Users & Security

Covers the account and access-control model, and the small set of hardening steps that matter most on a freshly provisioned machine.

• Disk Encryption (LUKS)

  LUKS (Linux Unified Key Setup) is the standard for full-disk and partition encryption on Linux, protecting data at rest so a lost or stolen drive doesn't expose its contents without the passphrase or key.

• Hardening Basics

  A short, high-value checklist for securing a freshly provisioned Linux machine before exposing it to the internet - not exhaustive, but covers the changes that matter most for the least effort.

• PAM Basics

  Pluggable Authentication Modules are the framework nearly every login path on Linux - console, SSH, sudo, su, screen lockers - defers to for actually authenticating a user, making authentication policy configurable in one place instead of hardcoded into each program.

• SELinux and AppArmor

  Mandatory access control systems that confine what a process can do beyond standard Unix permissions - SELinux on RHEL/Fedora, AppArmor on Debian/Ubuntu - and how to tell a genuine permission problem from a policy denial.

• SSH Keys and Authentication

  Public-key authentication lets you log into a remote machine by proving you hold a private key, rather than typing a password - how the key pair works, and how to set it up.

• Sudo and Privilege

  sudo lets an authorized user run specific commands as another user, usually root, without sharing the root password - /etc/sudoers controls exactly who's allowed to do what.

• Users and Groups

  The account and group model behind Linux's ownership and permission system - who a user is, how groups grant shared access, and the commands for managing both.