Freelan is a peer-to-peer VPN solution.
A free, open-source, multi-platform, highly-configurable and peer-to-peer VPN software, designed to easily connect remote hosts and mainly focused on security and performance.
It can be used to create from small to very large virtual private networks which can be dynamically modified.
Freelan works on top of UDP and implements a simple yet pretty secure VPN protocol that can create Ethernet tunnels over both IPv4 and IPv6.
Freelan is available as end-user binary packages and as a C++ library to ease its integration into other softwares.
Source:Freelan
