External Authentication

The External Authentication (externalauth) module provides a generic service for logging in and registering users that are authenticated against an external site or service and storing the authentication details.

The module does not provide or use an authentication mechanism by itself; it is intended only to be used by other modules that implement such authentication. The basic reason for module authors to use / depend on the externalauth module is: it is useful for a Drupal site to have a central registry for which user accounts are logging in from external authentication providers, using which external user IDs.