diff --git a/server.go b/server.go
index eca779e..6f80206 100644
--- a/server.go
+++ b/server.go
@@ -68,7 +68,7 @@ func handshakeWithClient(test *ethrTest, conn net.Conn) (testID EthrTestID, clie
 }
 
 func srvrRunTCPServer() error {
-	l, err := net.Listen(Tcp(), gLocalIP+":"+gEthrPortStr)
+	l, err := net.Listen(Tcp(), "["+gLocalIP+"]:"+gEthrPortStr)
 	if err != nil {
 		return err
 	}
@@ -233,7 +233,7 @@ func srvrRunTCPLatencyTest(test *ethrTest, clientParam EthrClientParam, conn net
 }
 
 func srvrRunUDPServer() error {
-	udpAddr, err := net.ResolveUDPAddr(Udp(), gLocalIP+":"+gEthrPortStr)
+	udpAddr, err := net.ResolveUDPAddr(Udp(), "["+gLocalIP+"]:"+gEthrPortStr)
 	if err != nil {
 		ui.printDbg("Unable to resolve UDP address: %v", err)
 		return err
diff --git a/utils.go b/utils.go
index 2fd835c..abbb169 100644
--- a/utils.go
+++ b/utils.go
@@ -362,7 +362,7 @@ func ethrDialAll(p EthrProtocol, dialAddr string) (conn net.Conn, err error) {
 }
 
 func ethrDialEx(p EthrProtocol, dialAddr, localIP string, localPortNum uint16, ttl int, tos int) (conn net.Conn, err error) {
-	localAddr := fmt.Sprintf("%v:%v", localIP, localPortNum)
+	localAddr := fmt.Sprintf("[%v]:%v", localIP, localPortNum)
 	var la net.Addr
 	network := Tcp()
 	if p == TCP {