OpenVPN is an open-source software application that implements virtual private network (VPN) techniques for creating secure point-to-point or site-to-site connections in routed or bridged configurations and remote access facilities.

It uses a custom security protocol that utilizes SSL/TLS for key exchange.

It is capable of traversing network address translators (NATs) and firewalls.

It was written by James Yonan and is published under the GNU General Public License (GPL).

, one of the oldest national universities (established by Japanese Government) and one of the most comprehensive research universities in Japan, is in the city of Tsukuba (known as Tsukuba Science City), Ibaraki Prefecture in the Kantō region of Japan.

The university has 28 college clusters and schools with around 16,500 students (as of 2014).

The main Tsukuba campus covers an area of 258 hectares (636 acres), making it the second largest single campus in Japan.

The branch campus is in Bunkyo-ku, Tokyo, which offers graduate programs for working adults in the capital and manages K-12 schools in Tokyo that are attached to the university.

A virtual private network (VPN) is a virtualized extension of a private network across a public network, such as the Internet.

It enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network.

Applications running across the VPN may therefore benefit from the functionality, security, and management of the private network.

Transport Layer Security (TLS) and its predecessor, Secure Sockets Layer (SSL), both frequently referred to as "SSL", are cryptographic protocols that provide communications security over a computer network.

Several versions of the protocols find widespread use in applications such as web browsing, email, Internet faxing, instant messaging, and voice-over-IP (VoIP).

Websites use TLS to secure all communications between their servers and web browsers.

Secure Socket Tunneling Protocol (SSTP) is a form of VPN tunnel that provides a mechanism to transport PPP traffic through an SSL/TLS channel.

SSL/TLS provides transport-level security with key-negotiation, encryption and traffic integrity checking.

The use of SSL/TLS over TCP port 443 allows SSTP to pass through virtually all firewalls and proxy servers except for authenticated web proxies.