Bt Home hub and it looks like you cant change it from looking on the web..
Yeah you can, I'm at work so cannot find the exact link on this site for the homehub but it's on this site
http://www.unofficialguidetolive.co.uk/index.htm
Occasionally you have to reboot the router to open up the nat depending on your firmware and hub. Very occasionally mine goes to strict but I just refresh it and it goes back to open.