In order to use the user and group mappings stored in an LDAP directory, which setting in smb.conf is correct?

This syntax is missing the `ldap:` prefix for the backend type, which is required before the LDAP URI to correctly identify the idmap module.

The correct syntax for configuring the `idmap backend` to use an LDAP server is `idmap backend = ldap:ldap://ldap.example.com:636`. This specifies `ldap` as the backend type and then provides the LDAP URI for the server where the mappings are stored, allowing Samba to retrieve user and group IDs from LDAP.

This syntax includes 'ldap server =', which is not the correct parameter name or format for specifying the LDAP server within the `idmap backend` directive; the URI should directly follow the backend type.

While `idmap backend = ldap` correctly sets the backend type, it does not specify the LDAP server address, making it incomplete for connecting to an external LDAP directory to retrieve mappings.