Preferred and Alternate DNS servers

asked 2021-04-14T16:10:38.623+00:00
Mario Nebbia 326 Reputation points

On Windows 10 PCs (and in all Windows machines) I can configure a Preferred and an Alternate DNS.
What exactly are the conditions under which alternate DNS is queried?
Only if Preferred DNS is down?
Even if the Preferred DNS cannot resolve the domain name?
What are the exact conditions?

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.
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  1. answered 2021-04-15T02:23:20.04+00:00
    Candy Luo 12,441 Reputation points


    If DNS client does not receive a response from primary DNS server, then it will send DNS query to secondary DNS server. A negative response, such as "name not found" is also considered a valid response.

    The following articles can help you understand DNS query process, you could have a look:

    DNS client resolver behavior

    Best Regards,


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  1. answered 2021-04-14T16:17:47.637+00:00
    Dave Patrick 328.5K Reputation points Microsoft MVP

    If the primary fails to reply then the alternate would be used. If the primary returns a reply that cannot resolve the alternate is not used.

    --please don't forget to Accept as answer if the reply is helpful--

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  2. answered 2021-04-15T02:26:26.07+00:00
    Dave Patrick 328.5K Reputation points Microsoft MVP

    Any progress or updates?

    --please don't forget to Accept as answer if the reply is helpful--

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