In order to use two factor authentication, you will need a certificate authority (CA) system. The CA system will create a digital certificate with the authentication information for each of your employees. Contained within the certificate will be the resources which they are allowed to access. Any resources using this type of authentication that are not contained within the certificate will not be able to be accessed.
Secure Different Types of Connections by Using Two Factor Authentication
You can use two factor authentication with all different types of electronic connections over your network, as well as over public networks. This type of authentication can be used to limit the resources your employees can use and access. It can also be used for authentication in order to connect to the internet, extranet, through your VPN, cloud networks and SaaS.