dhcp check server-identifier strict

Function

The dhcp check server-identifier strict command enables strict check for DHCP server IP addresses in DHCP Request messages. After the command is run, a user gateway does not send an ACK message in response to a DHCP Request message if the DHCP server IP address carried in the request is different from the user's gateway IP address.

The undo dhcp check server-identifier strict command restores the default configuration.

By default, strict check for DHCP server IP addresses in DHCP Request messages is disabled.

This command is supported only on the NetEngine 8000 F1A.

Format

dhcp check server-identifier strict packet-type request

undo dhcp check server-identifier strict [ packet-type request ]

Parameters

None

Views

System view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
ippool	write

Usage Guidelines

Usage Scenario

In a cold backup scenario, if the master and backup devices' gateway addresses are different but belong to the same network segment, the two devices may assign the same IP address to a user. As a result, the user goes online through both devices. To resolve this issue, run the dhcp check server-identifier strict command to enable strict check for DHCP server IP addresses in DHCP Request messages. After the command is run, a user gateway does not send an ACK message in response to a DHCP Request message if the DHCP server IP address carried in the request is different from the user's gateway IP address. The user then goes online only through the other device.

Prerequisites

The dhcp check-server-pkt loose command has been run in the system view.

The access packet strict-check dhcp command is not run in the system view.

Precautions

In VS mode, this command is supported only by the admin VS.

Example

# Enable strict check for DHCP server IP addresses in DHCP Request messages.

<HUAWEI> system-view
[~HUAWEI] dhcp check server-identifier strict packet-type request