Configures the system to relay DHCP client messages to an off-network DHCP server.
Use this command to configure the system as a DHCP relay agent.
A DHCP relay agent receives DHCP packets from DHCP clients and forwards them to a DHCP server. This allows you to place DHCP clients and DHCP servers on different networks; that is, across router interfaces.
The relay agent is configured with addresses of DHCP servers to which they should relay client DHCP messages. The relay agent intercepts the broadcast, sets the gateway address (the giaddr field of the DHCP packet) and, if configured, inserts the Relay Agent Information option (option 82) in the packet and forwards it to the DHCP server.
The DHCP server echoes the option back verbatim to the relay agent in server-to-client replies, and the relay agent strips the option before forwarding the reply to the client.
All interfaces involved in the DHCP relay for both clients and servers must be explicitly defined by using service dhcp-relay listen-interface <interface>.
Use the set form of this command to define DHCP relay configuration.
Use the delete form of this command to remove DHCP relay configuration.
Use the show form of this command to view DHCP relay configuration.