OpenVPN is an open-source VPN protocol that creates encrypted tunnels for network traffic using SSL/TLS technology over port 443. The protocol uses the OpenSSL library with 256-bit AES encryption and HMAC authentication to secure data transmission between clients and servers. OpenVPN operates in two modes: TCP for reliability and UDP for speed. The protocol routes traffic through secure VPN servers, replacing the user's IP address to provide anonymity and bypass geographic restrictions. It supports multiple use cases including remote access, site-to-site networking, and connecting distributed networks. The protocol runs on major operating systems including Windows, macOS, Linux, Android, iOS, and routers. OpenVPN can be tunneled over SSH and SSL protocols for additional security layers. The technology is maintained by an open-source community and undergoes independent security audits. OpenVPN is available in two versions: OpenVPN Community (free, self-configured) and OpenVPN Access Server (commercial). The protocol uses standard HTTPS traffic patterns to bypass firewalls and network restrictions. It relies on third-party plugins and the OpenSSL library rather than proprietary encryption methods. CyberGhost VPN implements OpenVPN as one of its supported protocols alongside IKEv2 and WireGuard, providing users with pre-configured access to OpenVPN servers without manual setup requirements.