The most secure in absolute terms is qmail[1] but I found OpenSMTPd[2] to be a joy to work with, something that can not be said for any other SMTPd system I wor

The most secure in absolute terms is qmail[1] but I found OpenSMTPd[2] to be a joy to work with, something that can not be said for any other SMTPd system I worked over the years (postfix, sendmail horror, exim, qmail and OpenSMTPd). OpenSMTPd seems to be fairly secure[3]. [1]: http://www.qmail.org/top.html http://www.qmail.org/top.html [2]: https://www.opensmtpd.org/ https://www.opensmtpd.org/ [3]: https://www.opensmtpd.org/security.html https://www.opensmtpd.org/security.html