Ethernet quit working after installing Lion

Question

I had a clean install of Lion and everything seemed to be working well. All of a sudden, after three days, my ethernet connection quit working. I can continue to connect through my Airport. I tried another computer on my wired network and it worked fine so I know the network is not at fault. Connecting the ethernet cable causes me to lose my connection even with Airport on. Any ideas?

Answer 1

Just got a call from the Apple Service rep. His solution worked-no idea why, but he said the problem was in some sort of "confusion" caused by the Location identification for the ethernet connection after the upgrade to Lion. Steps to fix the problem:
- Open System Preferences-Network
- Turn off Wi-Fi
- Select Ethernet and delete the connection (hit the - button at the bottom left)
- Hit the + button to establish a new connection. Select Ethernet in the dropdown next to Interface. Hit Create
- Select the Assist me... button at bottom, and then press the Assistant... button on the popup
- An Introduction screen appears which has a box with a Location designated for the new connection
- Hit Continue
- Select the appropriate modem being used to connect to the internet and hit Continue
- Hit Continue on the next screen
- Do not fill in any of the information on the screen that appears. Hit the Go Back button and then close out the Network Setup Assistant. Apparently, by going this far, you've established a new Location so no need to complete the setup if you've had an internet connection which was working.
At this point you're back on the Network Preferences screen, and my Ethernet connection reflected that I was connected and had an IP address. When I opened Safari and Chrome, both opened correctly with my home page and all seemed back to normal. I'll repost if the connection does not hold.
I hope this helps others with this problem.