arp trust source

Function

The arp trust source command enables ARP gateway protection for the specified IP address.

The undo arp trust source command disables ARP gateway protection for the specified IP address.

By default, ARP gateway protection is disabled.

Format

arp trust source ip-address

undo arp trust source { ip-address | all }

Parameters

Parameter	Description	Value
ip-address	Specifies the protected gateway IP address.	The value is in dotted decimal notation.
all	Disables ARP gateway protection for all IP addresses in the current view.	-

Views

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

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

If an attacker poses as a gateway to send ARP packets, other users on the network consider the attacker to be a gateway, causing a communication interruption between authorized users and gateway. This situation will also happen if a user incorrectly sets the host IP address as the gateway address. To prevent such bogus gateway attacks, configure ARP gateway protection on the device's interfaces connected to the gateway. When the ARP packets from a gateway address reach a device:

The interfaces with gateway protection enabled can receive and forward the ARP packets.
The interfaces without gateway protection enabled discard the ARP packets.

Precautions

A maximum of 8 protected gateway addresses can be specified on each interface, and 32 can be specified on the entire device. If the same gateway IP address is specified on different interfaces, the system considers that multiple protected gateway IP addresses have been configured.

Example

# Enable ARP gateway protection on GE0/0/1 and set the protected gateway IP address to 10.10.10.1.

<HUAWEI> system-view
[HUAWEI] interface gigabitethernet 0/0/1
[HUAWEI-GigabitEthernet0/0/1] arp trust source 10.10.10.1