Automatically fix IPv6 configuration when another process disables it

I had a problem where Freedom.to was turning my IPv6 off. This is not good™ because I work at Facebook, where many of our servers run IPv6 exclusively. So..... I wrote a quick thing to fix this on MacOS X. Essentially, it listens to the folder /Library/Preferences/SystemConfiguration and then runs a script every time it changes. This means every time freedom.to ruins my IPv6 configuration, this little agent fixes it.

<?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>dev.randallb.fixipv6</string>
    <key>ProgramArguments</key>
    <array>
        <string>/Users/randallb/fixipv6.sh</string>
    </array>
    <key>WatchPaths</key>
    <array>
        <string>/Library/Preferences/SystemConfiguration</string>
    </array>
</dict>
</plist>

and the script

#!/bin/bash
networksetup -setv6automatic Wi-Fi && networksetup -setv6automatic Ethernet
syslog -s -l notice "fixed IPV6"

Once you've got all the files in place, make sure to chmod +x on your fixipv6.sh script, and then run:

launchctl load ~/Library/LaunchAgents/dev.randallb.fixipv6.plist

Also I put my launch agent in my ~/Library/LaunchAgents folder.

Good luck!

Photo by Shahadat Shemul on Unsplash