Assigning IP address to a Cisco Router

To assign an IP address to the Ethernet interface on ROUTER, you will need to type the following
Commands (excluding what appears before > or #—those are the prompts):

ROUTER> enable
ROUTER# configure terminal
ROUTER(config)# interface ethernet0
ROUTER(config-if)# ip address 192.168.1.1 255.255.255.0
ROUTER(config-if)# no shutdown

Let’s take a look at what each of these commands do. The first command, enable, is used to move from user exec mode of the router to privilege exec mode. In user exec mode you are unable to make changes, so you had to go to privilege exec mode. In order to change the settings of the Ethernet interface, you need to go to the interface prompt, which is in global configuration, where most changes are made. To move to global configuration, you typed configure terminal, and to move to the interface prompt, you typed interface ethernet0. Ethernet0 is the first Ethernet interface on the router; the second Ethernet interface would be Ethernet1 (if you had a second Ethernet interface).

Once at the Ethernet interface prompt, you then assigned the IP address with the ip address command. The last command, no shutdown, is used to enable the interface. To disable the interface at any time, you could use the shutdown command. To assign the IP address to the Serial 0 port on ROUTER, you would type the following commands:

ROUTER> enable
ROUTER# configure terminal
ROUTER(config)# interface serial0
ROUTER(config-if)# ip address 192.168.2.1 255.255.255.0
ROUTER(config-if)# no shutdown