diff --git a/server/handler/link_tap.go b/server/handler/link_tap.go
index fe3ed13..a9ff4b0 100644
--- a/server/handler/link_tap.go
+++ b/server/handler/link_tap.go
@@ -65,15 +65,16 @@ func LinkTap(cSess *sessdata.ConnSession) error {
 	// arp on
 	cmdstr1 := fmt.Sprintf("ip link set dev %s up mtu %d multicast on", ifce.Name(), cSess.Mtu)
 	cmdstr2 := fmt.Sprintf("ip link set dev %s master %s", ifce.Name(), bridgeName)
-	// cmdstr3 := fmt.Sprintf("sysctl -w net.ipv6.conf.%s.disable_ipv6=1", ifce.Name())
-	cmdStrs := []string{cmdstr1, cmdstr2}
-	err = execCmd(cmdStrs)
+	err = execCmd([]string{cmdstr1, cmdstr2})
 	if err != nil {
 		base.Error(err)
 		_ = ifce.Close()
 		return err
 	}
 
+	cmdstr3 := fmt.Sprintf("sysctl -w net.ipv6.conf.%s.disable_ipv6=1", ifce.Name())
+	execCmd([]string{cmdstr3})
+
 	go tapRead(ifce, cSess)
 	go tapWrite(ifce, cSess)
 	return nil
diff --git a/server/handler/link_tun.go b/server/handler/link_tun.go
index 822c92a..3d0e456 100644
--- a/server/handler/link_tun.go
+++ b/server/handler/link_tun.go
@@ -46,15 +46,16 @@ func LinkTun(cSess *sessdata.ConnSession) error {
 	cmdstr1 := fmt.Sprintf("ip link set dev %s up mtu %d multicast off", ifce.Name(), cSess.Mtu)
 	cmdstr2 := fmt.Sprintf("ip addr add dev %s local %s peer %s/32",
 		ifce.Name(), base.Cfg.Ipv4Gateway, cSess.IpAddr)
-	// cmdstr3 := fmt.Sprintf("sysctl -w net.ipv6.conf.%s.disable_ipv6=1", ifce.Name())
-	cmdStrs := []string{cmdstr1, cmdstr2}
-	err = execCmd(cmdStrs)
+	err = execCmd([]string{cmdstr1, cmdstr2})
 	if err != nil {
 		base.Error(err)
 		_ = ifce.Close()
 		return err
 	}
 
+	cmdstr3 := fmt.Sprintf("sysctl -w net.ipv6.conf.%s.disable_ipv6=1", ifce.Name())
+	execCmd([]string{cmdstr3})
+
 	go tunRead(ifce, cSess)
 	go tunWrite(ifce, cSess)
 	return nil