About port forward, different IP address but same ports

Question

For example, I have two PC, the IP address (already set as static) of one is 192.168.1.1 and another one is 192.168.1.2

In each of them, I need to use two ports, e.g. 300 and 400

So I would need to use links as below:

192.168.1.1:300    
192.168.1.1:400    
192.168.1.2:300    
192.168.1.2:400

So does that mean I need to do port forwarding 4 times? Or I only need to do port forwarding for an IP, for example 192.168.1.1 and then there would be some way I could access all the ports for that IP?

Thanks!

Answer 1

You are not specifying where you are setting the port forwarding. I am going to assume it's on the router that is connecting the 2 PCs to the internet.

You could either set those IPs as being part of DMZ - in that case ALL of the ports are open - caution here, it's a security risk!

or you can setup the router to forward the ports, but you need to do it the following way:

Let's say public IP is 8.8.8.8 you would set it up as:

8.8.8.8:301 -> 192.168.1.1:300 8.8.8.8:302 -> 192.168.1.1:400 8.8.8.8:303 -> 192.168.1.2:300 8.8.8.8:304 -> 192.168.1.2:400

The reason for that is that the router can only translate 1 port on the external IP to 1 port on the interla IP - this is called NAT. If you need more info, look at here: NAT on WiKI