ClearOS provides directory services using a driver-based architecture. This allows users to choose their directory services:
With a driver-based architecture, the user interface and software APIs are the same, but the underlying engines are very different. You can read more about how the whole system is architected in the following document:
Directory plugins allow applications to extend the directory for user/group based services. For example, the Squid web proxy plugin provides the necessary glue to map users and groups to the proxy server settings. Changes to LDAP schemas and attributes are not required for plugins. Instead, plugins use the schema and attributes provided in the base ClearOS implementation.
Extensions are used to extend functionality of the directory system. Unlike plugins, these extensions require changes to LDAP schemas and attributes. For this reason, only the native ClearOS OpenLDAP directory system can use extensions.