....but not others. I have a mixed-mode Windows 2000 domain. Mix of

Windows 2000, XP Pro and Linux clients.

I installed an IPCop firewall, v1.4.10 and added the 'AdvanceProxy' add-on.

This add-on permits authenticating against the squid cache with MSNT.
From a client PC (XP Pro SP2 in this case):

tail /var/log/squid/access.log
1134854425.531 16 TCP_DENIED/407 1686 GET
http://www.microsoft.com/isapi/redir.dll? - NONE/- text/html
1134855902.508 462 TCP_DENIED/407 1752 GET
http://www.microsoft.com/isapi/redir.dll? - NONE/- text/html

but when I give my credentials, MyDomain\steven and a password I get
right in:

1134855903.628 1118 TCP_MISS/302 529 GET
http://www.microsoft.com/isapi/redir.dll? MyDomain\steven
DIRECT/ text/html

I can't find anything to 'turn-up' in order to watch what is going on
with my box, with this user.

I am pretty sure it is the user account that is giving me fits as she is
unable to authenticate from any workstation. I created a new account
but the new account suffers the same result.