Re: Multiple Domain Controllers -- who takes over if one is down?

From: Oscar (
Date: 10/18/04

Date: Mon, 18 Oct 2004 13:36:31 -0700

Thanks Mike for your answer. I answered all of your questions below. I
specifically had a new question based on one of your points...

You said:
....If domain controller fails client may need to reboot their computer...

We know this is the case right now and it works, so if a client reports
loss of connectivity they can reboot and the issue is solved. However
is there a way to have the domain, servers or client handle this event
on their own without having the user reboot? In other words, is there a
way to have the user "never know" that one of the DCs is unavailable?

Miha Pihler wrote:
> Hi Oscar,
> How are your domain controllers configured?
> * Make sure that you have at least two servers with global catalogs role
> assigned. If only one is assigned this role and this server goes down, users
> won't be able to logon.

> * Are all 3 of your server DNS servers? If you only have one server
> configured as DNS server and it fails, users won't be able to locate other
> servers since they use DNS service (to e.g locate global catalogs in
> domain)...

--- dc01 - schema master, dnaming master, pdc emulator, infrastructure
master - global catalogs
--- dc02 - dhcp, dns & master browser - global catalogs
--- ad3 - certificate services, dns & dhcp

> How are your clients configured?
> * Do they have one or more DNS servers configured under TCP/IP properties?
> If they have and this server that is listed as DNS server under TCP/IP
> properties fails, clients won't be able to look for other global catalogs in
> domain.

--- client systems do know about both dc01 and dc02.

> If domain controller fails client may need to reboot their computer. To find
> out which domain controller authenticated the client use this command
> echo %logonserver%
> Even with normal operation of your domain controllers clients should use
> different domain controllers...

--- what do you mean by "should" we looked at 6 or so clients and they
are authenticating to one or the other -- I assume as they are available.

> Mike
> "Oscar" <> wrote in message
> news:eTh9FzUtEHA.2196@TK2MSFTNGP14.phx.gbl...
>>Hello and thanks in advance to anyone that can help me.
>>Here's the scenario I'm refering to in my question.
>>1 Domain (2000 Native, migrated from NT4.0)
>>DC01 - Domain controller 1 - this is running the PDC emmulator (for
> NT4.0)
>>DC02 - Domain controller 2
>>DC03 - Domain controller 3 - Also doing Certificate Services
>>EX01 - Exchange 2000
>>EX02 - Exchange 2000
>>How can we ensure that if DC01 goes down users authenticated against it
>>do not loose connectivity/authentication? For example, one of our DCs
>>went down last night (specifically DC01). And this caused some people to
>>not be able to send email.
>>We thought that the DCs were redundant to where if one went down the
>>other 2 or at least one would "pick up the slack" and this process would
>>be transparent to the user.
>>I can answer any other questions you may need answers to so I you can
>>help me with this.
>>Can anyone point me in the right direction? I've looked around MS but
>>didnt find information on this, maybe I wasn't looking for the right
>>terms or I was looking in the wrong place. I also didn't find a more
>>appropriate group to post this on. Your help is greatly appreciated.
>>thank you.