C# UDP socket app to listen to messages from various sockets

0
votes

I have a system monitor app that needs to listen to messages from various UDP sockets on another machine. The other sockets continuously send heartbeats to this given IP/port.

This exception gets thrown when calling BeginReceiveFrom: "A request to send or receive data was disallowed because the socket is not connected and (when sending on a datagram socket using a sendto call) no address was supplied"

I shouldn't have to call connect because data is already getting sent to this ip endpoint. plus the data is coming from various sockets.

    private Socket m_socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
    private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        // bind socket
        // Establish the local endpoint for the socket.
        // Dns.GetHostName returns the name of the 
        // host running the application.
        IPHostEntry ipHostInfo = Dns.Resolve(Dns.GetHostName());
        IPAddress ipAddress = ipHostInfo.AddressList[0];
        m_localEndPoint = new IPEndPoint(ipAddress, 19018);
        m_socket.Bind(m_localEndPoint);

        m_socket.BeginReceiveFrom(m_data, 
                                  m_nBytes, 
                                  MAX_READ_SIZE, 
                                  SocketFlags.None,
                                  ref m_localEndPoint, 
                                  new AsyncCallback(OnReceive),
                                  null);

    }

    private void OnReceive(IAsyncResult ar)
    {
            int nRead = m_socket.EndReceiveFrom(ar, ref m_localEndPoint);
     }
2
c#.netsocketsudp
Are you running it as the administrator user, firewall off? Windows will block binding on "various ports" – FlavorScape
I'm not binding the socket to various ports, I'm binding it to one port. It is receiving data from various UDP sockets on another machine. I'm running the app on a windows xp machine under an administrator account. – Alex
Why are you using BeginReceiveFrom instead of BeginReceive? – Paulo Bu

2 Answers

0
votes

I was able to get the desired behavior with the UdpClient class.

0
votes

Your problem was you were binding to the IP assigned to you, you should bind to IP you want receive from - in your case:

m_socket.Bind(new IPEndPoint(IPAddress.Any, 12345));