diff --git a/src/tun2proxy.rs b/src/tun2proxy.rs
index de2167d..f305323 100644
--- a/src/tun2proxy.rs
+++ b/src/tun2proxy.rs
@@ -482,6 +482,50 @@ impl<'a> TunToProxy<'a> {
         Ok(connection_info)
     }
 
+    fn process_incoming_udp_packets_dns_over_tcp(
+        &mut self,
+        manager: &Rc<dyn ConnectionManager>,
+        info: &ConnectionInfo,
+        origin_dst: SocketAddr,
+        payload: &[u8],
+    ) -> Result<()> {
+        _ = dns::parse_data_to_dns_message(payload, false)?;
+
+        if !self.connection_map.contains_key(info) {
+            log::info!("DNS over TCP {} ({})", info, origin_dst);
+            let tcp_proxy_handler = manager.new_tcp_proxy(info, false)?;
+            let server_addr = manager.get_server_addr();
+            let state = self.create_new_tcp_connection_state(server_addr, origin_dst, tcp_proxy_handler, false)?;
+            self.connection_map.insert(info.clone(), state);
+
+            self.expect_smoltcp_send()?;
+            self.tunsocket_read_and_forward(info)?;
+            self.write_to_server(info)?;
+        } else {
+            log::trace!("DNS over TCP subsequent packet {} ({})", info, origin_dst);
+        }
+
+        // Insert the DNS message length in front of the payload
+        let len = u16::try_from(payload.len())?;
+        let mut buf = Vec::with_capacity(2 + usize::from(len));
+        buf.extend_from_slice(&len.to_be_bytes());
+        buf.extend_from_slice(payload);
+
+        let err = "udp over tcp state not find";
+        let state = self.connection_map.get_mut(info).ok_or(err)?;
+        state.udp_over_tcp_expiry = Some(Self::common_udp_life_timeout());
+        if state.tcp_proxy_handler.connection_established() {
+            _ = state.mio_stream.write(&buf)?;
+        } else {
+            // FIXME: Build an IP packet with TCP and inject it into the device,
+            //        or cache them and send them when the connection is established?
+            // self.device.inject_packet(&buf);
+            state.udp_over_tcp_data_cache.push_back(buf);
+        }
+
+        Ok(())
+    }
+
     fn process_incoming_udp_packets(
         &mut self,
         manager: &Rc<dyn ConnectionManager>,
@@ -489,44 +533,6 @@ impl<'a> TunToProxy<'a> {
         origin_dst: SocketAddr,
         payload: &[u8],
     ) -> Result<()> {
-        if self.options.dns_over_tcp && origin_dst.port() == DNS_PORT {
-            _ = dns::parse_data_to_dns_message(payload, false)?;
-
-            if !self.connection_map.contains_key(info) {
-                log::info!("DNS over TCP {} ({})", info, origin_dst);
-                let tcp_proxy_handler = manager.new_tcp_proxy(info, false)?;
-                let server_addr = manager.get_server_addr();
-                let state = self.create_new_tcp_connection_state(server_addr, origin_dst, tcp_proxy_handler, false)?;
-                self.connection_map.insert(info.clone(), state);
-
-                self.expect_smoltcp_send()?;
-                self.tunsocket_read_and_forward(info)?;
-                self.write_to_server(info)?;
-            } else {
-                log::trace!("DNS over TCP subsequent packet {} ({})", info, origin_dst);
-            }
-
-            // Insert the DNS message length in front of the payload
-            let len = u16::try_from(payload.len())?;
-            let mut buf = Vec::with_capacity(2 + usize::from(len));
-            buf.extend_from_slice(&len.to_be_bytes());
-            buf.extend_from_slice(payload);
-
-            let err = "udp over tcp state not find";
-            let state = self.connection_map.get_mut(info).ok_or(err)?;
-            state.udp_over_tcp_expiry = Some(Self::common_udp_life_timeout());
-            if state.tcp_proxy_handler.connection_established() {
-                _ = state.mio_stream.write(&buf)?;
-            } else {
-                // FIXME: Build an IP packet with TCP and inject it into the device,
-                //        or cache them and send them when the connection is established?
-                // self.device.inject_packet(&buf);
-                state.udp_over_tcp_data_cache.push_back(buf);
-            }
-
-            return Ok(());
-        }
-
         if !self.connection_map.contains_key(info) {
             log::info!("UDP associate session {} ({})", info, origin_dst);
             let tcp_proxy_handler = manager.new_tcp_proxy(info, true)?;
@@ -617,7 +623,12 @@ impl<'a> TunToProxy<'a> {
                     self.send_udp_packet_to_client(origin_dst, connection_info.src, response.as_slice())?;
                 } else {
                     // Another UDP packet
-                    self.process_incoming_udp_packets(&manager, &connection_info, origin_dst, payload)?;
+                    if self.options.dns_over_tcp && origin_dst.port() == DNS_PORT {
+                        let info = &connection_info;
+                        self.process_incoming_udp_packets_dns_over_tcp(&manager, info, origin_dst, payload)?;
+                    } else {
+                        self.process_incoming_udp_packets(&manager, &connection_info, origin_dst, payload)?;
+                    }
                 }
             } else {
                 log::warn!("Unsupported protocol: {} ({})", connection_info, origin_dst);