332 DHCP Snooping CommandsUser GuidelinesTo enable DHCP snooping, do the following:1 Enable DHCP Snooping globally.2 Enable DHCP Snooping per VLAN.3 Set DHCP Snooping trusted port on the port in the DHCP serverdirection.The bindings database populated by DHCP snooping is used by several otherservices, including IP source guard and dynamic ARP inspection. DHCPsnooping must be enabled for these services to operate.ExampleThe following configuration enables DHCP snooping on VLAN 1 for a switchconnected to a DHCP server over interface gi1/0/4:console(config)#ip dhcp snoopingconsole(config-if-vlan1)#ip dhcp snoopingconsole(config-if-vlan1)#exitconsole(config)#interface gi1/0/4console(config-if-Gi1/0/4)#ip dhcp snooping trustip dhcp snooping bindingUse the ip dhcp snooping binding command to configure a static DHCPSnooping binding. Use the “no” form of this command to remove a staticbinding.Syntaxip dhcp snooping bindingmac-address vlanvlan-id ip-address interface{gigabitethernet unit/slot/port | tengigabitethernet unit/slot/port |fortygigabitethernet unit/slot/port | port-channelport-channel-id}no ip dhcp snooping bindingmac-address•mac-address — The client's MAC address.•vlan-id — The number of the VLAN the client is authorized to use.•ip-address — The IP address of the client.•interface — The interface on which the client is authorized. The interface maybe a physical interface or a port channel.
