In the Linux distro scene, CentOS and RedHat Enterprise Linux (RHEL) are two of the big names when it comes to server OS. They're both super important and used by many companies and pros all over the world. Before we compare them, let's see what each one's all about.

RHEL is made by Red Hat Inc. and is a paid Linux distro aimed at businesses. It's known for being reliable, fast, and having great support. The main reason people go for RHEL is its solid stability and the fact that Red Hat Inc. officially backs it.

CentOS, short for Community ENTerprise Operating System, started as a free version of RHEL. It's basically a version of RHEL's source code but changed a bit to keep it free. Because it's a lot like RHEL and doesn't cost anything, CentOS is a favorite for startups, solo developers, and anyone wanting a strong OS without the price tag.

Linux servers are renowned for their stability, cost-effectiveness, and open-source nature. However, ensuring security is of utmost importance due to ever-evolving cyber threats and attacks. This guide presents an ultimate Linux server security checklist that covers essential steps to harden and secure a Linux server, providing explanations on the importance of each step and how it helps maintain system integrity and safeguard valuable data. We encourage you to use this checklist as a reference for achieving ultimate security on their Linux servers. The steps are sorted from most important to least important.