diff --git a/client_read_test.go b/client_read_test.go
index 28c54a00..6c03248c 100644
--- a/client_read_test.go
+++ b/client_read_test.go
@@ -354,13 +354,15 @@ func TestClientRead(t *testing.T) {
 
 				// client -> server (RTCP)
 				switch proto {
-				case "udp":
-					// skip firewall opening
-					buf := make([]byte, 2048)
-					_, _, err := l2.ReadFrom(buf)
-					require.NoError(t, err)
+				case "udp", "multicast":
+					if proto == "udp" {
+						// skip firewall opening
+						buf := make([]byte, 2048)
+						_, _, err := l2.ReadFrom(buf)
+						require.NoError(t, err)
+					}
 
-					buf = make([]byte, 2048)
+					buf := make([]byte, 2048)
 					n, _, err := l2.ReadFrom(buf)
 					require.NoError(t, err)
 					require.Equal(t, []byte{0x05, 0x06, 0x07, 0x08}, buf[:n])
@@ -414,20 +416,19 @@ func TestClientRead(t *testing.T) {
 				defer close(done)
 				conn.ReadFrames(func(id int, streamType StreamType, payload []byte) {
 					// skip multicast loopback
-					if proto == "multicast" && atomic.AddUint64(&counter, 1) <= 2 {
-						return
+					if proto == "multicast" {
+						add := atomic.AddUint64(&counter, 1)
+						if add >= 2 {
+							return
+						}
 					}
 
 					require.Equal(t, 0, id)
 					require.Equal(t, StreamTypeRTP, streamType)
 					require.Equal(t, []byte{0x01, 0x02, 0x03, 0x04}, payload)
 
-					if proto != "multicast" {
-						err = conn.WriteFrame(0, StreamTypeRTCP, []byte{0x05, 0x06, 0x07, 0x08})
-						require.NoError(t, err)
-					} else {
-						close(frameRecv)
-					}
+					err = conn.WriteFrame(0, StreamTypeRTCP, []byte{0x05, 0x06, 0x07, 0x08})
+					require.NoError(t, err)
 				})
 			}()
 
diff --git a/clientconn.go b/clientconn.go
index 48198868..33d1eb7c 100644
--- a/clientconn.go
+++ b/clientconn.go
@@ -475,13 +475,15 @@ func (cc *ClientConn) runBackground() {
 }
 
 func (cc *ClientConn) runBackgroundPlayUDP() error {
-	// open the firewall by sending packets to the counterpart
-	for _, cct := range cc.tracks {
-		cct.udpRTPListener.write(
-			[]byte{0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})
+	if *cc.protocol == ClientProtocolUDP {
+		// open the firewall by sending packets to the counterpart
+		for _, cct := range cc.tracks {
+			cct.udpRTPListener.write(
+				[]byte{0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})
 
-		cct.udpRTCPListener.write(
-			[]byte{0x80, 0xc9, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00})
+			cct.udpRTCPListener.write(
+				[]byte{0x80, 0xc9, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00})
+		}
 	}
 
 	for _, cct := range cc.tracks {
@@ -1379,7 +1381,8 @@ func (cc *ClientConn) doSetup(
 
 	switch proto {
 	case ClientProtocolUDP:
-		rtpListener.remoteIP = cc.nconn.RemoteAddr().(*net.TCPAddr).IP
+		rtpListener.remoteReadIP = cc.nconn.RemoteAddr().(*net.TCPAddr).IP
+		rtpListener.remoteWriteIP = cc.nconn.RemoteAddr().(*net.TCPAddr).IP
 		rtpListener.remoteZone = cc.nconn.RemoteAddr().(*net.TCPAddr).Zone
 		if thRes.ServerPorts != nil {
 			rtpListener.remotePort = thRes.ServerPorts[0]
@@ -1388,7 +1391,8 @@ func (cc *ClientConn) doSetup(
 		rtpListener.streamType = StreamTypeRTP
 		cct.udpRTPListener = rtpListener
 
