Dear We have an problem using $OpenLDAP: slapd 2.4.23 (Nov 22 2010 23:39:34) $#012#011@biber:/build/buildd-openldap_2.4.23-7-i386-mi96UQ/openldap-2.4.23/debian/build/servers/slapd The same issue has been be replicated on 2.4.24 When we analyze the debug logs, the crash is performed each time we see this line : is_entry_objectclass("", "2.16.840.1.113730.3.2.6") no objectClass attribute How can we prevent this crash or fix it ? here it is a piece of logs that detect the crash. Feb 22 14:50:21 pm02 slapd[12126]: >>> dnPrettyNormal: <cn=webmail.e.florasul.pt,cn=artica,dc=my-domain,dc=com> Feb 22 14:50:21 pm02 slapd[12126]: <<< dnPrettyNormal: <cn=webmail.e.florasul.pt,cn=artica,dc=my-domain,dc=com>, <cn=webmail.e.florasul.pt,cn=artica,dc=my-domain,dc=com> Feb 22 14:50:21 pm02 slapd[12126]: bdb_dn2entry("cn=webmail.e.florasul.pt,cn=artica,dc=my-domain,dc=com") Feb 22 14:50:21 pm02 slapd[12126]: => hdb_dn2id("cn=webmail.e.florasul.pt,cn=artica,dc=my-domain,dc=com") Feb 22 14:50:21 pm02 slapd[12126]: <= hdb_dn2id: get failed: DB_NOTFOUND: No matching key/data pair found (-30988) Feb 22 14:50:21 pm02 slapd[12126]: oc_check_required entry (cn=webmail.e.florasul.pt,cn=artica,dc=my-domain,dc=com), objectClass "ArticaHostName" Feb 22 14:50:21 pm02 slapd[12126]: oc_check_allowed type "objectClass" Feb 22 14:50:21 pm02 slapd[12126]: oc_check_allowed type "cn" Feb 22 14:50:21 pm02 slapd[12126]: oc_check_allowed type "structuralObjectClass" Feb 22 14:50:21 pm02 slapd[12126]: bdb_dn2entry("cn=webmail.e.florasul.pt,cn=artica,dc=my-domain,dc=com") Feb 22 14:50:21 pm02 slapd[12126]: => hdb_dn2id("cn=webmail.e.florasul.pt,cn=artica,dc=my-domain,dc=com") Feb 22 14:50:21 pm02 slapd[12126]: <= hdb_dn2id: get failed: DB_NOTFOUND: No matching key/data pair found (-30988) Feb 22 14:50:21 pm02 slapd[12126]: is_entry_objectclass("", "2.16.840.1.113730.3.2.6") no objectClass attribute Feb 22 14:50:21 pm02 kernel: [13697.801217] slapd[13777]: segfault at 811db38 ip 080c1e80 sp b2cf4b80 error 7 in slapd[8048000+11b000] best regards