A network gateway moves traffic between two networks, usually between a site’s local network and the internet. It routes packets, applies address translation and often filters traffic as a firewall. When the gateway fails, every camera and recorder behind it becomes unreachable.
The gateway is easy to overlook because it is usually a plain box in a closet. It is also the one device that all remote viewing, alerts and updates depend on.
Routing, translation and filtering
The gateway holds an address on each network and decides where a packet goes next. On a camera network it normally performs NAT, hands out addresses by DHCP and blocks unsolicited inbound traffic.
Where the gateway fails
Consumer routers are not built for a continuous camera load. A gateway that reboots, drops sessions or runs out of translation entries takes the whole system offline, so it belongs on the same UPS as the recorder.