arp dhcp-snooping-detect enable

Function

The arp dhcp-snooping-detect enable command enables association between the Address Resolution Protocol (ARP) and Dynamic Host Configuration Protocol (DHCP) snooping.

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

By default, 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

Usage Guidelines

Usage Scenario

After a DHCP client sends a DHCP Release message to release its IP address, the DHCP snooping-enabled device immediately deletes the binding entry of the DHCP client. If a DHCP client is abnormally disconnected and cannot send a DHCP Release message, the DHCP snooping-enabled device cannot immediately delete the binding entry of the DHCP client.

If association between ARP and DHCP snooping is enabled using this command and no ARP entry corresponding to the IP address in the DHCP snooping binding entry is found, the DHCP snooping-enabled device performs an ARP probe on the IP address. If no user is detected for consecutive four times, the DHCP snooping-enabled device deletes the DHCP snooping binding entry corresponding to the IP address. (The probe interval is 20 seconds, and the probe times and probe interval are fixed values and cannot be modified.) If the DHCP snooping-enabled device supports the DHCP relay function, this device then sends a DHCP Release message in place of the DHCP client to notify the DHCP server to release the IP address.

Prerequisites

Before association between the ARP and DHCP snooping is enabled, ensure that an IP address configured on the device is on the same network segment as the IP address of the client for ARP probe.

Example

# Enable association between ARP and DHCP snooping on the device.

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