This is the open-source version of the OpenVPN protocol. It is completely free, highly configurable, and widely supported. It requires more manual configuration (command-line) compared to Access Server but is just as secure.
With a legitimate license, you have access to 24/7 technical support from OpenVPN engineers. With a cracked version, you are entirely on your own if the routing tables break, configuration files corrupt, or certificates expire. Legitimate, Free Alternatives to Cracked Software openvpn access server crack link