Assign IP address to an interface

Router>enable
Password:
Router#config terminal
Router(config)#

Untuk Fast Ethernet 0

Router(config)#interface Fast 0
Router(config-if)#ip address 192.168.1.1 255.255.255.0

Untuk Serial 0

Router(config)#interface Serial 0
Router(config-if)#ip address 10.11.12.1 255.255.255.252

Beres Deh. tinggal kopi ke startup

Router(config-if)#Ctrl-Z
Router#copy running start

Source:
http://unilanet.unila.ac.id/~gigih/index.php?option=com_content&task=blogcategory&
id=24&Itemid=40