Which solution is a viable option to capture user identification when Active Directory is not in use?

Cloud Identity Engine typically relies on integrating with existing identity sources rather than being a standalone method to capture user identification when none exist.

Group mapping relies on existing user groups from an integrated directory service, which is not available if Active Directory is not in use.

Directory Sync Service synchronizes user and group information from an existing directory service, and thus requires such a service to be present.

An Authentication Portal is a feature on Palo Alto Networks NGFWs that prompts users to authenticate via a web page, thereby capturing their identity for User-ID purposes even in the absence of traditional directory services.