A loopback interface is a special virtual interface created in software that is not associated with any hardware interface.
Dynamic routing protocols typically use a loopback interface as a reliable IP interface for routing updates. You can assign the loopback IP address to the router rather than the IP address of a specific hardware interface. Services (such as Telnet) can access the router using the loopback IP address, which remains available independent of hardware interfaces status.
No limit exists on the number of loopback interfaces you can create.
A loopback interface does not have an internal VLAN ID or a MAC addresses and usually has a /32 network mask.
- Go to System > Network > Interface > Loopback.
- Select Add Interface.
- Enter a name for the loopback interface.
- Select Static for the mode and then enter the IP address and netmask in the IP/Netmask field.
- Select the protocols allowed to access the loopback interface.
- Select the administration status.
- Select Add.
config system interface
set ip 126.96.36.199 255.255.255.255
set allowaccess ping https http ssh telnet
set type loopback
set snmp-index 28