diff --git a/app/cmd/client.go b/app/cmd/client.go
index b20facb..9a785d2 100644
--- a/app/cmd/client.go
+++ b/app/cmd/client.go
@@ -179,7 +179,7 @@ func (c *clientConfig) fillConnFactory(hyConfig *client.Config) error {
 		if hyConfig.ServerAddr.Network() == "udphop" {
 			hopAddr := hyConfig.ServerAddr.(*udphop.UDPHopAddr)
 			newFunc = func(addr net.Addr) (net.PacketConn, error) {
-				return udphop.NewUDPHopPacketConn(hopAddr, c.Transport.UDP.HopInterval)
+				return udphop.NewUDPHopPacketConn(hopAddr, c.Transport.UDP.HopInterval, nil)
 			}
 		} else {
 			newFunc = func(addr net.Addr) (net.PacketConn, error) {
diff --git a/extras/transport/udphop/conn.go b/extras/transport/udphop/conn.go
index ccb0b38..f20c583 100644
--- a/extras/transport/udphop/conn.go
+++ b/extras/transport/udphop/conn.go
@@ -17,9 +17,10 @@ const (
 )
 
 type udpHopPacketConn struct {
-	Addr        net.Addr
-	Addrs       []net.Addr
-	HopInterval time.Duration
+	Addr          net.Addr
+	Addrs         []net.Addr
+	HopInterval   time.Duration
+	ListenUDPFunc ListenUDPFunc
 
 	connMutex   sync.RWMutex
 	prevConn    net.PacketConn
@@ -43,29 +44,37 @@ type udpPacket struct {
 	Err  error
 }
 
-func NewUDPHopPacketConn(addr *UDPHopAddr, hopInterval time.Duration) (net.PacketConn, error) {
+type ListenUDPFunc func() (net.PacketConn, error)
+
+func NewUDPHopPacketConn(addr *UDPHopAddr, hopInterval time.Duration, listenUDPFunc ListenUDPFunc) (net.PacketConn, error) {
 	if hopInterval == 0 {
 		hopInterval = defaultHopInterval
 	} else if hopInterval < 5*time.Second {
 		return nil, errors.New("hop interval must be at least 5 seconds")
 	}
+	if listenUDPFunc == nil {
+		listenUDPFunc = func() (net.PacketConn, error) {
+			return net.ListenUDP("udp", nil)
+		}
+	}
 	addrs, err := addr.addrs()
 	if err != nil {
 		return nil, err
 	}
-	curConn, err := net.ListenUDP("udp", nil)
+	curConn, err := listenUDPFunc()
 	if err != nil {
 		return nil, err
 	}
 	hConn := &udpHopPacketConn{
-		Addr:        addr,
-		Addrs:       addrs,
-		HopInterval: hopInterval,
-		prevConn:    nil,
-		currentConn: curConn,
-		addrIndex:   rand.Intn(len(addrs)),
-		recvQueue:   make(chan *udpPacket, packetQueueSize),
-		closeChan:   make(chan struct{}),
+		Addr:          addr,
+		Addrs:         addrs,
+		HopInterval:   hopInterval,
+		ListenUDPFunc: listenUDPFunc,
+		prevConn:      nil,
+		currentConn:   curConn,
+		addrIndex:     rand.Intn(len(addrs)),
+		recvQueue:     make(chan *udpPacket, packetQueueSize),
+		closeChan:     make(chan struct{}),
 		bufPool: sync.Pool{
 			New: func() interface{} {
 				return make([]byte, udpBufferSize)
@@ -121,7 +130,7 @@ func (u *udpHopPacketConn) hop() {
 	if u.closed {
 		return
 	}
-	newConn, err := net.ListenUDP("udp", nil)
+	newConn, err := u.ListenUDPFunc()
 	if err != nil {
 		// Could be temporary, just skip this hop
 		return