The idmap backend provides a plugin interface for Winbind to use varying backends to store SID/uid/gid mapping tables. This option is mutually exclusive with the newer and more flexible parameter. The main difference between the "idmap backend" and the "idmap domains" is that the former only allows on backend for all domains while the latter supports configuring backends on a per domain basis. Examples of SID/uid/gid backends include tdb ( idmap_tdb8), ldap (idmap_ldap 8), rid ( idmap_rid8), and ad (idmap_tdb 8). tdb