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 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.