Question

Here’s the properties and the method that connects.

protected Socket _socketConnection =
            new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.IP);
private string _host = "";
private string _hostIpAddress = "";
private int _port = 0;

  public void Connect()
        {
            // don't allow two connections
            if (_socketConnection.Connected)
                return;


            // get the ip address from the hostname
            IPHostEntry ipHostEntry = Dns.GetHostByName(_host);
            _hostIpAddress = ipHostEntry.AddressList[0].ToString();

            // create the socket endpoint
            IPAddress ipAddress = IPAddress.Parse(_hostIpAddress);
            IPEndPoint ipEndPoint = new IPEndPoint(ipAddress, _port);

            // connect
            try
            {
                _socketConnection.Connect(ipEndPoint);
                if (OnConnect != null)
                    OnConnect();
            }
            catch
            {
                throw;
            }
        }

When I run the app under Windows 7 I get the following error:

An unknown, invalid, or unsupported option or level was specified in a getsockopt or setsockopt call.

I’ve seen messages that talk about setting a particular option on the socket, but this is an app that has been working for years and is only happening when this app is installed on Windows 7.

Is there a compatibility flag to tweak or something?

Thanks!

Answer 1

Perhaps on Win7 you get a IPv6 as the _hostIpAddress. Try using something like this when instantiating the socket:

if(Socket.OSSupportsIPv6 && _hostIpAddress.AddressFamily == AddressFamily.InterNetworkV6) 
{
   // newer OS
   _socketConnection = new Socket(
       AddressFamily.InterNetworkV6, 
       SocketType.Stream, 
       ProtocolType.Tcp);
   _socketConnection.SetSocketOption(SocketOptionLevel.IPv6, SocketOptionName.IPv6Only, 0);
} else { 
   // older OS
   _socketConnection = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
}