N2n

n2n is an open source Layer 2 over Layer 3 VPN app utilising peer-to-peer architecture for network membership and routing.

n2n
Developer(s)	n2n team
Initial release	March 27, 2008 (2008-03-27)
Stable release	3.0[1] / 27 October 2021; 3 years ago (27 October 2021)
Repository	https://github.com/ntop/n2n
Written in	C
Operating system	FreeBSD, Linux, OpenWrt, Mac OS X, Unix, Windows, Android
Type	VPN
License	GNU General Public License
Website	https://www.ntop.org/products/n2n/

Unlike many other VPN programs, n2n can also connect computers which reside behind NAT routers. These connections are set up with help from a third computer that both computers can reach. This computer, called a supernode, can then route the information between NATed nodes.^[2]

It is free software licensed under the terms of the GNU General Public License v3.^[3]

n3n forked from n2n in 2023.^[4]

Turbo VPN is a custom Windows server/client implementation of n2n.^{[citation needed]}