3Com Switch 8800 Advanced Software V5 Configuration Guide

196 CHAPTER 20: ARP CONFIGURATION
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CAUTION:
■ A static ARP entry is effective when the Ethernet switch works normally.
However, when a VLAN or VLAN interface to which a static ARP entry
corresponds is deleted, the entry, if permanent, will be deleted, and if
non-permanent and resolved, will become unresolved.
■ The vlan-id argument must be the ID of an existing VLAN which corresponds to
the ARP entries. In addition, the Ethernet interface following the argument
must belong to that VLAN.
Configuring the
Maximum Number of
ARP Entries a VLAN
Interface Can Learn
Follow these steps to set the maximum number of dynamic ARP entries that a
VLAN interface can learn:
Setting Aging Time for
Dynamic ARP Entries
After dynamic ARP entries expire, the system will delete them from the ARP
mapping table. You can adjust the aging time for dynamic ARP entries according
to the actual network condition.
Follow these steps to set aging time for dynamic ARP entries:
Enabling the ARP Entry
Check
ARP entry check disables the device from learning multicast MAC addresses.
Follow these steps to enable the ARP entry check:
Enabling the Support for
ARP Requests from a
Natural Network
When learning MAC addresses, if the device finds that the source IP address of an
ARP packet and the IP address of the inbound interface are not on the same
subnet, the device will further judge whether these two IP addresses are on the
same natural network.
To do... Use the command... Remarks
Enter system view system-view -
Enter VLAN interface view interface vlan-interface
interface-number
-
Set the maximum number of
dynamic ARP entries that the
interface can learn
arp max-learning-num
number
Optional
4096 by default
To do... Use the command... Remarks
Enter system view system-view -
Set aging time for dynamic
ARP entries
arp timer aging aging-time Optional
20 minutes by default
To do... Use the command... Remarks
Enter system view system-view -
Enable the ARP entry check arp check enable Optional
Enabled by default. That is,
the device does not learn
multicast MAC addresses.