opensmtpd: opensmtpd (OpenSMTPd from the OpenBSD project) opensmtpd: opensmtpd: OpenSMTPD is a FREE implementation of the server-side SMTP protocol opensmtpd: as defined by RFC 5321, with some additional standard extensions. opensmtpd: It allows ordinary machines to exchange e-mails with other systems opensmtpd: speaking the SMTP protocol. opensmtpd: opensmtpd: Homepage: https://www.opensmtpd.org/ opensmtpd: opensmtpd: opensmtpd: