H3C Technologies H3C SecBlade NetStream Cards - Manual (Page 132)

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Enabling dynamic ARP entry check
The dynamic ARP entry check function controls whether the device supports dynamic ARP entries with
multicast MAC addresses.
When dynamic ARP entry check is enabled, the device cannot learn dynamic ARP entries containing
multicast MAC addresses.
When dynamic ARP entry check is disabled, the device can learn dynamic ARP entries containing
multicast MAC addresses.
Follow these steps to enable dynamic ARP entry check:
To do… Use the command… Remarks
Enter system view system-view —
Enable dynamic ARP entry
check
arp check enable
Optional
Enabled by default.
Enabling natural mask support for ARP requests
This feature enables the device to learn the sender IP and MAC addresses in a received ARP request
whose sender IP address is on the same classful network as but a different subnet from the IP address of
the receiving interface. A classful network refers to a class A, B, or C network.
For example, VLAN-interface 10 with IP address 10.10.10.5/24 receives an ARP request from
10.11.11.1/8. Because the subnet address calculated by the AND operation of 10.11.11.1 and the receiving
interface’s 24-bit subnet mask is not in the subnet 10.10.10.5/24, VLAN-interface 10 cannot process the
ARP packet.
With this feature enabled, the device calculates the subnet address by using the default mask of the class
A network where 10.10.10.5/24 resides. Because 10.10.10.5/24 is on the same class A network as
10.11.11.1/8, VLAN-interface 10 can learn the sender IP and MAC addresses in the request.
Follow these steps to enable natural mask support for ARP requests:
To do… Use the command… Remarks
Enter system view system-view —
Enable natural mask support for
ARP requests
naturemask-arp enable
Required
Disabled by default.
Displaying and maintaining ARP
To do… Use the command… Remarks
Display ARP entries in the ARP
table
display arp [ [ all | dynamic | static ] | vlan
vlan-id | interface interface-type
interface-number ] [ count ] [ | { begin |
exclude | include } regular-expression ]
Available in any view
Display the ARP entry for a
specified IP address display arp ip-address [ | { begin | exclude
| include } regular-expression ]
Available in any view