-		rtcpListener.remoteIP = cc.nconn.RemoteAddr().(*net.TCPAddr).IP
+		rtcpListener.remoteReadIP = cc.nconn.RemoteAddr().(*net.TCPAddr).IP
+		rtcpListener.remoteWriteIP = cc.nconn.RemoteAddr().(*net.TCPAddr).IP
 		rtcpListener.remoteZone = cc.nconn.RemoteAddr().(*net.TCPAddr).Zone
 		if thRes.ServerPorts != nil {
 			rtcpListener.remotePort = thRes.ServerPorts[1]
@@ -1398,14 +1402,16 @@ func (cc *ClientConn) doSetup(
 		cct.udpRTCPListener = rtcpListener
 
 	case ClientProtocolMulticast:
-		rtpListener.remoteIP = cc.nconn.RemoteAddr().(*net.TCPAddr).IP
+		rtpListener.remoteReadIP = cc.nconn.RemoteAddr().(*net.TCPAddr).IP
+		rtpListener.remoteWriteIP = *thRes.Destination
 		rtpListener.remoteZone = ""
 		rtpListener.remotePort = thRes.Ports[0]
 		rtpListener.trackID = trackID
 		rtpListener.streamType = StreamTypeRTP
 		cct.udpRTPListener = rtpListener
 
-		rtcpListener.remoteIP = cc.nconn.RemoteAddr().(*net.TCPAddr).IP
+		rtcpListener.remoteReadIP = cc.nconn.RemoteAddr().(*net.TCPAddr).IP
+		rtcpListener.remoteWriteIP = *thRes.Destination
 		rtcpListener.remoteZone = ""
 		rtcpListener.remotePort = thRes.Ports[1]
 		rtcpListener.trackID = trackID
diff --git a/clientconnudpl.go b/clientconnudpl.go
index 57083af6..b6dbcb38 100644
--- a/clientconnudpl.go
+++ b/clientconnudpl.go
@@ -21,7 +21,8 @@ const (
 type clientConnUDPListener struct {
 	cc            *ClientConn
 	pc            *net.UDPConn
-	remoteIP      net.IP
+	remoteReadIP  net.IP
+	remoteWriteIP net.IP
 	remoteZone    string
 	remotePort    int
 	trackID       int
@@ -31,6 +32,7 @@ type clientConnUDPListener struct {
 	lastFrameTime *int64
 	writeMutex    sync.Mutex
 
+	// out
 	done chan struct{}
 }
 
@@ -148,7 +150,7 @@ func (l *clientConnUDPListener) run() {
 
 			uaddr := addr.(*net.UDPAddr)
 
-			if !l.remoteIP.Equal(uaddr.IP) || (!isAnyPort(l.remotePort) && l.remotePort != uaddr.Port) {
+			if !l.remoteReadIP.Equal(uaddr.IP) || (!isAnyPort(l.remotePort) && l.remotePort != uaddr.Port) {
 				continue
 			}
 
@@ -167,7 +169,7 @@ func (l *clientConnUDPListener) run() {
 
 			uaddr := addr.(*net.UDPAddr)
 
-			if !l.remoteIP.Equal(uaddr.IP) || (!isAnyPort(l.remotePort) && l.remotePort != uaddr.Port) {
+			if !l.remoteReadIP.Equal(uaddr.IP) || (!isAnyPort(l.remotePort) && l.remotePort != uaddr.Port) {
 				continue
 			}
 
@@ -184,7 +186,7 @@ func (l *clientConnUDPListener) write(buf []byte) error {
 
 	l.pc.SetWriteDeadline(time.Now().Add(l.cc.c.WriteTimeout))
 	_, err := l.pc.WriteTo(buf, &net.UDPAddr{
-		IP:   l.remoteIP,
+		IP:   l.remoteWriteIP,
 		Zone: l.remoteZone,
 		Port: l.remotePort,
 	})