Ask Klaus!



I am hoping you can help me. I am writing this under Windows (ugh ) because whichever version of Linux I try I cannot get on the Internet or receive email. I was on Linux for about a year using SUSE, Xandros, or Mandrake 9, but one day all connectivity ceased.

Both my computers are AMD. I was using a D-LINK ASDL modem router DSL-504T and an Ethernet card. The machine detects the card , but I cannot call to configure, or the programs can't reach home to finish updates.

Both computers use Firefox and Thunderbird, the same as Windows, using the same asdl modem. As I said, all was working well and suddenly stopped. D-Link is advertised as Linux compatible. I am not a power user – just an old guy who rebels against Microsoft.


You don't need to be an expert or a rebel to use Linux, but you are right about the fact that free software is a way out of dependencies. By the way, I'm unfortunately living in a DSL-free zone, and I am waiting for bandwidth. Anyway, let's try to free your DSL modem.

There are two ways to configure the DSL modem, the easier of which is router mode. The default is probably modem/pppoe mode.

In router mode, all you need to do is send a DHCP request from the network card for a complete autoconfiguration. In modem mode, you need to configure authentication credentials on your computer, which can be done by using the program pppoeconf (or whatever tool is provided by your distribution).

To configure the modem for one or the other mode, you first need to reach it from the computer. If your modem's fixed address is, your network card must be configured as a member of the same network in order for you to connect to the modem. Usually, the modem is set up to deliver an appropriate local IP address to the connected network card when the card sends a DHCP broadcast, but this may depend on the modem's preset configuration.

If your network card is eth0, you would set an IP address for the card either via a graphical configuration front end of your Linux distribution – use DHCP with pump -i eth0 or dhclient eth0 – or set a static address by typing (as root)

ifconfig eth0 netmask broadcast

and add a gateway route through the modem with

route add default gw

which should, as soon as the modem is functional as a router, allow network traffic to and from the Internet.

One last thing you need, in case DHCP did not set a name server, is the line nameserver in the file /etc/resolv.conf. This tells Linux to use the modem as a name server for resolving computer names (such as into IP addresses (which is what every network connection needs).

After having configured your local network this way, you should be able to reach the modem with any browser by entering as a website address. If the modem is already set to router mode, then you'll already have immediate Internet access.

At each step, you can check to see whether the modem is reachable from the configured network card with the command:

(Control-C to quit)

I think that the only thing missing in your DSL configuration was the local IP address of the network card, which can be handled with either DHCP or a static setting.

Also, be aware that in rare cases, some DSL routers/modems only accept network cards when they have been plugged in prior to switching on the modem. However, this should not affect the DSL-504T.

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