smtpd --- Simple Mail Transfer Protocol daemon


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


     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 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.


     /etc/mailname       Alternate server name to use.
     /etc/smtpd.conf     Default smtpd configuration file.
                     UNIX-domain socket used for communication with
     /var/spool/smtpd/   Spool directories for mail during processing.


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


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


     The smtpd program first appeared in OpenBSD 4.6.


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