What is the correct database type for an OpenLDAP server configured as a proxy to a Microsoft Active Directory server?

An OpenLDAP server configured as a proxy to a Microsoft Active Directory server functions primarily as an LDAP (Lightweight Directory Access Protocol) server. This setup allows the OpenLDAP server to relay requests to the Active Directory, enabling the integration of LDAP-compliant applications with an AD environment.

Using the LDAP protocol is essential because it is specifically designed for accessing directory services, and OpenLDAP is an implementation of this protocol. In this configuration, OpenLDAP acts as an intermediary, handling LDAP queries and forwarding relevant requests or modifications to the Active Directory backend while presenting a unified LDAP interface to the clients.

In contrast, the other database types listed, such as Active Directory, MySQL, and PostgreSQL, serve different functions and do not support the same operational context for a directory service. Active Directory is a directory service that operates over LDAP but is not a client or a proxy itself; MySQL and PostgreSQL are relational database management systems and do not accommodate directory service functionalities in the same manner as LDAP. Thus, the choice of LDAP as the database type correctly identifies the protocol utilized by the OpenLDAP server in this specific role.