A presence index is used to match the fact that an attribute is
present on the entry, regardless of the value. The aci
attribute is indexed for presence by default to allow quick retrieval
of entries with ACIs.
$ ldapsearch --port 1389 --baseDN dc=example,dc=com "(aci=*)" - dn: dc=example,dc=com dn: ou=People,dc=example,dc=com
