Cisco Router interface configuration commands

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