diff --git a/admin/client.go b/admin/client.go
index 17537a2..71810c3 100644
--- a/admin/client.go
+++ b/admin/client.go
@@ -52,18 +52,26 @@ func (c *Client) RPCCall(addr, method string, params interface{}, result interfa
 		return err
 	}
 
-	onReply, err := c.Send(nkn.NewStringArray(addr), req, nil)
+	var onReply *nkn.OnMessage
+	var reply *nkn.Message
+Loop:
+	for i := 0; i < 3; i++ { // retry 3 times if timeout
+		onReply, err = c.Send(nkn.NewStringArray(addr), req, nil)
+		if err != nil {
+			return err
+		}
+
+		select {
+		case reply = <-onReply.C:
+			break Loop
+		case <-time.After(c.replyTimeout):
+			err = errReplyTimeout
+		}
+	}
 	if err != nil {
 		return err
 	}
 
-	var reply *nkn.Message
-	select {
-	case reply = <-onReply.C:
-	case <-time.After(c.replyTimeout):
-		return errReplyTimeout
-	}
-
 	resp := &rpcResp{
 		Result: result,
 	}
diff --git a/tests/config.go b/tests/config.go
index 8b4f00b..dc7927e 100644
--- a/tests/config.go
+++ b/tests/config.go
@@ -7,9 +7,9 @@ const (
 
 	seedHex = "e68e046d13dd911594576ba0f4a196e9666790dc492071ad9ea5972c0b940435"
 
-	tcpPort  = ":54321"
-	httpPort = ":54322"
-	udpPort  = ":54323"
+	tcpPort  = ":20001"
+	httpPort = ":20002"
+	udpPort  = ":20003"
 
 	tunaNodeStarted = "tuna node is started"
 )
diff --git a/tests/main_test.go b/tests/main_test.go
index d9eec9d..68a9edc 100644
--- a/tests/main_test.go
+++ b/tests/main_test.go
@@ -60,7 +60,7 @@ func TestMain(m *testing.M) {
 		return
 	}
 
-	time.Sleep(5 * time.Second)
+	time.Sleep(10 * time.Second)
 
 	exitVal := m.Run()
 	os.Exit(exitVal)
diff --git a/tests/pub.go b/tests/pub.go
index 2b66bb1..faf48d7 100644
--- a/tests/pub.go
+++ b/tests/pub.go
@@ -42,7 +42,7 @@ func startNconnect(configFile string, tuna, udp, tun bool, n *types.Node) error
 	}
 
 	if opts.Client {
-		port, err := getFreePort(port)
+		port, err = getFreePort(port)
 		if err != nil {
 			return err
 		}
@@ -66,7 +66,7 @@ func startNconnect(configFile string, tuna, udp, tun bool, n *types.Node) error
 		}
 	}()
 
-	time.Sleep(3 * time.Second) // wait for nconnect to create tunnels
+	time.Sleep(5 * time.Second) // wait for nconnect to create tunnels
 
 	tunnels := nc.GetTunnels()
 	for _, tunnel := range tunnels {
@@ -140,16 +140,16 @@ type Person struct {
 	Age  int
 }
 
-func getFreePort(port int) (int, error) {
+func getFreePort(p int) (int, error) {
 	for i := 0; i < 100; i++ {
-		addr, err := net.ResolveTCPAddr("tcp", fmt.Sprintf("127.0.0.1:%v", port))
+		addr, err := net.ResolveTCPAddr("tcp", fmt.Sprintf("127.0.0.1:%v", p))
 		if err != nil {
 			return 0, err
 		}
 
 		l, err := net.ListenTCP("tcp", addr)
 		if err != nil {
-			port++
+			p++
 			continue
 		}
 
@@ -164,8 +164,8 @@ func waitForSSProxReady() error {
 	for i := 0; i < 100; i++ {
 		conn, err := net.Dial("tcp", fmt.Sprintf("127.0.0.1:%v", port))
 		if err != nil {
-			fmt.Printf("waitForSSProxReady err: %v\n", err)
 			time.Sleep(2 * time.Second)
+			continue
 		}
 		if conn != nil {
 			conn.Close()
diff --git a/tests/tcp.go b/tests/tcp.go
index 5f39160..00783da 100644
--- a/tests/tcp.go
+++ b/tests/tcp.go
@@ -22,6 +22,7 @@ func StartTcpServer() error {
 			return err
 		}
 		go func(conn net.Conn) {
+			defer conn.Close()
 			b := make([]byte, 1024)
 			for {
 				n, err := conn.Read(b)
@@ -57,6 +58,8 @@ func StartTCPClient(serverAddr string) error {
 		fmt.Printf("StartTCPClient, dailer.Dial err: %v\n", err)
 		return err
 	}
+
+	defer conn.Close()
 	fmt.Printf("StartTCPClient, dail to %v success\n", serverAddr)
 
 	user := &Person{Name: "tcp_boy", Age: 0}
diff --git a/tests/udp.go b/tests/udp.go
index 842a455..5d44cb5 100644
--- a/tests/udp.go
+++ b/tests/udp.go
@@ -20,6 +20,7 @@ func StartUdpServer() error {
 		return err
 	}
 
+	defer udpServer.Close()
 	fmt.Printf("UDP server is listening at %v\n", udpPort)
 
 	b := make([]byte, 1024)