Re: DNS failover

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Date: Wed, 13 Oct 2004 01:15:03 -0700

"Roland Hall" wrote:

> DCs do not imply DNS. Are these also respective primary/secondary DNS
> servers running AD?
> Failed how? What happened/did not happen?

Our network is divided into sites and we are adding additional Windows 2000
Server based domain controllers to each site to improve the availability and
reliability of the network services. AD and DNS are installed on each DC and
the domain is in mixed-mode.

At each site each client is setup so that on the DNS configuration the
primary DNS is the IP address of the primary DC and the secondary DNS is the
IP address of the DC at the site. I was disconnecting the primary DC and
testing if each client will be able to connect to the local DC when logging
on to the network. The site I was testing has two PCs running on Windows NT
(SP 5 & 6) beside the additional Windows 200 Server based DC. Both clients
failed to logon to the network. The error message during the startup of a
client was;

"A Domain Controller for your domain could not be contacted. You have been
logged on using cached account information."

We are also running a Human Machine Interface (HMI) application on each
client whose security was configured to connect the domain for user access
rights. The above error message was also observed on the HMI application
during a logon;

'Unauthorized access attemted'

My understanding was that a client will contact a domain controller as part
of the logon process in the order defined under TCP/IP-DNS search order
settings. As one of the posts on this group says the setting on the client is
not related to the server side concept of 'primary' and 'secondary', that I
just figured out.

At another site which has PCs running on Windows 2000 and Windows NT (SP6)
when the primary DC was disconnected from the network all of the W2000 and 2
out of the 3 NT clients did logon to the network. However, the logon process
took an unacceptably long time.

I am not sure why the clients that failed to logon to the network when the
primary Dc was disconnected didnot connect the DC at the site.

Currently I am looking into NETBIOS name resolution (WINS server, LMHosts
file, or NetBIOS broadcast) as this is still reguired for earlier versions of
Windows to resolve network resources on an AC domain and PDC emulator which
acts as a Windows NT primary domain controller. I am not sure if I am in the
right track or not.

Thank you for your time! And I apologize for my late response.

Ezer

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