Linux Server Administration & Hardening Lab
Ubuntu Server administration focusing on SSH key-based authentication, UFW firewall configuration, Linux file permissions, and Nginx hosting.
Overview
This lab covers initial server provisioning, secure SSH configuration, firewall setup, and web service maintenance on Ubuntu Server.
Project Objective & Scope
To enhance Linux command-line fluency, master systemd service management, and implement server hardening baselines.
Lab Environment & Hardware/Software
Implementation & Configuration Steps
1. Provisioning & SSH Hardening
Disabled root SSH login, deactivated password authentication, and enforced ED25519 public-key authentication.
2. UFW Firewall Rules
Configured default deny incoming policy, explicitly allowing only required SSH and web ports.
3. Web Service & Process Management
Installed Nginx, validated configuration with nginx -t, and managed daemon states via systemctl.
Troubleshooting & Problems Encountered
SSH lockout occurred after modifying the default listening port.
SSH service was restarted before the new port was permitted in UFW.
Accessed virtual console to add the appropriate UFW allow rule.
What I Learned & Key Takeaways
- Mastered Linux file permission fundamentals (chmod/chown) and user management.
- Gained hands-on experience managing system services and troubleshooting via journalctl logs.