Configuring The Null Interface; Displaying And Maintaining Loopback And Null Interfaces - HP A5830 Configuration Manual

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 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, and you cannot 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 that leads to null interface 0), you can have all 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.
To enter null interface view:
Step...
1. Enter system view
2. Enter null interface
view
3. Set the interface
description
4. Restore the default
settings for the null
interface
Displaying and maintaining loopback and null
interfaces
Task...
Display information about
loopback interfaces
Display information about
the null interface
Clear the statistics on a
loopback interface
Command...
system-view
interface null 0
description text
default
Command...
display interface [ loopback ] [ brief [ down ] ] [ | {
begin | exclude | include } regular-expression ]
display interface loopback interface-number [ brief ]
[ | { begin | exclude | include } regular-expression ]
display interface [ null ] [ brief [ down ] ] [ | { begin
| exclude | include } regular-expression ]
display interface null 0 [ brief ] [ | { begin |
exclude | include } regular-expression ]
reset counters interface [ loopback [ interface-
number ] ]
15
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 a null interface is
interface name Interface
Optional
Remarks
Available in any view
Available in any view
Available in user view