How to forward ports on a router?

Question

Computer networks

How to forward ports on a router
The provider has a permanent ip connected 5.19.*.*
But the network settings for connecting via a static ip are 10.212.*.* with a gateway corresponding to the first digits
When you connect the wire directly to the computer and enter the network settings, all the necessary ports are open , and if you connect through a router and forward to the local address of the computer, all ports are closed

Answer 1

You are already behind the nat provider. And most likely it has DMZ set to your gray ip 10.212.*.* and when the cable is connected to the router, a double nat is formed, so the ports will not open on the end computers.