3com S7906E Manuel De Montage

 

1-5 

Set the maximum number of 
dynamic ARP entries that an 
interface can learn 

arp max-learning-num 
number 

Optional 

8192 by default 

 

To keep pace with the network changes, the ARP table is refreshed. Each dynamic ARP entry in the 

ARP table has a limited lifetime rather than is always valid. Dynamic ARP entries that are not refreshed 

before expiration are deleted from the ARP table. The lifetime is called the aging time. The aging time is 

reset each time the dynamic ARP entry is refreshed within the lifetime. You can adjust the aging time for 

dynamic ARP entries according to the actual network condition. 

Follow these steps to set the aging time for dynamic ARP entries: 

Enter system view 

— 

Set the aging time for dynamic 
ARP entries 

arp timer aging aging-time 

Optional 

20 minutes by default. 

 

The ARP entry check function disables the device from learning multicast MAC addresses. With the 

ARP entry check enabled, the device cannot learn any ARP entry with a multicast MAC address, and 

configuring such a static ARP entry is not allowed; otherwise, the system displays error messages. 

After the ARP entry check is disabled, the device can learn the ARP entry with a multicast MAC address, 

and you can also configure such a static ARP entry on the device. 

Follow these steps to enable the ARP entry check: 

Enter system view 

— 

Enable the ARP entry check 

Optional 

By default, the device is disabled from 
learning multicast MAC addresses. 

 

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 or not. 

Suppose that the IP address of VLAN-interface 10 is 10.10.10.5/24 and that this interface receives an 

ARP packet from 10.11.11.1/8. Because these two IP addresses are not on the same subnet, 

VLAN-interface 10 cannot process the packet. With this feature enabled, the device makes a judgment 

on natural network basis. Because the IP address of VLAN-interface 10 is a Class A address and its