You can connect using L2TP protocol in Mac OS X.
Click the network icon in the top right. And choose "Open Network Preferences ..."
Then press the + setup menu.
Select the following:
Interface: VPN
Vpn type: L2TP over IPsec
Service name: RoTunneling
After the following window will appear where you fill out:
Server Address: ro-3.rotunneling.net, buc-1.rotunneling.net, buc-2.rotunneling.net, france.rotunneling.net or usa.rotunneling.net
Account Name: your website username.
And click Authentication Settings...
Password: your website password.
Shared Secret: vpn
Then, click OK.
Check the bottom of the window Show VPN status in menu bar and click Advanced.
Here Check the 3 options in the Session.
Ok, Ok, and applay.
To connect press connect the right connections RoTunneling.
Tags: How to, configure, l2tp, MAC OS X