ip dhcp relay information option

Use this command to insert the circuit-id (1) and remote-id (2) sub-options of the Relay Agent Information option (82) into the relay agent DHCP packet.

Syntax

Parameters

None.

Defaults

None.

Mode

Configuration command, Global configuration.

Configuration command, Interface configuration.

Usage

When forwarding DHCP requests from a local client to a remote DHCP server, the DHCP relay agent needs to include information about itself in order for the DHCP server to determine which pool of client addresses to pull the lease from. Including Option 82 in the DHCP relay information provides the required DHCP relay information.

Refer to RFC 3046 for descriptions of these sub-options:

The default circuit-id sub-option value inserted into the relay agent DHCP packet is the interface name of the interface receiving the request from the client, in the form of vlan.0.x where x is the VLAN id between 1 and 4094. This default value can be over-ridden at the interface level by using the ip dhcp relay information option circuit-id command in interface configuration mode.

The remote-id sub-option is used to identify the remote host end of the circuit. The default value inserted into the relay agent DHCP packet is the MAC address of the chassis. This default value can be over-ridden by using the ip dhcp relay information option remote-id command in global configuration mode or interface configuration mode.

The “no” form of this command removes the sending of these sub-options of Option 82 in the DHCP relay information.