Cable Modems and High-Speed DSL


For the most part, if you installed your Linux system with the cable modem connected, this is probably already working, and you have nothing left to do. If, however, you are already up and running and you are just now getting a cable modem, it is probably time for a few pointers. Quite frankly, these days (with a modern Linux distribution), there isn't much to it.

To begin with, cable modems aren't modems in the classic sense. The so-called modem is connected to your cable TV service on one side and to an Ethernet card inside your PC on the other. High-speed access through your phone company's DSL service is similar in that they provide you with an external, modem-like device (in many cases, it is really a router) that also connects to an Ethernet card.

The Ethernet card (which should be automatically detected by your system) gets an IP address from the cable modem via the Dynamic Host Configuration Protocol (DHCP). Although this address may appear permanent in that it rarely (if ever) changes, it is nevertheless dynamic, because your actual Ethernet card gets its address whenever it connects.

The process of getting your system configured varies a bit from distribution to distribution, but only cosmetically. When you install your new Ethernet card (for access through the cable modem), it should be autodetected by the system on reboot. As part of that process, the system asks you whether you want to configure the card. The answer is yes, of course. Next, the system asks whether you want to supply an IP address or have it autoconfigure via DHCP. With a cable modem, as with DSL, autoconfiguring is what you want.

Now that I've told you how incredibly easy it is to do this, I'm going to mention that there are many different providers of high-speed cable and DSL access. This means that if your system doesn't autorecognize and configure your connection, you may need to do one of these things. For cable modems, the answers vary, but start by checking out the Cable Modem HOWTO at http://www.tldp.org for details on your particular geographic location.

If you are on a phone company DSL service, you want to use the pppoeconf package (already installed as part of your Ubuntu setup). Open a shell (Terminal) and run the command with administrator permissions. Do this by typing this command:

sudo pppoeconf

This is a text-only utility and basically a fill-in-the-blanks session. The first screen checks for your Ethernet card and asks you to confirm its location. Because most people only have one Ethernet card, this is usually a fairly simple choice to make. You want to make sure that your DSL modem is plugged in and turned on because the next screen scans for the existence of your DSL modem to continue with setup. Then, you are asked for the username and password provided by your Internet service provider for this connection.

The last step in this configuration dialog is a question about whether you want the connection to come up automatically. This is generally a good idea. After you have completed this setup, you likely don't need to run this utility again (unless you switch ISPs, of course).




Moving to Ubuntu Linux
Moving to Ubuntu Linux
ISBN: 032142722X
EAN: 2147483647
Year: 2004
Pages: 201

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