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DNS Entries Disappearing RRS feed

  • Question

  • We are noticing an issue with DDNS entries disappearing and I ma not sure exactly what is going on. The environment is 2012 R2 DHCP & DNS, clients are Win 7.

    The settings are:

    DNS

    • Scavenging 1 day
    • No-refresh interval 4 days
    • Refresh interval 4 days
    • TTL 1 hr

    DHCP

    • Lease duration 8 days
    • Enable DNS dynamic updates ON
    • Dynamically update DNS records only if requested by the DHCP client
    • Discard A and PTR records when lease is deleted

    I chose the DNS 4 day and DHCP 8 day intervals after reading an article recommending to set DNS to 50% of the DHCP lease time. My thinking is that the scavenging setting of 1 day might be causing this. That was set to clear out a bunch of stale records long ago and I didn't set it back. Should it be modified to 7 or 8 or is something else going on perhaps?

    Thanks in advance.

    Friday, October 7, 2016 6:03 PM

Answers

All replies

  • Hi Mtnman,

    >> Should it be modified to 7 or 8 or is something else going on perhaps?

    Please reference the article to deploy it:

    How DNS Scavenging and the DHCP Lease Duration Relate
    https://blogs.technet.microsoft.com/askpfe/2011/06/03/how-dns-scavenging-and-the-dhcp-lease-duration-relate/

    Have you tried to manually register DNS record?

    On DHCP server, please ping DNS server to check if connection is correct.

    >> We are noticing an issue with DDNS entries disappearing and I ma not sure exactly what is going on.

    Please following link below to troubleshoot DNS issue:

    Troubleshooting DNS

    https://technet.microsoft.com/en-us/library/cc753041(v=ws.11).aspx

    Best Regards

    John


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    • Proposed as answer by John Lii Wednesday, October 19, 2016 9:47 AM
    • Marked as answer by Leo HanModerator Wednesday, November 2, 2016 5:19 AM
    Monday, October 10, 2016 8:24 AM
  • Thanks John. I had read through the first document and decided to just increase the scavenging time to 3 days and monitor the situation.

    Manually registering works fine.

    Monday, October 10, 2016 11:05 AM
  • Hi Mtnman,

    Just want to confirm the current situations.

    Please feel free to let us know if you need further assistance.

    Best Regards,

    John


    Please remember to mark the replies as answers if they help and unmark them if they provide no help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Wednesday, October 19, 2016 9:46 AM