The problem: logging in to a remote system with a cryptographic solution
such as lsh or ssh takes time, due to the computationally expensive key
exchanges that occur when the connection is established.  The solution:
reuse the secure tunnel once it has been established.  fsh is a drop-in
rsh-compatible replacement for ssh that automatically reuses ssh tunnels.

Homepage:
https://www.lysator.liu.se/fsh/
