[2008-11: New installation on 10.3/8.6.0] [2007-04: Implementing SMTP Authorization with qpsmtpd running under SuSE 10.0 and Plesk 8.0 [2014-01: Here's an update to these instructions.] [2018-09: Update #2 on Installing qpsmtpd on Xenial, completely replaces 2014-01, replaced by the following]
