Securing Your Linux Servers: A Practical Checklist

Securing Your Linux Servers: A Practical Checklist

Essential security hardening steps for production Linux servers

Server security is not optional. Whether you are running a small web application or a large-scale infrastructure, these fundamental security practices should be in place from day one.

SSH Hardening

The most common attack vector for Linux servers is SSH. Lock it down:

# /etc/ssh/sshd_config
PermitRootLogin no
PasswordAuthentication no
PubkeyAuthentication yes
MaxAuthTries 3
AllowUsers deploy admin

Always use SSH keys instead of passwords, and consider changing the default port.

Firewall Configuration

Use nftables or iptables to restrict network access:

  • Allow only necessary inbound ports (22, 80, 443)
  • Block all other inbound traffic by default
  • Consider rate limiting for SSH connections

Automatic Security Updates

Enable unattended security updates to patch vulnerabilities quickly:

apt install unattended-upgrades
dpkg-reconfigure unattended-upgrades

Monitoring and Alerting

Set up monitoring to detect anomalies:

  • Monitor failed login attempts
  • Track disk usage and system resources
  • Alert on unexpected process activity
  • Log everything centrally

Regular Backups

A security incident without backups is a disaster. Ensure:

  • Daily automated backups with BorgBackup
  • Off-site backup copies
  • Regular restore testing
  • Encrypted backup storage

Conclusion

Security is an ongoing process, not a one-time setup. Review these practices regularly and stay updated on new vulnerabilities affecting your software stack.

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