public static void SendBackPositions(PositionList received) { using (MemoryStream ms = new MemoryStream()) { received.WriteTo(ms); Socket tempSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp); IPEndPoint replyEndPoint = new IPEndPoint(IPAddress.Parse("127.0.0.1"), replyPort); ms.Position = 0; tempSocket.SendTo(received.ToByteArray(), replyEndPoint); tempSocket.Close(); } Console.WriteLine("Data sent!"); StartBoth.ListeningMessage(); StartBoth._Positionlistening = false; }