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abhisheksharma-1341 avatar image
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abhisheksharma-1341 asked GloriaGu-MSFT commented

I want to know how DNS forwarding works in MS DNS.

My MS DNS is configured with three IP's in forwarding policy. Which IP the DNS query will be sent to amount three IP's.
Basically I want to know the whole packet flow when MS DNS decides to do forwarding.

Bind supports RTT when it comes about forwarding. Does MS also support it?

windows-dhcp-dns
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Hi ,
May I ask did you have any updates on this issue?

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MiguelFra avatar image
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MiguelFra answered MiguelFra edited

Hello Abhisheksharma,

Yes it does forwarding (as long as the disable recursion checkmark is not selected in the advanced tab).

You can set forwarding servers as follows:

Log into the DNS Server as an administrator. Click Start and type DNSMgmt.msc, then press enter to open the DNS Management Console. Locate the server in the list, then right click and choose properties. Navigate to the Forwarders tab and add your forwarding DNS servers. If you do not set forwarders it will use root servers for queries.

Here's a MS DNS server quick setup guide:

https://www.hostwinds.com/guide/setup-configure-dns-windows-server/

Here is a link to details about RTT question:

https://social.technet.microsoft.com/Forums/en-US/3350e02b-86d6-473e-a653-28fe19703be7/microsoft-dns-server-and-rtt?forum=winserverNIS

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GloriaGu-MSFT avatar image
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GloriaGu-MSFT answered GloriaGu-MSFT commented

Hi,

In regards to your issue, here're my suggestions:

  1. If you configure three forwarders in DNS server, the DNS queries are as follows:

(1) Client queries the DNS server. DNS server immediately forwards the query to its first forwarder

(2) After <forwarding_timeout> seconds, if the first forwarder didn’t reply, the DNS server queries the second forwarder

(3) After <forwarding_timeout> +1 more seconds, if the second forwarder didn’t reply, the DNS server queries the third forwarder

(4) During this time, after one of three forwarders answering the query, next time the query with this DNS suffix will be sent to this forwarder first.


  1. The Microsoft DNS Server support RTT. DNS server uses (RTT) to choose between name servers authoritative for the same zone. Roundtrip time is a measurement of how long a remote name server takes to respond to queries. When the name server must choose which of a group of authoritative name servers to query, it simply chooses the one with the lowest roundtrip time.

For more details, you can refer to the following links:
https://support.microsoft.com/en-us/help/2834250/net-dns-forwarders-and-conditional-forwarders-resolution-timeouts
https://social.technet.microsoft.com/Forums/windowsserver/en-US/3350e02b-86d6-473e-a653-28fe19703be7/microsoft-dns-server-and-rtt?forum=winserverNIS#:~:text=The%20Microsoft%20DNS%20Server%20uses,it%20starts%20an%20internal%20stopwatch.


-------If my answer is helpful to you, please remember to mark them as answer. Thank you!------

Regards
Gloria


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Hi,
Just want to confirm the current situations. Please feel free to let us know if you need further assistance.

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