vvrpgsporcupineorg aaron bennett ralf hildebrandt wrote mailerdaemon postmaster root fuucfylclarkuedu jgiangrandeclarkuedu understood got logs mailerdaemon curiosity point symmetry mail system sends delivery status notification uses rfc 2821 null envelope sender address mailerdaemon header thus postfix sends mail null address mailerdaemon ie default value empty_address_recipient wietse thu 07 aug 2008 192134 0500 accepting mail domaincom