Here is a situation which I have come across with Squid which may be a misunderstanding/abuse of Squid on my part or a bug. I have Squid 2.5 stable acting as a a reverse proxy for a zope instance. In Zope I have specified in the Vary tag as "Accept-Encoding, Cookie". Zope was setup to send a PURGE to Squid when it's content got changed. Zope normally sets a cookie for all browsers accessing it. It also by default sets a cookie when a user is authenticated. The Squid cache seems to work fine for Firefox and Konqueror clients. For IE we configured the HTTP header so that IE always requested URLs from Squid and to never touch it's own cache. However we saw some strange behaviour with IE <->Squid interaction when IE was the second browser to retrieve a recently PURGEd URL. We used 3 different browsers for : 1 authenticated to make changes(Firefox), and 2 to browse content anonymously (IE and Konqueror). When a URL is PURGEd and IE is the first to load it, then it gets the correct content. However if Konqueror loads it first, and IE is second then *Squid* returns the *old* content to IE. I can see this because using the Fiddler tool for IE I can see that the Content-Length is not correct. I can also see this by looking at the debug output from Squid and I can see the particular file in the disk cache which is returned. I hope that the above makes some sense. Now, is this a bug in Squid, or an abuse of the Vary tag by me ? Regards, CPH
