Today I upgraded my Ubuntu to latest release 8.10 ( aka intrepid ) and suddenly my wifi network stopped getting ip via DHCP. Google told me about the bug in network-manager which could have done evil work with my laptop. But if you are using wpa_supplicant with your own configuration file then you are in luck.
Just add following lines in /etc/network/interfaces
auto wlan0
iface wlan0 inet dhcp
pre-up wpa_supplicant -iwlan0 -c /etc/wpa_supplicant/home_wpa.conf -d -f /var/log/wpa_supplicant.log -B
down killall wpa_supplicant
don’t pass -W parameter to wpa_supplicant or it will fail to get IP from dhcp.
Post about Ubuntu network-manager bug http://journal.dedasys.com/2008/11/13/ubuntu-intrepid-regression-beware-of-wireless-and-wpa
