R3166-R3206-HP High-End Firewalls Network Management Configuration Guide-6PW101

192
Configuring gratuitous ARP
Introduction to gratuitous ARP
In a gratuitous ARP packet, the sender IP address and the target IP address are both the IP address of the
device issuing the packet, the sender MAC address is the MAC address of the device, and the target
MAC address is the broadcast address ff:ff:ff:ff:ff:ff.
A device implements the following functions by sending gratuitous ARP packets:
• Determining whether its IP address is already used by another device.
• Informing other devices about the change of its MAC address so that they can update their ARP
entries.
A device receiving a gratuitous ARP packet adds the information carried in the packet to its own dynamic
ARP table if it finds no corresponding ARP entry exists in the cache.
Configuring gratuitous ARP in the web interface
Select Advanced > ARP Management > Gratuitous ARP from the navigation tree to enter the page shown
in Figure 105.
Figure 105 Gratuitous AR
P configuration page
Table 40 Gratuitous ARP configuration items
Item Descri
p
tion
Disable gratuitous ARP packets learning function
Disable learning of ARP entries according to
gratuitous ARP packets.
Send gratuitous ARP packets when receiving ARP
requests from another network segment
Enable the device to send gratuitous ARP packets
upon receiving ARP requests from another network
segment.
Configuring gratuitous ARP in the CLI
Follow these steps to configure gratuitous ARP:
To do… Use the command…
Remarks
Enter system view system-view —
Enable the device to send
gratuitous ARP packets when
receiving ARP requests from
another network segment
gratuitous-arp-sending enable
Required
By default, a device cannot send
gratuitous ARP packets when
receiving ARP requests from
another network segment.