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AsadMalik-0261 avatar image
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AsadMalik-0261 asked SunnyQi-MSFT commented

How to Combine multiple DNS servers into single IP address?

Hello Everyone,

I have 3 Active directory DNS servers running in my domain which are hosting various forward and reverse lookup Zone. The IP for the DNS servers are:

DNS 1 : 10.2.0.20
DNS 2 : 10.2.0.21
DNS 3 : 10.2.0.22

I would like to combine these 3 IP into single IP address 10.2.0.100 that will be used by the clients and network devices for name resolution. basically instead of using 3 IP's to all the client, a single IP is used as round robin. Is there a way to map a single IP linked to 3 DNS servers or any other way to achieve this without using hardware solution like F5?

Thank you

windows-dhcp-dns
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Hi,

Just checking in to see if the information provided was helpful.

If yes, you may accept useful reply as answer, if not, welcome to feedback.

Best Regards,
Sunny

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Thanks Sunny for the follow up. I'm building some VM's to do the NLB tests. I will provide an update by Friday.

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Hi, many thanks for your update. I will wait for your good news. :)

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RileyMagnuson-2506 avatar image
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RileyMagnuson-2506 answered

You could use a software solution like Zevenet
https://www.zevenet.com/products/community/

I guess a better questions is...why would you want to do this? Unless you're wanting to combine x amount of DNS servers down to just two, you'd just be creating a single point of failure for yourself.

Anyway, yeah. Load balancer is probably your best route.

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SunnyQi-MSFT avatar image
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SunnyQi-MSFT answered

Hi,

Welcome to Q&A platform.

I'm afraid your goal cannot be achieved. Each DC & DNS server must be configured a static IP address, if DC & DNS servers share an IP address, there will be some issue occurred on your DC and domain name resolution. We recommend you configure different static IP for each DC & DNS server and set them as preferred DNS server and secondary DNS server from your client side.

Best Regards,
Sunny


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AsadMalik-0261 answered AsadMalik-0261 edited

@RileyMagnuson-2506

Thanks Riley for the reply. I will take a look at the zevenet solution. You asked me why? The reason for doing this we use infoblox as the primary DNS server as single IP for all the clients. Infoblox has multiple DNS server running under the grid station but it uses that single IP for all the clients and there is no single point of failure as the grid provides load balancing.
I'm migrating all the Zones from the infoblox to windows DNS due to cost saving. I'd like to use that same single DNS IP address 10.2.0.100 that is used on infoblox linked to the 3 new windows DNS. This way i don't have to point and change the clients to the 3 new windows DNS server. Some of our clients are using Static DNS entries as well so i cant' use DHCP scope.

If there is away in the DNS to create a record for that single DNS IP and link it to the 3 DNS windows server which would act as round robin to avoid the single point of failure you pointed out ? similar to the Cname that is map to multiple website address used under the same IP address. hope this make sense.

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AsadMalik-0261 answered SunnyQi-MSFT commented

@SunnyQi-MSFT

Thanks Sunny for the reply. I'm aware that IP address can not be shared. As i mentioned above that each DC and DNS has a different static IP. However If there is away in the DNS to create a record for that single DNS IP 10.2.0.100 and link it to the 3 DNS windows server which would act as round robin and name resolution. Similar to a Cname which maps to multiple website address used under the same IP address. hope this make sense. Would something like this work for DNS/DC?

Also under TCP/IP, we can add a secondary static IP address. Would adding that single IP 10.2.0.100 as secondary IP address do the trick?

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Hi,

May thanks for your update.

Before we go further, I would like to confirm the following information with you:

May I know whether your goal is achieving load balance of these 3 DC & DNS servers and when the clients request domain name (which hosted by these 3 DNS servers) resolution, you need it returns different IP of these 3 DC & DNS server every time. Or every time when client request specific domain name resolution, you need different DC & DNS servers resolve domain name.

Meanwhile, I would like to know whether these 3 DC & DNS server host same zones?

Best Regards,
Sunny

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AsadMalik-0261 avatar image
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AsadMalik-0261 answered AsadMalik-0261 edited

@SunnyQi-MSFT

Thanks Sunny for the reply. Below are the answers.

The 3 DNS/DC are already enabled for round-robin but not load balancing which I would like to achieve using the single IP address. The client should send all the DNS queries to the single IP address 10.2.0.100 which will use load balancing and forward the query to one of the DNS below in round-robin.

DC/DNS 1 : 10.2.0.20
DC/DNS 2 : 10.2.0.21
DC/DNS 3 : 10.2.0.22

What solution do i use for the server 10.2.0.100 to achieve this ?

The 3 DNS/DC host the same Zones for both forward and reverse. They are identical.

Hope this helps. Let me know if you have further questions.

Thanks

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SunnyQi-MSFT avatar image
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SunnyQi-MSFT answered

Hi,

Thanks for your update.

I understand that our goal is achieving these 3 servers use one single IP address. After discussing with our cluster support engineer and AD DS support engineer, from Windows perspective, I'm afraid that your goal cannot be achieved. I would suggest you could set these 3 DNS servers as preferred DNS server, alternate DNS server or configure them in DNS tab of Advanced TCP/IP Settings.

113824-image.png

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,
Sunny


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AsadMalik-0261 answered SunnyQi-MSFT commented

Thanks @SunnyQi-MSFT for the suggestion but i want to avoid this basic setup of having multiple IP's of the DNS. Some clients can only have single IP for DNS for example Audio/Video devices, Routers, printers etc.

Can NLB achieve my goal ? below is the article. Please discuss with your support engineer.


https://docs.microsoft.com/en-us/windows-server/networking/technologies/network-load-balancing

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Hi,

Thanks for your feedback.

Please kindly note that before I posted my reply yesterday, we had an internal discussion regarding your issue which also including NLB. Unfortunately, NLB cannot achieve your goal also.

Best Regards,
Sunny


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