[squid-users] Can't authenticate on a site going through Squid

Hello.

I'm having a weird problem: I can authenticate to the site:

http://olapserver.viatecla.pt/esvcontact/pga/

when connecting directly (using IE or Mozilla), but not going through Squid.

I can't give the username / password pair here, but the username is like
this: "Something\Somethingelse". Looks like a Windows domain user.

The web server (IIS, I believe)'s error message (after failing to
authenticate several times) includes:

    HTTP Error 401.1 - Unauthorized: Access is denied due to invalid
    credentials.
    Internet Information Services (IIS)

Oddly enough, if I access using Links *without* going through squid, I
have the same problem.

I'm not saying that this is a Squid bug - I'm guessing it's some kind of
authentication which doesn't work through a proxy, or some problem with
that site. But I'd like to know if anyone has seen something like this
before. I can give more information if neccessary (though I can't give
the username/password pair, as it belongs to the colleague who reported
this).

Thanks,

-- 
Pedro Timóteo <patimoteo@dti.pga.aero>
Systems Management & Internetworking Specialist
DTI - ext. 5682
PGA - Portugália Airlines