OSX Yosemite Search Domains Madness – RESOLVED

After upgrading a couple of my Macs to OSX Yosemite (10.10), I discovered that the former DNS resolution service, mDNSResponder, has been replaced by discoveryd.

This causes issues for me, as with mDNSResponder I was able to add “-AlwaysAppendSearchDomains” to the plist file, and it would do as it says, always append the search domains.

In my workplace, we have servers that have very long, multiple-part hostnames, for example:

host1.sub1.sub2.sub3.example.com

With “AlwaysAppendSearchDomains” enabled, I was able to access these servers via ssh like so:

ssh host1.sub1.sub2.sub3

With discoveryd, attempts to access them this way fail, as it does not add the search domains to anything longer than a single subdomain.

10.10.1 Resolution

As of Yostemite 10.10.1, the AlwaysAppendSearchDomains functionality is back!

sudo vim /System/Library/LaunchDaemons/com.apple.discoveryd.plist

Edit to add the option, so the first several lines appear as follows:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
 <key>Label</key>
 <string>com.apple.networking.discoveryd</string>
 <key>UserName</key>
 <string>_mdnsresponder</string>
 <key>GroupName</key>
 <string>_mdnsresponder</string>
 <key>ProgramArguments</key>
 <array>
 <string>/usr/libexec/discoveryd</string>
 <string>--udsocket</string>
 <string>standard</string>
 <string>--loglevel</string>
 <string>Basic</string>
 <string>--logclass</string>
 <string>Everything</string>
 <string>--logto</string>
 <string>asl</string>
 <string>--AlwaysAppendSearchDomains</string>
 </array>

Reload the discoveryd plist:

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

And there was much rejoicing!

Not as old resolution

As pointed out in the comments, this can be very easily resolved with some edits to ~/.ssh/config

For example, mine now contains:

Host *.sub3
HostName %h.example.com

Of course, this only works for SSH, but that was the major part of my workflow that was broken.

OLD resolution

This severely broke my workflow, until I discovered that nslookup still works without the search domain being added (this is likely due to the configuration of the DNS servers in my workplace).

I decided to write a small bash script to allow me to ssh to these servers:

#!/bin/bash 
# Created by tfmm to get around OSX 10.10's crappy dns resolution and lack of appending search domains.  
ip=`nslookup $1 | egrep -o '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' |tail -1`  
ssh $ip

Save to a file, like “ssh2.sh”, make it executable, and use like so:

./ssh2.sh host1.sub1.sub2.sub3

I created an alias, so I don’t have to call the file directly, and can call it from any location.

This script could be modified for any command-line function, I have also copied it and modified it for PING use by replacing “ssh $ip” with “ping $ip”.