im contemplating some pretty exoctic network topology's.
and i just realsied i have no idea how DHCP works....

okay... there is a DHCP server, which has a static IP address.
then DHCP clients communicate with that DHCP server with UDP protocol.
the DHCP server provides parameters like DNS servers, and an ip address to the dhcp client.

but what i dont understand, is how the DHCP server contacts the DHCP client...
before the DHCP server responds to a DHCP client, the client does not have an IP address.

i thought maybe the device would have a default IP address which it uses untill the DHCP assigns it a permenant one... but if that were true, the system would fail if 2 DHCP clients queried a DHCP server at the same time...

how does it work ?

Hi.

The DHCP protocol doesn't use IP addresses. It uses the MAC address of the client network interface instead.

Dave