If you're not instructed to add a port when you configure a camera, then simply add the camera's IP and the DVR will recognize it automatically. I've looked through various websites and forums, but didn't find anything related to a port.
My advice is to connect directly to camera to check its configuration, then you can see if it's needed to assign a port or not. Additionally, check the manual of the DVR to see how a camera needs to be added for live streaming.
