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Two DNS servers with conditional forwarding. One returns NXDOMAIN randomly

    Question

  • We have 2 dns servers. There's a conditional forwarder in place for business.com for those requests to be handled at a AWS Route53 private zone. 

    One of our servers works 100% of the time. The server in question will randomly return an error of NXDOMAIN. It returns the hostname with no IP. When the server producing errors is doing it consistently the 'good' server consistently responds with the correct IP.  Sometimes the issue will persist for minutes to hours but starts working if the DNS server service is restarted or if cache is flushed on the server having issues.

    Using nslookup during these 'bad' times will always result in DC2 providing the correct IP; however DC1 will randomly respond with no IP and log the error as NXDOMAIN according to DNS debug logging.

    This issue also only appears to happen with one specific host/dns name. It is an internal only server and is not reachable outside our corporate network. During the 'bad' times, the server has no issues resolving the names of other hosts located in our private zone for this same domain.

    Have seen other reports of people experiencing a similar issue when dealing with Conditional Forwarding but haven't found a solution that matches our issue yet.

    Both DNS servers are Win2016

    Here is the response when NXDOMAIN happens. These requests were done back to back within 2 seconds of each other.

    > site.business.com
    Server:  DC1.abc.ad
    Address:  10.20.10.50

    Non-authoritative answer:
    Name:    server1.abc.ad
    Address:  10.20.0.70
    Aliases:  intel.business.com

    > intel.business.com
    Server:  DC1.abc.ad
    Address:  10.20.10.50

    Name:    intel.business.com




    • Edited by ZachBowman Tuesday, May 15, 2018 5:56 PM
    Tuesday, May 15, 2018 5:53 PM

All replies

  • Hi,

    Thanks for your question.

    Please try the following steps to see if it helps.

    1 Please type the command “ipconfig /flushdns” & “ipconfig /registerdns” on the DNS server.

    2 Restart DNS service on the problematic server.

    3 Type the command Nslookup -d2 intel.business.com to trace the name query for troubleshooting. Please post me the result.

    4 I’m wondering of what is your conditional forwarder configured to handle the requests for business.com 

    Hope this helps. I look forward hearing your good news. If you have any questions, please feel free to let me know.

    Best regards,

    Michael


    Please remember to mark the replies as an answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com

    Wednesday, May 16, 2018 9:25 AM
  • Hi,

    How are things going on? Was the issue resolved?

    Please let me know if you would like further assistance.

    Best regards,

    Michael


    Please remember to mark the replies as an answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com

    Friday, May 18, 2018 2:10 PM
  • Hi,

    Just checking in to see if the information provided was helpful. Please let us know if you would like further assistance.

    Best Regards,

    Michael


    Please remember to mark the replies as an answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com

    Monday, May 21, 2018 2:32 PM