In a number of contexts, we hear about directory services plug-ins.  A directory services plug-in is a way for a Mac OS X computer to leverage the DirectoryServices daemon to obtain account information (be it authentication or policy information) from a server.  This might be an Active Directory server that uses the Active Directory Plug-in or an Open Directory server that uses LDAP. You disable plug-ins that you don’t need and enable plug-ins (ie Active Directory plug-in or third party plug-ins) that you need in order to access directory services of various types.  These  plug-ins are developed in the form of .dsplug files.  The default plug-ins that Apple includes with…