For the Mac users who recently upgraded to Mac OS X 10.7 Lion, maybe you noticed recently that there is no “Off” option to disable IPv6 from the user interface. IPv6 is very dangerous if you plug your box into an IPv6 which is not controlled and
configured properly. This is the 0-day attack that takes advantage of SLAAC – Stateless Address Auto Configuration. Therefore if you are travelling with your Mac and connect to another network that you don’t control, if you use IPv6 now, you might fall into a man-in-the-middle attack. So, edit the following file with the following command:
sudo vi /Library/Preferences/SystemConfiguration/preferences.plist # Go to the following IPv6 section and change it to: <key>IPv6</key> <dict> <key>ConfigMethod</key> <string>__INACTIVE__</string> </dict>
Then you need to reboot. You will notice after this reboot that there is no IPv6 that is automatically assigned.