The loopback networking interface is a virtual network device implemented entirely in software. All traffic sent to it “loops back” and just targets services on your local machine.
There can only be one loopback
lo interface on the system. If
you need multiple interfaces, please use the Dummy
A lookback interface is always up, thus it could be used for management traffic or as source/destination for and IGP like BGP so your internal BGP link is not dependent on physical link states and multiple routes can be chosen to the destination. A Dummy Interface should always be preferred over a Loopback interface.
Show brief interface information.
[email protected]:~$ show interfaces loopback Codes: S - State, L - Link, u - Up, D - Down, A - Admin Down Interface IP Address S/L Description --------- ---------- --- ----------- lo 127.0.0.1/8 u/u ::1/128
Show detailed information on given loopback interface lo.
[email protected]:~$ show interfaces ethernet eth0 lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever RX: bytes packets errors dropped overrun mcast 300 6 0 0 0 0 TX: bytes packets errors dropped carrier collisions 300 6 0 0 0 0