In general cable users don't have to do anything special, but your ISP may vary. The real question is "Do you use a cable/dsl router?" I would never run a high speed Internet connection without one. These things are dirt cheap now, and extremely usefil. In addition to forming the basis of a local network, they provide an important hardware firewall. And they do what you are most concerned about, they take care of all the connection issues to the ISP for you, and hand out network setup information to a local system by DHCP. You boot the Knoppix CD, you are on the Internet. It's really that simple.

I paid over $100 for my first one and still got a good deal. Now I see both wired and wireless ones often for $10 or less after rebate. There is a 802.11b wireless (with 4 wired ports also) Linksys model that has been offeded for less than $10 after rebate at many stores in recent weeks, and there is even an 802.11g (faster local networking, although 802.11b is likely faster than your cable connection) wireless router at CompUSA this week for $5 after rebate. There is simply no reason to run without one.

And one should always insist on an Ethernet based modem, the USB stuff is crap. You will get what you want if you insist.