@RAOF i set it up today, actually! dovecot >=2.3 can act as a submission /relay/, it passes the messages on to your actual mta for delivery but handles auth and enables more advanced smtp features?

most importantly is burl, which enables you to upload sent messages once rather than both to smtp (for actual sending) and to imap (for saving in your sent folder) - since dovecot effectively provides both smtp and imap, burl Just Works™ :3