let Some (tcp_port) = tcp_port {
 			let cfg = udp_over_tcp::server::Config {
 				tcp_port,
 				udp_port: listen_addr.port (),
@@ -262,6 +265,7 @@ struct RelayState {
 #[derive (Default)]
 struct Config {
 	ip_nicknames: BTreeMap <[u8; 4], String>,
+	tcp_listen_port: Option <u16>,
 	webhook_url: Option <String>,
 }
 
@@ -269,6 +273,7 @@ impl From <ConfigFile> for Config {
 	fn from (x: ConfigFile) -> Self {
 		Self {
 			ip_nicknames: x.ip_nicknames.into_iter ().collect (),
+			tcp_listen_port: x.tcp_listen_port,
 			webhook_url: x.webhook_url,
 		}
 	}
@@ -277,6 +282,7 @@ impl From <ConfigFile> for Config {
 #[derive (Deserialize)]
 struct ConfigFile {
 	ip_nicknames: Vec <([u8; 4], String)>,
+	tcp_listen_port: Option <u16>,
 	webhook_url: Option <String>,
 }
 
@@ -319,13 +325,18 @@ impl ConnectEvents {
 
 struct P4State {
 	req_channel: mpsc::Sender <RequestP2ToP4>,
-	
+}
+
+async fn load_config () -> anyhow::Result <ConfigFile>
+{
+	let s = tokio::fs::read_to_string ("config/ptth_quic_relay_server.json").await?;
+	let cfg: ConfigFile = serde_json::from_str (&s)?;
+	Ok (cfg)
 }
 
 impl RelayState {
 	async fn reload_config (&self) -> anyhow::Result <()> {
-		let s = tokio::fs::read_to_string ("config/ptth_quic_relay_server.json").await?;
-		let config: ConfigFile = serde_json::from_str (&s)?;
+		let config = load_config ().await?;
 		let config = Arc::new (Config::from (config));
 		
 		self.config.store (config);