Normal configuration is set to DHCP supplied. Confirmation both via netsh and
visual via gui on affected machines. I have temporarily set them to static via
netsh to prevent the problem from stopping production while we trouble shoot it
on some of the idle machines.
--
There are 10 kinds of people in the world...
those who understand binary and those who don't.
From: [email protected] [mailto:[email protected]] On
Behalf Of Micheal Espinola Jr
Sent: Thursday, April 24, 2014 10:59 AM
To: ntsysadm
Subject: Re: [NTSysADM] DNS server settings getting changed
I still havent received Melvin's original reply, so I'm just gonna reply to
this:
Are you saying you used netsh to add DNS servers, or you used netsh to confirm
that the "bad" DNS servers were via added DHCP or static?
--
Espi
On Thu, Apr 24, 2014 at 7:35 AM, Andrew S. Baker
<[email protected]<mailto:[email protected]>> wrote:
If static works rather than DHCP, then it might not be a Group Policy issue.
Time to look at Kevin's suggestion.
ASB
http://XeeMe.com/AndrewBaker<http://xeeme.com/AndrewBaker>
Providing Virtual CIO Services (IT Operations & Information Security) for the
SMB market...
On Thu, Apr 24, 2014 at 10:31 AM, Melvin Backus
<[email protected]<mailto:[email protected]>> wrote:
Yep, been there. That's actually our temp solution, make them static instead
of dhcp.
--
There are 10 kinds of people in the world...
those who understand binary and those who don't.
From: [email protected]<mailto:[email protected]>
[mailto:[email protected]<mailto:[email protected]>]
On Behalf Of Micheal Espinola Jr
Sent: Thursday, April 24, 2014 10:26 AM
To: ntsysadm
Subject: Re: [NTSysADM] DNS server settings getting changed
Have you confirmed if the DNS addresses are static or DHCP provided? This
netsh should help you:
netsh interface ip show dns
--
Espi
On Thu, Apr 24, 2014 at 5:26 AM, Melvin Backus
<[email protected]<mailto:[email protected]>> wrote:
OK, this has been driving us nuts for a couple of days now.
One of our remote sites is seeing seemingly random PCs change their DNS server
settings. They're all configured to get them from the DHCP server, and it has
the correct DNS servers. All the PCs do in fact get the correct settings when
they get or renew an IP. That all seems to be working as we expect. But
periodically we'll see a machine change the DNS servers to something else.
This causes applications to start failing because the hosts they need no longer
resolve. As soon as the PC renews it's IP, whether automatically or manually,
everything goes back to normal and stuff works again.
We have a short term fix (force the DNS server settings manually instead of
DHCP) but that doesn't explain what's going on, and since we're using this same
setup in 20 offices it also begs the question of why just this office.
Background:
Multiple small offices with either /28 or /27 networks. They are publicly
routable IPs due to requirements for a partner VPN. The DHCP server is on the
Juniper SSG FW. It servers two pools, one for PCs, another for phones. The PC
subnet is publicly routable, the phone subnet is a non-routable 10.x subnet
with matching ranges. (12.x.x.x/27 and 10.x.x.x/27). All DNS points to the
home office. Until recently these pointed strictly to our domain DNS servers.
As part of the VPN requirement we have set up a second set of DNS servers which
are used to resolve hosts in the partner's domains. This is done with
conditional forwarders. Partner DNS traffic gets resolved by their servers,
everything else goes to our domain DNS or the Internet as required.
This all works fine except in a single office. Even in that office it worked
fine for weeks and has suddenly started this "revert" behavior. When the PCs
change, they go back to pointing to our domain DNS which can't resolve the
partner hosts.
My question becomes (sorry it took so long) how do we track what is actually
changing the DNS settings? I can tell when it happens fairly easily, but
nothing in the event logs, etc., seems to indicate what triggered it, or what
process is doing it. It doesn't happen as part of a DHCP operation as best we
can tell.
--------------------
Melvin Backus | Sr. Systems Analyst | Byers Engineering Company |
404.497.1565<tel:404.497.1565>
Service Desk | 404-497-1599<tel:404-497-1599> | http://servicedesk.byers.com
--
There are 10 kinds of people in the world...
those who understand binary and those who don't.
