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Configuring the null interface, Introduction to the null interface, Configuration procedure – H3C Technologies H3C WX3000E Series Wireless Switches User Manual

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To do…

Use the command…

Remarks

Enter system view

system-view

Create a loopback interface and
enter loopback interface view

interface loopback
interface-number

Set the interface description

description text

Optional
By default, the description of a loopback
interface is interface name Interface.

Shut down the loopback interface

shutdown

Optional
By default, a loopback interface is up.

NOTE:

You can configure settings such as IP addresses and IP routes on loopback interfaces. For more
information, see

Layer 3 Configuration Guide.

Configuring the null interface

Introduction to the null interface

A null interface is a completely software-based logical interface, and is always up. However, you cannot

use it to forward data packets or configure an IP address or link layer protocol on it. 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. The null interface provides a simpler way to filter packets than ACL. You
can filter uninteresting traffic by transmitting it to a null interface instead of applying an ACL.
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 null interface 0), you can have all the packets destined to the network segment

92.101.0.0/16 discarded.
Only one null interface, interface Null 0, is supported on your device. You cannot remove or create a null

interface.

Configuration procedure

Follow these steps to enter null interface view:

To do…

Use the command…

Remarks

Enter system view

system-view

Enter null interface view

interface null 0

Required
The Null 0 interface is the default null interface
on your device. It cannot be manually created

or removed.

Set the interface
description

description text

Optional
By default, the description of a null interface is
interface name Interface.