I upgraded to Ubuntu 12.10 using update manager. After the upgrade, the wifi gets connected but would not display any webpages. If I ping 184.108.40.206 or google.com, there is response.
I managed to fix this problem by using the command
sudo dhclient wlan0. But, now the problem is that every time I switch wireless networks, I have to give that command. how do I make this permanent?