https://bugs.openldap.org/show_bug.cgi?id=9256
--- Comment #1 from Howard Chu hyc@openldap.org --- (In reply to Karl O. Pinc from comment #0)
E.g. knowing that (objectClass=*) is the default filter, and that there's _always_ _some_ filter,
This is fundamental to LDAP. Everyone administering slapd should already know this.