reference doc – Catalyst 9800 Wireless Controllers Common Wireless Client Connectivity Issues
WLC 9800 provides ALWAYS-ON tracing capabilities. This ensures all client connectivity related errors, warning and notice level messages are constantly logged and you can view logs for an incident or failure condition after it has occurred.
Note: Depending on volume of logs being generated, you can go back few hours to several
Verify clock and NTP settings
Verify if any debug conditions are enabled.
Note: If you see any condition listed, it means the traces are being logged up to debug level for all the processes that encounter the enabled conditions (mac address, ip address etc). This would increase the volume of logs. Therefore, it is recommended to clear all conditions when not actively debugging. >> clear platform condition all
Enable the debug condition for the wireless client mac address that you want to monitor.This commands start to monitor the provided mac address for 30 minutes (1800 seconds). You can optionally increase this time to up to 2085978494 seconds.
Note: In order to monitor more than one client at a time, run debug wireless mac command per mac address.
Note: You do not see the output of the client activity on terminal session, as everything is buffered internally to be viewed later.
Example: client enters incorrect PSK
conclusion – if you truly understand 802.11 networks and in the past was able to successfully troubleshoot AireOS issues, the 9800 wireless controller flow and logic is the same.