A company wants all corporate laptops to authenticate to Wi-Fi using device certificates instead of shared passwords. It also wants to deny network access to systems that do not meet the baseline requirement for disk encryption and current endpoint protection. Which approach best satisfies both goals?
802.1X using EAP-TLS or a similar certificate-based protocol provides mutual authentication: the corporate laptop presents a client certificate stored in its machine store, and the RADIUS/AAA server validates it against the CA, ensuring only authorized corporate devices connect. Network Access Control (NAC) posture checks then assess compliance criteria such as OS patch level, antivirus status, and disk encryption, automatically quarantining noncompliant devices until they are remediated.
Why this answer
802.1X with certificate-based authentication ensures that only devices with valid certificates can authenticate to the Wi-Fi network, eliminating reliance on shared passwords. Network access control (NAC) posture checks then evaluate each device against baseline requirements (e.g., disk encryption, current endpoint protection) and deny access to non-compliant systems. This combination directly satisfies both goals of certificate-only authentication and conditional access based on security posture.
Exam trap
The trap here is that candidates often confuse 802.1X with simple certificate authentication and overlook the NAC posture check component, assuming that certificate-based authentication alone meets the baseline requirement, but the question explicitly requires denying access to non-compliant systems, which only NAC can enforce.
How to eliminate wrong answers
Option A is wrong because WPA2-Personal uses a single shared passphrase, which does not enforce device-specific authentication or posture checks, and emailing the passphrase to all employees introduces a security risk. Option C is wrong because allowing any device to join and relying on post-login antivirus scans does not prevent non-compliant devices from accessing the network initially, violating the requirement to deny access to systems that do not meet baseline requirements. Option D is wrong because MAC address filtering can be spoofed and does not verify device certificates or security posture, and a captive portal typically only controls web access after connection, not the initial network authentication or compliance checks.