A Dynamic Host Configuration Protocol for IPv6 (DHCPv6) relay agent relays messages between the client and the server.
A client locates a DHCPv6 server using a reserved, link-scoped multicast address. Direct communication between the client and server requires them to be attached by the same link. In some situations where ease-of-management, economy, and scalability are concerns, you can allow a DHCPv6 client to send a message to a DHCPv6 server using a DHCPv6 relay agent.
A DHCPv6 relay agent, which may reside on the client link but is transparent to the client, relays messages between the client and the server. Multiple DHCPv6 relay agents can exist between the client and server. DHCPv6 relay agents can also receive relay-forward messages from other relay agents. These messages are forwarded to the DHCPv6 server that is specified as the destination.
When the relay agent receives a message, it creates a new relay-forward message, inserts the original DHCPv6 message, and sends the relay-forward message as the DHCPv6 server.