Recently I have started seeing a strange behavior with my notebook which runs opensuse 12.1
The internet became extremely slow, though it seemed to have an IP Address etc obtained through DHCP. The internet was fine before that I have not made any major changes like OS installation etc. The internet seemed to be fine when accessed from the Windows boot. At work there was no internet connection at all.
I saw a few posts about ipv6, etc. However the internet was working fine earlier on. This led me to compare the processes running on the notebook with those on my desktop where the internet access is fine.
I saw that dhcpcd was not running on the notebook and once I had that up and running the Internet was blazing fast again 
It will be interesting to find out why the dhcpcd stopped running in the first place, is there any way to identify why this stopped running.
Hope this helps.