yosemite_dnsfix

Yosemite update 10.10.2

I've had reports that the 10.10.2 update again breaks DNS by removing --AlwaysAppendSearchDomains from /System/Library/LaunchDaemons/com.apple.discoveryd.plist. If you want to fix it, just re-add the argument and reload discoveryd, using e.g.

sudo launchctl unload /System/Library/LaunchDaemons/com.apple.discoveryd.plist
sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.discoveryd.plist

Yosemite update 10.10.1+

With the release of 10.10.1, Apple has added the --AlwaysAppendSearchDomains argument to /usr/libexec/discoveryd, so you can add this to /System/Library/LaunchDaemons/com.apple.discoveryd.plist. You may find that this works well enough that you no longer need yosemite_dnsfix, although yosemite_dnsfix can still be used to support search domains resolution like .prod -> .prod.example.com now that .prod has become a TLD. yosemite_dnxfix may also be faster than --AlwaysAppendSearchDomains, as it doesn't wait for the unqualified resolution to fail before appending the search domain.

With the release of OS X 10.10 Yosemite, it appears those no good bush whackin’ barracudas at Apple have put the final nail in the coffin of their crippled DNS search domain functionality.

Specifically, search domains don't work at all for any name containing ".", and I'm not aware of any simple workaround.

In Lion/Mavericks, we could at least fix this by adding -AlwaysAppendSearchDomains to the mDNSResponder launchd args, but with the switch to discoveryd it seems the muley-headed mavericks have removed even that small consolation.

Dem's fight'n words! I suggest you complain to those lily-livered, bow-legged varmints through any available channel so that we don't have to resort to hacks like this.

yosemite_dnsfix abuses the twisted.names DNS server and /etc/resolver/ functionality (both present in OS X) to restore (some of) this basic DNS functionality, which works in all other OSes by default.

Now quit stallin’ and start roastin’!

yosemite_dnsfix runs a patched twisted.names DNS server on localhost that automatically appends a search domain to all queries before forwarding them to the system nameservers (read periodically from /etc/resolv.conf). When combined with resolver(5) config files, this can kind of be used to simulate a sane client resolver.

For example, let's say your company has hostnames that follow a scheme like this:

• server1.env1.example.com
• server1.env2.example.com
• server1.env3.example.com
• ...

You obviously want to be able to resolve these as server1.env1, server1.env2 etc - or do you like RSI?

So, run yosemite_dnsfix:

sudo -i
cd /opt
git clone https://github.com/joedj/yosemite_dnsfix.git
cd yosemite_dnsfix
twistd --nodaemon --uid=_mdnsresponder --gid=_mdnsresponder yosemite_dnsfix --interface=127.0.0.1 --recursive --search-domain=.example.com

And then set up your /etc/resolver/ files:

sudo -i
for env in env1 env2 env3; do
    echo 'nameserver 127.0.0.1' > /etc/resolver/$env
done

Blast your ornery hide, if ya does that just once more... I ain’t a-going after it

You'll want to start it on boot, so edit the included net.joedj.yosemite_dnsfix.plist, and then:

sudo -i
cp /opt/yosemite_dnsfix/net.joedj.yosemite_dnsfix.plist /Library/LaunchDaemons/
launchctl load -w /Library/LaunchDaemons/net.joedj.yosemite_dnsfix.plist