OpenVPN
Networks with Internet access can be configured to allow Internet-connected clients remote access using a VPN connection --a “secure encrypted tunnel” over which traffic will travel, making the data unreadable to prying eyes. Setup will require each client to be configured by generating and assigning a certificate, and a server to which clients connect. Depending on the nature and complexity of a given network, additional tasks may be required.
DOWNLOADS
32-bit:
http://swupdate.openvpn.org/community/releases/openvpn-install-2.3.14-I002-i686.exe
64-bit:
http://swupdate.openvpn.org/community/releases/openvpn-install-2.3.14-I002-x86_64.exe
RESOURCES
Documentation on using OpenVPN to establish a VPN connection is complete and concise. IT personnel skilled in such matters should be able to follow along without much trouble.
OpenVPN: HowTo - This is a technical process, and assumes a rudimentary knowledge of basic TCP/IP networking concepts: protocols including TCP/IP, DNS, netmasks, subnets, routers and routing tables, gateways, firewalls, and Ethernet connections.
https://openvpn.net/index.php/open-source/documentation/howto.html
Support Forum
Additional Documentation
https://openvpn.net/index.php/open-source/documentation.html
Various Articles
https://openvpn.net/index.php/open-source/articles.html
FAQ
https://community.openvpn.net/openvpn/wiki/FAQ
Security
https://www.sans.org/reading-room/whitepapers/vpns/openvpn-ssl-vpn-revolution-1459
https://en.wikipedia.org/wiki/Virtual_private_network#Security_mechanisms
https://community.openvpn.net/openvpn/wiki/293-what-is-the-principle-behind-openvpn-tunnels
https://openvpn.net/index.php/open-source/337-why-openvpn-uses-tls.html
https://openvpn.net/index.php/open-source/333-what-is-openvpn.html