In the context of network security, what best describes the function of network access control (NAC)?

Network Access Control (NAC) primarily focuses on identifying and restricting unauthorized devices from accessing a network. This function is crucial for maintaining the security and integrity of the network environment. By enforcing policies that determine which devices are allowed to connect based on their compliance with predefined security standards, NAC helps organizations minimize the risk of unauthorized access and potential attacks.

The ability of NAC to assess the security posture of devices before granting access—ensuring that they meet criteria such as security updates, antivirus status, and other configurations—enhances the overall security framework. This proactive approach in managing access ensures that only trusted endpoints, which are compliant with security policies, can interact with sensitive network resources.

While preventing data leakage, monitoring user activity for compliance, and encrypting data are all important security functions, they do not specifically capture the core function of NAC, which is centered on controlling access to the network itself.