To put it simple, you can understand DNS forwarding as a method for DNS server to resolve a query by “asking for a help” from another DNS server. It is supported by on Windows DNS server, including Windows Server 2012 R2. The default behaviour is that Windows DNS Server will forward query that it cannot resolve to a list of public DNS servers on the internet which is called the root hints. But if you Configure DNS Forwarding in Windows Server 2012 R2, then it will forward the query to the designated DNS server which is called the forwarder.
How to Configure DNS Forwarding in Windows Server 2012 R2
If you install DNS server on Windows Server 2012 R2, you can configure DNS forwarding by using DNS Manager or PowerShell.
Using DNS Manager
On the server where DNS Server role installed, open Server Manager then navigate to Tools > DNS to open up the DNS Manager.
In the DNS Manager, right click the DNS server hostname on the left-pane and select Properties.
Click on Forwarders tab, then click on Edit button.
Enter the IP address of the other DNS server (forwarder) then press Enter. If the IP address is a valid DNS server then it will show green checklist icon as in the picture below. Repeat this for each forwarder servers that you want.
You can click OK to confirm the settings.
You can also configure DNS forwarding in Windows Server 2012 R2 by using PowerShell. Below is the command you need to enter in an elevated PowerShell window:
Add-DnsServerForwarder —IPAddress FORWARDER_IP
Alternatively, you can also use the command below:
Set-DnsServerForwarder —IPAddress FORWARDER_IP
You only need to adjust the FORWARDER_IP value to match your configuration plan. You can specify more than one forwarder in a single command by separating each IP address with a comma. Note that there is difference between the two commands above. The “Add” command will append the specified forwarder IP to the existing list of forwarders that you have. Meanwhile, the “Set” command will overwrite the existing forwarders list with the specified IP address.
Hereâ€™s example of adjustment in the query that will resulting the same as the previous example:
To verify that DNS forwarding works, you can attempt to resolve any names that is not in the DNS server data. In this example, our DNS server only has data for names in domain mustbegeek.com. Therefore, now we will test to resolve for domain corp.mbg.com.
Before we have DNS forwarding configured to the authoritative server for domain corp.mbg.com, our DNS clients unable to get the name resolution for corp.mbg.com.
After DNS forwarding configured, our clients able to get the name resolution for corp.mbg.com.
Working with DNS Forwarding in Windows DNS Server
Before you configure DNS forwarding, you should make sure that recursion is not disabled on the server. DNS forwarding requires recursion to request for information from the forwarders on behalf of the client.
By default recursion is enabled on Windows DNS Server but in some case it may be disabled. To check if recursion enabled, you can go to the DNS server properties in the Advanced tab. Then, under Server Options, confirm that no tick mark on the check box for Disable recursion setting.
And thatâ€™s all you need to know to configure DNS forwarding in Windows Server 2012 R2.