arp-fake expire-time

Function

The arp-fake expire-time command sets the aging time of temporary ARP entries.

The undo arp-fake expire-time command restores the default aging time of temporary ARP entries.

By default, the aging time of temporary ARP entries is 3 seconds.

Format

arp-fake expire-time expire-time

undo arp-fake expire-time

Parameters

Parameter	Description	Value
expire-time	Specifies the aging time of temporary ARP entries.	The value is an integer that ranges from 1 to 36000, in seconds.

Views

Ethernet interface view, GE interface view, XGE interface view, 25GE interface view, 40GE interface view, 100GE interface view, MultiGE interface view, Eth-Trunk interface view, VLANIF interface view, VBDIF interface view, VE interface view, port group view

Default Level

2: Configuration level

Usage Guidelines

When IP packets trigger ARP Miss messages, the device generates temporary ARP entries and sends ARP Request packets to the destination network.

In the aging time of temporary ARP entries:
- Before receiving an ARP reply packet, the device discards the IP packets matching the temporary ARP entry and does not generate ARP Miss messages.
- After receiving an ARP Reply packet, the device generates a correct ARP entry to replace the temporary entry.
When temporary ARP entries age out, the device clears them. If no ARP entry matches the IP packets forwarded by the device, ARP Miss messages and temporary ARP entries are repeatedly generated

When a device undergoes an ARP Miss attack, you can run the arp-fake expire-time command to extend the aging time of temporary ARP entries to reduce the frequency of triggering ARP Miss messages and minimize the impact on the device.

Example

# Set the aging time of temporary ARP entries to 10 seconds on VLANIF10.

<HUAWEI> system-view
[HUAWEI] vlan 10
[HUAWEI-vlan10] quit
[HUAWEI] interface vlanif 10
[HUAWEI-Vlanif10] arp-fake expire-time 10

# Set the aging time of temporary ARP entries to 10 seconds on Layer 3 interface GE0/0/1.

<HUAWEI> system-view
[HUAWEI] interface gigabitethernet 0/0/1
[HUAWEI-GigabitEthernet0/0/1] undo portswitch
[HUAWEI-GigabitEthernet0/0/1] arp-fake expire-time 10