FirstClass authentication
From MoodleDocs
Note: The FirstClass authentication plugin has been removed in Moodle 3.4. It is still available from https://github.com/moodlehq/moodle-auth_fc.
FirstClass is a client/server groupware, email, online conferencing, voice/fax services, and bulletin-board system for Windows, Macintosh, and Linux. FirstClass authentication uses the FirstClass Server for the authentication process i.e. to check for user accounts.