How to Harden SSH on a Linux Server: A Practical Security Checklist

Secure remote Linux access with SSH keys, disable risky authentication methods, configure firewall rules, and avoid locking yourself out.

Introduction: SSH is powerful, but it needs proper configuration

You have just deployed a Linux server. You can connect remotely using SSH, install packages, manage services, and perform administrative tasks.

Everything works.

But there is one problem: your server may still allow password-based SSH authentication, direct root access, and other settings that increase the risk of unauthorized access.

An exposed SSH service can attract automated login attempts from scanners and bots looking for weak passwords and misconfigured servers.

In my previous Harristar Tech project, we used Python to analyze Linux authentication logs and identify suspicious SSH login attempts.

This time, we will take the next step: hardening the SSH service itself.

We will configure a Linux server to:

• Use SSH key-based authentication.
• Disable direct root login.
• Disable password authentication after verifying key access.