The client begins in INIT-REBOOT state and sends a DHCPREQUEST message. The client MUST insert its known network address as a 'requested IP address' option in the DHCPREQUEST message. The client may request specific configuration parameters by including the 'parameter request list' option. The client generates and records a random transaction identifier and inserts that identifier into the 'xid' field. The client records its own local time for later use in computing the lease expiration. The client MUST NOT include a 'server identifier' in the DHCPREQUEST message. The client then broadcasts the DHCPREQUEST on the local hardware broadcast address to the 'DHCP server' UDP port.
Once a DHCPACK message with an 'xid' field matching that in the client's DHCPREQUEST message arrives from any server, the client is initialized and moves to BOUND state. The client records the lease expiration time as the sum of the time at which the DHCPREQUEST message was sent and the duration of the lease from the DHCPACK message.