SSH tunneling to connect to remote computers

We present software to establish secure shell (command prompt) connections remote computers perform maintenance, configuration, or debugging, even when the are connected Internet such that incoming not allowed. The is easy install and operate, has few dependencies, provides many useful security guarantees, scales large number of computers, possibly partitioned into isolated groups. relies on one two inexpensive cloud services. A preliminary version system been used for nine years access geographically-remote serve as sensors in wildlife tracking systems.