Sockets Authentication is failing using NegotiateStream

Question

I've got a Socket that is connected that I use to get HTTP header responses. If I skip authentication, everything works fine (unless the page requires authentication). But when I step into this code, it always throws an IOException on the AuthenticateAsClient line. The message is: of "Unable to read data from the transport connection: The connection was closed." I've tried both DefaultCredentials and DefaultNetworkCredentials.

Any ideas as to what I am missing? What is causing the connection to close?

thanks

if (Authenticate)
{

    NetworkStream clientStream = new NetworkStream(webSocket, false);
    NegotiateStream authStream = new NegotiateStream(clientStream);

    NetworkCredential netcred = CredentialCache.DefaultNetworkCredentials;


    try
    {
        authStream.AuthenticateAsClient(netcred,
            String.Empty,
            ProtectionLevel.None,
            TokenImpersonationLevel.Identification);

        if (!authStream.IsAuthenticated)
        {
            Console.WriteLine("Authentication failed");
            ErrorText = "Authentication using default credentials failed";
            return (HttpStatusCode)(-1);
        }
    }
    catch (Exception ex)
    {
        Console.WriteLine(ex.Message);
        ErrorText = ex.Message;
        return (HttpStatusCode)(-1);
    }
}

Answer 1

NegotiateStream doesn't perform HTTP authentication:

On Windows 95/98 systems, Windows NT LAN Manager (NTLM) is the protocol used for authentication. On other platforms the Kerberos protocol is used for authentication if both client and server support it; otherwise NTLM is used.

Have a look at the WebClient class which provides a Credentials and a ResponseHeaders property.