arp dhcp-snooping-detect enable

Function

The arp dhcp-snooping-detect enable command enables the association between ARP and DHCP snooping.

The undo arp dhcp-snooping-detect enable command disables the association between ARP and DHCP snooping.

By default, the association between ARP and DHCP snooping is disabled.

Format

arp dhcp-snooping-detect enable

undo arp dhcp-snooping-detect enable

Parameters

None

Views

System view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
dhcp	write

Usage Guidelines

Usage Scenario

If a client obtains an IP address and gets offline abnormally, the client cannot release its IP address by sending a DHCP release packet. As a result, the IP address cannot be reassigned to other clients. To resolve this problem, you can run the dhcp snooping user-bind arp-detect enable command to enable the association between ARP and DHCP snooping.

Prerequisites

DHCP snooping has been enabled globally by running the dhcp snooping enable command.

Configuration Impact

After the association between ARP and DHCP snooping is configured:

The system uses ARP to detect a client periodically. If the system cannot detect the client for specified times (using arp detect-times command to set the aging detection times), the system will delete the DHCP snooping binding entry for the client. The system also sends a release packet to the DHCP server to release the client's IP address.
If no ARP entry is matched, the system sends ARP probe packets to the user with the IP address corresponding to the ARP entry, causing ARP packets on the network to accumulate.

Example

# Enable the association between ARP and DHCP snooping.

<HUAWEI> system-view
[~HUAWEI] dhcp enable
[~HUAWEI] dhcp snooping enable
[~HUAWEI] arp dhcp-snooping-detect enable