Which of the following is true about a port scanner in cybersecurity?

A port scanner is a tool used in cybersecurity to identify open ports on devices within a network. Open ports can indicate which services are running on a machine and can help an administrator assess security posture by identifying potentially vulnerable services. By scanning a system for open ports, security professionals can understand better how a system might be exposed to attacks and can take proactive measures to close unnecessary ports or apply security controls to the open ones.

In contrast, detecting network anomalies typically involves monitoring traffic patterns and behaviors to identify unusual activities, which is not a primary function of a port scanner. Blocking malicious traffic is usually accomplished by firewalls or intrusion prevention systems, while data encryption is a method for securing communications and protecting data integrity, unrelated to the functionalities of a port scanner. Therefore, the role of a port scanner is crucial for network discovery and security assessment, making it primarily focused on identifying open ports.