Loopback Interface

Can you please explain what are loopback interfaces are!
How do they work?
Can you explain how lookback interfaces works in EIGRP ansd OSPF!

Thanks in advance!

Hello Akshay

A loopback interface is a virtual interface on a router or layer 3 switch that can be created and assigned an IP address. The loopback interface has no physical counterpart, it is essentially a virtual interface with an IP address internally on the device. It doesn’t connect to any devices on its subnet and is usually the only “device” within its assigned subnet.

Loopback interfaces are used for several purposes including:

* providing an Router ID for EIGRP and OSPF routing protocols
* providing an “always up” interface for device configuration
* providing an “always up” interface for use as the BGP peer address
* creating extra interfaces with IP addresses on devices for training and educational purposes

Most interface configurations can be applied to a loopback interface, just like to any physical interface. The interface itself, if configured to participate in a dynamic routing protocol, will be included in the routing table.

I hope this has been helpful!