We are using the Shrew Soft VPN client on all of our windows machines. It works great, at least version 2.1.7. It looks like they may have a MAC OS version according to this site: http://ulaptech.blogspot.com/2012/11/shrew-soft-vpn-client-for-mac-os-x.html
but I am not sure if it works or not. I plan on testing it. I would like to know if anyone has been successful with using some kind of VPN software on a MAC with the MFE? Our MFE is v8.3.1 I appreciate any insight anyone might have into this. Thanks!
This one will probably work: http://www.lobotomo.com/products/IPSecuritas/
There is also the built-in FreeBSD/KAME IPsec daemon and the Raccoon IKE daemon that can be configured on the command-line. I think IPSecuritas might just be a front-end/GUI for the built-in daemons in Mac OS.