By default Ubuntu uses DHCP and Gnome NetworkManger to configure interfaces. This is not optimal in many cases.
How to configure a desktop machine for a static IP address that applies to all users?
Additional background: For 99.9% of users a static DHCP entry is probably the easiest solution, however I have found a conflict with mythtv-background
process and any changes to the eth0 interface. If the interface is brought up/down after mythtv is running, it hangs the process (which also broke system suspend). So my questions really needs a static IP address, where the interface is brought up with a known IP, and stays up permanently.
Best Answer
Right click nm, choose Edit connections... find your interface, click Edit..., click IPv4 Settings, choose Manual and configure your interface.
An alternative would be to edit /etc/network/interfaces. an example configuration would be:
then run
Keep in mind that this will deactivate nm for this interface and you will have to delete (or uncomment) the entries to activate nm again.
Edit (see Casey's post): You also have to set a DNS after editing /etc/network/interfaces: