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  • DNS Forwarders

    Setup has 2 windows 2003 sp1 DCs on our network

    We are suddenly having Internet problems and cannot do any name resolution, can access websites by IP address but not by name.

    There has been no change to our network or DCs

    We have forwarders going to external DNS Servers

    When we run the dcdiag with DNS test

    we get everything passed apart from the fowarders and we get

    Error: Forwarders list has invalid forwarder:dnsserverIPaddress (<name unavaiable>)

    really need some help on this one

    thanks
    We have tried to change the external dns server from OpenDNS to our ISP, but we get the same message.

    I cannot find anything at all on the net apart from your DNS must not be configured correctly, i have been running this setup for around 6 years now without any real chanages

    Services has been stopped and started various times

  • #2
    Re: DNS Forwarders

    Hi,

    It looks like this is a known issue with Windows 2003 sp1 : http://support.microsoft.com/kb/914058

    Ta
    Caesar's cipher - 3

    ZKHQ BRX HYHQWXDOOB GHFLSKHU WKLV BRX ZLOO UHDOLVH LW ZDV D ZDVWH RI WLPH!

    SFX JNRS FC U6 MNGR

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    • #3
      Re: DNS Forwarders

      Personally I don't use forwarders. I let my DNS servers query the root hint servers for external domains. That way my DNS doesn't rely on someone else's DNS for external name resolution.

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      • #4
        Re: DNS Forwarders

        I have upgraded to sp2 and still get the same messages, removed the forwarders and restarted the services and still no internet access

        I know my firewall is working as I have changed my dns setting to use my ISP and I can access the web fine

        there is nothing in the event logs and I am really getting nowhere with this now

        is there a way to rebuild the dns incase i have come corruption somewhere

        thanks for the info so far

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        • #5
          Re: DNS Forwarders

          Presuming you have configured your ISP Ip address as a forwarder after the Upgrade to SP2, and cleared the DNS Cache on the clients (Ipconfig /flushdns), you can try the following on the server

          dnscmdServerName/ResetForwarders [ISP IPAddress ...] [ / NoSlave ]

          Ta
          Caesar's cipher - 3

          ZKHQ BRX HYHQWXDOOB GHFLSKHU WKLV BRX ZLOO UHDOLVH LW ZDV D ZDVWH RI WLPH!

          SFX JNRS FC U6 MNGR

          Comment


          • #6
            Re: DNS Forwarders

            On the Root Hints tab of the properties of the DNS server are the root hint servers listed? does this problem affect the DC's as well as client machines? Can you do an nslookup for www.google.com from a client machine and from the DC's and post the results here.

            Also, for the heck of it, have you rebooted your router and firewall?

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            • #7
              Re: DNS Forwarders

              thanks for all the information, and all good stuff

              I brought up and old firewall that we have not made full redundant yet and changed the DG on one of the DCs, straight out onto the internet

              ran dcdiag it passed all tests on that particular DC

              This means that there must be a problem with my firewall, cannot see anything on it but back to the support company with my results as I think I can prove the firewall is blocking something along the way

              port 53 is open for TCP and UDP, so cannot see what else it can be, all packets are being discarded apart from vpn traffic so no smtp traffic or web traffic getting through

              again thanks for the quick replies

              Firewall was working up until last night, no changes or anything made

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