diff --git a/examples/ss.client.toml b/examples/ss.client.toml
index 0d5891a..26aef03 100644
--- a/examples/ss.client.toml
+++ b/examples/ss.client.toml
@@ -17,4 +17,4 @@ uuid = "method:AES-128-GCM\npass:iloveverysimple"
 
 #encrypt_algo = "AES-128-GCM"  # chacha20-ietf-poly1305,AES-128-GCM, AES-256-GCM, 大小写均可；一般应该是 aes 更快， 如果 encrypt_algo 给出，会覆盖 uuid中的 method 部分
 
-#network = "dual"   #ss同时使用tcp和udp分别传输tcp和udp数据，属于双栈
\ No newline at end of file
+#network = "dual"   #ss同时使用tcp和udp分别传输tcp和udp数据，属于双栈, 如果设成tcp，则不会传输udp。
\ No newline at end of file
diff --git a/main.go b/main.go
index c1b048a..1654d13 100644
--- a/main.go
+++ b/main.go
@@ -73,8 +73,9 @@ non-blocking. closer used to stop listening. It means listening failed if closer
 func ListenSer(inServer proxy.Server, defaultOutClient proxy.Client, env *proxy.RoutingEnv) (closer io.Closer) {
 	var extraCloser io.Closer
 
+	var is, tcp, udp bool
 	//tproxy 和 shadowsocks 都用到了 SelfListen
-	if is, tcp, udp := inServer.SelfListen(); is {
+	if is, tcp, udp = inServer.SelfListen(); is {
 		var chantcp chan proxy.IncomeTCPInfo
 		var chanudp chan proxy.IncomeUDPInfo
 
@@ -179,8 +180,19 @@ func ListenSer(inServer proxy.Server, defaultOutClient proxy.Client, env *proxy.
 
 	var err error
 
+	network := inServer.Network()
+	if network == netLayer.DualNetworkName && is {
+		if is != tcp && udp {
+			if tcp {
+				network = "udp"
+			} else {
+				network = "tcp"
+			}
+		}
+	}
+
 	closer, err = netLayer.ListenAndAccept(
-		inServer.Network(),
+		network,
 		inServer.AddrStr(),
 		inServer.GetSockopt(),
 		inServer.GetXver(),