Max OS X Setup

Similar to iOS.

Open System Preferences > Network
Click on the + sign to create a new service
For Interface select VPN. For VPN type select Cisco IPSec'. Give the service a name, like Amahi Home and click on Create
Once added, select it. In the Server Address put YOURNICK.yourhda.com (replace YOURNICK with your nickname).
In Account Name, put your username. Leave password empty unless you trust this computer.
Click on Authentication Settings
In Shared Secret, put the Group Setting from your internal IPSec VPN. In Group Name, enter Amahi. Click OK
You can now click on Connect to connect!
You can also click on "Show VPN status in menu bar" for quick access to the VPN connection
Click on Apply to save these settings

Amahi Wiki