How do I connect xbox to internet through router?

I have bought a second hand xbox and ethernet cable. I have Virgin broadband through a router, and currently my laptop is connected to it via USB cable. We have plugged in the ethernet cable to xbox and router, but when it starts trying to connect, it says there's an error with the IP address? Help!How do I connect xbox to internet through router?
First thing you want to do is go into your dash to network settings and set everything to auto configure. Then shut off your box. (assuming your still plugged in to the router) Turn off the router and wait a few minutes. Turn it back on. Turn on your xbox. Then go in to network and test connection. It should go right through at this point. If it doesn't then you will need to open your gaming ports on the router. First call microsoft(18004myxbox) once you get a live person ask them what ports you have to open on your router(they will ask you which kind you have) then they will tell you. Next you have to call customer service for the router and tell them what you need to do. they will walk you through it(it's pretty easy to do right from your comp) then just reset your xbox and you should be good. It can be kinda a pain but I had to do it to mine and it works great now.How do I connect xbox to internet through router?
what sort of router? and it should work. probably you need to open the port. email me for help or preferably you should post this message on the xbox forum or contact xbox