Loopback Interface
The Junos OS automatically configures one loopback interface (lo0), choosing the first interface to come online as the default. You can also configure the loopback interface.
When you enter the show interfaces command, the loopback interface and its logical interfaces are displayed:
user@host> show interfaces ?... lo0 lo0.0 lo0.16385 ...
The logical interface lo0.16385 is a nonconfigurable interface for router control traffic.
