Allied Telesis AT-FS970M Series - Manual (Page 644)

Chapter 42: DHCP Snooping Commands
644
SERVICE DHCP SNOOPING
Syntax
service dhcp snooping
Parameters
None
Mode
Global Configuration mode
Description
Use this command to enable the DHCP snooping service on the switch
globally. You must enable the SERVICE DHCP-SNOOPING command
before entering other DHCP snooping commands. By default, DHCP
snooping is disabled on the switch.
For DHCP snooping to operate on a VLAN, it must be enabled on the
switch by using this command and also enabled on the specified VLAN by
using the IP DHCP SNOOPING command. See “IP DHCP SNOOPING”
on page 626.
For DHCP snooping to operate on a VLAN, it must:
 Be enabled globally on the switch with this command
 Be enabled on the specified VLAN with the IP DHCP SNOOPING
command (see “IP DHCP SNOOPING” on page 626)
 Have at least one port connected to a DHCP server that is
configured as a trusted port using the IP DHCP SNOOPING
TRUST command (see “IP DHCP SNOOPING TRUST” on
page 637)
If you disable the DHCP snooping service by using the NO SERVICE
DHCP SNOOPING command, all DHCP snooping configuration (including
ARP security, but excluding maximum bindings and ACLs) is removed
from the running configuration, and the DHCP snooping database is
deleted from active memory. If your reenable the service, the switch
repopulates the DHCP snooping database from the dynamic lease entries
in the database backup file (in NVS by default). The lease expiry times are
updated.