Vista - Disable connect to a network dialog

Hello,

I have windows server 2008 installed on a pc witch i use exclusively to develop a website on localhost and it may be strange but i don't need an internet connection, actually it keeps me working rather then navigating on the internet.

And it kills me a diolog everytime i open firefox asking a connection to the internet. And it keep popping up. I actualy have an internet connection(PPPoE) that is workin but when i'm developing my website i want to disable the internet connection... but i didn't find a way to do that...

Putting firefox offline does not work, i can't navigate not even in localhost. Setting up a fake internet connection is not working either, it shows me a dialog that i have a problem with my network connection.

I know this is a vista forum but from what i know the network connection is the same in windows vista and windows server 2008.

Thanks.