Yesterday I installed Ubuntu 8.10 (Intrepid Ibex) on my Thinkpad R50e laptop. This time I decided to do a complete install rather than just an upgrade because I wanted to get rid of several years of accumulated cruft. I did remember to first back up the files I wanted to keep, though. I downloaded the .iso image file from here and following the instructions here, I burnt it to a CD. I then put the CD into the laptop and rebooted. The installation was pretty simple and quick (it took only about an hour or so, whereas I remember upgrades taking several hours). There is a good overview of the installation process here. However, when I booted up the new installation, the wired network connection was not working. I wasn't even able to ping the ADSL modem router.
A bit of googling (from my other computer) revealed that the problem was probably a bug in NetworkManager 0.7, which is a new package in Ubuntu 8.10. A work-around was recommended here. Following this work-around I first disabled NetworkManager from starting up by opening a terminal and entering:
sudo update-rc.d -f NetworkManager remove
I then rebooted the laptop.
Then I opened another terminal and opened the /etc/network/interfaces file in an editor:
sudo gedit /etc/network/interfaces
This file already contained the lines:
iface lo inet loopback
To the end of this file I added these lines:
iface eth0 inet dhcp
I then saved /etc/network/interfaces and exited the editor.
My /etc/resolv.conf file already contained the required line:
So I rebooted the laptop again and the network connection was working properly: I was able to ping the modem router and connect to the web.