You're using knoppix? I didn't even know that existed in BackTrack?
I would like to know, is it a dialup-modem you're using? Or is it cable-modem?
Or is it the most used, adsl-modem? Or is it neither of these?
With non-dialup modems BackTrack should make you able to automatic connect
to the internet, if you're using an usb-cable then pull that out and use a real cable!
After that if you still can't access the internet, make sure you have your external
interface up by writing ifconfig. In most cases when speaking non-wifi it would be eth0.
(i think as i haven't seen anything else so far).
For example if your internet device is eth0 and to bring it up i would write:
(very simple, and very good)Code:ifconfig eth0 up
If it's up write
(i am of course just assuming you get an ip normally by dhcp.)Code:dhcpcd eth0
If you are on a lan network, then you might have to specify the ip
yourself. I haven't come out for this yet, but to do this i would either
use the GUI form which is located in your 'home' directory or you could
try do it in console. (i've forgotten that command as i'm used to use dchp though)
But one thing i DO happen to know is there's probably more info here
on these forums if you use the search button, or you could try the BackTrack Wiki.
If not then you could try go to offensive-security.com and try look at some of their
vids. I do happen to know that there is a vid about general commands in BackTrack2
That's my 2 cents.