<< Part 3 Part 5 >> Hardening the Linux server - Part 4 Monitor your system There is a saying in computer security circles that the only way to truly secure a computer is to completely disconnect it and lock it in a box. Not too practical, but the underlying message is that if an attacker really wants into a system, odds are they will find a way in. After you take steps toward intrusion prevention, you need to set up a monitoring system to detect whether an attack against your server has taken place. Then, if you're alerted to an attack, you're better prepared to deal with it early on. The following sections walk you through the steps of installing and configuring two programs t...