.\"	$OpenBSD: smtpd.8,v 1.33 2023/03/02 17:09:53 jmc Exp $
.\"
.\" Copyright (c) 2012, Eric Faurot <eric@openbsd.org>
.\" Copyright (c) 2008, Gilles Chehade <gilles@poolp.org>
.\" Copyright (c) 2008, Pierre-Yves Ritschard <pyr@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd $Mdocdate: March 2 2023 $
.Dt SMTPD 8
.Os
.Sh NAME
.Nm smtpd
.Nd Simple Mail Transfer Protocol (SMTP) daemon
.Sh SYNOPSIS
.Nm
.Op Fl dFhnv
.Op Fl D Ar macro Ns = Ns Ar value
.Op Fl f Ar file
.Op Fl P Ar system
.Op Fl T Ar trace
.Sh DESCRIPTION
.Nm
is a Simple Mail Transfer Protocol
.Pq SMTP
daemon which can be used as a machine's primary mail system.
.Nm
can listen on a network interface and handle SMTP
transactions; it can also be fed messages through the standard
.Xr 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
.Nm
can be controlled through
.Xr smtpctl 8 .
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl D Ar macro Ns = Ns Ar value
Define
.Ar macro
to be set to
.Ar value
on the command line.
Overrides the definition of
.Ar macro
in the configuration file.
.It Fl d
Do not daemonize.
If this option is specified,
.Nm
will run in the foreground and log to
.Em stderr .
.It Fl F
Do not daemonize.
If this option is specified,
.Nm
will run in the foreground and log to
.Xr syslogd 8 .
.It Fl f Ar file
Specify an alternative configuration file.
.It Fl h
Display version and usage.
.It Fl n
Configtest mode.
Only check the configuration file for validity.
.It Fl P Ar system
Pause a specific subsystem at startup.
Normal operation can be resumed using
.Xr smtpctl 8 .
This option can be used multiple times.
The accepted values are:
.Pp
.Bl -tag -width "smtpXXX" -compact
.It mda
Do not schedule local deliveries.
.It mta
Do not schedule remote transfers.
.It smtp
Do not listen on SMTP sockets.
.El
.It Fl T Ar trace
Enables real-time tracing at startup.
Normal operation can be resumed using
.Xr smtpctl 8 .
This option can be used multiple times.
The accepted values are:
.Pp
.Bl -bullet -compact
.It
imsg
.It
io
.It
smtp (incoming sessions)
.It
filters
.It
transfer (outgoing sessions)
.It
bounce
.It
scheduler
.It
expand (aliases/virtual/forward expansion)
.It
lookup (user/credentials lookups)
.It
stat
.It
rules (matched by incoming sessions)
.It
mproc
.It
all
.El
.It Fl v
Produce more verbose output.
.El
.Sh FILES
.Bl -tag -width "/etc/smtpd.confXXX" -compact
.It Pa /etc/mailname
Alternate server name to use.
.It Pa /etc/smtpd.conf
Default
.Nm
configuration file.
.It Pa /var/run/smtpd.sock
.Ux Ns -domain
socket used for communication with
.Xr smtpctl 8 .
.It Pa /var/spool/smtpd/
Spool directories for mail during processing.
.It Pa ~/.forward
User email forwarding information.
.El
.Sh SEE ALSO
.Xr forward 5 ,
.Xr smtpd.conf 5 ,
.Xr mailwrapper 8 ,
.Xr smtpctl 8
.Sh STANDARDS
.Rs
.%A J. Klensin
.%D October 2008
.%R RFC 5321
.%T Simple Mail Transfer Protocol
.Re
.Sh HISTORY
The
.Nm
program first appeared in
.Ox 4.6 .