Network Address Translation
One other concept we will be talking about quite a lot is inner and outer addresses, or routable and nonroutable addresses. At the heart of things, this concept is not directly related to firewalls or packet filtering, but because of the way the world works today, we need to touch on it.
In fact, let us be very clear about this: NAT does not a firewall make. That is a common misconception, and if you read on you will realize both why some less well-informed people tend to believe that NAT equals firewall and vice versa and why that does not, in fact, make sense. But first, let us go back to the whys and hows.
Why the Internet Lives on a Few White Lies
The addressing terminology that we now take more or less for granted ...