Server hardening is a step-by-step approach to secure an operating system and hence reduce the overall surface area for vulnerabilities.
Linux comes with a great set of inbuilt tools, such as iptables, SELinux, PAM, and auditd, that can be used in conjunction with external open source tools, such as OSSEC, LUKS, and Spacewalk to achieve a high level of security posture of any organization.
Just implementing a single set of tools cannot ensure security. We have to use various sets of tools to achieve a particular use case, and in the end, we will have many tools working together to ensure an effective security posture of your server.
Let's look at an example to understand this better. Nowadays, most cars come with a seat belt as a safety feature. However, the driver can choose not to wear the seat belt. Hence, the overall functionality of having a seat belt...