First off, I am well aware that port-knocking does create more security-feeling than real saftey, and that it is mainly a security-by-obscurity thing. Nevertheless: Are there are open-source projects around which use e.g. knockd as replacement for a full-fledge architecture to steer a simple IOT-device?
More details on the setup
Let me elaborate a bit my idea: The IOT-device is a Raspberry (or any other single board computer) which performs a visible action (like opening or closing a window shutter). In other words, I do not need any feedback from the device via IP or UDP protocol. All I need is a demon of some kind listening for a handful of commands (for the window shutter this may be open-completely, close completely, open further by a third if state allows, close further by a third if state allows). The Raspberry is aware of the current state of the shutter, accepts a new command only once the last one is fully executed, and limits the number of commands per time interval. If my knocking-sequence is long-enough, I would reach a higher security than many IOT-devices on the market (remember the old joke: "S" stands for security in IOT).
While brain-storming the idea of my simple Raspberry-window-shutter-project, the old CGI bin approach came into my mind, nowadays it would possibly be a python http.server or something similar. Both these approaches seem a bit overkill to me. There are some ready-to-use mobile apps like Knock on Ports which I could immediately use to test my setup. But before I reinvent the wheel, I would love to know whether I have overseen some existing projects going in a similar direction.
