In order to protect computer systems against hacker attacks, various firewalls are used today. Doubtlessly, firewalls increase IT security. However, firewalls cannot ward off all attacks. They are useless against attacks initiated from within the network itself (the majority!). The Intrusion Detection Systems (IDS) are utilized for this type of protection. Intrusion Detection is the art of detecting inappropriate, incorrect, or suspicious activity. In this specialized course, the participants are taught the possibilities and limitations of the IDSs . They learn comprehensive network protection capabilities, using built-in, proactive defenses for damage prevention.