Linux Server Security: A Beginner's Guide

Linux servers are used in a wide range of applications, from websites to databases, email services to application servers. However, the moment you expose a server to the internet, you become a target for automated attack bots worldwide. In this guide, we'll walk you through how to protect your Linux server with essential security measures.

1. Strengthening SSH Security

SSH (Secure Shell) is the most critical service that allows you to remotely connect to your server. When left with default settings, it becomes vulnerable to brute-force attacks. The first things you should do are disable direct SSH access with the root user and change the standard port 22.

• Disable root login (PermitRootLogin no)Change SSH port (e.g., 2222)Use SSH key-based authenticationDisable password login (PasswordAuthentication no)Limit MaxAuthTries to 3Allow only specific users with AllowUsers

2. Firewall Configuration (UFW)

UFW (Uncomplicated Firewall) is the most commonly used firewall in Ubuntu and Debian-based systems. By keeping only the ports you need open, you minimize the attack surface. For a basic web server, you only need to open HTTP (80), HTTPS (443), and SSH ports.

3. Brute-Force Protection with Fail2Ban

Fail2Ban monitors failed login attempts and automatically bans attacker IP addresses. It comes with pre-defined rules for services like SSH, Nginx, and Apache. Installation is simple and it effectively protects your server against automated attacks.

4. System Updates and Backup

Regularly applying security patches prevents exploitation of known vulnerabilities. On Ubuntu, you can automate security updates with the 'unattended-upgrades' package. Also, by creating a regular backup strategy, you can recover your data even in the worst-case scenario.

Conclusion

Linux server security is not a one-time job but an ongoing process. By implementing the basic steps in this guide, you can significantly improve your server's security level. Check out our services for professional server setup and security configuration.