Cisco Router interface configuration commands

If you are not familiar with basics of cisco routers, click the following links to learn more.

How to view the summary of the router interfaces

To view the summary of the router interfaces, run the IOS command "show ip interface brief" from privileged mode.

omnisecu.com.router01#show ip interface brief
Interface IP-Address OK? Method Status Protocol

FastEthernet0/0 172.16.0.1 YES manual up up

FastEthernet0/1 unassigned YES unset administratively down down

Serial0/0 172.17.0.1 YES manual up up

Serial0/1 unassigned YES unset administratively down down

How to open interface configuration mode

To open interface configuration mode, type "interface interface_name" from global configuration mode.

omnisecu.com.router01(config)#interface fa0/0
omnisecu.com.router01(config-if)#

How o assign an IP address to a router interface

To assign an IP address to an interface run the following command from interface configuration mode.

omnisecu.com.router01(config-if)#ip address 172.16.0.1 255.255.0.0

You have to enter both IP address and subnet mask.

How to add a description to router interface

To add a description to router interface, run the following command from router interface configuration mode.

omnisecu.com.router01(config-if)#description Main Building LAN

The configured description can be viewed in the output of the "show interfaces" command.

How to disable a router interface

To disable a router interface run "shutdown" IOS command from interface configuration mode.

omnisecu.com.router01(config-if)#shutdown

%LINK-5-CHANGED: Interface FastEthernet0/0, changed state to administratively down

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down

How to enable a router interface

To enable a router interface run "no shutdown" IOS command from interface configuration mode.

omnisecu.com.router01(config-if)#no shutdown

omnisecu.com.router01(config-if)#
%LINK-5-CHANGED: Interface FastEthernet0/0, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up