There are 10 systems with Windows XP connected via proxy under squid in my office. Now we thought of using Microsoft Exchange Server in all those systems. How to configure Microsoft Exchange Server under squid?
Squid & Exchange are not particularity related...
If you are using Outlook & connecting locally to Exchange, you will use MAPI and hence not hit Squid.
If you are using Outlook & connecting to a non local Exchange server using RPC over HTTP you will potentially use Squid - it normally works fine, if you have a specific error let us know. Alternatively since you won't get any benefits using Squid for Exchange connectivity you can avoid the issues and place an exception for you Exchange server in your proxy.pac file.
If you are using OWA (webmail) then you will use Squid and perhaps get a slight performance benefit from caching the OWA site, although since you connect by HTTPS I'm not sure of the top of my head if Squid will cache the images.
In conclusion using Squid specifically to connect to
microsoft exchange server will give you little or no benefit. That's not to say it won't benefit you in other ways.
Perhaps a bit more detail in your question will help us to answer it better.