Hello, I'm trying to enable unique overlay to enforce uniqueness of uid and mail attributes with no luck. My server is debian 7 based with packaged slapd (2.4.31]. Here's the config for the unique overlay : DN: cn=module{1},cn=config objectClass: olcModuleList objectClass: olcConfig objectClass: top cn: module{1} olcModuleLoad: {0}memberof olcModuleLoad: {1}refint olcModuleLoad: {2}unique olcModulePath: /usr/lib/ldap DN: olcOverlay={4}unique,olcDatabase={1}hdb,cn=config objectClass: olcUniqueConfig objectClass: olcOverlayConfig objectClass: olcConfig objectClass: top olcOverlay: {4}unique olcUniqueURI: ldap:///?mail?sub olcUniqueURI: ldap:///?uid?sub assuming the configuration is good, I've tried to create 2 entries : uid=test,ou=people,dc=mydomain,dc=com and uid=test2,ou=people,dc=mydomain,dc=com with the same mail : test(a)mydomain.com => created without error. change mail to test2(a)mydomain.com on entry uid=test2,ou=people,dc=mydomain,dc=com works going back to test(a)mydomain.com => no error The first time, I've used the main administrative account. So I created a sub administrator account, changed the ACLs, fine. Deleted the two entries, recreated the two entries with the same mail without error. I've tried to put slapd in debug mode, the only ting I've noticed is : 51f7df1e >>> dnPrettyNormal: <uid=test2,ou=people,dc=mydomain,dc=com> 51f7df1e <<< dnPrettyNormal: <uid=test2,ou=people,dc=mydomain,dc=com>, <uid=test2,ou=people,dc=mydomain,dc=com> 51f7df1e ==> unique_modify <uid=test2,ou=people,dc=mydomain,dc=com> 51f7df1e *unique_modify: administrative bypass, skipping* 51f7df1e bdb_dn2entry("uid=test2,ou=people,dc=mydomain,dc=com") 51f7df1e bdb_entry_get: rc=0 If someone has a clue... Rgds -- Philippe MARASSE Service Informatique - Centre Hospitalier Henri Laborit CS 10587 - 370 avenue Jacques Coeur 86021 Poitiers Cedex Tel : 05.49.44.57.19