dhcpinform request from Vista gets wrong Name servers

Randall C Grimshaw rgrimsha at syr.edu
Thu Aug 16 03:56:18 UTC 2007

>David W. Hankins wrote:
>> On Wed, Aug 15, 2007 at 09:55:14PM +0200, Sten Carlsen wrote:
>>> Maybe I misunderstood? I understood the problem so that DHCPOFFER gives
>>> the correct values and DHCPINFORM gives wrong values.
>> It's twisty.
>>> If that is correct, my proposal will solve the problem. DHCPOFFER taking
>>> values from the options in the subnet declaration (or range) and the
>>> DHCPINFORM takes the values from the general options. So matching
>>> DHCPINFORM to the range its address belongs to and using those values
>>> should work.
>> Remember the DHCPINFORM would be used by both parties...there are
>> Vista boxes that get a lease and then INFORM anyway on both sides.
>> To the question 'what are my nameservers?' there are 2 answers in
>> this hypothetical network.  Half the population should get one, half
>> should get the other answer.  It's broken if either gets the other's
>> answer.
>> If you reverse the search order on DHCPINFORM, then you fix the first
>> population and give them their correct answer.  But you also break
>> the second population by giving them the first's answer.
>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.

As you consider this, please remember that there are other overriding definitions for Name Services. There is a third source of who are my name-servers in this network. In addition to the subnet based definition of known and unknown, there are groups of known hosts that are also given specific name server values in support of Active Directory Trees that take precidence over the subnet values. (it would be nice to be able to fix the precidence to subnet values in some cases). It seems to me that name servers should become an element of the lease tracking table for the purpose of dhcpinform and omapi manipulation. 


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