03-05-2015 11:58 PM - edited 03-07-2019 10:58 PM
Discover - Broadcast
Offer - Unicast
Request - Broadcast
How it is possible that OFFER and ACK sent by
Confused, please clarify.
03-06-2015 07:28 AM
Hi
Firstly, the best way to learn the detail of things like this is fire up WireShark and take a look.
However.. to answer you directly:
A unicast is a packet that is destined to a single address, IP or MAC.
After a client does s DISCOVER, it gets an OFFER from the server.
The server (whether a local server or a relay agent) sends the response with a target IP address of the address it would assign to the client, and the clients L2 MAC address in the L2 header. Therefore it's a unicast, but one based on an assumption of the IP address.
Typically a sending device would ARP for the MAC based on the IP address it wants to reach; in this scenario the cleint wouldn't respond to the ARP (it doesn't have the address, as you say) but the server 'knows better'.
Regards
Aaron
03-10-2015 05:18 AM
@Aaron..
03-10-2015 07:37 AM
No problem.
Please remember to mark questions 'answered' when appropriate to highlight useful content.
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide