I was recently investigating two factor authentication solutions to use with a Watchguard XTM appliance for mobile VPN solutions, to where I came across FreeRADIUS (http://freeradius.org/). FreeRADIUS server is a daemon of a UNIX (like) operating system which allows for a radius protocol server to be setup.  FreeRADIUS is an open-source project and is developed … More Integrating Google Authenticator PAM module with FreeRADIUS Server