Loopback Interfaces; Null Interfaces - Dell S4048T Configuration Manual

ip ospf authentication-key force10
ip ospf cost 1
ip ospf dead-interval 60
ip ospf hello-interval 15
no shutdown
!

Loopback Interfaces

A Loopback interface is a virtual interface in which the software emulates an interface. Packets routed to it are
processed locally.
Because this interface is not a physical interface, you can configure routing protocols on this interface to
provide protocol stability. You can place Loopback interfaces in default Layer 3 mode.
To configure, view, or delete a Loopback interface, use the following commands.
• Enter a number as the Loopback interface.
CONFIGURATION mode
interface loopback number
The range is from 0 to 16383.
• View Loopback interface configurations.
EXEC mode
show interface loopback number
• Delete a Loopback interface.
CONFIGURATION mode
no interface loopback number
Many of the commands supported on physical interfaces are also supported on a Loopback interface.

Null Interfaces

The Null interface is another virtual interface. There is only one Null interface. It is always up, but no traffic is
transmitted through this interface.
To enter INTERFACE mode of the Null interface, use the following command.
• Enter INTERFACE mode of the Null interface.
CONFIGURATION mode
interface null 0
The only configurable command in INTERFACE mode of the Null interface is the ip unreachable
command.
Interfaces 464