Silverlight client consuming WCF service

Question

Please bear with me as I am new to WCF services/ Windows services. I've created a WCF service hosted in a Windows service. I want to consume that WCF service in a Silverlight in-browser application over TCP. Below is the code fragment in Silverlight to access WCF service:

        var messageEncoding = new BinaryMessageEncodingBindingElement();
        var tcpTransport = new TcpTransportBindingElement();
        var binding = new CustomBinding(messageEncoding, tcpTransport);

        // Create a channel factory for the service endpoint configured with the custom binding.
        var cf = new ChannelFactory<ICalcService>(binding, new EndpointAddress("net.tcp://192.168.2.104:4508"));

        // Open the channel.
        ICalcService channel = cf.CreateChannel();

        // Invoke the method asynchronously.
        channel.BeginAdd(9, 5, AddCallback, channel);

    private void AddCallback(IAsyncResult asyncResult)
    {
        try
        {
            double endAdd = ((ICalcService) asyncResult.AsyncState).EndAdd(asyncResult);
        }
        catch (Exception exception)
        {
            throw exception;
        }
    }

The code works fine sometimes but often it throws an infamous System.ServiceModel.CommunicationException with the following message for some reasons:

Could not connect to net.tcp://192.168.2.104:4508/. The connection attempt lasted for a time span of 00:00:00.1010058. TCP error code 10013: An attempt was made to access a socket in a way forbidden by its access permissions.. This could be due to attempting to access a service in a cross-domain way while the service is not configured for cross-domain access. You may need to contact the owner of the service to expose a sockets cross-domain policy over HTTP and host the service in the allowed sockets port range 4502-4534.

The innerException of type System.Net.Sockets.SocketException says

An attempt was made to access a socket in a way forbidden by its access permissions.

What are the possible reasons behind this exceptions? Based on what I investigated so far, I could find only one reason: Improper ClientAccessPolicy.xml. What may be the other reasons? If you have any useful resources, please provide me the same. One more question, if I want to make Windows service hosted WCF service to get consumed by other machines on LAN, what settings do I have to make? E.g. firewall settings? My code cannot access WCF service on other machine. It throws the same exception I mentioned above. Any ideas about how to get rid of this exception?

Other than this link: http://msdn.microsoft.com/en-us/library/cc197955(v=vs.95).aspx I cannot help you with the error, but the firewall should be configured to allow incoming requests either for the windows service executable, or, if you do not intend to change the services port, to allow incoming requests on that certain port for tcp traffic. — Andreas, Jul 08 '14 at 09:51

score 0 · Accepted Answer · answered Jul 09 '14 at 05:03

Problem sorted..!! I had to do following things:

1) Specified SecurityMode.None while creating NetTcpBinding in Windows service.

2) Created an Inbound Rule in Windows Firewall With Advanced Security to allow TCP traffic on the port I specified in the end point address.

Silverlight client consuming WCF service

1 Answers1