Network Address Translator overview

In the IPv4 network addresses section of, Chapter 2, Communication in Computer Networks, it is said that the total number of IPv4 addresses is 2³² = 4,294,967,296. Comparing that with the world population, it is obvious that nearly 3 billion IP addresses are missing if a single IPv4 address is assigned to every person on the planet. That was a sign that the Internet Engineering Task Force (IETF) should do something to overcome the problem of exhaustion of the IPv4 address space. In light of that, the Request for Comment (RFC) 1918 document was created, which precisely specified the IP address ranges for private use. That enabled the birth of the Network Address Translator (NAT). As the name suggests, NAT translates private IPv4 addresses to public IPv4 addresses. In fact, private IP addresses as specified by the document RFC 1918 cannot be routed...