Cisco IOS Tip Number 1

If you configure interfaces on a Cisco router and then you decide you want to configure it with something else, you may have to remove some of the old configuration and then re-configure the interface with the new information. If the old configuration comprised quite a number of commands then the task could take a little while, overwriting some and negating some with the NO prefix. What if you could turn the interface back to its default settings? Well you can!!

To turn an IOS-based Cisco Router or Switch interface back to its default settings just use the following command in Global Configuration Mode:

default interface [interface type/number]

For example, if you wanted to set interface Serial 0/0 back to defaults then just type:

router(config)#default interface Serial 0/0

Building configuration…

Interface Serial0/0 set to default configuration

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To confirm, enter the show running-config command, or show run for short.

Scroll down to the Serial 0/0 interface and you should see something like this example:

interface Serial0/0
no ip address
no ip directed-broadcast
no ip mroute-cache
shutdown
no fair-queue

 Then you can configure the new parameters without the possibility of leaving old configuration commands in place.