I'm a cisco network engineer in my professional life so IP stuff is very familiar to me...
Awesome. I'm working on getting my certification right now. I'm done with semesters 1+2, only one year to go!
Anyways, What is your network setup? I have always had a bunch of problems when running xbconnect. Have you had any luck when using kai? And when you're testing it online, are you using an original disc and booting from the MS bios/dash, or are you playing the games on the hard drive?