PAM Order Settings
It is recommended not to keep the same username for different PAM modules.
If Authentication fails, the reason of failure could be invalid user or invalid password.
If Radius Authentication fails, it is always treated as invalid username error since the system cannot differentiate whether it is invalid user or invalid password. When this occurs, PAM will try other authentication methods.
If AD contains secret username and password as empty, Authentication failures will be always treated as invalid password error. For invalid password error, PAM will not try other authentication methods. So, it is recommended to keep AD in the last location in PAM order.
Whenever the configuration is modified, the web server will be restarted automatically. Logged-in session will be logged out.