diff --git a/connector/relay/bind.go b/connector/relay/bind.go
index cc0f994c..1ab8d3a6 100644
--- a/connector/relay/bind.go
+++ b/connector/relay/bind.go
@@ -102,6 +102,9 @@ func (c *relayConnector) bind(conn net.Conn, cmd relay.CmdType, network, address
 		Network: nid,
 	})
 	fa := &relay.AddrFeature{}
+	if h, _, e := net.SplitHostPort(address); e == nil && h == "" {
+		address = net.JoinHostPort("0.0.0.0", address)
+	}
 	fa.ParseFrom(address)
 	req.Features = append(req.Features, fa)
 	if _, err := req.WriteTo(conn); err != nil {
diff --git a/connector/tunnel/bind.go b/connector/tunnel/bind.go
index b9f51643..5991e845 100644
--- a/connector/tunnel/bind.go
+++ b/connector/tunnel/bind.go
@@ -69,6 +69,9 @@ func (c *tunnelConnector) initTunnel(conn net.Conn, network, address string) (ad
 	req.Features = append(req.Features, af)
 
 	af = &relay.AddrFeature{}
+	if h, _, e := net.SplitHostPort(address); e == nil && h == "" {
+		address = net.JoinHostPort("0.0.0.0", address)
+	}
 	af.ParseFrom(address)
 	req.Features = append(req.Features, af) // dst address
 
diff --git a/handler/tunnel/bind.go b/handler/tunnel/bind.go
index da2e4bbc..77bb47f2 100644
--- a/handler/tunnel/bind.go
+++ b/handler/tunnel/bind.go
@@ -57,9 +57,12 @@ func (h *tunnelHandler) handleBind(ctx context.Context, conn net.Conn, network,
 			ID: connectorID,
 		},
 	)
-	resp.WriteTo(conn)
+	if _, err = resp.WriteTo(conn); err != nil {
+			log.Error(err)
+			return
+		}
 
-	// Upgrade connection to multiplex session.
+		// Upgrade connection to multiplex session.
 	session, err := mux.ClientSession(conn, h.md.muxCfg)
 	if err != nil {
 		return