In this scenario, a new HPE Aruba Networking Mobility Controller (MC) and campus APs (CAPs) are deployed, with a WLAN configured for 802.1X authentication using HPE Aruba Networking ClearPass Policy Manager (CPPM) as the RADIUS server. A client test fails, and no record of the authentication attempt appears in ClearPass Access Tracker. However, a ping from the MC to CPPM is successful, confirming basic network connectivity between the MC and CPPM.

The absence of a record in Access Tracker indicates that CPPM did not receive the RADIUS authentication request from the MC, or the request was rejected at a low level before being logged in Access Tracker. Access Tracker typically logs all RADIUS authentication attempts (successful or failed), so the lack of a record suggests a configuration or connectivity issue at the RADIUS level.

Option C, "Check CPPM Event Viewer," is correct. The CPPM Event Viewer logs system-level events, including RADIUS-related errors that might not appear in Access Tracker. For example, if the MC’s IP address is not configured as a Network Access Device (NAD) in CPPM, or if the shared secret between the MC and CPPM does not match, CPPM may reject the RADIUS request before it reaches Access Tracker. The Event Viewer will log such errors (e.g., "RADIUS authentication attempt from unknown NAD"), providing insight into why the request was not processed.

Option A, "Renew CPPM's RADIUS/EAP certificate," is incorrect because the issue is that CPPM did not receive or process the authentication request (no record in Access Tracker). If there were a certificate issue (e.g., an expired or untrusted certificate), the request would still reach CPPM, and Access Tracker would log a failure with a certificate-related error.

Option B, "Check connectivity between CPPM and a backend directory server," is incorrect because the issue occurs before CPPM processes the authentication request. If CPPM cannot contact a backend directory server (e.g., Active Directory), the authentication attempt would still be logged in Access Tracker with a failure reason related to the directory server.

Option D, "Reset the user credentials," is incorrect because the issue is not related to the user’s credentials. The authentication request never reached CPPM, so the credentials were not evaluated.

The HPE Aruba Networking ClearPass Policy Manager 6.11 User Guide states:

"If an authentication attempt does not appear in Access Tracker, it indicates that the RADIUS request was not received by ClearPass or was rejected at a low level before being logged. The Event Viewer (Monitoring > Event Viewer) should be checked for system-level errors, such as ‘RADIUS authentication attempt from unknown NAD’ or shared secret mismatches. For example, if the Network Access Device (NAD) IP address of the Mobility Controller is not configured in ClearPass, or if the shared secret does not match, the request will be dropped, and an error will be logged in the Event Viewer." (Page 301, Troubleshooting RADIUS Issues Section)

Additionally, the HPE Aruba Networking AOS-8 8.11 User Guide notes:

"When troubleshooting 802.1X authentication issues, verify that the Mobility Controller can communicate with the RADIUS server. If a ping is successful but no authentication records appear in the RADIUS server’s logs (e.g., ClearPass Access Tracker), check the RADIUS server’s system logs (e.g., ClearPass Event Viewer) for errors related to NAD configuration or shared secret mismatches." (Page 498, Troubleshooting 802.1X Authentication Section)