An intrusion prevention system (IPS) includes all the features of an intrusion detection system but also has the ability to act upon malicious traffic. Since the IPS usually sits in line with network traffic it can shut down attacks, typically by blocking access from the attacker or blocking access to the target. In some cases, the IPS can talk to the firewall to block an attack.

The timing and targets in a recent wave of distributed denial-of-service (DDoS) attacks has some security experts pointing the finger at North Korea. After all, the attacks coincided with the rogue state's firing of missiles during the July 4 Independence Day Weekend and the U.S. and South Korea were the countries in the cyber crosshairs.