Introduction

Loopback interfaces can be created in GNS3. In this tutorial, we will learn what is a loopback interface how we can create it.

Loopback Interface is a virtual interface which can be created on the routers. Since it is virtual, it is not dependent on any physical interface and hence is always up.

How to create:

Lets create 3 loopbacks on the same router- Loopback 1, Loopback 2 and Loopback 3 with IP Address- 10.1.1.1, 10.1.2.1 and 10.1.3.1 respectively.

Router(config)#int loopback 1

Router(config-if)#ip address 10.1.1.1 255.255.255.0

Router(config)# int loopback 2

Router(config)# ip address 10.1.2.1 255.255.255.0

Router(config)# int loopback 3

Router(config)# ip address 10.1.3.1 255.255.255.0

Please note that each loopback interface must belong to a different Network/ Subnet.

We need not to give “No Shutdown” command after giving IP Address to the Loopback interfaces; like we do when we give IP Address to a real interface. This is because Loopback interfaces are virtual interfaces and they are always up.