I guess I just ran into one of the most undocumented file formats: saslauthd.conf. But eventually I got it working (as authentication provider for a local ldap server). To use Windows active directory domain controllers as backend for slapd:ldap_servers: ldap://dc01.example.com:389/ ldap://dc02.example.com:389/ ldap_bind_dn: DC=example,DC=com ldap_auth_method: fastbind ldap_filter: EXAMPLE\%UWhich means you can have ldap users withuserPassword: {SASL}username@EXAMPLE.COM