Switched Rack PDU
USER’S GUIDE
DHCP & BOOTP boot process
When Boot mode is set to its default DHCP & BOOTP setting, the following occurs when the Switched Rack PDU is started or reset:
1.The Rack PDU makes up to five requests for its network assignment from any BOOTP server. If a valid BOOTP response is received, the Rack PDU starts the network services and sets Boot mode to BOOTP Only.
2.If the Rack PDU fails to receive a valid BOOTP response after five BOOTP requests, the Rack PDU makes up to five requests for its network assignment from any DHCP server. If a valid DHCP response is received, the Rack PDU starts the network services and sets Boot mode to DHCP Only.
To configure the Switched Rack PDU so that it always uses the DHCP & BOOTP setting for Boot mode, enable the
Remain in DHCP & BOOTP mode after accepting TCP/IP settings option, which is disabled by default.
See Switched Rack PDU settings.
3.If the Switched Rack PDU fails to receive a valid DHCP response after five DHCP requests, it repeats BOOTP and DHCP requests until it receives a valid network assignment. First it sends a BOOTP request every 32 seconds for 12 minutes, then one DHCP request with a time- out of 64 seconds, and so forth.
If a DHCP server responds with an invalid offer (e.g., without the APC Cookie), the Switched Rack PDU accepts the lease from that server on the last request of the sequence and immediately releases that lease. This prevents the DHCP server from reserving the IP Address associated with its invalid offer.
For more information on what a valid response requires, see
DHCP response options.
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