DNS Aging and Scavenging

Grace Yin 111 Reputation points
2020-08-03T02:09:37.783+00:00

Hi,

I have 2016 Windows domain with 3 DNS servers. I have 2 questions regarding the DNS Aging and Scavenging.

  1. Should I enable "DNS Aging and Scavenging" on all three DNS server or only one? If I enable it on only one, the other two should replicate with it, right? My concern is if it will cause any conflict if I enable it on all of them.
  2. I enabled the setting for "DNS Aging and Scavenging" with 7 days non-refresh interval and 7 days refresh interval, and my DHCP server leasing period is 7 days, the stale records with the time stamp older than 14 days should be removed automatically, right? Why are they still in DNS server? Where should I look into?

Need help!

Thanks in advance!

Windows DHCP
Windows DHCP
Windows: A family of Microsoft operating systems that run across personal computers, tablets, laptops, phones, internet of things devices, self-contained mixed reality headsets, large collaboration screens, and other devices.DHCP: Dynamic Host Configuration Protocol (DHCP). A communications protocol that lets network administrators manage centrally and automate the assignment of Internet Protocol (IP) addresses in an organization's network.
1,023 questions
0 comments
Accepted answer
  1. Candy Luo 12,661 Reputation points Microsoft Vendor
    2020-08-03T05:09:49.787+00:00

    Hi ,

    >>Should I enable "DNS Aging and Scavenging" on all three DNS server or only one? If I enable it on only one, the other two should replicate with it, right? My concern is if it will cause any conflict if I enable it on all of them.

    Microsoft's Best practice analyser recommends scavenging enabled on all DNS servers. However, with AD-integrated zones, it doesn't particularly matter since it handles if the record is deleted from one name server and deleted from another at the same time before replication kicks in.

    You just need to enable DNS scavenging on one DC in main site. The results will be replicated to other DCs.

    >>I enabled the setting for "DNS Aging and Scavenging" with 7 days non-refresh interval and 7 days refresh interval, and my DHCP server leasing period is 7 days, the stale records with the time stamp older than 14 days should be removed automatically, right? Why are they still in DNS server? Where should I look into?

    Even after the no-refresh and refresh intervals have both expired, a record will most likely not be scavenged immediately, as scavenging is controlled by a server's scavenging period, which is independent of the other two intervals.

    15073-222.png

    When the scavenging period is configured on a DNS server, the timer starts for 7 days (or whatever the configured value is). Once the timer expires, the scavenging process runs.

    7 days for scavenging is a default setting, you can leave it alone or configure whatever value you want.

    So the formula should be: NoRefresh + Refresh + Scavenge period.

    For your reference:

    https://flamingkeys.com/how-dns-aging-and-scavenging-actually-work/

    Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.

    ---Please Accept as answer if the reply is helpful---

    Best regards,

    Candy

    1 person found this answer helpful.

3 additional answers

Sort by: Most helpful
Most helpful Newest Oldest
  1. William Rivet 1 Reputation point
    2020-10-27T11:55:02.847+00:00

    Candy.

    I have been looking for a reason why my scavenging settings have never "scavenged" for years. I have never been instructed to enable this until now...

    Thank you.

    0 comments
  2. Michał Witwicki 6 Reputation points
    2021-02-17T22:36:00.213+00:00

    If I turn on Scavenging within the zone then it should be enough and the records should be deleted, right? What is the difference between the Scavenging setting for DNS server and the Scavenging setting for DNS zone? As part of the DNS server, Scavenging has an additional option to specify the days in the zone that does not exist. Can someone explain this?

    69253-2.png

    69254-1.png

    0 comments
  3. Josh Jones 1 Reputation point Microsoft Employee
    2021-02-24T20:34:18.967+00:00
    0 comments