Configuring DHCP option 82

Configure the DHCP option 82 to enable the circuit ID to encode an agent-local identifier of the circuit from which a DHCP client-to-server packet is received. Configure the DHCP option 82 to enable the remote ID to encode the MAC address of the interface on which the packet is received. By default, the DHCP option 82 is disabled.

Before you begin

You must enable ip and dhcp-relay on the VLAN.

About this task

To configure the DHCP option 82 on a VLAN, you must enter the VLAN Interface Configuration mode.

To configure the DHCP option 82 on a brouter port, you must enter the GigabitEthernet Interface Configuration mode.

Procedure

Enter Interface Configuration mode:

enable

configure terminal

interface GigabitEthernet {slot/port[/sub-port][-slot/port[/sub-port]][,...]} or interface vlan <1–4059>

Note

If the platform supports channelization and the port is channelized, you must also specify the sub-port in the format slot/port/sub-port.
Enable the circuit ID:

ip dhcp-relay circuitID
Enable the remote ID:

ip dhcp-relay remoteID
Configure the circuit as trusted:

ip dhcp-relay trusted
Show statistics for option 82, which is the relay agent information option:

show ip dhcp-relay counters option82 [vrf WORD<1–16>] [vrfids WORD <0–512>]

Example

Switch:1> enable
Switch:1# configure terminal
Switch:1(config)# interface gigabitethernet 1/10

Enable the circuit ID:

Switch:1(config-if)# ip dhcp—relay circuitID

Enable the remote ID:

Switch:1(config-if)# ip dhcp-relay remoteID

Configure the circuit as trusted:

Switch:1(config-if)# ip dhcp-relay trusted

Show statistics for option 82, which is the relay agent information option:

Switch:1(config-if)# show ip dhcp-relay counters option82

Variable Definitions

Use the data in the following table to configure the DHCP option 82.


Variable	Value
circuitID	Enables the Circuit ID.
remoteID	Enables the Remote ID.
trusted	Sets the circuit as trusted.

Use the data in the following table to use the show ip dhcp-relay counters option82 [vrf WORD<1–16>] [vrfids WORD <0–512>] command.


Variable	Value
vrf WORD<1–16>	Displays DHCP counters for a particular VRF. WORD<1–16> specifies the VRF name.
vrfids WORD <0–512>	Displays a DHCP forward path for a particular VRF. WORD <0–512> specifies the VRF ID.