19
Step Command
Remarks
4.
Shut down the loopback
interface.
shutdown
Optional
By default, a loopback interface is up.
5.
Restore the default settings for
the loopback interface.
default
Optional
NOTE:
You can configure settings such as IP addresses and IP routes on loopback interfaces. For more
information, see
Layer 3—IP Services Configuration Guide and Layer 3—IP Routing Configuration Guide.
Configuring a 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 that leads 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, Null 0, is supported on your switch. You cannot remove or create a null interface.
Configuration procedure
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter null interface
view.
interface null 0
The Null 0 interface is the default null interface on
your switch. It cannot be manually created or
removed.
3.
Set the interface
description.
description
text
Optional
By default, the description of a null interface is
interface name
Interface.
4.
Restore the default
settings for the null
interface.
default
Optional
Displaying and maintaining loopback and null
interfaces
