HP FlexNetwork NJ5000, User Manual

Page: 208 / 475

196
Gratuitous ARP
In a gratuitous ARP packet, the sender IP address and the target IP address are the IP address of
the sending device, the sender MAC address is the MAC address of the sending device, and the
target MAC address is the broadcast address ff:ff:ff:ff:ff:ff.
A device sends a gratuitous ARP packet for either of the following purposes:
•
Determine whether its IP address is already used by another device. If the IP address is already
used, the device is informed of the conflict by an ARP reply.
•
Inform other devices of a MAC address change.
Gratuitous ARP packet learning
This feature enables a device to create or update ARP entries by using the sender IP and MAC
addresses in received gratuitous ARP packets.
When this feature is disabled, the device uses the received gratuitous ARP packets to update
existing ARP entries only.
Configuring ARP entries
Displaying ARP entries
From the navigation tree, select
Network
>
ARP Management
. The default
ARP Table
page
appears, as shown in Figure 195 .
This page displays all ARP entries.
Figure 195 ARP Table configuration page
Creating a static ARP entry
1.
From the navigation tree, select
Network
>
ARP Management
.
The default
ARP Table
page appears, as shown in Figure 195 .
2.
Click
Add
.
The
New Static ARP Entry
page appears.