Basics on Intrusion Detection and Intrusion Prevention

Intrusion Detection:
This encompasses a range of security techniques that are designed to detect or report any instance of intrusion into the security system to the user/ network administrator. Intrusion detection technologies are detective rather than preventive, but they can help mitigate following types of risks by providing a security administrator with information on attempted or actual security events.
-> Destruction of data
-> Network intrusion
-> Unauthorized access
-> Denial of service attacks.

Intrusion Prevention:
These systems combine all levels of firewall and intrusion detection technologies, they often end up with systems that can operate at all levels of network stack. The only disadvantage of intrusion prevention systems is that they are not fast and robust. For this reason IPS may not be appropriate where speed is of high importance.
Intrusion prevention systems are a sophisticated class of network security implementation that not only has the ability to detect the presence of intruders and their actions but also to prevent them from successfully launching any attack.These systems are designed to detect malicious packets within normal network traffic and stop network intrusion, blocking unauthorized traffic automatically before it does damage rather than simply raising an alert.