I have been having a very rough time getting re-aquainted with Linux. After installing Debian 3.0, I found that my sound card wouldn't work. Rebuilding the kernel solved that problem just fine, but it broke my DSL network connection.
My assumption was that rebuilding the network driver (8139too) caused the problem even though dmesg reported that the same driver version was being loaded.
After many days of searching, I began to suspect DHCP because my ifconfig output had no "inet addr" field. Is this a good conclusion?
Anyway, an anonymous poster at http://www.debianhelp.org
said that it is necessary to enable "Packet Socket" and "Socket Filtering" in xconfig to get DHCP to work.
I had "Socket Filtering" off because the [HELP] button recommended it to be off. (I know, I know, "Do you do everything that HELP tells you to do?").
By the way, PPP was not needed even though my DSL hub mentions PPPoE.
The sound and network are now cohabitating with the penguin.