If you have an LDAP directory in your organization, your PGP Universal Server can be synchronized with this directory. If you select Enroll clients using directory authentication when you enable Directory Synchronization, you allow clients to enroll with LDAP. LDAP enrollment requires certain attributes in the directory to bind the client to the PGP Universal Server.
For technical information regarding the behavior of PGP Desktop and PGP Universal Server during PGP Desktop's LDAP enrollment process, please refer to the following PGP Desktop LDAP Enterprise Enrollment document.