It’s an ethernet wire that’s going to be exiting my house and running to a camera in a publicly accessible space. An attacker could disconnect the camera, connect a laptop and access my network. How could I protect against that (other than a physical lock)? I basically want to lock down that cable to the point where nothing works on it unless it’s the intended camera. If this was wireless, I’d just use MAC filtering, but I don’t see an equivalent for wired connections.
Mac filtering is not real security. It is very easy to bypass it that filtering macs is almost as secure as not doing it. Your best options are :