diff --git a/tuic-server/src/connection/handle_task.rs b/tuic-server/src/connection/handle_task.rs
index 7d584baa..850cde8c 100644
--- a/tuic-server/src/connection/handle_task.rs
+++ b/tuic-server/src/connection/handle_task.rs
@@ -32,7 +32,7 @@ impl Connection {
         let target_addr = conn.addr().to_string();
 
         info!(
-            "[{id:#010x}] [{addr}] [{user}] [TCP] {target_addr}",
+            "[{id:#010x}] [{addr}] [{user}] [TCP] {target_addr} ",
             id = self.id(),
             addr = self.inner.remote_address(),
             user = self.auth,
@@ -63,6 +63,7 @@ impl Connection {
                 // a <- b rx
                 let (tx, rx, err) =
                     exchange_tcp(&mut conn, &mut stream, self.ctx.cfg.stream_timeout).await;
+                // let (tx, rx) = tokio::io::copy_bidirectional(&mut conn, &mut stream).await?;
                 _ = conn.reset(ERROR_CODE);
                 _ = stream.shutdown().await;
 
diff --git a/tuic-server/src/connection/mod.rs b/tuic-server/src/connection/mod.rs
index fbc20d23..658fd79e 100644
--- a/tuic-server/src/connection/mod.rs
+++ b/tuic-server/src/connection/mod.rs
@@ -19,7 +19,7 @@ mod handle_stream;
 mod handle_task;
 mod udp_session;
 
-pub const ERROR_CODE: VarInt = VarInt::from_u32(0);
+pub const ERROR_CODE: VarInt = VarInt::from_u32(6000);
 pub const INIT_CONCURRENT_STREAMS: u32 = 32;
 
 #[derive(Clone)]
diff --git a/tuic-server/src/io.rs b/tuic-server/src/io.rs
index 25eb2a52..c184e500 100644
--- a/tuic-server/src/io.rs
+++ b/tuic-server/src/io.rs
@@ -4,6 +4,7 @@ use tokio::io::{AsyncReadExt, AsyncWriteExt};
 
 const BUFFER_SIZE: usize = 8 * 1024;
 
+#[allow(dead_code)]
 pub async fn exchange_tcp(
     a: &mut tuic_quinn::Connect,
     b: &mut tokio::net::TcpStream,
@@ -18,6 +19,7 @@ pub async fn exchange_tcp(
     let mut last_err = None;
     let mut timeout = tokio::time::interval(timeout);
     timeout.reset();
+
     loop {
         tokio::select! {
             _ = timeout.tick() => {
@@ -28,7 +30,7 @@ pub async fn exchange_tcp(
             a2b_res = a.recv.read(&mut a2b) => match a2b_res {
                 Ok(Some(num)) => {
                     a2b_num += num;
-                    if let Err(err) = b.write(&a2b).await {
+                    if let Err(err) = b.write_all(&a2b[..num]).await {
                         last_err = Some(err.into());
                         break;
                     }
@@ -50,7 +52,7 @@ pub async fn exchange_tcp(
                         break;
                     }
                     b2a_num += num;
-                    if let Err(err) = a.send.write(&b2a).await {
+                    if let Err(err) = a.send.write_all(&b2a[..num]).await {
                         last_err = Some(err.into());
                         break;
                     }