Possible Duplicate: What is port forwarding and what is it used for?
What is the difference between NAT and port forwarding? Are they two different names for the same thing? What would be a short practical example?
Solution:
NAT and port forwarding are different, but they are often used in conjunction with each other.
NAT is network address translation. It translates traffic from one IP address to another. An example: NATing your WAN IP address 1.2.3.4 to your internal webserver 192.168.0.1.
Port forwarding (sometimes called PAT – Port Address Translation) is similar, but it functions on the port level. You can forward port 80 from your WAN IP address to your internal webserver, for example. You can also forward to a different port – i.e. port 8080 on the WAN is forwarded to port 80 on your internal web server.