Port/Protocol forwarding
 

Can someone explain port/protocol NAT forwarding to me? I don't see how or why it's used.

I understand IP Masquerading and such, but I don't get port/protocol forwarding.

DNAT (port forward) is used to publish server behind linux firewall.
go to www.netfilter.org and read the docs for detailed info.

Because how the NAT functions you can't reach a server behind the NAT.
The only IP addresses that are known to the outside world is the official IP of the server.
To get to a server behind the NAT you would have to forward the request using port forwarding.

So when a request or packet comes to the server requesting a particular service/port the router changes destination IP and port to a local computer behind the NAT.

Thanks I get it now.

I've always wondered how my router worked using two PCs and both of the IPs stuck in the 192.168.1.0 range.

Your PC's shouldn't have the same IP address i.e the last digit. 192.168.1.xxx will be different.