Lost eth0 after apt-get upgrade

[Gralfus]

I installed Knoppix 3.7 to my hard drive. All was well, but then I decided to use apt-get to upgrade stuff. Now my eth0 lights up, but is not recognized as a device. There is no entry in /dev for eth0 (I assume there should be). Trying to give eth0 an address, or bring it up using ifconfig yields:

SIOCSIFADDR: No such device
eth0: Error while getting interface flags: No such device

Doing ifconfig only shows the loopback. My /etc/network/interfaces reads as
follows:

auto lo
iface lo inet loopback

The /var/log/messages file has nothing of interest.

During boot, there is something about eth0 being redirected to /dev/null, but I'm not sure why. During the upgrade process it did ask to shut down the PCMCIA service and didn't bring it back up afterwards. The NIC lit up after reboot, so I thought it was fine, but then found otherwise.

I could just nuke it all and start over, but where's the fun in that? Where can I troubleshoot to find out the cause of why this isn't working. I'm somewhat new to linux, but not a complete newbie.

Hardware:
HP Omnibook 4100 laptop
3Com card-style network adapter
6gig hard drive

[CrashedAgain]

This must be a Knoppix style install, right. I had this happen also. (see this post: http://www.knoppix.net/forum/viewtopic.php?t=14325)
The boot sequence is /etc/init.d/knoppix-autoconfig which starts everything then /etc/init.d/knoppix-hd-config shuts down then attempts to restart eth0 but is unable to. I have no idea why. I edited /etc/init.d/knoppix-hd-config commenting out the eth0 shutdown/restart bit & it worked.

[Durand Hicks]

Most likely it would have something to do with the pcmcia-cs package being replaced. I assume you replaced it with the developer's version instead of keeping the custom one as configured by knoppix.
You can partially restore the old version by looking in the /etc/pcmcia directory and look for a file with a dpkg-old extension. Copy the new version to pcmcia.dpkg-new and copy the old version back to pcmcia.
You'll need to restart the pcmcia service to reinitialize the pcmcia slot(s).

HTH,

Durand

[Gralfus]

I looked in the /etc/pcmcia folder and didn't find any old packages. I also couldn't find the file that "CrashedAgain" referenced. This one stumped me but good.
I finally gave in last night and reinstalled. Everything is working fine, so I will make a note of the pertinent config files, just to make sure I have them right next time.

I still see the redirection to /dev/null during boot, but networking is working fine, so I evidently have much to learn about this OS.