SoftEther VPN is a free open-source, cross-platform, multi-protocol VPN solution developed as part of Daiyuu Nobori's master's thesis research at the University of Tsukuba. VPN protocols such as SSL VPN, L2TP/IPsec, OpenVPN and Microsoft Secure Socket Tunneling Protocol are provided in a single VPN server. It was released using the GPLv2 license on January 4, 2014. The architecture of SoftEther VPN was designed for firewall penetration.