Firefox not picking up the wpad auto config file

I've decided to setup firefox on the new Windows image but it turns out it doesn't like the options:

• Use system proxy settings
• this is the one I prefer as I can set it using group policy/workgroup manager
• Auto-detect proxy settings for this network

Whenever either of these are ticked you cannot browse the internet.

Had a quick search and think I've found the problem. The browser looks for the file:

http://wpad/wpad.dat

Now when I typed this in the address bar of; Safari, Internet Explorer and Google Chrome; they all downloaded the wpad.dat file. But Firefox was the odd one out as it just displayed the "Unable to connect" and "Problem loading page" errors.

Did a quick search and found this Knowledge Base Article describing how all other browser now use DHCP to help find this address, but Firefox only uses DNS. Also found it here in a blog and more importantly in Mozillas bug reports here (takes a while to load).

The fix apparently is to put a "DNS record for the WPAD server" (described here under 7.2.2)