Chapter 3: Introducing Network Address Translation (NAT)
Exam Objectives
Identifying the purpose of Network Address Translation
Describing the different types of NAT
Explaining the basic operation of NAT
Configuring NAT
Describing NAT management
Troubleshooting NAT issues
The short supply and high demand of IPv4 address space have led to the development of IPv6, which now provides more address space than we will ever need. Implementing IPv6 is not without hurdles of its own. Migrating to IPv6 has proven to be a slow, time-consuming process. It can take years to finally realize a new Internet infrastructure based solely on IPv6. Until then, certain tools can minimize the limitations brought on by the IPv4 address space. One of these tools, developed by Cisco, is Network Address Translation (NAT), sometimes referred to as the Network Address Translator. Think of NAT as a “middleman” that resides on a device (typically a router, firewall, or computer) between internal and external internetworks, translating private, nonroutable IP addresses into publicly registered IP addresses allocated by the IANA. This creates a binding between a public and private IP address. Only one routable IP address is required to provide an entire NAT-enabled network with access to publicly held resources.
Purpose of NAT
There is more to Network Address Translation than just the benefits of saving IPv4 address space. Security and administration features are also benefits of NAT. The three main purposes ...
