Hi there and welcome
Can you tell me please the make and model of the IP Cameras?
ok, checking the manual the Wanscam says port 99 and 4000
For the Foscam, when you set them up you set the port, so it is the port you configured it to.
If they are the ports you set, then they are the ports you forward
You do not need to port forward on the LAN, you only need to forward on the router, and the ports you indicated is what you have to forward.
I am sorry you feel this is wrong,but it is how port forwarding works, but no problem, you are of course entitled to your onion, I will opt out for another expert who can work with you to do port forwarding that does not involve the router.
Thanks and all the best.