Pioneering research has discovered how smart devices talk to Android apps and each other to share data that allows them to know who enters a home, when, and how much they earn
Those ports are closed when the session is disconnected provided they have been open via NAT upnp rules and even then you’d need to know what the random high 5000 port is open on your target and that’s even assuming that the router they are using is vulenerable to whatever exploit you’re trying to run.
You’re correct about an outside individual accessing your network, but that still doesn’t prevent a device on your network from phoning home.
I think most people have at least some open ports, though. Isn’t port forwarding required for a lot of online games? It used to be at least.
Those ports are closed when the session is disconnected provided they have been open via NAT upnp rules and even then you’d need to know what the random high 5000 port is open on your target and that’s even assuming that the router they are using is vulenerable to whatever exploit you’re trying to run.