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For a Windows DNS server stub zone, we have 2 NS servers listed there and the SOA information is correct. Both NS servers are "identical" (they sync the zones, so both are masters, so to speak, but obviously only one of them is "THE master" according to the SOA record). Now, for different versions of Windows server, what would be the logic for recursing(forwarding?) a DNS request for that zone?

Will it query the first or random NS server on the list of 2?
Will it query the 2 NS servers on round robin fashion?
Some other logic?
What happens if the connection to the first NS server fails (timeout, e.g. blocked by a firewall, or no other network level connection issue, but not "NOANSWER" or another valid DNS response). Will it try to connect to the second listed NS server?
Please provide references to Microsoft documentation where possible, I could not find a good answer for this in their docs.

Alex
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1 Answers1

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"By default, DNS will perform round-robin rotation for all resource record types."

https://technet.microsoft.com/en-us/library/dd197418(v=ws.10).aspx

That document is specific to Windows Server 2003 and Windows Server 2008. I'm not aware of any change in the default behavior in 2012.

The DNS server you use will ask for the NS records and try them in the order received (which from above should be in a rotating order) If that fails then it will try the first NS record, then the next, until it runs out or gets a response.

More information on the DNS process is in here: https://technet.microsoft.com/en-us/library/cc772774(v=WS.10).aspx

E-Rock
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