Geovision has had a ton of security incidents. Perhaps they're easy to set up, but they definitely aren't secure.
In larger installs it’s a VRF dedicated to the camera subnets and a similar dedicated NIC arrangement on the server.
Nothing should talk to the cameras except the recording server they’re streaming to.
Annoyingly, few TVs have multicast receivers, it's all Chromecast etc, so you need your own computers to decode and display.