Windows authentication through a reverse proxy problem

Have a IIS Reverse proxy redirect on speci开发者_开发百科fic request on WebSite with windows authentication and impersonation to another local site with win.auth + impersonation.

Reverse proxy and the web application placed on a different machines and iis versions (proxy- IIS 7.5 , webApp IIS6) and the same domain.

Requests through the reverse proxy does not allow the user to be authenticated on the remote server. has an infinite authentication request.

This is inherent to the way windows authentication (NTLM) works: the password is never sent, authentication is done with a salted hash of the password, so the first server can authenticate the user but cannot re-use those credentials to impersonate the same user on a remote server (since without the password it cannot authenticate).
Look at this blog post to get more information about this problem (which is known as "double-hop problem").