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  • Possible DNS issue

    HI,

    We recently replaced 2 old windows 2003 dc'S with windows 2008r2 dc'S. All is working ok except on odd occasions when query the AD i get errors such as "Server not operational" or "Domain does not exist" Everything looks correct on DNS and there are no entries for the old servers so i am looking at alternatives. If i run wireshark i get entries such as

    192.168.180.132 192.168.180.255 NBNS 92 Name query NB XXXXXXX

    192.168.180.132 is the ip of a standard workstation
    192.168.180.255 is an ip that has no harware associated with it
    XXXXXX is the server name for one of the old servers i removed

    not sure if this is realted or not, but i think both need to be resolved.

    New to all this, can anybody guide on where to start

    Thank

    Gareth

  • #2
    Re: Possible DNS issue

    Go through all the DNS folders (_msdcs, _sites, _tcp, etc.) and make sure there are no references to the old servers. Usually they are some records left behind when demoting DCs.

    192.168.180.255 is the broadcast address for your subnet. Those packets get forwarded to all nodes in the broadcast domain (we're talking layer 2 switching domain, not active directory). Basically all nodes in the subnet. That query is looking for XXXXXXX to respond. But since it's not there then it won't respond.

    I think if you go through your DNS you'll find the issue.
    Regards,
    Jeremy

    Network Consultant/Engineer
    Baltimore - Washington area and beyond
    www.gma-cpa.com

    Comment


    • #3
      Re: Possible DNS issue

      Yes, you need to go through the new server keenly and remove traces of the old server that might be there.

      After that do a metadata clean up in the new server ,restart it and test.

      Check the DNS event log for any warnings/errors as well

      Comment


      • #4
        Re: Possible DNS issue

        Hi,

        i have gone completely through the DNS server and there are no references toeither of the old servers.

        I tried to do a meta cleanup, broguht up a lsit of servers and neither of the old servers were in the list

        no errors in the DNS logs

        thanks

        Comment


        • #5
          Re: Possible DNS issue

          Do you use WINS on your network?
          Regards,
          Jeremy

          Network Consultant/Engineer
          Baltimore - Washington area and beyond
          www.gma-cpa.com

          Comment


          • #6
            Re: Possible DNS issue

            Hi,

            Not sure how would i check?

            Comment


            • #7
              Re: Possible DNS issue

              ipconfig/all, see if there's a WINS server listed. Check your servers and see if one is running the WINS service (usually on DC's and DNS servers).

              WINS is obsolete but was used for name and service resolution.
              Regards,
              Jeremy

              Network Consultant/Engineer
              Baltimore - Washington area and beyond
              www.gma-cpa.com

              Comment


              • #8
                Re: Possible DNS issue

                is your dhcp scope assigning name server addresses for the old hosts ?
                Please do show your appreciation to those who assist you by leaving Rep Point https://www.petri.com/forums/core/im.../icon_beer.gif

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                • #9
                  Re: Possible DNS issue

                  Hi,

                  Most of the workstations are DHCP and the WINS PROXY Enabled is NO.
                  On the servers it is also set to NO.
                  There is no servers with it enabled either. If i click on the network properties then Details it shows WINS in the list but the entry is blank.
                  The DHCP server scope does not have anyhting about WINS in it.
                  We have LMHOSTS set to enabled and Netbios set to Default (which is enabled as it is not mentioned in the dhcp scope.)

                  On one of the DC's i can get into the properties for
                  "Client for Microsoft Networks" and in there the "Name Service Provider" is set to blank. If i try to change it, it does not hold the setting. Is this Normal?

                  The DHCP still has the reservations for the old servers so i have deleted them.

                  In the DHCP scope i hve entries for :

                  Router
                  DNS Servers
                  DNS DOmain Name
                  NTP servers

                  None of which mention the old servers. Under DNS servers i have the 2 new DNS servers and also 2 entries for our ISP. Is this correct?

                  thanks

                  Comment


                  • #10
                    Re: Possible DNS issue

                    Hi,

                    did anyone have another chance to look at this?

                    thanks

                    Comment


                    • #11
                      Re: Possible DNS issue

                      Originally posted by kebabinho View Post
                      Hi,

                      did anyone have another chance to look at this?

                      thanks
                      What happens if you do an NSLOOKUP for the server name?

                      Comment


                      • #12
                        Re: Possible DNS issue

                        Thanks for everyones help on this. i think i may have resolved the problem.

                        Our DHCP was set to give every workstation / laptop their IP details, and as part of the DNS settings it was giving both the internal servers AND our ISP Servers. I have removed the ISP servers from the settings and added them into the DNS server as forwarders instead. figures crossed

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