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.
You want to get an IP camera and a switch/router/firewall that supports 802.1x - Port Authentication, along with a VLAN for segregation and MAC filtering because more is better.
With 802.1x the camera has to authenticate / re authenticate using EAP for the port to remain active. If someone rips off the camera and figures out its MAC address to spoof it’s still not going to pass the EAP challenge.