H3C Technologies H3C S7500E Series Switches - Manual (Page 18)

1-6
When the ARP entry check enabled, you cannot configure a static ARP entry with a multicast MAC
address on the device; otherwise, the system displays error messages.
When the ARP entry check is disabled, you can configure a static ARP entry with a multicast MAC
address on the device.
Follow these steps to enable the ARP entry check:
To do… Use the command… Remarks
Enter system view system-view —
Enable the ARP entry check arp check enable
Optional
Enabled by default.
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 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
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 corresponding to the source IP address 10.11.11.1.
Follow these steps to enable the support for ARP requests from a natural network:
To do… Use the command… Remarks
Enter system view system-view —
Enable the support for ARP
requests from a natural network
naturemask-arp enable
Required
Disabled by default.
ARP Configuration Example
Network requirements
As shown in Figure 1-3 , hosts are connected to Switch, which is connected to Router through interface
GigabitEthernet2/0/1 belonging to VLAN 10. The IP address of Router is 192.168.1.1/24. The MAC
address of Router is 00e0-fc01-0000.
To enhance communication security for Router and Switch, static ARP entries are configured on
Switch.