I had query in DHCP. I understood well working of DORA process in single broadcast domain( i.e DHCP client and DHCP server in the same broadcast domain).
How DORA process will work if DHCP client and DHCP server are in the different broadcast domains. I know it will work if we configure helper-address in the router interface of client broadcast domain. So at that time the router will send unicast meesage to the DHCP server. But how DHCP offer message will reach the DHCP client from DHCP server( First i want to know DHCP offer message from server is broadcast or unicast at both layer 2 and layer 3 levels).
Please Give me in more dertail for understand purpose.
Solved! Go to Solution.
If DHCP clients and servers on the same subnet the the communicate via UDP broadcasts.
If the client and server are on different subnets, a DHCP Helper or DHCP Relay Agent may be used. Clients requesting renewal of an existing lease may communicate directly via UDP unicast.
Please rate all the helpfull posts.
Thanks for your prompt reply.!!!!!
I know in this scenario, we will use helper or relay agent to get IP address. If it is the first time, how DHCP offcer msg will come to the client from DHCP server( Because the client doesn't have IP address i.e 0.0.0.0, right???)
Please help me to understood this scenario...
i just tried it here with my existing equipment(no cisco) and made a trace with my network analyzer.
the result was surprising to me.
ethernet frame: source mac: mac of the dhcp server; dest. mac: FF:FF:FF:FF:FF:FF
ip packet: source ip: ip of the dhcp server; dest. ip: 0.0.0.0
but there was an additional packet or protocol or dont know how to call it.
bootstrap: dest. mac: mac of the pc
dest. ip: ip address which was offered to the pc by the dhcp server.
i actually thought that unicasts are used.