Enabling The Arp Entry Check; Enabling The Support For Arp Requests From A Natural Network; Arp Configuration Example - 3Com MSR 50 Series Configuration Manual

Enabling the ARP Entry
Check
Enabling the Support for
ARP Requests from a
Natural Network
ARP Configuration
Example
To do...
Set aging time for dynamic
ARP entries
The ARP entry check can control the device to learn multicast MAC addresses.
With the ARP entry check enabled, the device cannot learn any ARP entry with a
multicast MAC address. Configuring such a static ARP entry is not allowed either;
otherwise, the system prompts error information.
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:
To do...
Enter system view
Enable the ARP entry check
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.
Suppose that the IP address of VLAN-interface 10 is 10.10.10.5/24 and 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 will make judgment on natural
network basis. Because the IP address of VLAN-interface 10 is a Class A address
and its default mask length is 8, these two IP addresses are on the same natural
network. In this way, VLAN-interface 10 can learn the MAC address of the source
IP address 10.11.11.1.
Follow these steps to enable the support for ARP requests from a natural network:
To do...
Enter system view
Enable the support for ARP
requests from a natural
network
Network requirement
Enable the ARP entry check.
■
Set the aging time for dynamic ARP entries to 10 minutes.
■
Enable the support for ARP requests from a natural network.
■
Use the command...
arp timer aging aging-time
Use the command...
system-view
arp check enable
Use the command...
system-view
naturemask-arp enable
Configuring ARP 553
Remarks
Optional
20 minutes by default
Remarks
-
Optional
Enabled by default. That is,
the device does not learn
multicast MAC addresses.
Remarks
-
Required
Disabled by default