Perhaps if there is no such program out there, there is some way to hack a broadband router to do this?
The bit I am unclear on is how this authentication is supposed to happen, who is authenticating what and how.
If the stream was SSL then you want the true client to provide the authentication data in the stream, then the server authenticates the client.
The box is the middle should be as dumb as possible and only have to do the port redirection. The authentication injected by the man in the middle looks and feels wrong.
My broadband router lets an externally visible port be forwarded to any port on any computer on the internal network, so, for example I have the sshd port on the broadband router forwarding to one of my servers on my internal network.
ssh can do alot of port redirection just by itself.
MacOS can do anything that somebody has already written a program for.
UNIX can do many new things by arranging existing programs in some cunning fashion.
