Between TCPMUX and ETSN, all else being equal, ETSN is simpler and doesn't have the built in "autoportscanner" HELP command. I get the arguments for both sides about it being Internet-facing, so as to that I will simply shrug. For non-Internet facing internal network kinda stuff it's still a great solution, regardless, so I cleaned up my code and pushed it to github, if anyone wants to play with it: https://github.com/JImmyFrasche/etsn (warning: I only tested it with the example code in the readme)