OpenSMTPD!

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OpenSMTPD is primarily developed by Gilles Chehade, Eric Faurot, Charles Longeau and Sunil Nimmagadda, with contributions from various OpenBSD hackers. OpenSMTPD is part of the OpenBSD Project https://www.openbsd.org.
The software is freely usable and re-usable by everyone under an ISC license. The OpenBSD project sells CDs, T-shirts and posters https://openbsdstore.com.
Sales of these items help to fund development. --- * * *

OpenSMTPD alternatives

  • Courier-MTA

  • The Courier mail transfer agent (MTA) is an integrated mail/groupware server based on open commodity protocols, such as ESMTP, IMAP, POP3, LDAP, SSL, and HTTP. Courier provides ESMTP, IMAP, POP3, webmail, and mailing list services within a single, consistent, framework. Individual components can be customized, enabled or disabled at will.

    tags: imap smtp mail-server mailing-list mail-filter

  • Sendmail

  • Sendmail is a general purpose internetwork email routing facility that supports many kinds of transfer and delivery methods, including the Simple Mail Transfer Protocol (SMTP) used for email transport over the Internet. A descendant of the delivermail program written by Eric Allman, Sendmail is a well-known project of the free and open source software and Unix communities, and has spread both as free software and proprietary software.

    tags: mail-server

  • Dragonfly Mail Agent

  • A small Mail Transport Agent (MTA), designed for home and office use. Part of DragonFly BSD , it accepts mails from locally installed Mail User Agents (MUA) and delivers the mails either locally or to a remote destination. Remote delivery includes several features like TLS/SSL support and SMTP authentication. dma is not intended as a replacement for real, big MTAs like Sendmail or Postfix. Consequently, dma does not listen on port 25 for incoming connections. ยป

    tags: smtp email-transfer message-transfer-agent

  • Microsoft SMTP Server

  • Available in Windows and Windows Server via the optional IIS role.

    tags: email-via-smtp exchange mail-smtp mta outbound-smtp

  • sSMTP

  • SSMTP is a program which delivers email from a local computer to a configured mailhost (mailhub). It is not a mail server (like feature-rich mail server sendmail) and does not receive mail, expand aliases or manage a queue. One of its primary uses is for forwarding automated email (like system alerts) off your machine and to an external email address.

    tags: mta smtp

  • Haraka

  • Haraka is an open source SMTP server written in Node.js which provides extremely high performance coupled with a flexible plugin system allowing Javascript programmers full access to change the behaviour of the server. It is used heavily in some high traffic sites - see the "Known Users" link above for testimonials.

    tags: smtp-server