Guide: Network Address Translation (NAT)

What is NAT:
Network Address Translation (NAT) is a mechanism that helps in the conservation of public IP addresses by allowing multiple devices on a local network to use one public IP address while connecting to the Internet. It is crucial for mitigating the exhaustion of IPv4 address space.

How NAT Works:
NAT modifies the source and/or destination addresses of IP packets as they traverse through a router or firewall. It maintains a translation table that maps the internal private addresses to the external public address and vice-versa. NAT can operate in several modes, most notably static NAT, dynamic NAT, and Port Address Translation (PAT).

Importance of NAT:
NAT is vital as it allows multiple devices to communicate over the internet using a single public IP address. In doing so, it conceals private IP addresses, adding a layer of security.

Exam tips:
Understanding the Types of NAT: Learn the differences between static NAT, dynamic NAT, and PAT. Remember that static NAT creates a one-to-one mapping between private and public addresses, dynamic NAT maps unregistered IP addresses to registered IP addresses from a pool, and PAT assigns multiple private IPs to a single public IP using different ports.
Understanding NAT Terminology: Familiarize yourself with terms like inside local, inside global, outside local, and outside global.
Practice NAT Configuration: Understand how to configure NAT on a router or firewall. Practice with several examples.