Full-featured SSL VPN solution using a TUN/TAP Interface

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.

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 runs on: Linux, Windows 2000/XP and higher, OpenBSD, FreeBSD,
NetBSD, Mac OS X, and Solaris.

OpenVPN is not a web application proxy and does not operate through a
web browser.