Network Address Translation (NAT) and Classless InterDomain Routing (CIDR) are alternative options to addressing IP address shortage problems.
According to this Vanguard article, NAT enables a LAN to use one set of IP address for internal traffic and a second set of address for external traffic. This allows a company to shield internal addresses from the public Internet.
“While NAT came into being in the 1990’sas a popular tool for alleviating the IPv4 address exhaustion problem, it eventually became an indispensable tool for most home and small-business networks. NAT is a Cisco version of Port Address Translation (PAT), and enables a LAN to use one set of IP address for internal traffic and a second set of address for external traffic. This allows a company to shield internal addresses from the public Internet.
“NAT is used by a device (firewall, router, or computer) that sits between an internal network and the rest of the world. There are TWO main types of NAT : dynamic and static. In static NAT, the public IP address is always the same, allowing an internal host, such as a Web server, to have an unregistered private IP address and still be reached over the Internet.”
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