Understanding NAT
A device that is assigned a private IPv4 address is not able to simply communicate with devices on the internet on its own—it needs some assistance. For example, your computer or smart device is mostly likely assigned a private IPv4 address on your network, but it's able to connect to devices on the internet. This is because of something called NAT. NAT makes our lives in networking that bit easier as it allows a router to translate a private address into a public address. Let's take a look at the following diagram to get a clear idea of how NAT really works:
Figure 9.2 – NAT topology
In the preceding figure, there are two networks—a corporate network and the internet—and in between both is a NAT router. Let's imagine that there is a device on the corporate network, PC 1, with an IP address of 192.168.1.10. PC 1 wants to send a message to a device on the internet, let's say a Cisco web server...
