Hey MikroTik folks )
Over the last few days I ended up building a little tool (well, two). In short: it's UDP port-knocking with a PSK — instead of leaving a dst-nat port exposed to the internet 24/7, the port stays closed and only opens for a short window, for your specific IP, after a successful secret-keyed "knock". It all runs on native RouterOS (firewall rules + a poller) — no external service sitting on the router.
The client CLI builds for most platforms; there's also a native macOS menu-bar client and a desktop provisioning app. I just didn't have a need to build desktop clients for Windows/Linux (the CLI covers those).
Everything's here (details, screenshots, binaries):
Would be glad if it turns out useful to anyone — not selling anything, no ads / affiliate / tracking, just giving it back and hoping for feedback.! 