How to quickly remove interface configuration

Sometimes you need to remove all configuration lines on some interface to make a fresh start. Most of the people either go into interface mode and type a series of no commands or copy the whole chunk to text editor to add no in front of each line and paste it into console.

There is a quicker way to do this:

default interface interface_name

This command clears the interface configuration by restoring it to defaults (except for admin shutdown status).  Here is some interface which is configured:

R2#sh run int f2/1
Building configuration…

Current configuration : 87 bytes
!
interface FastEthernet2/1
ip address 1.2.0.0 255.0.0.0
duplex full
speed 100
end

Then we reset it to defaults:

R2(config)#default int f2/1
Building configuration…

Interface FastEthernet2/1 set to default configuration

The result:

R2#sh run int f2/1
Building configuration…

Current configuration : 73 bytes
!
interface FastEthernet2/1
no ip address
duplex auto
speed auto
end

As you can see, I used only one command to remote several configuration lines.