In the cameras configuration menu it's set up in Network > Advanced Settings > Http Listening as shown in the screenshot below. It may be called "Alarm Server" or something else depending on the version of firmware on your camera, but it's in the same place. It'll only work if your camera is on the same network range as your LAN - it's no good if the camera is on the PoE port of an NVR because that will be on a different network segment.