Domain 4 marks a transition from availability and performance into security—protecting the integrity and confidentiality of the network. In this episode, we introduce the core topics that make up Network Security, including authentication, access control, attack types, and hardening techniques. The goal of this domain is to teach you how to prevent, detect, and respond to threats at every layer of the OSI model.

You’ll also get an overview of best practices and security frameworks used in enterprise environments, from Zero Trust to NIST and CIS controls. Security isn’t just a checkbox—it’s an ongoing mindset that touches every part of your infrastructure. This introduction sets the stage for understanding what it takes to build and maintain secure networks.