In March 2013, a Japanese student by the name of Daiyuu Nobori set up VPN Gate, a free VPN service that he hoped would be used by Internet users who wish to avoid their country’s online content restrictions but don’t have the necessary funds to use a paid VPN service.

The service relies on volunteers with a broadband connection to download the server software and set up Public VPN Relay Servers for others to use. Initially, that number was around 100, today there are over 5200 of these servers around the world.

Since the very beginning, users from all around the world – even from Western democracies – used the service, and the number of daily unique users is currently estimated at over 110,000.

VPN Gate is an application based on the SoftEther VPN freeware, which was developed by the students at University of Tsukuba, Japan. SoftEther VPN binaries were released around the same time that VPN Gate was presented to the world, but its source code has only been released under the GPLv2 license this past Saturday.

“We believe that our release of SoftEther VPN source code will have an impact on both the free-VPN software circumstances and the commercial VPN product industry,” Nobori commented for Help Net Security. “There are no other open-source VPN programs that implement all of today’s popular VPN protocols: SSL-VPN, IPsec, L2TP, OpenVPN, EtherIP and MS-SSTP. Furthermore, because SoftEther VPN is licensed under GPLv2, anyone will be able to modify, re-compile and release a derivative of SoftEther VPN.”

“We believe that easy-to-use software-based VPN tools are necessary to achieve the free Internet world,” Nobori noted, adding that they hope that the release of SoftEther VPN source code will help to achieve that goal.

The SoftEther VPN server software runs on Windows, Linux, OS X, FreeBSD and Solaris, and the client application can be used by Windows, Linux, Mac, Android, iOS and Windows Phone users.

The released source code will allow developers to design and implement a VPN protocol-engine able to achieve the “high-performance, multi-protocol support VPN communication with high-level penetrating-ability against firewalls,” says Nobori.

“They can also study the know-how to implement kernel-mode device drivers which access to low-level Ethernet packet processing fabric on Windows and other modern operating systems.”

For more details and the source code, visit the project’s Github page.