Apple broke DNS compatibility towards partially qualified domain names with the latest OS X release. On Nov. 18th they released an update with a patch to this issue (since I spent the time to escalate it). From http://support.apple.com/en-us/HT204017 release notes I quote:

Allows you to append search domains for partially qualified domain names when performing DNS lookups (consult the discoveryd man page for more information)

How was it supposed to work? And how can we activate it?

If you are a big corporation you are going to have a very complicate and hierarchically designed DNS system. Sometimes you just want to shorten the amount of data you type in to jump from one box to another, so… taking as a sample the Akamai mirror of apple.com you’ll see that will CNAME to e3191.dscc.akamaiedge.net. Imagine you are working for Akamai, and you need to ssh into e3191.dscc , without the partially qualified domain name feature you’ll have to type in the full fqdn. Instead, if you have akamaiedge.net in your domain search field, you don’t have to, your resolver will do it for you.

So, on OS X… I quote from my Apple Support guy’s email:

You can edit /System/Library/LaunchDaemons/com.apple.discoveryd.plist and add ‘–AlwaysAppendSearchDomains’ as a string to the ‘ProgramArguments’ array. That should re-enable search domains for PQDNs once you reboot after saving.

I add… you can simply “sudo launchctl unload /System/Library/LaunchDaemons/com.apple.discoveryd.plist” and “load” to refresh the daemon after having edited the file, without rebooting your laptop/workstation…

enjoy 😉