SMTPCTL(8) BSD System Manager’s Manual SMTPCTL(8)


smtpctl, mailq — control the Simple Mail Transfer Protocol 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:

discover envelope-id | message-id

Schedule a single envelope, or all envelopes with the same message ID that were manually moved to the queue.

encrypt [string]

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.

log brief

Disable verbose debug logging.

log verbose

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.

pause envelope envelope-id | message-id | all

Temporarily suspend scheduling for the envelope with the given ID, envelopes with the given message ID, or all envelopes.

pause mda

Temporarily stop deliveries to local users.

pause mta

Temporarily stop relaying and deliveries to remote users.

pause smtp

Temporarily stop accepting incoming sessions.

profile subsystem

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

queue, to profile cost of queue IO

imsg, to profile cost of event handlers

remove envelope-id | message-id | all

Remove a single envelope, envelopes with the given message ID, or all envelopes.

resume envelope envelope-id | message-id | all

Resume scheduling for the envelope with the given ID, envelopes with the given message ID, or all envelopes.

resume mda

Resume deliveries to local users.

resume mta

Resume relaying and deliveries to remote users.

resume route route-id

Resume routing on disabled route route-id.

resume smtp

Resume accepting incoming sessions.

schedule envelope-id | message-id | all

Mark as ready for immediate delivery a single envelope, envelopes with the given message ID, or all envelopes.

show envelope envelope-id

Display envelope content for the given ID.

show hosts

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.

show hoststats

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 "|":


UNIX timestamp of last delivery.

Status of last delivery.

show message envelope-id

Display message content for the given ID.

show queue

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.

show relays

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).

show routes

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.

show stats

Displays runtime statistics concerning smtpd(8).

show status

Shows if MTA, MDA and SMTP systems are currently running or paused.

spf walk

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.

trace subsystem

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



smtp (incoming sessions)


mta (outgoing sessions)



expand (aliases/virtual/forward expansion)

lookup (user/credentials lookups)


rules (matched by incoming sessions)



unprofile subsystem

Disables real-time profiling of subsystem.

untrace subsystem

Disables real-time tracing of subsystem.

update table name

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.

BSD September 14, 2020 BSD