arp auto-scan enable

Function

The arp auto-scan enable command enables automatic ARP scanning on a sub-interface.

The undo arp auto-scan enable command disables automatic ARP scanning on a sub-interface.

By default, automatic ARP scanning is disabled on a sub-interface.

Only the S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-HI, S6730-H, S6730S-H, S6730-S, and S6730S-S support this command.

Format

arp auto-scan enable

undo arp auto-scan enable

Parameters

None

Views

GE sub-interface view, XGE sub-interface view, MultiGE sub-interface view, 25GE sub-interface view, 40GE sub-interface view, 100GE sub-interface view, Eth-Trunk sub-interface view, VE sub-interface view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

After automatic ARP scanning is enabled on a sub-interface of which the IP address mask is greater than or equal to 24 bits and the protocol status is Up, the switch scans IP addresses on the network segment where the sub-interface's primary IP address belongs and learns ARP entries of the remote device immediately.

Precautions

Automatic ARP scanning can be enabled on a maximum of 512 sub-interfaces of a switch simultaneously. If automatic ARP scanning is enabled on multiple interfaces simultaneously and the protocol status of the sub-interfaces are Up, the switch sends detection packets to the sub-interfaces, causing a high CPU usage.

To prevent the delay of the interface Up event caused by loop detection, the switch enabled with automatic ARP scanning sends detection packets after a delay of 10s.

Example

# Enable automatic ARP scanning.

<HUAWEI> system-view
[HUAWEI] interface gigabitethernet 0/0/1.10
[HUAWEI-GigabitEthernet0/0/1.10] arp auto-scan enable