dhcp snooping nni server enable

Function

The dhcp snooping nni server enable command enables NNIs to send DHCP reply messages to the host in a VSI scenario.

The undo dhcp snooping nni server enable command disables NNIs from sending DHCP reply messages to the host in a VSI scenario.

By default, NNIs are not enabled to send DHCP reply messages to the host in a VSI scenario.

Format

dhcp snooping nni server enable

undo dhcp snooping nni server enable

Parameters

None

Views

VSI-AUTO view, VSI-BD view, VSI-BVSI view, VSI-DEFAULT view, VSI-IVSI-MP2MP view, VSI-IVSI-P2P view, VSI-STATIC view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
dhcp	write

Usage Guidelines

Usage Scenario

In a VSI scenario, if DHCP snooping needs to be configured for an AC interface when the DHCP server is deployed on the network side, you can run the dhcp snooping nni server enable command to enable NNIs to send DHCP reply messages to the host. After the command is run, binding entries can be generated, and users can go online.

Prerequisites

DHCP snooping has been enabled globally using the dhcp snooping enable command.

Follow-up Procedure

Enable DHCP snooping on an AC interface using the dhcp snooping enable command.

Precautions

In a VSI scenario, if dhcp snooping enable and dhcp snooping trusted commands are run on an NNI, and the dhcp snooping nni server enable command is run in the VSI view, the configurations on the NNI take effect. If multiple VSIs share the same NNI, the dhcp snooping nni server enable command takes effect on all VSIs, which may provoke the following problems:

VSIs cannot be identified when the NNI sends DHCP reply messages to the host. As a result, DHCP snooping does not take effect, but users can go online.
The NNI sends DHCP reply messages to the host even when DHCP snooping is not enabled on some of the VSIs, which increases device load.
If a whitelist has been applied when dhcp snooping nni server is enabled, ensure that whitelist rules have been configured for all valid DHCP servers in the whitelist.
When the dhcp snooping nni server enable command is configured in a VSI where a whitelist has been applied, the following message is displayed: Info: A whitelist has been applied. Configure complete whitelist rules for valid DHCP servers.

Example

# Enable the NNI to send DHCP reply messages to the host in the view of VSI 1.

<HUAWEI> system-view
[~HUAWEI] mpls
[*HUAWEI-mpls] quit
[*HUAWEI] mpls l2vpn
[*HUAWEI-l2vpn] quit
[*HUAWEI] dhcp snooping enable
[*HUAWEI] vsi vsi1
[*HUAWEI-vsi-vsi1] dhcp snooping nni server enable