dhcp select relay

Function

The dhcp select relay command enables the DHCP relay function.

The undo dhcp select relay command disables the DHCP relay function.

By default, the DHCP relay function is disabled.

Format

dhcp select relay

undo dhcp select relay

Parameters

None

Views

Interface view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

The dhcp select relay command applies to DHCP relay agents. If the DHCP server and client are on the same network segment, they can directly communicate with each other using DHCP. In this case, no DHCP relay agent is needed. If the DHCP server and client are on different network segments, the DHCP relay function must be enabled to forward DHCP messages.

Prerequisites

The DHCP function has been enabled using the dhcp enable command in the system view.

Follow-up Tasks

To ensure that a DHCP relay agent can forward DHCP packets to a DHCP server, run the dhcp relay server-select or dhcp relay server-ip command on the DHCP relay-enabled interface to configure the correct IP address of the DHCP server.
To ensure that a DHCP server can forward DHCP packets to a DHCP relay agent, you must configure a route to the DHCP relay agent on the DHCP server.

Precautions

The DHCP server must select an IP address in the same network segment with the DHCP relay agent from the global address pool to ensure that the DHCP client obtains an IP address on the local network segment. No interface address pool can be configured on the interface that connects the DHCP server and relay agent.

Example

# Enable the DHCP relay function on VLANIF100.

<HUAWEI> system-view
[HUAWEI] dhcp enable
[HUAWEI] interface vlanif 100
[HUAWEI-Vlanif100] dhcp select relay

# Enable the DHCP relay function on GE0/0/1.

<HUAWEI> system-view
[HUAWEI] dhcp enable
[HUAWEI] interface gigabitethernet 0/0/1
[HUAWEI-GigabitEthernet0/0/1] undo portswitch
[HUAWEI-GigabitEthernet0/0/1] dhcp select relay