Windows XP client machines running IE7 in a domain behind an ISA Server 2004 on Win2k3. The ISA Firewall Client is installed on all clients. Machines are managed via group policy. IE7 is configured to use the ISA server as a proxy. Using NOD32 antivirus on the clients with all network protection disabled. Windows firewall is enabled on all clients using default settings.
There are a couple of sites that users have trouble connecting to. They are both service portals, but from two different companies. One is used to manage healthcare benefits, the other 401k benefits. Connections use SSL on the standard port.
What happens is that the sites will not completely load. Only some of the resources (images, etc) will come down, and then IE sits there waiting. Clicking on any link then results in "Internet Explorer cannot display this web page"...the standard connection error page. When this happens at one of the sites, other tabs in the same browser instance start producing the same error message, even though they are open to completely different websites. At this point IE7 has to be restarted (it doesn't crash, it just won't load anything).
I've tried adding the sites to IE7's trusted zone, have excluded them from ISA server's cache, and even tried bypassing the proxy.
Here's what's interesting: the sites have always worked fine in Firefox without any special configuration on the client or the ISA server.
I'm not sure what to look into next?
Update:
I've tried disabling the ISA HTTP cache completely. Nothing. I tried Firefox configured with and without the proxy. Works either way.
It seems to get stuck on the Phishing Filter...or the Phishing Filter just happens to be running when it gets stuck. This is enabled via GPO so I haven't had time to experiment more with it.
Update 2:
I upgraded to IE8. This time it doesn't get stuck on the Phishing Filter, of course, but the problem looks the same. It just sits there saying it's waiting for X more items to load. At this point the entire browser has to be restarted because no pages will load.