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SBS 2008 DNS Issue

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  • SBS 2008 DNS Issue

    Hi All Great Forum!!

    I have run into a dns issue that I just can't seem to solve.

    The network is a smaill 2 server AD network with 1 SBS 2008 server and 1 2003 server.

    Both are domain controllers and both run dns for internal and external clients behind a watchguard firewall.

    This setup has been running fine for almost a year now untill last week.

    Neither server will answer requests from external clients now. Internally they work just fine but from outside the firewall I get the following when using nslookup.


    server (not real server name of course)
    Default Server
    Server Address:
    so at this point I am connected to the server from outside.

    But when I do a lookup

    DNS request timed out.
    timeout was 2 seconds.
    DNS request timed out.
    timeout was 2 seconds.
    Request to server timed out.

    Anybody got any ideas


  • #2
    Re: SBS 2008 DNS Issue

    If you have SBS 2008 and Windows Server 2003, I'm not too sure why you posted this in the Windows Server 2008 forum...

    Flagged for mod attention.
    Gareth Howells

    BSc (Hons), MBCS, MCP, MCDST, ICCE

    Any advice is given in good faith and without warranty.

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    • #3
      Re: SBS 2008 DNS Issue

      Moved to DNS forum
      Tom Jones
      MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
      PhD, MSc, FIAP, MIITT
      IT Trainer / Consultant
      Ossian Ltd

      ** Remember to give credit where credit is due and leave reputation points where appropriate **


      • #4
        Re: SBS 2008 DNS Issue

        Install a network sniffer on the DNS server, start a capture and filter for DNS traffic, run nslookup on the client against the server, look in the capture for the DNS traffic related to the client, if you see the traffic in both directions (the client query and the server answer) then you can be assured that the server is OK and your issue is firewall or network related.


        • #5
          Re: SBS 2008 DNS Issue

          wow.. great!! can you post snapshot sample..


          • #6
            Re: SBS 2008 DNS Issue

            does your DNS work within the network ?

            If so, I'd be looking at your watchguard. Did the network engineers make any changes ?

            using nslookup and "server" doesn't actually connect you to that server - it tells it to use that server for queries.
            As dns is a udp based query, there are no actual "connects" involved..
            Please do show your appreciation to those who assist you by leaving Rep Point


            • #7
              Re: SBS 2008 DNS Issue

              Are you using root hints, or forwarders for DNS?
              If you are using root hints, see this

              Other then that, can you get to websites using IP address of the sites?
              Are you able to get a 2nd DNS server (on a different network (a laptop)) and plug it into the same router as the servers, see if it can resolve the names stright from the net?

              Good to be back....


              • #8
                Re: SBS 2008 DNS Issue

                I'm not quite getting this.

                Is your DNS server an external facing DNS server???

                If so why???

                Have you allowed TCP and UDP ports 53 through your firewall to the server???