Projects / Smail


Smail is a Mail Transport Agent. Its job is to accept mail messages from sources on the local machine, or from remote hosts, and deliver those messages to the appropriate destinations, be they to remote hosts or to files or programs on the local machine. Smail is designed to be mostly compatible with sendmail but uses a much simpler configuration scheme.

Operating Systems

Last announcement

New Preview release available.... 26 Feb 2012 05:42

A new release will soon be available with some important fixes and changes. If you are interested in testing the prerelease, please see the project web site for details. Thanks!

Recent releases

  •  26 Feb 2012 05:39

    Release Notes: This is a major update fixing reported security problems and fixing may other bugs big and small.

    •  27 Aug 2004 14:53

      Release Notes: This release deals solely with a problem in a minor change in the previous release which unexpectedly resulted in sender addresses being truncated to just their mailbox part.

      •  27 Aug 2004 03:00

        Release Notes: This release is primarily a bugfix and clean-up release. It also includes a first cut at message arrival and delivery delay accounting. This release further adapts the makefiles to be portable between all major variants of make in use on modern systems while at the same time still supporting useful developer and maintainer features such as automated dependency tracking.

        •  01 Jun 2004 21:18

          Release Notes: This release fixes a major botch that was made in the host domain name RE parsing and matching code. The checkerr utility script now automatically recognizes and registers all non-local double-bounce original senders in the dead-mail.senders database so that future messages from these addresses will not accumulate in the error queue.

          •  31 May 2004 18:02

            Release Notes: This is a minor bugfix and minor release update. Handling of regular expressions for host domain name lists is now more consistent, and their associated messages may now make use of sub-string substitution in the same way as in content filters. Duplicate HELO reject records are suppressed from the log file. The log analysis utility has been further improved. Networks and hosts that are clients only and that should not send fake bounces can now be specified.

            Recent comments

            08 Aug 2002 11:48 jhmartin

            Definetely handy when you want a sendmail-compatible (ie /usr/sbin/sendmail) MTA for a firewall type machine that should only be send-only, no daemon (although this supports receiving as well). An example is a firewall machine w/Arpwatch -- it requires /usr/sbin/sendmail to exist, but who wants to install all of sendmail just to send a status message? Well done.

            30 Jan 2000 23:59 woods

            Smail history
            Smail-3 definitely came after Sendmail.

            It was written as a sendmail replacement for normal people and as such has a much simpler configuration interface insted of the finite state machine that drives sendmail. in fact the most recent versions should work out of the box with no post-compilation configuration necessary on most leaf node sites.

            The major version number of Smail is "3" because it came after Smail-2, a very simple UUCP mailer written a very long time ago by Chris Seiwald when he was at AT&T in order to do automatic UUCP routing using pathalias and the UUCP Map Project database. Smail-2 replaced an earlier Smail-1. Smail-1 was probably written just about the same time, or maybe before, sendmail, but I'm not sure (sendmail is first copyright in 1983 and smail-2 is first dated 1985). Smail-3's authors liked the simplicity of Smail-2 and the idea was to write a mailer to replace Smail-2 and bring new gateway and Internet capability without sacrificing the simplicity. Other than that Smail-2 and Smail-3 are really linked only in name.

            Most other currently used SMTP-capable mailers, including zmailer, exim, qmail, postfix, and so on were written long after sendmail was first released and most were written to address the shortcomings of sendmail. Exim was in fact modeled after Smail-3 and could in some senses be considered to be a full rewrite.


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