I'm in a situation where I'm being asked to solve a problem where computers are being migrated from one network/DNS domain to another. As this transition occurs, there will be machines in the original (call it xxx.org) DNS domain, that need to communicate by "short name" to the machines moved to the new network/DNS domain (call it yyy.org). Note that this is all internal, using private address space, nothing traversing the Internet.
The software involved resolves the target by short hostname only, not fqdn, apparently addresses cannot be entered, and the code cannot be modified.
My immediate suggestion was modifying the hosts file on the machines left on xxx.org with the addresses/names for the machines that have been moved, as the moves are made with the name and new IP address in yyy.org. This will require that the machines being moved obtain fixed addresses and the host file be updated/disseminated sporadically for about a month or so. This is troublesome, but not impossible to somewhat automate.
Is there a way in DNS to do this some other way that I'm missing? In my mind, the DNS server is only going to try the local domain for a short name and that is the end of it. I don't know how to setup any kind of static interception for specific names and forward resolution requests to the other domain's DNS.
