dhcpinform request from Vista gets wrong Name servers

David W. Hankins David_Hankins at isc.org
Thu Aug 16 16:55:44 UTC 2007

On Thu, Aug 16, 2007 at 01:42:49AM +0200, Sten Carlsen wrote:
> Basically I would want to use the exact same search order for both
> message types, hoping to get the same results. So what ever
> group/class/subnet/range the host belongs to when the OFFER is sent,
> would also apply when the INFORM is sent; if this will not give the same
> answer, I am missing something important here.

Right, and where we fall short is that we don't source the lease (so
we miss out on 'binding scopes' or the lease's pool), and we don't
source host records (from which known/unknown would follow).

I can't remember if we source classes.  I think we probably do because
I think classing is done before message-specific processing.

The main hinky point here is that the purpose of DHCPINFORM is to
serve clients that have not been allocated a dynamic address.  So
it would be, for example, very unusual to deny service to clients
that weren't addressed by DHCP.

'Optionally' sourcing this information when it's available, however,
sounds reasonable...

But if you run multiple disjoint DHCP servers (no failover), then you
can still run into problems where the servers will give out
conflicting answers.

I think we can work around that by supplying a new config option
to enable or suppress DHCPINFORM processing (right now we use the
'authoritative' setting).

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

More information about the dhcp-users mailing list