I believe I'm having similar DNS/Routing issues from PlusNet at the moment because I have problems in accessing certain sites using Firefox, such as assessing Amazon.co.uk;
"Firefox can't find the server at www.amazon.co.uk"
while assessing other sites such as MSN, Thinkbroadband.com etc are O.K
It appeared to affect me this Thursday morning after I have had the MS updates for my Windows 7,
When will Plusnet, if that is the rooting cause, to fix all these????
Intel E4300 OC with 2GB RAMs,Speedtouch 585 Modem/Router and Windows 7 Pro !
Current ISP: Plusnet FTTC