Juniper Networks Field Guide and Reference

On the router, you can configure one physical loopback interface, lo0 , and one or more addresses on the interface. To do this, include the following statements:

[edit interfaces] lo0 { unit 0 { family inet { loopback-address ; < loopback-address2 >; ... } } }

When specifying the loopback address, do not include a destination prefix. Also, do not specify a loopback address on any unit number other than unit 0.