tinc is a Virtual Private Network (VPN) daemon that uses tunnelling and
encryption to create a secure private network between hosts on the
Internet.

tinc is Free Software and licensed under the GNU General Public
License version 2 or later. Because the VPN appears to the IP level
network code as a normal network device, there is no need to adapt
any existing software. This allows VPN sites to share information
with each other over the Internet without exposing any information
to others.