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.
