I documented this about 5 months ago and it got tagged "won't fix"...I've struggled to figure it out and can't, especially given the quandary that Drupal's outgoing mail seems to get to hotmail no problem, while CiviMail's doesn't even show up in the Junk folder. Furthermore, my mailserver's IP passes all blacklist tests.
Am I missing something in the smtp settings?
How do the mail senders in Drupal and CiviMail differ?
confused in NYC,