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DNS Setup (A, CNAME, PTR) question

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  • DNS Setup (A, CNAME, PTR) question

    Hi all,

    Our environment W2k3 server DNS integrated in AD (tranfered from W2K DC).

    I want to setup (forward lookup zone)
    actual-name IN A actual-address.
    aliased-name IN CNAME actual-name

    What shoud I put in reverse lookup zone, how should I configure
    PTR records ?

    Thank in advance

  • #2
    Re: DNS Setup (A, CNAME, PTR) question

    When you create a reverse lookup zone, it will ask you for the network address. When you add the records to DNS or when they are added automatically, there is an option on the record for the PTR to be updated/added automatically. AFAIK, it updates the reverse lookup zone automatically providing you first setup a reverse lookup zone before servicing clients.
    Last edited by Virtual; 13th May 2009, 09:55. Reason: spelling


    • #3
      Re: DNS Setup (A, CNAME, PTR) question

      The PTR record for the A record was updated automatically.

      My problem is that certain clients (W2K pro SP4 specifically) are unable to run
      intermitently some apps (Oracle apps).

      I suspect that is a DNS problem reverse resolving to the CNAME record.
      Is it valid to put a (second) PTR record pointing to CNAME record.

      Putting two A records pointing to the same address and two PTR records pointing to the
      A records WinXP clients work, but W2K clients doesn't.

      In the above configuration nslookup <IP_ADDR> resolves one time to first A record and
      the next time to the second A record.

      I hope I made myself clear.


      • #4
        Re: DNS Setup (A, CNAME, PTR) question

        DNS has 'Round Robin' configured as default, so will cause the behaviour you mention. You can set costs on hte records I believe though I've never had to do it.

        Not entirely sure of wat may be causing the issue but have you tried adding the appropriate names and IPs to the Windows 2000 machines LMHOSTS and HOSTS files and tested. Not sure how many machines you have but worth testing on one now to rule out it being caused by another issue.


        • #5
          Re: DNS Setup (A, CNAME, PTR) question

          After restarting the client machine the problem vanished.
          But, still, I don't understand the cause.
          If I restart again the client would it apear again )


          • #6
            Re: DNS Setup (A, CNAME, PTR) question

            Hopefully not.

            It may be that the DNS resolver needed clearing. Another time, try te ipconfig /flushdns command and test, though not sure if that works on a windows 2000 client.

            Thanks for posting back and glad it is sorted, subject to testing over the next few days.