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Domain Controller - DNS Issue

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  • Domain Controller - DNS Issue

    I brought up a domain controller in a new site in the same AD domain/forest.

    The default gateway points to a VPN connection to my primary site.

    When a user connects to a client machine and uses the DNS server it works fine.

    When i switch the default gateway on the Domain Controller to my "point to point line" and the user tries to connects it works fine as well.

    Then after 10 minutes of inactivity - I lose access (via the host) to the internet.

    My internal DNS is still working no problem but client's are not able to reach the internet either via the "forwarder dns" external or even root hints.

    The only current fix i have is to do a ipconfig/registerdns which temporarily fixes the issue but then it happens again.

    Any ideas/suggestions -- i am going crazy here...

    BTW - i demoted the server and repromoted the server to see if it would fix it but nothing...

  • #2
    Re: Domain Controller - DNS Issue


    Where you do /registerdns.......?

    On your DC or on the clients?

    Kapil Sharma
    Life is too short, Enjoy It.


    • #3
      Re: Domain Controller - DNS Issue

      I do a ipconfig/registerdns on my client machines.

      The DC also loses connection to the internet, and i do the same for it.


      • #4
        Re: Domain Controller - DNS Issue

        Isn't the VPN connection down?
        How did you setup the VPN?
        Can you ping to the remote site when the connection fails?
        Technical Consultant

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        "No matter how secure, there is always the human factor."

        "Enjoy life today, tomorrow may never come."
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        • #5
          Re: Domain Controller - DNS Issue

          The VPN connection is up -- and so is the point to point line.

          I think the issue may be an ACL blocking the DNS traffic, because DNS should simply work or not work.

          The only reason this baffles me is because it works then stops (usually network issues work/don't work).


          • #6
            Re: Domain Controller - DNS Issue

            No, an ACL would not cause this problem. An ACL would not cause flaky DNS behavior as witnessed by your ipconfig /registerdns statement. An ACL is either "on" all the time or "off" all the time, it does not go "on" and "off" randomly. I would look more closeley at your DNS components.


            • #7
              Re: Domain Controller - DNS Issue

              Firslty what firewall are you using, ISA? I have observed a intermitent conectivity problem once.

              It so happened that the ISA server was also configured as a web cache, so the drives used to be always trashing and overall net conncetivity and even access would go down, Another observation was that the admin on this particular site had someting like 25 rules, some of which were just redundant.

              Solution, first reorder all the rules and removed unwanted rules. Second I made the company replace the SATA drives with SCSI. RAM was already 2GB so no change there. sufficient for a small enterprise.

              Hope this helps


              • #8
                Re: Domain Controller - DNS Issue

                pianoman20, are you sure that there is not a network issue?
                did you try to ping an internet host using its ip address, like ( If there is no icmp restriction firewall rule in place, it should work.
                Csaba Papp
                MCSA+messaging, MCSE, CCNA
                Remember to give credit where credit is due and leave reputation points where appropriate