At the beginning, we need to ask a question. Is Linux secured 100% or at least secured enough? The answer is no. The danger posed by these unskilled attackers has also increased these days. New vulnerabilities are discovered daily and sometimes hourly. Exploits are frequently built on these vulnerabilities within hours of them being discovered. Some vulnerabilities are not even discovered until someone uses them to exploit a host. The security is the main concern for all of us and we will see some practical examples of how to harden your system security.