How to assign a static IP address in Ubuntu
Setting a static IP address in Ubuntu involves editing /etc/network/interfaces. If the interface is currently using DHCP, you will find these lines in the file.
auto lan
iface lan inet dhcp
You will have to replace the above lines with a section that looks like:
auto lan
iface lan inet static
address 192.168.1.80
netmask 255.255.255.0
network 192.168.1.0
broadcast 192.168.1.255
gateway 192.168.1.200
dns-nameservers 8.8.8.8
Make the changes effective by either rebooting or by issuing this command:
sudo /etc/init.d/networking restart