Hi, We're seeing some TLS LDAP related issues in our Samba 4 PDC. Slapd gives the same message with SSL turned on and off in smb.conf slapd.service - LSB: OpenLDAP standalone server (Lightweight Directory Access Protocol) Loaded: loaded (/etc/init.d/slapd; bad; vendor preset: enabled) Active: active (running) since Tue 2018-04-03 14:54:38 AEST; 4min 12s ago Apr 03 14:54:37 mypdc slapd[9883]: nss_ldap: reconnecting to LDAP server... Apr 03 14:54:37 mypdc slapd[9883]: nss_ldap: could not connect to any LDAP server as cn=admin,dc=mytest - Can't contact LDAP server Apr 03 14:54:37 mypdc slapd[9883]: nss_ldap: failed to bind to LDAP server ldap://mypdc.mytest: Can't contact LDAP server Apr 03 14:54:37 mypdc slapd[9883]: nss_ldap: reconnecting to LDAP server (sleeping 1 seconds)... Apr 03 14:54:38 mypdc slapd[9883]: nss_ldap: could not connect to any LDAP server as cn=admin,dc=mytest - Can't contact LDAP server Apr 03 14:54:38 mypdc slapd[9883]: nss_ldap: failed to bind to LDAP server ldap://mypdc.mytest: Can't contact LDAP server Apr 03 14:54:38 mypdc slapd[9883]: nss_ldap: could not search LDAP server - Server is unavailable Apr 03 14:54:38 mypdc slapd[9884]: slapd starting Apr 03 14:54:38 mypdc slapd[9875]: ...done. Apr 03 14:54:38 mypdc systemd[1]: Started LSB: OpenLDAP standalone server (Lightweight Directory Access Protocol). I can run the ldapwhoami (with and without -d1) ldapwhoami -H ldap:// -x -ZZ anonymous ldap_url_parse_ext(ldap://) ldap_create ldap_url_parse_ext(ldap://:389/??base) ldap_extended_operation_s ldap_extended_operation ldap_send_initial_request ldap_new_connection 1 1 0 ldap_int_open_connection ldap_connect_to_host: TCP localhost:389 ldap_new_socket: 4 ldap_prepare_socket: 4 ldap_connect_to_host: Trying ::1 389 ldap_pvt_connect: fd: 4 tm: -1 async: 0 attempting to connect: connect success ldap_open_defconn: successful Following is /etc/ldap/ldap.conf BASE dc=mytest URI ldap://mypdc.mytest TLS_CACERT /etc/ldap/ca_certs.pem TLS_REQCERT allow Smb.conf #LDAP passdb backend = ldapsam:ldap://mypdc.mytest ldap admin dn = cn=admin,dc=mytest ldap suffix = dc=mytest ldap group suffix = ou=groups ldap machine suffix = ou=computers ldap user suffix = ou=users idmap backend = ldap ldap idmap suffix = ou=idmap idmap config *: backend = ldap idmap config *: range = 10000-19999 idmap config *: ldap_url = ldap://mypdc.mytest/ idmap config *: ldap_base_dn = ou=idmap,dc=mytest idmap config *: ldap_user_dn = cn=admin,dc=mytest ldap delete dn = yes ldap password sync = yes # ldap ssl = off If I uncomment #ldap ssl = off and restart the services (smbd , nmbd and slapd) I get the same message Regards, Praveen Ghimire