Hamachi is a zero-configuration virtual private networking (VPN) freeware application. It is the first and so far the only VPN application capable of establishing direct links between computers that are both NATed. Currently available for Microsoft Windows and Linux. Mac OS X version is in development.
=External links=
[http://www.hamachi.cc/ www.hamachi.cc] - official site.
[http://www.hamachi.cc/security www.hamachi.cc/security] - security architecture description.
[http://www.hamachi.cc/get www.hamachi.cc/get] - downloads.