I hope the forum moderator doesn't think I'm illegally bumping this thread but it should be sticky (at least temporarily) or maybe on the 'Tips & Tricks' section. I'm not being able to connect to the Internet (with Knoppix) ever since I routed my modem so I'll find out my address, netmask and gateway and have a try.

Hi, johnmd. At first I couldn't connect also, even the default connection apparently having the right settings. The trick is to restart it (only it can't be done through Network Manager).
Code:
# /etc/init.d/networking restart