The scenario involves an AOS-CX switch that needs to send RADIUS debug messages to a central SIEM server at 10.5.15.6. The switch has already been configured to send logs to the SIEM server with the command logging 10.5.15.6, and the command debug radius all has been entered to enable RADIUS debugging.

Debug Command: The debug radius all command enables debugging for all RADIUS-related events on the AOS-CX switch, generating detailed debug messages for RADIUS authentication, accounting, and other operations.

Debug Destination: Debug messages on AOS-CX switches can be sent to various destinations, such as the console, a file, the debug buffer, or a Syslog server. The logging 10.5.15.6 command indicates that the switch is configured to send logs to a Syslog server at 10.5.15.6 (using UDP port 514 by default, unless specified otherwise).

Option D, "syslog," is correct. To send RADIUS debug messages to the SIEM server, the debug destination must be set to "syslog," as the SIEM server is already defined as a Syslog destination with logging 10.5.15.6. The command to set the debug destination to Syslog is debug destination syslog, which ensures that the RADIUS debug messages are sent to the configured Syslog server (10.5.15.6).

Option A, "file," is incorrect. Sending debug messages to a file (e.g., using debug destination file) stores the messages on the switch’s filesystem, not on the SIEM server.

Option B, "console," is incorrect. Sending debug messages to the console (e.g., using debug destination console) displays them on the switch’s console session, not on the SIEM server.

Option C, "buffer," is incorrect. Sending debug messages to the buffer (e.g., using debug destination buffer) stores them in the switch’s debug buffer, which can be viewed with show debug buffer, but does not send them to the SIEM server.

The HPE Aruba Networking AOS-CX 10.12 System Management Guide states:

"To send debug messages, such as RADIUS debug messages, to a central SIEM server, first configure the Syslog server with the logging command (e.g., logging 10.5.15.6). Then, enable the desired debug with a command like debug radius all, and set the debug destination to Syslog using debug destination syslog. This ensures that all debug messages are sent to the configured Syslog server for centralized logging." (Page 92, Debug Logging Section)

Additionally, the HPE Aruba Networking AOS-CX 10.12 Security Guide notes:

"RADIUS debug messages can be sent to a Syslog server for centralized monitoring. After enabling RADIUS debugging with debug radius all, use debug destination syslog to send the messages to the Syslog server configured with the logging command, such as a SIEM server at 10.5.15.6." (Page 152, RADIUS Debugging Section)