What sort of single user script will do this though?
Basically I have two different IoT WLANs, one for some safer open-source devices (Tasmota, etc) and one with "dangerous" call-home type gadgets (FireTVs, etc). I want several devices on the latter WLAN to be able to chat with the hardwired Pi, and it currently cannot. Specifically, this is for the androidtv: integration in Home Assistant, which is running on the Pi. ADB uses tcp/5555, but it is likely there is more involved in the connection. I will investigate that as needed, but isolating the video devices is a privacy issue, not security, so starting with things wide open and then closing it as a second step is palatable.
In short, I have sold my soul (or, at least the sovereignty of my household) to Amazon, and want at least the illusion of mitigation. But it is super-cool to see the Plex Media Player integration show up for every TV in the house, and I want to add more control. Of course, Plex is a bit more flexible, of course.