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Secure your server

This guide presents the essential steps to secure your server.

Prerequisites​

  • SSH root or sudo access

Security steps​

  1. Update the system:

    apt update && apt upgrade -y

  2. Create a non-root user:

    adduser votre_utilisateur
    usermod -aG sudo votre_utilisateur

  3. Configure SSH securely:

    nano /etc/ssh/sshd_config

    Modify these lines:

    PermitRootLogin no
    PasswordAuthentication no
    Port 2222  # Change the default port

  4. Install and configure a firewall:

    apt install ufw
    ufw default deny incoming
    ufw default allow outgoing
    ufw allow 2222/tcp  # Your SSH port
    ufw enable

  5. Install Fail2ban:

    apt install fail2ban

  6. Configure automatic updates:

    apt install unattended-upgrades
    dpkg-reconfigure --priority=low unattended-upgrades
  • Test SSH connection with the new user
  • Check firewall status: ufw status
  • Monitor logs: tail -f /var/log/auth.log

Best practices​

  • Change passwords regularly
  • Monitor system logs
  • Perform regular backups
  • Keep the system up to date
  • Use SSH keys rather than passwords
  • Limit exposed services to the strict minimum

Troubleshooting​

  • Check system logs in /var/log/
  • Make sure essential services are active
  • Check firewall rules
  • Review connection attempts blocked by Fail2ban