Securing a Linux server is crucial to prevent cyberattacks, data breaches, and unauthorized access. Whether you’re running a personal project or a business-critical application, these 10 essential steps will help you lock down your server effectively.
1. Keep Your System Updated
How?
sudo apt update && sudo apt upgrade -y # Debian/Ubuntu
sudo dnf update -y # RHEL/FedoraEnable automatic security updates:
sudo apt install unattended-upgrades
sudo dpkg-reconfigure unattended-upgrades2. Secure SSH Access
How?
Disable root login:
sudo nano /etc/ssh/sshd_configSet:
PermitRootLogin no
PasswordAuthentication no # Use SSH keys insteadChange default SSH port (optional but recommended):
Port 2222 # ExampleRestart SSH:
sudo systemctl restart sshd3. Configure a Firewall (UFW)
How?
sudo apt install ufw
sudo ufw allow 22/tcp # Or your custom SSH port
sudo ufw allow 80/tcp # HTTP
sudo ufw allow 443/tcp # HTTPS
sudo ufw enable4. Use SSH Key Authentication (Instead of Passwords)
How?
Generate SSH keys (on your local machine):
ssh-keygen -t ed25519Copy public key to server:
ssh-copy-id user@your_server_ip -p 22225. Install & Configure Fail2Ban
How?
sudo apt install fail2ban
sudo systemctl enable --now fail2banCustomize jail rules:
sudo nano /etc/fail2ban/jail.local6. Disable Unnecessary Services
How?
sudo systemctl list-unit-files --type=service | grep enabledDisable unused services:
sudo systemctl disable servicename7. Set Up 2FA for SSH (Optional but Recommended)
How?
sudo apt install libpam-google-authenticator
google-authenticatorThen edit /etc/pam.d/sshd and add:
auth required pam_google_authenticator.so8. Monitor Logs for Intrusion Attempts
How?
sudo tail -f /var/log/auth.log # SSH attempts
sudo grep "Failed password" /var/log/auth.log9. Regular Backups
How?
sudo tar -czvf /backup/server-backup-$(date +%F).tar.gz /var/www /etcOr use rsync:
rsync -avz /var/www user@backup-server:/backups/10. Audit Security with Lynis
How?
sudo apt install lynis
sudo lynis audit systemBy following these 10 critical steps, your Linux server will be far more secure against common attacks.
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