Strange one this; this has only just started happening and everyone swears blind that nothing has changed ..
I have a GPO that sets proxy avoidance lists...alwaqys worked never a problem. Just recently one specific internal site just wont work unless I clear the list ... if I put all the external sites back in everything else works but this one internal site doesnt .. I have found a ISA error that states (I have a test box that I filetered on the ISA logs) "12209 the ISA server requires authorization to fulfill the request. access to the web proxy fileter is denied" and am wondering if this is to do with it...and the issue isnt the avoidnace list but the ISA server (the ISA server is only internal NOT used on permieter, has only 1 NIC)
I cant work out why the avoidnace list has anything to do with an internal site but this internal site seems to not like anythiung in the avoidance list...as i said i take all the exceptions out force the GPupdate and voila this internal site works again !!! ... I have plenty of other internal sites that work...its just one !!