Static IP address under Ubuntu 11.10

Ubuntu 11.10 has changed the network startup process. The old way of configuring network settings in /etc/network/interfaces and /etc/resolv.conf do not work anymore. The new startup will rewrite the /etc/resolve.conf by erasing your name servers. Making no connectivity to outside world.

Looks like there are no other directives or configurations which instruct the new startup not to modify the /etc/resolv.conf. So the choice is to either use the new configuration or uninstall the Network Manager and use the old style configurations.

Using Network Manager Applet

Settings->Network->Your-Network-Connection->Configure->IPV4 Settings will bring up the following dialog. The static IP address and the rest of the configuration parameters can be specified here, including the gateway and DNS server.

Or manually modify the new Network Manager configuration file instead of using the GUI

The Network Manager saves the configuration in the file /etc/NetworkManager/system-connections directory. Open th the file using sudo permissions to edit it.

As you can see the [ipv4] section has the information provided in the GUI.

Uninstall Network Manager and use old style configuration

sudo apt-get remove network-manager network-manager-gnome

Change the /etc/resolv.conf to add the nameserver.

nameserver 192.168.72.2

Change the /etc/network/interfaces to add the static IP configuration

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
address 192.168.72.131
netmask 255.255.255.0
gateway 192.168.72.2

Then Restart the networking.