openvpn

OpenVPN is a full-featured SSL VPN solution which can accomodate a wide range of configurations, including remote access, site-to-site VPNs, WiFi security, and enterprise-scale remote access solutions with load balancing, failover, and fine-grained access-controls (articles) (examples) (security overview) (non-english languages).

OpenVPN implements OSI layer 2 or 3 secure network extension using the industry standard 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. OpenVPN is not a web application proxy and does not operate through a web browser.

For a good conceptual introduction to OpenVPN, see the program notes for James Yonan's talk at Linux Fest Northwest 2004 -- Understanding the User-Space VPN: History, Conceptual Foundations, and Practical Usage. See also OpenVPN and the SSL VPN Revolution by Charlie Hosner.

OpenVPN is an Open Source project and is licensed under the GPL. Commercial licenses are also available for firms who would like to redistribute OpenVPN with their own proprietary applications. Contact info@openvpn.net for more information.

http://openvpn.net/