I am doing a review of the configuration of all our Cisco equipment after taking over from my predecessor. I noticed in one of the routers has a loopback interface on it but I can’t account for the actual interface that corrects to the loopback interface in the configuration. Is this something that I can delete?
I am doing a review of the configuration of all our Cisco equipment after taking over from my predecessor. I noticed in one of the routers has a loopback interface on it but I can’t account for the actual interface that corrects to the loopback interface in the configuration. Is this something that I can delete?
— Via the Internet.
First, before deleting anything on any piece of network equipment, make sure you have a backup of the configuration. This is especially important since you are just taking over the network and the quality/quantity of the documentation may not be enough to help you reconstruct things if a problem occurs. If you don’t have a full diagram of the network in your documentation, now would be a good time to contruct one before making any changes.
With that said, you might not want to delete the loopback interface.
A loopback interface is a virtual interface that doesn’t correspond to anything physical in the router. Unlike some other interfaces on a Cisco router, it is one that should always be up unless you have issued the shutdown command. For those working towards their CCNA or other certifications, a loopback interface can allow you to populate the router with one or more “networks” so you can work with a network that is larger than what you actually have the equipment for.
Some companies use the loopback interface to telnet/ssh to the router – if you have more than one route to the router, you should still be able to reach the device using a single IP address instead of having to try multiple addresses. When working with the router console, you can use the extended ping command to test the routing functionality without having to try from another device initially. With a little time and learning, you will find that the loopback interface is one that you will be rewarded with knowing how to use.
