Bug in IE 5.5 WPAD mechanism? - was Re: IE 5.5 doesn't work?

On Wed, 19 Jul 2000, David Minor wrote:

> What I see is that when the browser starts up it says "Detecting Proxy
> Settings" for a long time, and then starts up OK. However, when you
> hit a URL that is supposed to prompt you for username and password,
> it doesn't. Usually when I have seen this behavior it's because the
> browser hasn't grabbed the cache.pac file correctly, so it doesn't know
> that it's supposed to do something at the appropriate times.

We've been seeing this with certain version of IE 5 too (not just
5.5). It seems to be a problem with the 'Automatically Detect Proxy
settings' option not working - however, I'm not sure why.

When I look at an effected machine here (usually W2K) - it does the DNS
lookup for wpad.<domain> and fetches the WPAD file correctly. However, it
then doesn't seem to use it - looking at the Squid logs, the browser never
asks Squid for the page, so I don't think it's a Squid issue.

You can solve it [at least in my experience] each time by doing Options ->
Connection -> LAN Settings -> OK -> OK - then it works.

The only correlation I've found so far is that the machines affected seem
to be those which have had Microsoft patch Q262509 applied (see
http://support.microsoft.com/support/kb/articles/Q262/5/09.ASP - the bit
about WPAD spoofing). This article says something about fixing a problem
with the 'third level domain' which we are (rdg.ac.uk).

I've tried fiddling around with the ways responses are returned, etc. but
it doesn't appear to work.

The problem [as always with MS problems] - is what avenues do we have to
explore this further - what exactly does this patch do (so can we
eliminate it)?

  - Bob

-- 
 Bob Franklin <r.c.franklin@reading.ac.uk>     Tel. +44 (0)118 931 8432
 Systems and Communications, IT Services, The University of Reading, UK