Loopback Interface

Loopbacks are essentially internal virtual interfaces. Loopback interfaces are not bound to a physical port and are used for device management and routing protocols.

Configuration commands

(switch(config)#)

interface loopback LOOPBACK
ip address IP-ADDR/<SUBNET|PREFIX>

(switch(config)#)

interface loopback 1
ip address 99.99.99.1/32
end
show run interface loopback1

Example output:

interface loopback1
   no shutdown
   ip address 99.99.99.1/32
   exit

(switch(config)#)

show ip interface loopback1

Example output:

Interface loopback1 is up
 Admin state is up
 Hardware: Loopback
 IPv4 address 99.99.99.1/32

Expected results

  • Administrators can create a loopback interface.
  • Administrators can give a loopback interface an IP address.
  • Administrators can validate the configuration using the show commands.

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