The “default interface” command is used to return an interface to its default configuration; its implementation is in global configuration mode, and the interface to be modified is specified.
It is a handy command when it comes to deleting the current configuration of the interface; it prevents us from denying each of the commands that exist in the interface. The types of interface to be reset depend on the interfaces that each device has, this command can be used in switches, routers, firewalls, etc.
Its syntax is as follows:
default interface-type interface-number
- interface-type depends on each device, e.g. FastEthernet, GigabitEthernet, serial, loopback, atm, tunnel, etc.
- interface-number indicates the port number according to the slot or position, e.g. 1/0, 0/1, 3/22, 2/0, etc.
JMCristobalMX(config)#default interface fa0/9 Interface FastEthernet0/9 set to default configuration JMCristobalMX(config)#default interface serial 2/0 Interface Serial2/0 set to default configuration
Another example remove the current configuration of GigabitEthernet port 22; its configuration is as follows:
JMCristobalMX# sh run int g0/22 Building configuration... Current configuration : 189 bytes ! interface GigabitEthernet0/22 description "Switch Cisco 2960 - IDF" switchport trunk encapsulation dot1q switchport trunk allowed vlan 1,20,26-28,30 switchport mode trunk switchport nonegotiate speed 1000 duplex full storm-control broadcast level 10.00 storm-control multicast level 10.00 storm-control unicast level 40.00 no cdp enable end
To return the port to its default configuration is as follows:
JMCristobalMX(config)#default interface GigabitEthernet 0/22 Interface GigabitEthernet0/22 set to default configuration JMCristobalMX(config)#
We visualize the interface again from the running configuration file:
JMCristobal(config)#do show run int g0/22 Building configuration... Current configuration : 37 bytes ! interface GigabitEthernet0/22 end JMCristobalMX(config)#
As you can see, it is a handy command for port management on a switch or router and can also be used in conjunction with the “range” command to modify a range or several ports at once, for example:
JMCristobalMX(config)# default interface range GigabitEthernet 0/5 - 12
I hope this article has been helpful for you, best regards!