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

smtpctl, mailqcontrol the SMTP daemon

smtpctl command [argument ...]


The smtpctl program controls smtpd(8). Commands may be abbreviated to the minimum unambiguous prefix; for example, sh ro for show routes.

The mailq command is provided for compatibility with other MTAs and is simply a shortcut for show queue.

The following commands are available:

envelope-id | message-id
Schedule a single envelope, or all envelopes with the same message ID that were manually moved to the queue.
Encrypt the password string to a representation suitable for user credentials and print it to the standard output. If string is not provided, cleartext passwords are read from standard input.

It is advised to avoid providing the password as a parameter as it will be visible from top(1) and ps(1) output.

Disable verbose debug logging.
Enable verbose debug logging.
Display updates of some smtpd(8) internal counters in one second intervals. Each line reports the increment of all counters since the last update, except for some counters which are always absolute values. The first line reports the current value of each counter. The fields are:

  • Current number of active SMTP clients (absolute value).
  • New SMTP clients.
  • Disconnected clients.
  • Current number of envelopes in the queue (absolute value).
  • Newly enqueued envelopes.
  • Dequeued envelopes.
  • Successful deliveries.
  • Temporary failures.
  • Permanent failures.
  • Message loops.
  • Expired envelopes.
  • Envelopes removed by the administrator.
  • Generated bounces.
envelope-id | message-id |
Temporarily suspend scheduling for the envelope with the given ID, envelopes with the given message ID, or all envelopes.
Temporarily stop deliveries to local users.
Temporarily stop relaying and deliveries to remote users.
Temporarily stop accepting incoming sessions.
Enables real-time profiling of subsystem. Supported subsystems are:

  • queue, to profile cost of queue IO
  • imsg, to profile cost of event handlers
envelope-id | message-id |
Remove a single envelope, envelopes with the given message ID, or all envelopes.
envelope-id | message-id |
Resume scheduling for the envelope with the given ID, envelopes with the given message ID, or all envelopes.
Resume deliveries to local users.
Resume relaying and deliveries to remote users.
Resume routing on disabled route route-id.
Resume accepting incoming sessions.
envelope-id | message-id |
Mark as ready for immediate delivery a single envelope, envelopes with the given message ID, or all envelopes.
Display envelope content for the given ID.
Display the list of known remote MX hosts. For each of them, it shows the IP address, the canonical hostname, a reference count, the number of active connections to this host, and the elapsed time since the last connection.
Display status of last delivery for domains that have been active in the last 4 hours. It consists of the following fields, separated by a "|":

  • Domain.
  • UNIX timestamp of last delivery.
  • Status of last delivery.
Display message content for the given ID.
Display information concerning envelopes that are currently in the queue. Each line of output describes a single envelope. It consists of the following fields, separated by a "|":

  • Envelope ID.
  • Address family of the client which enqueued the mail.
  • Type of delivery: one of "mta", "mda" or "bounce".
  • Various flags on the envelope.
  • Sender address (return path).
  • The original recipient address.
  • The destination address.
  • Time of creation.
  • Time of expiration.
  • Time of last delivery or relaying attempt.
  • Number of delivery or relaying attempts.
  • Current runstate: either "pending" or "inflight" if smtpd(8) is running, or "offline" otherwise.
  • Delay in seconds before the next attempt if pending, or time elapsed if currently running. This field is blank if smtpd(8) is not running.
  • Error string for the last failed delivery or relay attempt.
Display the list of currently active relays and associated connectors. For each relay, it shows a number of counters and information on its internal state on a single line. Then comes the list of connectors (source addresses to connect from for this relay).
Display status of routes currently known by smtpd(8). Each line consists of a route number, a source address, a destination address, a set of flags, the number of connections on this route, the current penalty level which determines the amount of time the route is disabled if an error occurs, and the delay before it gets reactivated. The following flags are defined:

The route is currently disabled.
The route is new. No SMTP session has been established yet.
The route has a timeout registered to lower its penalty level and possibly reactivate or discard it.
Displays runtime statistics concerning smtpd(8).
Shows if MTA, MDA and SMTP systems are currently running or paused.
Recursively look up SPF records for the domains read from stdin. For example:
$ smtpctl spf walk < domains.txt

SPF records may contain macros which cannot be included in a static list and must be resolved dynamically at connection time. spf walk cannot provide full results in these cases.

Enables real-time tracing of subsystem. Supported subsystems are:

  • imsg
  • io
  • smtp (incoming sessions)
  • filters
  • mta (outgoing sessions)
  • bounce
  • scheduler
  • expand (aliases/virtual/forward expansion)
  • lookup (user/credentials lookups)
  • stat
  • rules (matched by incoming sessions)
  • mproc
  • all
Disables real-time profiling of subsystem.
Disables real-time tracing of subsystem.
Updates the contents of table name, for tables using the “file” backend.

When smtpd receives a message, it generates a message-id for the message, and one envelope-id per recipient. The message-id is a 32-bit random identifier that is guaranteed to be unique on the host system. The envelope-id is a 64-bit unique identifier that encodes the message-id in the 32 upper bits and a random envelope identifier in the 32 lower bits.

A command which specifies a message-id applies to all recipients of a message; a command which specifies an envelope-id applies to a specific recipient of a message.

UNIX-domain socket used for communication with smtpd(8).


The smtpctl program first appeared in OpenBSD 4.6.

March 2, 2023 OpenBSD-current