Explanation: Policy Manager looks for the device or user by executing the first filter associated with the authentication source.
After the device or user is found, Policy Manager then authenticates this entity against this authentication
source. The flow is outlined below:
* On successful authentication, Policy Manager moves on to the next stage of policy evaluation, which
collects role mapping attributes from the authorization sources.
* Where no authentication source is specified (for example, for unmanageable devices), Policy Manager
passes the request to the next configured policy component for this service.
* If Policy Manager does not find the connecting entity in any of the configured authentication sources, it
rejects the request.
References: ClearPass Policy Manager 6.5 User Guide (October 2015), page 134
https://community.arubanetworks.com/aruba/attachments/aruba/SoftwareUserReferenceGuides/52/1/ClearPass%20Policy%20Manager%206.5%20User%20Guide.pdf