home network question

I have a home network with a linux box hooked up to a DSL connection and 2 other machines with windows. The internal network is connected through a hub. So when I surf the web or do anything involving the internet on my windows machine, it has to go through the linux box.

I have no problems getting to the mma.tv website this way through my windows boxes on the internal network. However, my linux box with the direct connection can't. It can get to other websites, but with mma.tv the browser says it can't find the site. This isn't a particularly urgent issue since I usually websurf in windows, but it vexes me 'cause I can't figure out what's broken.