The scenario involves an AOS-8 controller-based solution with a WPA3-Enterprise WLAN using HPE Aruba Networking ClearPass Policy Manager (CPPM) for authentication. The company is using digital certificates for authentication (likely EAP-TLS, as it’s the most common certificate-based method for WPA3-Enterprise). A user’s Windows domain computer has certificates installed, but authentication fails. The Mobility Controller (MC) logs show Access-Rejects from CPPM, indicating that CPPM rejected the authentication attempt.
Access-Reject: An Access-Reject message from CPPM means that the authentication failed due to a policy violation, certificate issue, or other configuration mismatch. To troubleshoot, we need to find detailed information about why CPPM rejected the request.
Option C, "The Alerts tab in the authentication record in CPPM Access Tracker," is correct. Access Tracker in CPPM logs all authentication attempts, including successful and failed ones. For a failed attempt (Access-Reject), the authentication record in Access Tracker will include an Alerts tab that provides detailed reasons for the failure. For example, if the client’s certificate is invalid (e.g., expired, not trusted, or missing a required attribute), or if the user does not match a policy in CPPM, the Alerts tab will specify the exact issue (e.g., "Certificate not trusted," "User not found in directory").
Option A, "The reports generated by HPE Aruba Networking ClearPass Insight," is incorrect. ClearPass Insight is used for generating reports and analytics (e.g., trends, usage patterns), not for real-time troubleshooting of specific authentication failures.
Option B, "The RADIUS events within the CPPM Event Viewer," is incorrect. The Event Viewer logs system-level events (e.g., service crashes, NAD mismatches), not detailed authentication failure reasons. While it might log that an Access-Reject was sent, it won’t provide the specific reason for the rejection.
Option D, "The packets captured on the MC control plane destined to UDP 1812," is incorrect. Capturing packets on the MC control plane for UDP 1812 (RADIUS authentication port) can show the RADIUS exchange, but it won’t provide the detailed reason for the Access-Reject. The MC logs already show the Access-Reject, so the issue lies on the CPPM side, and Access Tracker provides more insight.
The HPE Aruba Networking ClearPass Policy Manager 6.11 User Guide states:
"Access Tracker (Monitoring > Live Monitoring > Access Tracker) logs all authentication attempts, including failed ones. For an Access-Reject, the authentication record in Access Tracker includes an Alerts tab that provides detailed reasons for the failure. For example, in a certificate-based authentication (e.g., EAP-TLS), the Alerts tab might show ‘Certificate not trusted’ if the client’s certificate is not trusted by ClearPass, or ‘User not found’ if the user does not match a policy. This is the primary place to look for deeper insight into authentication failures." (Page 299, Access Tracker Troubleshooting Section)
Additionally, the HPE Aruba Networking AOS-8 8.11 User Guide notes:
"If the Mobility Controller logs show an Access-Reject from the RADIUS server (e.g., ClearPass), check the RADIUS server’s authentication logs for details. In ClearPass, the Access Tracker provides detailed failure reasons in the Alerts tab of the authentication record, such as certificate issues or policy mismatches." (Page 500, Troubleshooting 802.1X Authentication Section)
[References:, HPE Aruba Networking ClearPass Policy Manager 6.11 User Guide, Access Tracker Troubleshooting Section, Page 299., HPE Aruba Networking AOS-8 8.11 User Guide, Troubleshooting 802.1X Authentication Section, Page 500., ]
