You can actually authenticate against the GA product from any system - hook it into PAM for sshd access, use it for another factor in OpenVPN, or even just wire

You can actually authenticate against the GA product from any system - hook it into PAM for sshd access, use it for another factor in OpenVPN, or even just wire it into Apache: http://code.google.com/p/google-authenticator-apache-module/ http://code.google.com/p/google-authenticator-apache-module/