diff --git a/ostp-client/src/bridge.rs b/ostp-client/src/bridge.rs
index 98b2383..0ba9b1e 100644
--- a/ostp-client/src/bridge.rs
+++ b/ostp-client/src/bridge.rs
@@ -315,7 +315,7 @@ impl Bridge {
                     self.metrics.connection_state.store(1, Ordering::Relaxed);
                     
                     let session_count = if self.mux_enabled { self.mux_sessions.max(1) } else { 1 };
-                    let (udp_tx, udp_rx) = mpsc::channel(100000);
+                    let (udp_tx, udp_rx) = mpsc::channel(1024);
                     let mut sessions = Vec::with_capacity(session_count);
                     let mut rtt_sum = 0.0;
                     let mut successful_sessions = 0;
@@ -412,7 +412,7 @@ impl Bridge {
                     self.last_valid_recv = Instant::now() - Duration::from_secs(100);
 
                     let session_count = if self.mux_enabled { self.mux_sessions.max(1) } else { 1 };
-                    let (udp_tx, udp_rx) = mpsc::channel(100000);
+                    let (udp_tx, udp_rx) = mpsc::channel(1024);
                     let mut new_sessions = Vec::with_capacity(session_count);
                     let mut successful_sessions = 0;
                     let mut rtt_sum = 0.0;
@@ -548,7 +548,7 @@ impl Bridge {
             self.metrics.connection_state.store(1, Ordering::Relaxed);
 
             let session_count = if self.mux_enabled { self.mux_sessions.max(1) } else { 1 };
-            let (udp_tx, udp_rx) = mpsc::channel(100000);
+            let (udp_tx, udp_rx) = mpsc::channel(1024);
             let mut new_sessions = Vec::with_capacity(session_count);
             let mut successful_sessions = 0;
             let mut rtt_sum = 0.0;
diff --git a/ostp-client/src/tunnel/native_handler.rs b/ostp-client/src/tunnel/native_handler.rs
index b1fe5b1..9cfcf20 100644
--- a/ostp-client/src/tunnel/native_handler.rs
+++ b/ostp-client/src/tunnel/native_handler.rs
@@ -104,9 +104,9 @@ pub async fn run_native_tunnel(
 
     // ── 7. Build smoltcp network stack ────────────────────────────────────────
     let (stack, tcp_runner, udp_socket, tcp_listener) = StackBuilder::default()
-        .stack_buffer_size(100_000)
-        .tcp_buffer_size(100_000)
-        .udp_buffer_size(100_000)
+        .stack_buffer_size(1024)
+        .tcp_buffer_size(1024)
+        .udp_buffer_size(1024)
         .enable_tcp(true)
         .enable_udp(true)
         .mtu(config.ostp.mtu)
@@ -454,9 +454,9 @@ pub async fn run_native_tunnel_from_fd(
     let tun_stream = tokio::io::unix::AsyncFd::new(file)?;
 
     let (stack, tcp_runner, udp_socket, tcp_listener) = StackBuilder::default()
-        .stack_buffer_size(100_000)
-        .tcp_buffer_size(100_000)
-        .udp_buffer_size(100_000)
+        .stack_buffer_size(1024)
+        .tcp_buffer_size(1024)
+        .udp_buffer_size(1024)
         .enable_tcp(true)
         .enable_udp(true)
         .mtu(config.ostp.mtu)
diff --git a/ostp-client/src/tunnel/udp_nat.rs b/ostp-client/src/tunnel/udp_nat.rs
index ad99dcb..5f94301 100644
--- a/ostp-client/src/tunnel/udp_nat.rs
+++ b/ostp-client/src/tunnel/udp_nat.rs
@@ -30,7 +30,7 @@ pub async fn run_udp_nat(
                         if payload.is_empty() { continue; }
 
                         if !sessions.contains_key(&src) {
-                            let (session_tx, mut session_rx) = mpsc::channel::<(Vec<u8>, SocketAddr)>(100000);
+                            let (session_tx, mut session_rx) = mpsc::channel::<(Vec<u8>, SocketAddr)>(1024);
                             sessions.insert(src, session_tx);
 
                             let proxy_addr_clone = proxy_addr.clone();
@@ -89,8 +89,14 @@ pub async fn run_udp_nat(
                         }
 
                         if let Some(sender) = sessions.get(&src) {
-                            if sender.send((payload, dst)).await.is_err() {
-                                sessions.remove(&src);
+                            match sender.try_send((payload, dst)) {
+                                Err(mpsc::error::TrySendError::Closed(_)) => {
+                                    sessions.remove(&src);
+                                }
+                                Err(mpsc::error::TrySendError::Full(_)) => {
+                                    // Drop packet to avoid blocking the TUN interface loop
+                                }
+                                Ok(_) => {}
                             }
                         }
                     }