Configuring Gratuitous Arp; Introduction To Gratuitous Arp - 3Com MSR 50 Series Configuration Manual

554 C 30: ARP C
HAPTER
Configuring
Gratuitous ARP
Introduction to
Gratuitous ARP
Configuring Gratuitous
ONFIGURATION
Set the maximum number of dynamic ARP entries that Ethernet 1/0 can learn
■
to 1,000.
Add a static ARP entry, with the IP address being 192.168.1.1/24, the MAC
■
address being 00e0-fc01-0000, and the outbound interface being Ethernet 1/0
of VLAN 10.
Configuration procedure
<Sysname> system-view
[Sysname] arp check enable
[Sysname] arp timer aging 10
[Sysname] naturemask-arp enable
[Sysname] vlan 10
[Sysname-vlan10] quit
[Sysname] interface vlan-interface 10
[Sysname- vlan-interface10] quit
[Sysname] interface ethernet 1/0
[Sysname-Ethernet1/0] port access vlan 10
[Sysname-Ethernet1/0] arp max-learning-num 1000
[Sysname-Ethernet1/0] quit
[Sysname] arp static 192.168.1.1 00e0-fc01-0000 10 ethernet1/0
A gratuitous ARP packet is a special ARP packet, in which the source IP address
and destination IP address are both the IP address of the sender, the source MAC
address is the MAC address of the sender, and the destination MAC address is a
broadcast address.
A device can implement the following functions by sending gratuitous ARP
packets:
Determining whether its IP address is already used by another device.
■
Informing other devices of its MAC address change so that they can update
■
their ARP entries.
A device receiving a gratuitous ARP packet can add the information carried in the
packet to its own dynamic ARP mapping table if it finds no corresponding ARP
entry for the ARP packet in the cache.
Follow these steps to configure gratuitous ARP:
ARP
To do...
Enter system view
Enable the device to send
gratuitous ARP packets when
receiving ARP requests from
another network segment
Use the command...
system-view
gratuitous-arp-sending
enable
Remarks
-
Required
By default, a device cannot
send gratuitous ARP packets
when receiving ARP requests
from another network
segment.