diff --git a/switch/src/handle/tun_tap/tun_handler.rs b/switch/src/handle/tun_tap/tun_handler.rs
index 7b5abcf..fa50c4f 100644
--- a/switch/src/handle/tun_tap/tun_handler.rs
+++ b/switch/src/handle/tun_tap/tun_handler.rs
@@ -90,7 +90,7 @@ async fn start_(sender: ChannelSender,
         }
         let len = device_reader.read(&mut buf[12..])? + 12;
         #[cfg(any(target_os = "macos"))]
-            let mut buf = &mut buf;
+            let mut buf = &mut buf[4..];
         match handle(&sender, &mut buf, len, device_writer, &igmp_server, current_device.load(), &ip_route, &ip_proxy_map, &cipher).await {
             Ok(_) => {}
             Err(e) => {