Cisco Cyber Security Practice Exam

Which solution is most effective for preventing unauthorized access to a private network?

1. Intrusion Detection System (IDS)

2. Network Access Control (NAC)

3. Encryption

4. Virtual Private Network (VPN)

The correct answer is: Network Access Control (NAC)

Network Access Control (NAC) is most effective for preventing unauthorized access to a private network because it enforces security policies at the network level before a device is allowed to access network resources. NAC solutions authenticate devices and users, and assess their compliance with security policies—including software updates and antivirus status—before granting connection rights. This proactive approach not only restricts unauthorized devices but also ensures that only compliant devices can connect to the network, thereby minimizing risks associated with potential breaches. Other solutions, such as Intrusion Detection Systems (IDS), focus on monitoring and alerting for suspicious activities after they have already occurred within the network, rather than preventing unauthorized access outright. Encryption secures data in transit but does not control who can access the network itself. Virtual Private Networks (VPNs) provide secure remote access but do not inherently authenticate devices or users before they attempt to connect, which means they are less effective in preventing unauthorized access compared to NAC.