I recently installed SL6, replacing my older Ubuntu installation that had freezing issues, and noticed that I was unable to detect ethernet connections anymore. I still have full access to wireless connections, however these did vanish a few days ago and I was unable to connect to any networks until I reinstalled from the .iso file. I was switching from a 64bit to 32bit client anyways so this didn't bother me much, however I am wondering why I am still unable to detect an ethernet connection. I've checked the boards here and have found similar problems, but none exactly the same as mine and none of the workaround seems to fit my scenario.

To show where I'm at in the trouble shooting process, networkmanager is enabled in the System settings, and when I type ifconfig -a I do see 2 nic's, here is what I see:

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:10 errors:0 dropped:0 overruns:0 frame:0
TX packets:10 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:578 (578.0 b) TX bytes:578 (578.0 b)

wlan0 Link encap:Ethernet HWaddr 78:E4:00:60:7E:F3
inet addr:172.16.42.12 Bcast:172.16.42.255 Mask:255.255.255.0
inet6 addr: fe80::7ae4:ff:fe60:7ef3/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:32710 errors:0 dropped:0 overruns:0 frame:0
TX packets:21515 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:42777601 (40.7 MiB) TX bytes:3002124 (2.8 MiB)

When I click on Network Connections, with a working ethernet cable connected, I see no default connection under the Wired tab, and when adding an etho0 connection, with Automatically Connect enabled to this tab, none of the information regarding the MAC address and various other bits gets filled out by the automatic detection, as if the computer doesn't detect the ethernet port at all.

Furthermore, I can boot from an Ubuntu 10.04 livecd and still detect a working etho0 connection, so the port itself is not failing.

Still no progress, I realize I am most likely missing the driver for my wired connection on SL6, however I cannot figure out how to find out what driver I need and where to find and place it.

You're only seeing one physical interface. The loopback interface ("lo") is not associated with any hardware.

What does "lspci" list in SL6? What interfaces does "ifconfig" show when you are running from the Ubuntu live CD?

FYI, posting a reply to your initial question makes it less likely that you will get a response. "Zero Reply" threads get additional exposure and are automatically bumped to the top of the "New Posts" list for a while. Until the thread has seen at least one reply, it would be better to use the "Edit" button (at the bottom of the message) to add new information.

I'm at work at the moment but I'll boot the Ubuntu cd when I get home and post those results.