OpenVPN is a full-featured open source SSL VPN solution that accommodates a wide range of configurations, including remote access, site-to-site VPNs, Wi-Fi security, and enterprise-scale remote access solutions with load balancing, failover, and fine-grained access-controls.
OpenVPN’s lightweight design sheds many of the complexities that characterize other VPN implementations. The OpenVPN security model is based on SSL, the industry standard for secure communications via the internet. OpenVPN implements OSI layer 2 or 3 secure network extension using the SSL/TLS protocol, supports flexible client authentication methods based on certificates, smart cards, and/or 2-factor authentication, and allows user or group-specific access control policies using firewall rules applied to the VPN virtual interface. The community version of the software is developed openly and transparently in community-driven fashion. OpenVPN runs on Linux, Windows 2000/XP/Vista/7 and higher, OpenBSD, FreeBSD, NetBSD, Mac OS X, and Solaris.