smtpd(8) — Linux manual page
SMTPD(8) System Manager's Manual SMTPD(8)
NAME
smtpd — Simple Mail Transfer Protocol (SMTP) daemon
SYNOPSIS
smtpd [-dFhnv] [-D macro=value] [-f file] [-P system] [-T trace]
DESCRIPTION
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
/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
forward(5), smtpd.conf(5), mailwrapper(8), smtpctl(8)
STANDARDS
J. Klensin, Simple Mail Transfer Protocol, RFC 5321, October
2008.
HISTORY
The smtpd program first appeared in OpenBSD 4.6.
COLOPHON
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
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