I have two Windows domains/separate forests. One forest consist of what is left of the bought-out company's domain. They have 5 servers that still have important data and need to be worked with on a daily basis by a large group of employees. We have a forest level trust setup to ease file access. We manually create DNS A records for the 5 servers so their short names would resolve to the IP addresses. I need the FQDN to resolve though. Should I create CName records to achieve this?

I hope this question makes sense, I am learning DNS on the fly... :)

3 Answers 3


You need to configure a dns suffix. See here for more information: Configuring DNS client settings

A dns suffix simply adds a domain name behind the host, for example you have the host server (where you have created an A record for), and you have the domain name serverfault.com. Then serverfault.com is the dns suffix, which finally gives server.serverfault.com. server.serverfault.com is then also the FQDN.

  • I disagree that this is the best method. This changes the fundamental configuration and operation of the DNS clients, which isn't neccessary in my opinion. This will cause the DNS clients to append the configured DNS suffix(es) to every unqualified query, which isn't really the goal here. The OP wants to resolve the FQDN for a specific DNS suffix and as such, using conditional forwarders is the best solution.
    – joeqwerty
    Mar 12, 2011 at 19:21

There are a couple of ways to do this, but I might suggest setting up conditional forwarders to forward DNS queries for the other forests DNS zone to the DNS servers in that forest. You don't specifiy what version the OS is, but the process is basically the same for W2K3 and W2K8 DNS servers.


  • This is the correct approach. Either use a conditional forwarded for that DNS zone in the other forest, or setup a zone transfer or stub zone that points to multiple domain controllers in the other domain so you don't have a single point of failure. Also, remove those host records you created in your DNS zone as they are just going to confuse you down the line.
    – BoxerBucks
    Mar 12, 2011 at 20:36
  • I like the conditional forwarding approach since I can specify any querys for the oldcompany.com go to IP Then the old DNS server will pick up the request and resolve it. I knew my A record method would work but it is sloppy in my opinion and not the way I want to run things. My next question is this: I have only two out of 8 sites that need to access these old company servers. Can I do the conditional forwarders on only the new company DNS servers at the two sites? Or do I need to set this up on each of the new company DNS servers? Mar 13, 2011 at 6:11
  • If you choose not to store the conditional forwarders in AD then you should be able to set them up only on specific DNS servers, then they'll be used only by those servers and the clients being served by those servers.
    – joeqwerty
    Mar 13, 2011 at 19:36

From my experience to accomplish the OP's question you need to do both of what @shadowman12 & @joeqwerty suggest. You will need conditional forwarders on your DNS servers to tell them where to send queries for the trusted domain. You also need to push out DNS search suffixes to your clients to tell them to append the trusted domain name to unqualified queries.

Otherwise your clients will not be able to resolve the FQDN of the trusted domain servers by single name.

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