400 Bad Request - Intranet Sites - v4

I recently update to version 4 on a test machine and every since then I am getting a “400 Bad Request” error when connecting to certain intranet sites, on two different servers. On one server there are several sites, but the only one that has issues is the one with “Integrated Windows authentication” enabled. “Integrated Windows authentication” is also enabled for the website on the second server. Everything worked fine on version 3, what between version 3 and 4 is causing this error to occur and what is the fix?

 

Try setting up an exclusion for the URLs in the HTTP module.

 

I have added *servername* to the exclusion list and I can connect to the site, but after some time has passed clicking a link on the site I get the “400 Bad request” error again.

 

I had a similar problem but found that it was caused by firefox V3.09.
Firefox quickly released V3.10 and problem disappeared.