TCP/IP Tutorial and Technical Overview - IBM Redbooks

Figure 3-46 shows the DHCP process and changing client state during that
process.
Figure 3-46 DHCP client state and DHCP process
3.7.5 Reusing a previously allocated network address
If the client remembers and wants to reuse a previously allocated network
address, the following steps are carried out:
1. The client broadcasts a DHCPREQUEST message on its local subnet. The
DHCPREQUEST message includes the client's network address.
2. A server with knowledge of the client's configuration parameters responds
with a DHCPACK message to the client (provided the lease is still current),
renewing the lease at the same time.
3. If the client's lease has expired, the server with knowledge of the client
responds with DHCPNACK.
138 TCP/IP Tutorial and Technical Overview