Module 9: Security Essentials
This module covers Linux security from the ground up: the security model itself, authentication and access control, file and directory security, and network hardening.
You’ll start with how multi-user systems implement security boundaries and why the different mechanisms work together the way they do. From there, the focus moves to PAM — the authentication framework that most Linux services depend on — along with password policy enforcement and account lockout configuration.
File and directory security goes beyond basic permissions. You’ll work with Access Control Lists for complex multi-user access patterns, and with LUKS for filesystem encryption. Network security covers firewalld zone configuration, service hardening, and traffic filtering, with a practical emphasis on monitoring and incident response.
The goal throughout is a security mindset that informs everyday administrative decisions, not just a set of commands to memorize.