I recently updated my MAC OS X version to 10.8.2. After this update, my VPN started having random issues. Sometimes while connecting it would show me authentication failure or no server response while at other times it would connect perfectly. On some networks it refused to let me connect at all. I have found a solution to this and now my VPN connects fine every time. Here’s how:
Open terminal and type:
# Create backup cp -r /Library/Preferences/SystemConfiguration ~ # Delete the SystemConfiguration sudo rm -rf /Library/Preferences/SystemConfiguration
This will delete all your custom networks. Make sure you have the settings written down somewhere.
Reboot and recreate the VPN network connection
Test your VPN now. Voila! It works !