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Interactions with other features – Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) User Manual

Page 1431

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DHCP Snooping Introduction and Configuration

Software Reference for x310 Series Switches

C613-50046-01 REV A

AlliedWare Plus

TM

Operating System - Version 5.4.4C

55.9

Interactions with Other Features

DHCP snooping interacts with other switch features as follows:

Ports in trunk mode

The DHCP snooping feature is enabled or disabled per VLAN, and several of the
related configuration settings are applied to ports. If there are multiple VLANs on a
port, all the VLANs will be subject to the same per-port settings.

DHCP relay

The switch cannot use DHCP snooping to filter IP traffic from a DHCP relay device.

DHCP snooping (

service dhcp-snooping command on page 56.24

) and the DHCP

relay agent option (

ip dhcp-relay agent-option command on page 64.10

) cannot

both be enabled on the switch at the same time.

DHCP snooping can be configured with port provisioning.

Authentication

DHCP snooping cannot be enabled on a switch that is configured for web
authentication (

auth-web enable command on page 43.33

), roaming authentication

(

auth roaming enable command on page 43.17

,

auth roaming disconnected

command on page 43.15

), or guest VLAN authentication (

auth guest-vlan command

on page 43.8

), or vice versa.

Stacking

If DHCP snooping is enabled in a stack, the DHCP snooping database and its backup
file are automatically synchronized across all stack members, so that a new stack
master can reinstate this database.

Link aggregators

DHCP snooping can operate over switch ports, and over static and dynamic (LACP)
link aggregators (channel groups). If a switch port is added to an aggregator, DHCP
snooping configuration is applied to the aggregator; configuration of the original
switch port is not preserved. If the switch port is then removed from the aggregator, it
returns to default DHCP snooping settings.

Private VLANs

Private VLANs are not supported for DHCP snooping.