After a Kernel update the Ethernet network adapters were renamed, making an Internet connection no longer possible.
OS: openSUSE Linux 11.3 64bit
Kernel Version: 22.214.171.124-0.2
After determining the name of the Ethernet adapters with the ifconfig -a command (this requires root privileges), I ended up with eth0 (which did not have a valid Hardware Address, 00:00:...., eth1_renamed (which had a valid Hardware Address) and lo (the loopback adapter).
I went into the \etc\sysconfig\networks folder and deleted the profiles for eth0 and eth1_renamed (namely the files ifcfg-eth0 and ifcfg-eth1_renamed) and rebooted the system. After that I went into the network configuration and configured eth0 with the correct module (e1000, connected with the correct Hardware Address) and also eth1_renamed (xen_vnif module). eth1_renamed was not really needed, so I disabled it for booting at system start.
A quick check with ifconfig-a showed the correct adpaters with the correct Hardware Address and a ping confirmed the connection to the Internet.
Hope this will help someone else also.