Dhclient
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=177846
This bug has kept my thinkpad at home off the net for a couple of days.
I had to boot a Live-CD. Mount my hard drive in write mode. chroot, run aptitude and install pump.
pump -i iface
Gets you back into action.
I have been a fool. The reason why my network was not working, is that my wireless and ethernet interface swapped around. I am such a moron.