I have read this article on split-DNS: http://www.isaserver.org/tutorials/You_Need_to_Create_a_Split_DNS.html. I think I understand the concept, but to set up the optimal solution suggested in the article I need to control the DNS servers on "the outside" (which I cannot in my case).
My scenario is as follows: one internal domain called corp.local. One public domain called corp.com. I have a web site on the address www.corp.com, which actually points to a published server on the domain corp.local. I would like to publish this web server to internal clients as well (clients on the domain corp.local), without them going to the external IP and back. So I just setup a new zone on the DNS server the internal clients (corp.local) are using called corp.com, and add an entry for www.corp.com, this time pointing to a internal IP address.
To my problem: I have a lot of other entries on the external web server which should be left as they are. I know I could just copy and maintain two DNS servers, but ideally I would like this:
- Internal client asks for www.corp.com.
- The Internal DNS server looks if it has an entry for www.corp.com.
- It has, so it answers with the internal IP address for www.corp.com.
- Internal client asks for someother.corp.com.
- The Internal DNS server looks if it has an entry for someother.corp.com, and it finds none.
- It then forwards the request to the external DNS server, to see if that has an entry defined for someother.corp.com.
- The external DNS server responds back to the Internal DNS server with the external IP for someother.corp.com.
- The Internal DNS server responds back to the Internal client.
What happens in reality for Case 2 is that the Internal DNS server thinks it is authoritive for the zone corp.com (which it kind of is), and if it does not find a record for someother.corp.com it responds to the client with a negative answer.
Hope I made myself clear, looking forward to your input! Thanks in advance! Also, I'm running Windows domain with Windows DNS servers (Windows Server 2008).