Does an IPv4 DHCP Relay Agent care about Option 80 (rapid-commit) I'm trying to figure out if an IPv4 DHCP Relay Agent needs to care about a rapid-commit (Option 80) included in a DHCP Discover. My understanding is that the Relay Agent is supposed to simply converts the DHCPDISCOVER broadcast packet into a unicast packet before sending it to the DHCP Server (who should/must care about rapid-commit). Then, converts the received unicast DHCPACK into a broadcast message and send it back to the server's network. What I don't understand is what behavior change would the Relay Agent have between standard DORA and Rapid-Commit DA?

It should be a mostly transparent process to the relay agent. The agent gets the broadcast client request, adds it's relay information, and unicasts it on to the server(s). The server uses the relay information to return any message through the agent, who then broadcasts an answer back to the client. The client won't have an address at this point, so it has to be broadcast. At most, the agent may need to recognize the rapid-commit option to know it _must_ be a broadcast reply, but the DHCP options should already indicate a broadcast answer.