I had some security problems with my cams a while ago (passwords were reset, etc). If I recall correctly, the cameras automatically opened ports on my router. There was some function to disable this feature and since then all camera problems disappeared. However, I also lost connection to my home automation system, streaming services, etc since all ports were shut down. Now I just use a VPN connection if I need to connect to my system at home. But I am considering changing my PoE switch to a fanless "smart" (that allows VLANs) one. 16 port smart PoE switches without fans are not easy to find at "reasonable" prices, though.