(cross-post added to ISA Clients)
"Jim in Cleveland" <JiminCleveland@discussions.microsoft.com> wrote in message
>I work for a Public Library that provides the Public with computers to access
> the Internet. We are running Windows XP and using IE7. Our firewall
> solution is Microsoft's ISA 2004. Some of our patrons are college students
> who gain access to online material thru "blackboard software". When a lot of
> them try to access their college's Blackboard site using IE7, they get a "502
> proxy error msg". This only happens when using IE.
> If they use Firefox,
> they do not get this error and they are able to get to the web site. At
> first I thought it was a ISA setting but if that were the case, I would
> assume that Firefox would get the same error msg.
I suspect the proxy server is issuing the error message.
So, the question is: why?
Looks like you need to get a more precise symptom description.
E.g. ask your users to see if there is more detail than just HTTP 502
The following search produces several possibilities if you just want
to keep guessing:
(Live Search for
client http 502 ISA 2004 site:support.microsoft.com
- 19 hits
I had to add the words client and 2004 to cut my first search results
down to a more practical number, so you could probably also get more
ideas by using a less specific search but that will mean more reading
for you. ; )
> If I go to IE >>Tools >> Internet Options >> Connections >> LAN settings and
> uncheck Auto detect settings, Use auto config script and Proxy server
> setting, IE will gain access to the Blackboard site. We've tried unchecking
> these settings in the past and have had trouble getting out to the Internet.
> Sometimes these settings work, sometimes they don't.
That's entirely dependent on what the proxy server does with
the resulting protocol changes.
> Is there anything else
> within IE 7 settings that I can set or unset that will help alleviate this
> 502 Proxy error msg and allow access to blackboard sites?
If you don't get any better clues by getting more details from the error
message or by checking on the server side for why it is being issued,
I suggest getting TCP packet traces of all your cases and comparing them
to understand what is happening in each. E.g. on the client side you could
use netcap for capture and Ethereal (aka WireShark) for procol analysis.