It shouldn't need any configuration other than to ensure it's set to connect via ethernet. I'm not in front of my Mac at the moment but from memory, open Sytem Preferences, then click Network, and look for the connect via option.
Provided this is done it should happily talk to your Cable Modem without any further ado. Just make sure you're using the ethernet cable and not trying to use USB.
If Lew is still online he may be able to give further details, otherwise I'll check mine when I get home and post back if I got it wrong.
to the forum.