by dn="uid=admin,ou=users,dc=debian,dc=org" write
by group="uid=admin,ou=users,dc=debian,dc=org" write
+# Overlays are useful to enforce constraints:
+
+moduleload /usr/lib/ldap/unique.so
+overlay unique
+unique_base ou=users,dc=debian,dc=org
+unique_attributes uid keyFingerPrint
+
# End----------
Note that in more modern versions of slapd, the "by addr" and "by domain"