26
Step Command
Remarks
3.
Set the interface description.
description
text
Optional.
By default, the description of a
loopback interface is
interface
name Interface
.
4.
Shut down the loopback
interface.
shutdown
Optional.
A loopback interface is up on
being created.
NOTE:
You can configure settings such as IP address on a loopback interface. For more information, see
Layer
3—IP Services Configuration Guide.
Configuring a null interface
Introduction
Null interfaces are completely software-like logical interfaces. Null interfaces are always up. However,
they can neither forward data packets nor have IP addresses and link layer protocols configured on them.
With a null interface specified as the next hop of a static route to a specific network segment, any packets
routed to the network segment are dropped. Null interface provides you a way to filter packets. That is,
you can simply transmit unwanted traffic to a null interface rather than applying ACLs.
For example, by executing the
ip route-static 92.101.0.0 255.255.0.0 null 0
command (which configures
a static route leading to a null interface), you can have all the packets destined to the network segment
92.101.0.0/16 discarded.
Configuration procedure
To configure a null interface:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter null interface view.
interface null 0
Interface Null0 is the default null
interface on a switch. It can neither
be created nor removed.
3.
Set the interface description.
description
text
Optional.
By default, the description of a null
interface is
interface name
Interface
.
