This document specifies techniques for hardening a Linux server based on the state of the art. It defines best practices that the system administrator should implement to enhance the server's hardware and software security.

The aspects covered in this guide are common to all GNU/Linux systems regardless of the distribution used (Debian, RedHat, etc.) and the function performed (Email, Web, DNS, etc.).

The recommendations presented in this document are not exhaustive. They merely outline the main hardening areas to explore to protect a Linux server against malicious activities.