When a configuration device boots, it sends a broadcast using the RARP protocol (Reverse Address Resolution Protocol). Mostly, it says:
Well, here I am. Here is a small message from me. From this message you should get my ethernet MAC address (6 hex digits uniquely identifying any Ethernet adapter ever built). From my MAC address, someone should be able to tell me my primary IP number. Thanks!:)
One Linux server may act as a RARP server. It will answer such a query only if it knows the answer.