Networking Fundamentals

Port Address Translation

Port Address Translation (PAT) is a derivative of dynamic NAT, in that there is no static mapping of private IP addresses to a public IP address. With PAT (also referred to as NAT Overload), all devices share a single public IP address.

Figure 7.33 is the same screenshot as we have just seen. We are going to use that for this explanation:

Figure 7.33: Networking with NAT

PC 1 wants to communicate with a website. The NAT process that is followed is as follows:

1. PC 1 opens up a network port to communicate to the web server. For this example, it opens port 64001.
2. PC 1 sends the data to the router.
3. The router updates its ...