Windows Forum

Ask something
Discussion Locked

Split DNS Prob. in MS environment

0 helpful
9 replies

by elliotross

Closed to new repliesThis discussion is closed. It stays readable, but it takes no new replies.

I am having a DNS problem. Behind the firewall I am using NAT addresses in the 192.x.x.x range. I also have a DNS server behind the firewall for local resources. I also have a DNS server outside the firewall for external resolution.

On the clients, the DNS server that is "first" works OK, the second one does not. I thought that if DNS server #1 could not resolve, the client would then check DNS server #2.

What happens is that DNS server #1 is checked & then will simply fail. (So I can access either internal, or external - not both)

I also tried to set the internal DNS as a secondary of the external primary - that also did not work.

What is required for proper split DNS on NT ?

Thanks.

9 replies

by timber

Make sure you add the DNS Service to your internal net going out to the internet.
Make sure you can ping the external DNS servers. If you can't ping them it is a network related problem not DNS.

e-mail me if you need more info. I have my network setup this way so I should be able to help.

by soren.albeck

Use the Forwarders tab on the properties page of the internal DNS to specify the external DNS as a forwarding server. Any query unanswered by the internal DNS will then go to the external DNS. The same goes for Windows 2000. Do not set the internal server to Operate as Slave Server, that way the internal server is in effect a caching-only server and doesn't use any configured zones.

by rlardinois

Answer 2 is the way to go. The configuration depends on the firewall. You may have to allow the port for DNS through the firewall the get to the external DNS. Or, the firewall may resolve DNS for you and can point the internal DNS forwarder directly at the firewall.

by fred_e944

Depends on you client OS. DNS resolution varies between Win95, 98, and NT. Some of these only look to the secondary DNS server if the first is unreachable, not if the first is contacted but unable to resolve a FQDN

This discussion is closed to new replies.