title: Custom NTLM authentication with HttpWebRequest
body: <p>I need to authenticate to a server which exposes a custom NTLM-based authentication scheme, using the standard HttpWebRequest object.
  It's pretty much basic NTLM except that during the NTLM handshake protocol I receive a cookie from the server which I must send back during the handshake, otherwise the authentication will fail.</p>
  
  <p>My question is: how do I hook into the HttpWebRequest's handshake protocol so that I can add the cookies in the header, during the handshake?</p>