dhcp giaddr zero

Function

The dhcp giaddr zero user-type layer2 command enables a device to set the giaddr field to zero in a DHCPv4 message to be sent to a DHCPv4 client in Layer 2 access scenarios.

The undo dhcp giaddr zero user-type layer2 command disables a device from setting the giaddr field to zero in a DHCPv4 message to be sent to a DHCPv4 client in Layer 2 access scenarios.

By default, a device inserts the gateway address into the giaddr field of a DHCPv4 message to be sent to a DHCPv4 client in Layer 2 access scenarios.

This command is supported only on the NetEngine 8000 F1A.

Format

dhcp giaddr zero user-type layer2

undo dhcp giaddr zero user-type layer2

Parameters

None

Views

System view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
dhcp	write

Usage Guidelines

Usage Scenario

To make clients unaware that IPv4 addresses are assigned by a relay agent, run the dhcp giaddr zero user-type layer2 command to enable a device to set the giaddr field to zero in a DHCPv4 message to be sent to a DHCPv4 client in Layer 2 access scenarios. This protects the gateway address carried in the giaddr field of a DHCPv4 message. A DHCP server inserts the gateway address into the giaddr field of a DHCPv4 message to be sent to a client. However, in Layer 2 access scenarios, setting the giaddr field to 0.0.0.0 is more appropriate.

Layer 2 access DHCPv4 clients include DHCPv4 users who go online through a BAS interface with access type set to <layer2-subscriber> or <layer2-leased-line> using the access-type command.

Precautions

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

Example

# Enable a device to set the giaddr field to zero in a DHCPv4 message to be sent to a DHCPv4 client in Layer 2 access scenarios.

<HUAWEI> system-view
[~HUAWEI] dhcp giaddr zero user-type layer2