Different DNS server response for dhcpdiscover than for dhcpinform

David Forrest drf at maplepark.com
Fri Apr 16 15:26:25 UTC 2010

On Fri, 16 Apr 2010, Randall C Grimshaw wrote:

> It would be good for someone to bring this to the RFC design table because it makes it very unreliable to configure different settings. Because info requests only deliver the global values, over-riding more localized administrator settings based on the client behavior in making the info requests.
> Randy
> -----Original Message-----
> From: dhcp-users-bounces+rgrimsha=syr.edu at lists.isc.org [mailto:dhcp-users-bounces+rgrimsha=syr.edu at lists.isc.org] On Behalf Of Glenn Satchell
> Sent: Thursday, April 15, 2010 8:55 PM
> To: Users of ISC DHCP
> Subject: Re: Different DNS server response for dhcpdiscover than for dhcpinform

Randy, I had continual DHCPINFORM requests from XP and, IIRC, from Vista
machines that I was able to stop by providing AD server information via a
SRV RR in my domain DNS server.  It may be because some Windows machines
are configured for services I don't offer here (ISC BIND on Linux servers
using Samba for file sharing).  Maybe this link is relevant to the

As I'm not using/serving Active Directory services, I just added this RR 
in my domain zone file:

$ORIGIN maplepark.com.
_ldap._tcp.dc._msdcs SRV 0 0 0 .

and that seemed to silence the DHCPINFORM requests as they were told,
somehow, that I didn't have any such servers.  I'm not facile with Windows
but Macs, Windows 7, XP and Vista visiting laptops have had no problems
getting dynamic pooled IPs from a registered MAC pool with specific
nameservers and lease times and DDNS updates from dhcpd.

I'm not convinced these problems aren't configuration rather than
RFC problems but then I'm a "know-next-to-nothing" guy.

David Forrest
St. Louis, Missouri    (Sent by ALPINE 2.01 FEDORA 11 LINUX)

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