Network manager cannot connect to a wifi, if the wifi is password protected (WEP or WPA). However it can connect to passwordless wifis. Also, I can conned to password protected wifis manually as:

sudo service network-manager stop

sudo iwconfig eth1 essid "<WIFI-NAME>" key s:<WIFI-PASSPHRASE>

sudo dhclient eth1

But it would be nice to get the network manager working again. Any suggestions where to look for the cause of this problem?

The network manager does see the wifi, but then it just keeps forever trying to connect, never succesfully. I also tried installing an alternative manager, wicd, and it has the same problem, looks like it gets stuck to trying to get IP, never succeeds.

After update to 12.04 and trying several desktop environments (finally settling to xfce), I removed KDE, Gnome3 and Ubuntu desktop following these advice:

• http://www.psychocats.net/ubuntu/pureubuntu


• Remove Gnome Shell completely after installing it?


• http://ubuntublog.org/how-to-remove-unity-desktop-in-ubuntu-12-04.htm

Maybe those removed some (maybe dhcp-related) component, that is causing my problem, but this is just a guess.

EDIT: As I said, I also tried with WICD, and it gets stuck in exactly same way.