Null Interface; Configuring Null 0 Interface - HP 5820X series Configuration Manual

To do...
4. Shut down the loopback
interface
5. Restore the default settings for
the interface
Configure settings such as IP addresses and IP routes on Loopback interfaces. For more information, see
the Layer 3—IP Services Configuration Guide and Layer 3—IP Routing Configuration Guide.

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. 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 packets destined to the network segment
92.101.0.0/16 discarded.
Only one null interface, interface Null 0, is supported on your switch. You cannot remove or create a null
interface.

Configuring null 0 interface

To enter null interface view:
To do...
1. Enter system view
2. Enter null interface
view
3. Set a description for
the null interface
4. Restore the default
settings of the
interface
Use the command...
shutdown
default
Use the command...
system-view
interface null 0
description text
default
23
Remarks
Optional.
By default, a loopback interface is
up once created.
Optional.
Remarks
—
Required.
The Null 0 interface is the default null interface
on your switch. It cannot be manually created
or removed.
Optional.
By default, the description of an interface is
the interface name followed by the "Interface"
string.
Optional.