An Intrusion Detection System (IDS) is a defense system, which detects hostile activities in a network. The key is then to detect and possibly prevent activities that may compromise system security, or a hacking attempt in progress including reconnaissance/data collection phases that involve e.g. port scans One key feature of intrusion detection systems is their ability to provide a view of unusual activity and issue alerts notifying administrators and/or block a suspected connection. Intrusion detection is a process of identifying and responding to malicious activity targeted at computing and networking resources. In addition, IDS tools are capable of distinguishing between insider attacks originating from inside the organization coming from own employees or customers and external ones attacks and the threat posed by hackers.