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Unavailable fw DNS after connection is down

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2007-02-27
2013-03-12
  • Theodor Ciobanu

    Theodor Ciobanu - 2007-02-27

    Due to a bad ISP, I recently started to encounter the following problem often: I have a computer (using DualServer as DNS) set to wake up automatically at a specified time, but when it does, my connection is down, so none of the forward DNS servers are reachable when the server starts. Although after a few minutes the connection is back online, I still have a crippled internet connection because of no DNS server. The only workaround I found for this is have someone restart DualServer on that machine. So my question is: Wouldn't it be possible for DualServer to periodically check previously unavailable DNS servers?

     
    • Achal Dhir

      Achal Dhir - 2007-02-28

      You can specify the DNS Servers in ini file.
      If your DNS Servers are changing, you may use public DNS Servers and specify them in ini file like:=

      [DNS-SERVERS]
      4.2.2.1
      4.2.2.2

       
    • Theodor Ciobanu

      Theodor Ciobanu - 2007-02-28

      Let me rephrase, to be understood:

      When the system starts, the connection is down. The following log is produced:

      Varifying DNS Server 4.2.2.1.....Failed
      Varifying DNS Server 4.2.2.2.....Failed
      Varifying DNS Server 4.2.2.3.....Failed
      Varifying DNS Server 4.2.2.4.....Failed
      Varifying DNS Server 4.2.2.5.....Failed

      Starting DNS...

      Domain Name: bochss
      Expiry: 36000 (sec)
      Server Name: 2k3-bochs
      Listening On: 192.168.1.2

      Accepting requests..
      Failed to forward query www.euronews.com

      After a few minutes the connection is back online, but DualServer still doesn't work. So I still get

      Failed to forward query www.eurosport.com

      So my suggestion was to periodically check previously failed connections to the forwarded DNS.

       
      • Achal Dhir

        Achal Dhir - 2007-02-28

        Sorry for mistyping, I meant 4.01 only.

        DNS Availablility checking is no more there in version 4.01, can you please re-download it and re-install.

        Thanks
        Achal

         
    • Achal Dhir

      Achal Dhir - 2007-02-28

      Oh okay

      Dual Server Vesion 4.1 do not varify servers at start time, this version varifies it at run time and does again and again.

      Using latest version will resolve your issue.

      Thanks

       
    • Theodor Ciobanu

      Theodor Ciobanu - 2007-02-28

      I'll wait for 4.1 in that case. For the moment I'm using 4.01, which is the latest available for download, as far as I can see.

      Thank you.

       
    • Theodor Ciobanu

      Theodor Ciobanu - 2007-02-28

      Indeed the check is no longer there. It seems I downloaded the kit for 4.01 but forgot to install it and was still using 4.0. I apologize for all the noise.

      Unfortunately, I still have something to comment on the new behavior. Version 4.0 would sometimes give me:

      Varifying DNS Server 4.2.2.1.....Failed
      Varifying DNS Server 4.2.2.2.....OK
      ...

      and starts using directly 4.2.2.2. Version 4.01, on the other hand, starts with 4.2.2.1 so I get a bunch of timeouts before it switches to the next one. So I reiterate: would it be too much of a hassle to do periodic checks for availability?

      Thank you for the tool, support and putting up with me.

       
      • Achal Dhir

        Achal Dhir - 2007-02-28

        No Problem !

        DNS Specification do not allow to interrupt the service, DNS Server Varification needs 5 secs for each DNS (at least you need to wait), this being single thread server, cannot do that while in service. What is done is count the query failures, if there are 5 or more failures, switch to next server and so on.

         
    • Theodor Ciobanu

      Theodor Ciobanu - 2007-03-01

      Would that be 5 failures for different hosts or just 5 consecutive failures? Or are you referring to future behavior? Because currently I receive _a lot_ of "Failed to forward query ..." before the DNS is switched (for the moment I removed 4.2.2.1 from the external DNS list to eliminate the timeouts I got because of this, which really mess up a bunch of scripts I have on that machine)

       
    • Achal Dhir

      Achal Dhir - 2007-08-01

      Now the DNS Server does not wait for 5 failures. After every failure, it sends a localhost query message to failed server and if this also fails, the DNS Server is switched to next in list. Please download Build 5.13. You can also set up service to ReStart using Windows Recovery Options.

      This should solve your problem.

       

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