D-Link DES-3326 User Manual page 86

24-port NWay Ethernet Switch User's Guide
When the address lease expires, the DHCP client enters the
renewing state. The client sends a request message to the DHCP
server that provided the address. The DHCP server sends an
acknowledgement that contains the new lease and configuration
parameters. The client then updates its configuration values and
returns to the bound state.
When the DHCP client is in the renewing state, it must release
its address immediately in the rare event that the DHCP server
sends a negative acknowledgment. The DHCP server sends this
message to inform a client that it has incorrect configuration
information, forcing it to release its current address and acquire
new information.
If the DHCP client cannot successfully renew its lease, the client
enters a rebinding state. The client then sends a request
message to all DHCP servers in its range, attempting to renew
its lease. Any DHCP server that can extend the lease sends and
acknowledgement containing the extended lease and updated
configuration information. IF the lease expires or if a DHCP
server responds with a negative acknowledgement, the client
must release its current configuration, and then return to the
initializing state.
If the DHCP client uses more than one network adapter to
connect to multiple networks, this protocol is followed for each
adapter that the user wants to configure for TCP/IP. Multi-
homed systems are selectively configured for any combination of
the system' s interfaces.
When a DHCP-enabled computer is restarted, it sends a message
to the DHCP server with its current configuration information.
The DHCP server either confirms this configuration or sends a
negative reply so that the client must begin the initializing state
again. System startup mignt, therefore, result in a new IP
address for a client computer, but neither the user nor the
70 Switch Management and Operating Concepts