OpenVPN is a robust and highly configurable VPN
(Virtual Private Network) daemon which can be used
to securely link two or more private networks
using an encrypted tunnel over the Internet.
OpenVPN's principal strengths include wide
cross-platform portability, excellent stability,
support for dynamic IP addresses and NAT, adaptive
link compression, single TCP/UDP port usage, a
modular design that offloads most crypto tasks to
the OpenSSL library, and relatively easy
installation that in most cases doesn't require a
special kernel module.