dhcp reply trust broadcast-flag

Function

The dhcp reply trust broadcast-flag command enables a device to use the broadcast flag value in a DHCP request packet to determine the destination MAC address type for a DHCP response packet.

The undo dhcp reply trust broadcast-flag command restores the default configuration.

By default, the destination MAC address in a DHCP response packet is the user MAC address.

This command is supported only on the NetEngine 8000 F1A.

Format

dhcp reply trust broadcast-flag

undo dhcp reply trust broadcast-flag

Parameters

None

Views

BAS interface view (GE), BAS interface view (VE), BAS interface view (trunk)

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
bras-control	write

Usage Guidelines

Usage Scenario

By default, a device replies to a DHCP request packet with a DHCP response packet that carries the user MAC address as the destination MAC address. If you want your device to use the broadcast flag value in a DHCP request packet to determine the destination MAC address type for a DHCP response packet, run the dhcp reply trust broadcast-flag command.

Configuration Impact

After the dhcp reply trust broadcast-flag command is run, if the broadcast flag value in a DHCP request packet is 1, the device replies with a DHCP response packet that carries the broadcast address of all Fs as the destination MAC address; if the broadcast flag value in a DHCP request packet is 0, the device replies with a DHCP response packet that carries the user MAC address as the destination MAC address.

Precautions

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

The dhcp reply trust broadcast-flag command applies only to Layer 2 access users. The dhcp reply trust broadcast-flag command is mutually exclusive with the dhcp-broadcast command.

Example

# Enable a device to use the broadcast flag value in a DHCP request packet to determine the destination MAC address type for a DHCP response packet.

<HUAWEI> system-view
[~HUAWEI] interface GigabitEthernet 0/1/8
[~HUAWEI-GigabitEthernet0/1/8] bas
[~HUAWEI-GigabitEthernet0/1/8-bas] access-type layer2-subscriber
[*HUAWEI-GigabitEthernet0/1/8-bas] commit
[~HUAWEI-GigabitEthernet0/1/8-bas] dhcp reply trust broadcast-flag