public bool PingPort(string IP, int port, int timeout_mcek = 500)
    {
        bool ret = false;
        using (Socket socket = new Socket(AddressFamily.InterNetwork,
                    SocketType.Stream,
                    ProtocolType.Tcp))
        {
            IPEndPoint point = new IPEndPoint(IPAddress.Parse(IP), port);
            var result = socket.BeginConnect(point, null, null);

            ret = result.AsyncWaitHandle.WaitOne(timeout_mcek, true);
            if (ret)
            {
                if (socket.Connected)
                socket.EndConnect(result);

            }
            else
            {
                socket.Close();
            }
        }
        return ret;
    }