While using Debian based systems(like Ubuntu), I often found that network manager just got into the way whenever I wanted to fix an internet connection. So, first thing to do is to kill the associated processes (
kill -9) after you find the process ID by using
ps. Or you can totally get rid of these packages (usually network-manager,
network-manager-gnome in GNOME or
knetworkmanager in KDE).
Then, edit
/etc/network/interfaces file.
$ sudo vi /etc/network/interface
auto eth0
iface eth0 inet dhcp
again assuming that we want to have a DHCP based connection.
Then restart the network connection by issuing the following command:
$ sudo /etc/init.d/networking restart
