at boot (sendmail_enable=NO), a localhost-only daemon may started
(sendmail_submit_enable) as it is needed to accept mail from command line
submissions. If this isn't desired, see etc/mail/README for more hints.
Optionally (sendmail_msp_queue_enable) start a queue runner for the
submission queue in case a daemon isn't available to accept command line
submitted mail at submission time.
Note that the syslog labels for all of these sendmail processes have been
uniquified for easier log parsing.