Linux Server Hardening: Essential Security Checklist
1. Introduction Linux server hardening remains the task with the highest security return per hour invested, and yet it is the one most often left to improvisation. A freshly installed server connected to the public Internet receives brute-force login attempts within minutes, and most automated scans look for exactly what an unhardened server exposes: password-based SSH, open administration ports and unpatched packages. In this article I have prepared a complete Linux server hardening checklist that can be applied in order to any distribution (Debian, Ubuntu, RHEL or Rocky), with real sshd configuration, UFW firewall rules, fail2ban and SELinux, plus the …

