Internal DNS Server Not Cannot Query Recursively to other DNS Servers

Wilfred2010 used Ask the Experts™
I have inherted a network which has 1 primary(Lets call it primo 1) and one secondary DNS server - we also have 1 primary dns server(Lets call it primo 2)that enables external communication since it has its root hints populated with external DNS servers.

The issue is that  primo 1 is a domain controller with dns functionality but it fails on recursive dns quries to external servers.I have had to populate its root hints with data from primo 2 (Which was querying recursively previously but now has the same issue as  primo 1).
Now users are complaining that internet connectivity drops out every now and then- I really rhink it is dns related as no other changes have been made.

Primo 1 is also a very old machine that takes 30 minutes just to reboot - I really want to transfer the primary dns to a faster machine.Primo 2 is up for reformatting so that rules it out for at least 2 weeks.

Any help will be greatly appreciated- I have dns forwarding activated and forwarding to the correct external ISP dns servers but it still does not work; hence my populating  dns servers root hints.
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If I understand you correctly

You have three Windows 2003 DNS servers dns-1, dns-2 and dns-3

dns-1 and dns-2 are the primary and secondary DNS servers used by clients for resolving

dns-3 is not used by internal clients, but is presumably a third Domain Contoller.

Both dns-1 or dns-2 fail the recursive lookup test

dns-3 is able to do recursive lookups.

Presuming that the above is correct...

If you want to use root hints, you should disable EDNS

I tend to use root hints, as overall as they are not subject to any caching by ISP name servers.

Can you confirm what DNS server addresses are configured on dns-1 and dns-2. NICs They should each have one of the other two as the first name server, then the other one of the two as the second and themselves as the first. Apart from SBS, an AD DC with DNS should not be configured to have itself as the first DNS server to check.

Can you confirm if dns-1 and dns-2 can do recursive lookups if you set them to use dns-3 as a forwarder

Then repeat the test using as the forwarder
I have installed dns on a different server and I have managed to fix the issue.


I was able to resolve the issue when I installed dns on a different server.

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