OpenVPN is a secure tunneling daemon that implements a virtual private network by creating encrypted connections between systems over untrusted networks.
OpenVPN solves the problem of establishing secure, authenticated communication channels across public networks. It uses a custom protocol built on SSL/TLS encryption to create point-to-point or site-to-site VPN tunnels. The daemon runs on both endpoints and handles the encryption, decryption, and routing of traffic through the tunnel, with configuration managed through text-based config files and command-line options.
OpenVPN suits organizations and individuals needing cross-platform VPN capability, as it runs on Linux, Windows, and other systems. It is appropriate for both client-to-server and server-to-server deployments, from small personal use cases to large enterprise networks. The project provides sample configuration files, key generation tools, and authentication scripts to help with setup. Related tools like easy-rsa for certificate management and tap-windows for Windows network drivers are maintained as separate subprojects, and community-built installers are available through a dedicated build repository.
The project maintains active issue tracking on GitHub and provides comprehensive documentation including man pages and configuration howtos. Development follows a traditional autotools-based build system with configure scripts and makefiles, alongside CMake support for Windows builds with MinGW or MSVC. The codebase is written primarily in C and includes sample keys, certificates, and Perl scripts for custom authentication workflows within the distribution itself.
