Hello,

We have Exchange 2013 and Outlook 2010 up and running in a Win2003 and Win2012 DC environment. Recently we promoted the Win2012 to be the PDC along with all the FSMO roles. We're trying to get rid of the Win2003 DC, so during the last patch cycle, I turned the Win2003 DC off. Exchange was still running fine along with emails going back and forth, however I would see some messages in the logs, MSExchangeADTopology - "No Minimal Required Number of Suitable Directory Servers Found in Forest ABC.local Site ABC and connected Sites". I ran DCDIAG and everything looked good. It complained about the Win2003 DC being off, but the PDC was working fine and it was connecting to it.

Today we had a slight network issue and I had to restart the Exchange server. It came back, but I saw lots of errors related to not being able to connect to DC along with the same problem of - "MSExchangeADTopology - No Minimal Required Number of Suitable Directory Servers Found in Forest ABC.local Site ABC and connected Sites" Unfortunately, Exchange services wouldn't start. So I started my Win2003 DC and voila, everything started working.

So I'm confused now as to what and how to fix this issue. The only thing I can think of being different is that my Win2012 PDC does not have WINS, while my Win2003 DC does have it. I thought WINS wasn't being used since Exchange 2007, but I may be wrong. Can someone please suggest as to what I can try to fix this issue? Do I have to demote my Win2003 DC to get this working, but if I do, then won't I have the same problem? Is there somewhere in Exchange that my Win2003 server is hardcoded maybe?

Any help is appreciated.

Thank you,

-Sau

Hello

check eventlog for 2080 id for

CDG 1 7 7 1 0 1 1 7 1 please share log.

What CU are you running on Exchange 2013?  Are your DC's 2012R1 or r2?

Hello,

@Sneff_Gabor:

My event log for ID 2080 currently shows:

SVR01Win2003.ABC.local CDG 1 0 0 0 0 0 0 0 0

SVR02Win2003.ABC.local CDG 1 7 7 1 0 1 1 7 1

PDCSVR03Win20012R2.ABC.local CDG 1 7 7 1 0 1 1 7 1

SVR04Win2012R2.ABC.local CDG 1 7 7 1 0 1 1 7 1      

As you can see, I have 2 Win2003DCs and 2 Win2012R2 DCs. I had turned both of the Win2003DCs off and then due to the problem, I had to turn one (SVR02Win2003.ABC.local) of them back on.

@Hinte:

I am on Exchange2013 CU6. The Win2012 DCs are R2.

Another thing I forgot to mention is that I have IPv6 unchecked from my network adapter on servers and workstations, to try to disable IPv6. Not sure if that would be a problem or not.

Thanks for all the replies!

-Sau

Hello

please set logging high
Get-EventLogLevel -Identity "MSExchangeADTopology\*" |Set-EventLogLevel -Level high
and get maintenance time and restart exchange and check eventlog
if you can shutdown 2003 server. and check dns settings on exchange server  /need new dc present in dns setting/

I've set the logging levels to High. Will I see those logs in the Application logs or somewhere else?

Thanks,
-Sau

Hello

in application log :)

Hi Sau,

Please run the following command to hard code domain controller to have a try:

Set-ExchangeServer -identity DNEX01-V -StaticDomainControllers PDCSVR03Win20012R2.ABC.local,SVR04Win2012R2.ABC.local -StaticConfigDomainController PDCSVR03Win20012R2.ABC.local -StaticGlobalCatalogs PDCSVR03Win20012R2.ABC.local,SVR04Win2012R2.ABC.local

Regards,

Thanks, will have to try those in my next maintenance interval. So can someone confirm that I can turn off IPv6 (in my network adapter) at least and have Exchange running properly?

Thanks,

-Sau