Pass credentials along to new WebRequest

Question

I am making a page in SharePoint that is used to proxy other content in SharePoint. The user is authenticated at the time they hit this proxy page, but I am getting an Unauthorized Access error.

The page has the following code behind:

var request = (HttpWebRequest) WebRequest.Create(urlToProxy);
request.Method = "GET";
request.Credentials = CredentialCache.DefaultNetworkCredentials; //This isn't working, apparently
var response = (HttpWebResponse) request.GetResponse();

My first thought was to use the credentials from the incoming WebRequest, but this is an HttpRequest and doesn't seem to have the Credentials property.

Does anyone know how I can pass the user's existing logged in credentials to this outgoing HttpWebRequest?

Answer 1

It sounds like you are facing the infamous double-hop issue. In a nutshell, with NTLM you are authenticated to the server, but your credentials cannot be used by the server to access other servers.

Here is a good MSDN blog post explaining it: http://blogs.msdn.com/b/besidethepoint/archive/2010/05/09/double-hop-authentication-why-ntlm-fails-and-kerberos-works.aspx

Basically you either have to use a service account (one you can access the credentials for in your code, storing them in the web.config or in the Secure Store Service) or use a different authentication method that lets you pass the credentials (i.e. kerberos).