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# qmqpd - Unix, Linux Command

# NAME

qmqpd - Postfix QMQP server

# SYNOPSIS

    qmqpd [generic Postfix daemon options]

# DESCRIPTION

The Postfix QMQP server receives one message per connection. Each message is piped through the cleanup(8) daemon, and is placed into the incoming queue as one single queue file. The program expects to be run from the master(8) process manager.

The QMQP server implements one access policy: only explicitly authorized client hosts are allowed to use the service.

# SECURITY

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.

# DIAGNOSTICS

Problems and transactions are logged to syslogd(8).

# BUGS

The QMQP protocol provides only one server reply per message delivery. It is therefore not possible to reject individual recipients.

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.

# CONFIGURATION PARAMETERS

Changes to main.cf are picked up automatically, as qmqpd(8) processes run for only a limited amount of time. Use the command "postfix reload" to speed up a change.

The text below provides only a parameter summary. See postconf(5) for more details including examples.

# CONTENT INSPECTION CONTROLS

Tag | Description
--- | ---
content_filter (empty) | The name of a mail delivery transport that filters mail after it is queued.
receive_override_options (empty) | Enable or disable recipient validation, built-in content filtering, or address mapping.

# RESOURCE AND RATE CONTROLS

Tag | Description
--- | ---
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

Tag | Description
--- | ---
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 the sender.

# TARPIT CONTROLS

Tag | Description
--- | ---
qmqpd_error_delay (1s) | How long the QMQP server will pause before sending a negative reply to the client.

# MISCELLANEOUS CONTROLS

Tag | Description
--- | ---
config_directory (see ’postconf -d’ output) | The default location of the Postfix main.cf and master.cf configuration files.
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 communication channel.
max_idle (100s) | The maximum amount of time that an idle Postfix daemon process waits for the next service request before exiting.
max_use (100) | The maximal number of connection requests before a Postfix daemon process terminates.
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 clients are allowed to connect to the QMQP server port.
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 (postfix) | The mail system name that is prepended to the process name in syslog records, so that "smtpd" becomes, for example, "postfix/smtpd".
verp_delimiter_filter (-=+) | The characters Postfix accepts as VERP delimiter characters on the Postfix sendmail(1) command line and in SMTP commands.

# SEE ALSO

    http://cr.yp.to/proto/qmqp.html, QMQP protocol
    cleanup(8), message canonicalization
    master(8), process manager
    syslogd(8), system logging

# README FILES

Use "postconf readme_directory" or "postconf html_directory" to locate this information.

    QMQP_README, Postfix ezmlm-idx howto.

# LICENSE

The Secure Mailer license must be distributed with this software.

# HISTORY

The qmqpd service was introduced with Postfix version 1.1.

# AUTHOR(S)

    Wietse Venema
    IBM T.J. Watson Research
    P.O. Box 704
    Yorktown Heights, NY 10598, USA

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