fix wifi sharing on mac

fixwifishare.sh

sudo lsof -i udp:67 | grep bootpd |awk '{ print $2 }'| while read pid; do echo killing $pid; sudo kill -9 $pid&&echo "successfull..."; done

Definitive workaround to wifi-sharing constant breaking down in MacosX

I have found a system that finally works and when, less frequently wifi sharing breaks, it manages to recover it automatically in a minute.

The solution is a ~/Library/LaunchAgents/com.me.wifisharingup.plist daemon with the next contents:

<?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.juanfal.wifisharingup</string>

  <key>ProgramArguments</key>
  <array>
    <string>/Users/mi/bin/wifisharingup.sh</string>
  </array>
  <key>Nice</key>
  <integer>1</integer>

  <key>StartInterval</key>
  <integer>60</integer>

  <key>RunAtLoad</key>
  <true/>

  <key>StandardErrorPath</key>
  <string>/Users/me/Library/Logs/wifisharingup.err</string>

  <key>StandardOutPath</key>
  <string>/Users/me/Library/Logs/wifisharingup.out</string>
</dict>
</plist>

You can see, each minute it runs the simple script that follows. Be careful making the previous plist be owned by the root and launch it with:

sudo chown root com.me.wifisharingup.plist
sudo launchctl load /Users/me/Library/LaunchAgents/com.me.wifisharingup.plist

The script it launches each minute (don't forget to make it executable) is:

#!/bin/sh

if [[ ! `ipconfig getifaddr en1` ]]; then
    /usr/sbin/networksetup -setairportpower en1 off
    /usr/sbin/networksetup -setairportpower en1 on
    echo `date` >> "/Users/me/Library/Logs/wifisharingup.err"
else
    touch "/Users/me/Library/Logs/wifisharingup.out"
fi

I think the simple periodically (each minute) call to ipconfig getifaddr en1 refreshes something in what is the wifi sharing daemon. Whatever it is, any moment the wifi sharing fails, it looses the self assigned IP address, and then, ipconfig getifaddr en1 fails, so my script totally resets wifi, making it rebuild its previous status and recovering the wifi-sharing.

It has been working for days so far inside a MacMini without keyboard, mouse or monitor, but only plugged into the Ethernet and giving my wifi gadgets access to the world.