Learning Objectives

By the end of this chapter, you should be able to:

• Explain what Network Address Translation (NAT) is.
• Understand why NAT was created.
• Describe how private IP addresses communicate with the Internet.
• Differentiate between Source NAT (SNAT), Destination NAT (DNAT), and Port Address Translation (PAT).
• Explain the role of NAT Gateways in AWS.
• Identify the advantages and limitations of NAT.
• Apply NAT concepts to real-world DevOps and cloud networking scenarios.

Introduction

Imagine you work in a large company with 5,000 employees.

The company has one public mailing address, but every employee has an internal office number.

When someone outside the company sends a letter:

• It arrives at the company's public address.
• The mailroom checks who the recipient is.
• The mailroom forwards the letter to the correct office.

When an employee sends a letter out:

• The mailroom replaces the employee's internal office number with the company's public mailing address.
• The recipient only sees the company's address.