Here's my situation

I have both my PC and my xbox hooken up to a router, and the router is plugged into my schools network

If I plug my computer directly into the wall, I can access the internet
If I plug my xbox directly into the wall, I can play on system link with the other people on campus, but i can't surf the web.

Now, i'd like to play system link with the xbox and surf/download on my xbox at the same time. I can use/forward almost any port from 0 to 65535...

However, I'm wondering if this is actually possible, because i think the xbox won't search outside my router for games... is there any ports i need to forward?

If you're worried, a switch will do the exact same, however you should be just fine with a router, as it's really a router + built in switch. I have no problems at my campus