Is there a service that wraps/proxies a port with a different or custom protocol? (kind of like SSL for HTTP)
Idea: instead of ssh'ing a server, you would run your custom command which communicates to port XXXX, communicate with a custom protocol and then if validation succeeds, would proxy to SSH (or any other internal port/protocol).
Why? Because as others suggested you could scan all ports very quickly to break this, but if you scan a port and just receive garbage or something only you can understand when opening it, then you could hide it from the outside..
Idea: instead of ssh'ing a server, you would run your custom command which communicates to port XXXX, communicate with a custom protocol and then if validation succeeds, would proxy to SSH (or any other internal port/protocol).
Why? Because as others suggested you could scan all ports very quickly to break this, but if you scan a port and just receive garbage or something only you can understand when opening it, then you could hide it from the outside..
(Just curious)