How to setup L2TP VPN on Mac OS X?
Click the Apple icon, then open System Preferences.
Click Network under Internet & Wireless.
Click on the + sign.
Select VPN for the Interface, L2TP for the VPN Type, and enter LimeVPN L2TP for Service Name.
In the Server Address field, enter any one of the server mentioned under http://network.limevpn.com/
Click Authentication Settings.
Enter your LimeVPN Password in the Password field.
Under Machine Authentication, click the radio button for Shared Secret and enter LimeVPN share key: private
Click Advanced, check Send all traffic over VPN connection.
Then click OK.
Click Connect to your new VPN connection.
To disconnect click on Disconnect.