Hi
I flashed my phone with the latest CM 9.1.
After some time my phone did not get any IP-Address via dhcp.
Static IP’s were working. So it should be the dhcp-client I thought.
Googled for the problem:
http://code.google.com/p/freexperia/issues/detail?id=778
* switch off WiFi android:/ $ su android:/ $ rm data/misc/dhcp/* * switch on WiFi
WiFi is working again :-)
Have fun!