How do I move from using a conditional forwarder to a forward lookup zone for a limited number of host records?

drichman
drichman used Ask the Experts™
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How do I move from using a conditional forwarder to a forward lookup zone for a limited number of host records?

To expand, I host AD integrated DNS for our domain (xyz.com), but we also need to lookup addresses for our parent company (abc.com). I currently have a conditional forwarder for them pointing to their internal DNS servers, which works fine. They now need me to add a A record for a service that has both an internal and external IP address (i.e. 192.168.1.100 internal and 23.23.23.5 external). When my users resolve the address, they get the internal IP address of the server, but we want them to connect to the external IP address.

I was thinking of just deleting the conditional forwarder reference and adding a forward lookup zone for abc.com, and then adding the A record for that server with the external address, but I am concerned that it will stop all other resolution for other abc.com services (due to the loss of the conditional forwarders pointing to their internal DNS server). Do I resolve this problem by adding their internal DNS server to the Forward lookup zone>Properties>Name Servers tab?
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Distinguished Expert 2018
Commented:
You can't do what you want. If you create a forward lookup zone for abc.com, your DNS server will believe it is authoritative snf. Even with forward records, won't work.. Your DNS server will believe there is no record. For anything that doesn't match a record in its zone and therefore won't bother to forward at all.

What you *can* do is create a zone for some-service.abc.com with the only A record beong rotlot (*or @) with the IP address you desire.

Yesxl that means for every A record that they want you to do, you need to create an entire zone, not just records in an existing zone l. But that means Tha lookups for other records in abc.com will continue to use your conditional forwarder.

With that said, if this is a partner or parent company then the RIGHT way to fix this is to fix it on their end. BIND has long since had the concept of "views" that can return the proper address based on a variety of criteria. Windows, though late to the game, added this functionality under the name "DNS Policies" in server 2016.  

It is a generally accepted best practice that whoever controls DNS for a resource should be the one addressing the address returned. While workarounds can be done in a pinch, and I've suggested one, the entity that controls abc.com should be the ones making sure their DNS returns the address they want using the tools available to do so.
Pete LongTechnical Consultant

Commented:
If you have a Cisco ASA firewall you can re-write the DNS reply to change it to the internal IP (DNS Doctoring)

P
kevinhsiehNetwork Engineer

Commented:
Cliff's answer is what I would propose also.

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