Section: Maintenance Commands (8)
Postfix QMQP server
qmqpd [generic Postfix daemon options]
The Postfix QMQP server receives one message per connection.
Each message is piped through the cleanup
daemon, and is placed into the incoming
queue as one
single queue file. The program expects to be run from the
(8) process manager.
The QMQP server implements one access policy: only explicitly
authorized client hosts are allowed to use the service.
The QMQP server is moderately security-sensitive. It talks to QMQP
clients and to DNS servers on the network. The QMQP server can be
run chrooted at fixed low privilege.
Problems and transactions are logged to syslogd
The QMQP protocol provides only one server reply per message
delivery. It is therefore not possible to reject individual
The QMQP protocol requires the server to receive the entire
message before replying. If a message is malformed, or if any
netstring component is longer than acceptable, Postfix replies
immediately and closes the connection. It is left up to the
client to handle the situation.
Changes to main.cf
are picked up automatically, as qmqpd
processes run for only a limited amount of time. Use the command
" to speed up a change.
The text below provides only a parameter summary. See
postconf(5) for more details including examples.
CONTENT INSPECTION CONTROLS
- content_filter (empty)
After the message is queued, send the entire message to the
- receive_override_options (empty)
Enable or disable recipient validation, built-in content
filtering, or address mapping.
Preliminary SMTPUTF8 support is introduced with Postfix 3.0.
- smtputf8_enable (yes)
Enable preliminary SMTPUTF8 support for the protocols described
in RFC 6531..6533.
- smtputf8_autodetect_classes (sendmail, verify)
Detect that a message requires SMTPUTF8 support for the specified
mail origin classes.
Available in Postfix version 3.2 and later:
- enable_idna2003_compatibility (no)
Enable 'transitional' compatibility between IDNA2003 and IDNA2008,
when converting UTF-8 domain names to/from the ASCII form that is
used for DNS lookups.
RESOURCE AND RATE CONTROLS
- line_length_limit (2048)
Upon input, long lines are chopped up into pieces of at most
this length; upon delivery, long lines are reconstructed.
- hopcount_limit (50)
The maximal number of Received: message headers that is allowed
in the primary message headers.
- message_size_limit (10240000)
The maximal size in bytes of a message, including envelope information.
- qmqpd_timeout (300s)
The time limit for sending or receiving information over the network.
TROUBLE SHOOTING CONTROLS
- debug_peer_level (2)
The increment in verbose logging level when a remote client or
server matches a pattern in the debug_peer_list parameter.
- debug_peer_list (empty)
Optional list of remote client or server hostname or network
address patterns that cause the verbose logging level to increase
by the amount specified in $debug_peer_level.
- soft_bounce (no)
Safety net to keep mail queued that would otherwise be returned to
- qmqpd_error_delay (1s)
How long the Postfix QMQP server will pause before sending a negative
reply to the remote QMQP client.
- config_directory (see 'postconf -d' output)
The default location of the Postfix main.cf and master.cf
- daemon_timeout (18000s)
How much time a Postfix daemon process may take to handle a
request before it is terminated by a built-in watchdog timer.
- ipc_timeout (3600s)
The time limit for sending or receiving information over an internal
- max_idle (100s)
The maximum amount of time that an idle Postfix daemon process waits
for an incoming connection before terminating voluntarily.
- max_use (100)
The maximal number of incoming connections that a Postfix daemon
process will service before terminating voluntarily.
- process_id (read-only)
The process ID of a Postfix command or daemon process.
- process_name (read-only)
The process name of a Postfix command or daemon process.
- qmqpd_authorized_clients (empty)
What remote QMQP clients are allowed to connect to the Postfix QMQP
- queue_directory (see 'postconf -d' output)
The location of the Postfix top-level queue directory.
- syslog_facility (mail)
The syslog facility of Postfix logging.
- syslog_name (see 'postconf -d' output)
A prefix that is prepended to the process name in syslog
records, so that, for example, "smtpd" becomes "prefix/smtpd".
- verp_delimiter_filter (-=+)
The characters Postfix accepts as VERP delimiter characters on the
Postfix sendmail(1) command line and in SMTP commands.
Available in Postfix version 2.5 and later:
- qmqpd_client_port_logging (no)
Enable logging of the remote QMQP client port in addition to
the hostname and IP address.
Available in Postfix 3.3 and later:
- service_name (read-only)
The master.cf service name of a Postfix daemon process.
http://cr.yp.to/proto/qmqp.html, QMQP protocol
cleanup(8), message canonicalization
master(8), process manager
postlogd(8), Postfix logging
syslogd(8), system logging
Use "postconf readme_directory
" to locate this information.
QMQP_README, Postfix ezmlm-idx howto.
The Secure Mailer license must be distributed with this software.
The qmqpd service was introduced with Postfix version 1.1.
IBM T.J. Watson Research
P.O. Box 704
Yorktown Heights, NY 10598, USA
111 8th Avenue
New York, NY 10011, USA