Nokia ESB26 User Manual page 249

19. DHCP Client
The client may suggest values for the IP address and lease time in the DHCPDISCOVER
message. The client may include the requested IP address option to suggest that a particular
IP address be assigned, and may include the IP address lease time option to suggest the lease
time it would like to have. The requested IP address option is to be filled in only in a
DHCPREQUEST message when the client is verifying network parameters obtained
previously.
If a server receives a DHCPREQUEST message with an invalid requested IP address, the
server should respond to the client with a DHCPNAK message and may choose to report the
problem to the system administrator. The server may include an error message in the message
option.
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