smtpd(8) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | FILES | SEE ALSO | STANDARDS | HISTORY | COLOPHON

SMTPD(8)                 System Manager's Manual                SMTPD(8)

NAME         top

       smtpd — Simple Mail Transfer Protocol (SMTP) daemon

SYNOPSIS         top

       smtpd [-dFhnv] [-D macro=value] [-f file] [-P system] [-T trace]

DESCRIPTION         top

       smtpd is a Simple Mail Transfer Protocol (SMTP) daemon which can
       be used as a machine's primary mail system.  smtpd can listen on
       a network interface and handle SMTP transactions; it can also be
       fed messages through the standard sendmail(8) interface.  It can
       relay messages through remote mail transfer agents or store them
       locally using either the mbox or maildir format.  This
       implementation supports SMTP as defined by RFC 5321 as well as
       several extensions.  A running smtpd can be controlled through
       smtpctl(8).

       The options are as follows:

       -D macro=value
               Define macro to be set to value on the command line.
               Overrides the definition of macro in the configuration
               file.

       -d      Do not daemonize.  If this option is specified, smtpd
               will run in the foreground and log to stderr.

       -F      Do not daemonize.  If this option is specified, smtpd
               will run in the foreground and log to syslogd(8).

       -f file
               Specify an alternative configuration file.

       -h      Display version and usage.

       -n      Configtest mode.  Only check the configuration file for
               validity.

       -P system
               Pause a specific subsystem at startup.  Normal operation
               can be resumed using smtpctl(8).  This option can be used
               multiple times.  The accepted values are:

               mda      Do not schedule local deliveries.
               mta      Do not schedule remote transfers.
               smtp     Do not listen on SMTP sockets.

       -T trace
               Enables real-time tracing at startup.  Normal operation
               can be resumed using smtpctl(8).  This option can be used
               multiple times.  The accepted values are:

               imsg
               io
               smtp (incoming sessions)
               filters
               transfer (outgoing sessions)
               bounce
               scheduler
               expand (aliases/virtual/forward expansion)
               lookup (user/credentials lookups)
               stat
               rules (matched by incoming sessions)
               mproc
               all

       -v      Produce more verbose output.

FILES         top

       /etc/mail/mailname       Alternate server name to use.
       /etc/mail/smtpd.conf     Default smtpd configuration file.
       /var/run/smtpd.sock      Unix-domain socket used for
                                communication with smtpctl(8).
       /var/spool/smtpd/        Spool directories for mail during
                                processing.
       ~/.forward               User email forwarding information.

SEE ALSO         top

       forward(5), smtpd.conf(5), mailwrapper(8), smtpctl(8)

STANDARDS         top

       J. Klensin, Simple Mail Transfer Protocol, RFC 5321, October
       2008.

HISTORY         top

       The smtpd program first appeared in OpenBSD 4.6.

COLOPHON         top

       This page is part of the OpenSMTPD (a FREE implementation of the
       server-side SMTP protocol) project.  Information about the
       project can be found at https://www.opensmtpd.org/.  If you have
       a bug report for this manual page, see
       ⟨https://github.com/OpenSMTPD/OpenSMTPD/issues⟩.  This page was
       obtained from the project's upstream Git repository
       ⟨https://github.com/OpenSMTPD/OpenSMTPD.git⟩ on 2024-06-14.  (At
       that time, the date of the most recent commit that was found in
       the repository was 2024-06-09.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

GNU                           March 2, 2023                     SMTPD(8)