Without Option 50 in DHCPDICSCOVER

David W. Hankins David_Hankins at isc.org
Wed Aug 1 17:53:51 UTC 2007

On Wed, Aug 01, 2007 at 01:40:32PM -0400, DavidWang at UoGuelph wrote:
> Good day, I have seen multiple cases that Windows XP/Vista machines sending
> out DHCP DISCOVER packet without Option 50. Does this normal? Is there any
> way to change client side's behavior? (like changing some registry keys)

This is normal.  Any DHCP client will omit the dhcp-requested-address
in a DHCPDISCOVER if the lease has expired and been removed from its
cache, or has been invalidated (as from a DHCPNAK).

The dhcp-requested-address option is somewhat confusingly, but
normally, included and omitted at different stages of a client's

Ash bugud-gul durbatuluk agh burzum-ishi krimpatul.
Why settle for the lesser evil?	 https://secure.isc.org/store/t-shirt/
David W. Hankins	"If you don't do it right the first time,
Software Engineer		     you'll just have to do it again."
Internet Systems Consortium, Inc.		-- Jack T. Hankins

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