Jame Clay said in a message to All:

 JC>        How does the dhcp client identify itself to the dhcp server?
 JC> (So that the server 'knows' who it is that trying to get an IP...) 
 JC> The MAC address on the NIC?  The hostname of the client?

A DHCP client sends a broadcast packet 'requesting' an IP address to the
DHCP port. The DHCP server listens on this port for 'broadcasts' and
replies to them as appropriate.

As with any other packet sent out on the network, the packet header
contains the MAC address of the transmitting Ethernet card.

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