What type of network-based security technologies take active countermeasures against security breaches?

The correct answer is IPS, which stands for Intrusion Prevention System. IPS technology actively monitors network traffic and can take direct action to mitigate potential threats. When a potential security breach is detected, an IPS can automatically block malicious traffic, terminate connections, or take other predefined countermeasures to prevent an attack from succeeding. This proactive approach helps in maintaining network security by responding to threats in real time.

In contrast, other technologies mentioned serve different roles in network security. Firewalls primarily focus on controlling and filtering traffic based on predetermined security rules but do not take immediate action against threats like an IPS does. VPNs (Virtual Private Networks) provide secure access to a network by encrypting data, but they do not actively prevent breaches; instead, they protect data in transit. IDS (Intrusion Detection Systems) monitor network activity for suspicious behavior and send alerts but do not take direct action against threats. Therefore, the key distinguishing feature of an IPS is its ability to respond actively to threats, which makes it an integral part of a robust network security posture.