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Fixing Active Directory DNS (_msdcs, _sites, _tcp, _udp)

By Jesse | April 23, 2009

Have you ever accidentally deleted the AD DNS settings such as _msdcs, or installed AD and then needed to add a DNS server? How do you get AD to build it’s DNS settings. As you know AD is very tightly bound to DNS so if those settings are not there, DNS is probably going to cause a world of hurt moving forward.

Never fear, this can easily be fixed. To fix this, download the Windows Support Tools :

After installing the support tools, verify your dns on the server is set correctly.  Generally I set domain controllers to have their DNS boxes BLANK.. (ie they use themselves to resolve DNS.   If they cannot find the DNS entry they seek, they use the root servers to do recursive queries.).

To check dns, goto TCP/IP properties of your Local Area Connection.. and in the “Use  the following DNS server addresses:”  set this value to blank.  It should give you a message when you hit ok that it is using localhost as the DNS server.

Now goto the command prompt and in c:\program files\support tools run :

dcdiag /fix

then run

netdiag /fix

Finally run

ipconfig /flushdns
ipconfig /registerdns
net stop server
net start server

If you refresh your DNS you should now have all your entries in DNS that you need for AD to work properly..  The above command verify more than just fixing the DNS issues, but it doesnt hurt to run them and the dcdiag and netdiag will make sure your AD / DNS are the way they need to be.

One other note.   Net stop server stop more than just DNS .. it also stops Netlogon and Distributed File systems.   THESE SERVICES DO NOT START BACK UP ON THEIR OWN–   so after you’ve done the steps above I recommend either a quick reboot or if you cant do that go into service and start any automatic services that are stopped (such as netlogon and distributed file systems..   Your server should now work fine!

Now sit back and relax.

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Topics: How To, Microsoft Windows | 21 Comments »

21 Responses to “Fixing Active Directory DNS (_msdcs, _sites, _tcp, _udp)”

  1. Alper AYDIN Says:
    February 16th, 2010 at 10:47 am

    thank you for your helping, its quatly good for me, your site. I saved my server with your DNS helping

  2. Mike Harraf Says:
    March 17th, 2010 at 5:02 pm

    Thanks you for the great step by step articel. It help me to solw my DNS issue. cheers,

  3. Jesse Says:
    March 22nd, 2010 at 2:03 pm

    What would you recommend setting this to then?, I suppose alternately you could set the DNS to no do recursive lookups…. But then if the server isnt authoratative, you have a problem. Alot of people put their ISP’s DNS settings, but this is wrong as these are supposed to list alternate DNS servers that are DNS peers.


  4. Dinesh Says:
    August 25th, 2010 at 8:00 am

    this is very useful information. thanks alot.

  5. Alex Says:
    October 2nd, 2010 at 12:35 pm

    NICE !!! 10/05/2010 test this solution !!!

  6. ghassan Says:
    November 7th, 2010 at 7:00 am

    how Fix Active Directory DNS (_msdcs, _sites, _tcp, _udp) in windows 2008 server, can you kindly guide me to solve this issue on my server.

  7. Adam Says:
    December 19th, 2010 at 8:19 pm

    I have a similar issue to the above but when i go through your steps i get errors mainly i think because it is trying to contact the second Dc in the Network and that is not avaliable

    Any Suggestions

    Thanks in Advance


  8. Brian Says:
    January 3rd, 2011 at 1:11 pm

    Wicked ! Fixed my problem. Many thanks.

  9. Jesse Says:
    January 19th, 2011 at 1:52 pm

    Also remember that if net stop server stops any other services you’ll also need to go back and start those services up too..

  10. JM Says:
    December 12th, 2011 at 8:56 pm

    fixed my issue…thanks.

  11. jaie Says:
    December 21st, 2011 at 2:01 am

    Thx alot :)

  12. jaie Says:
    December 21st, 2011 at 2:04 am

    thx alot

  13. Iwan Essery Says:
    March 22nd, 2012 at 8:23 am

    I just wanted to say thank you very much. This fix is just what I needed. Thank you for being one amongst many of people who can do their job better than I can.

  14. Tom Says:
    June 26th, 2012 at 7:50 am

    +1K thx for your tips couldn’t dcpromo a new controller because of an error on the trailing .local domain name which was not accessible

  15. Kenneth Moeng Says:
    October 29th, 2012 at 5:41 am

    Well done with the fix and thank you. this did the trick quickly and i am back online

  16. Johnny Says:
    March 18th, 2013 at 11:07 pm

    Thank you!

  17. Marlon Roa Says:
    April 1st, 2013 at 6:45 pm

    Gracias- thanks
    Pero El comando netdiag no me funciono en windows 2008

  18. Clancy Says:
    September 6th, 2013 at 2:58 pm

    Hey, just wanted to say thanks this helped! There are still people running server 2003 out there (against my wish personally) But this was a great fix!

  19. Ahson Ali Shaikh Says:
    November 11th, 2013 at 6:22 am

    Thank you very much, My AD works fine.

  20. chanrita Says:
    February 19th, 2015 at 6:35 am

    thanks a lot.. great help..

  21. Remy Says:
    July 22nd, 2015 at 6:57 pm

    Thank you!! I ran scavenge old records and it delete all my AD settings in DNS. This looks to have repaired them all.

    Thank you!!!