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Linux 2.6 - man page for pipe (linux section 8postfix)

PIPE(8postfix)									   PIPE(8postfix)

NAME
       pipe - Postfix delivery to external command

SYNOPSIS
       pipe [generic Postfix daemon options] command_attributes...

DESCRIPTION
       The  pipe(8)  daemon processes requests from the Postfix queue manager to deliver messages
       to external commands.  This program expects to be run from the master(8) process manager.

       Message attributes such as sender address, recipient address and next-hop host name can be
       specified  as  command-line  macros  that are expanded before the external command is exe-
       cuted.

       The pipe(8) daemon updates queue files and marks recipients as finished, or it informs the
       queue manager that delivery should be tried again at a later time. Delivery status reports
       are sent to the bounce(8), defer(8) or trace(8) daemon as appropriate.

SINGLE-RECIPIENT DELIVERY
       Some destinations cannot handle more than one recipient per delivery request. Examples are
       pagers  or  fax	machines.   In	addition,  multi-recipient  delivery  is undesirable when
       prepending a Delivered-to: or X-Original-To: message header.

       To prevent Postfix from sending multiple recipients per delivery request, specify

	   transport_destination_recipient_limit = 1

       in the Postfix main.cf file, where transport is the name in the first column of the  Post-
       fix master.cf entry for the pipe-based delivery transport.

COMMAND ATTRIBUTE SYNTAX
       The  external  command  attributes are given in the master.cf file at the end of a service
       definition.  The syntax is as follows:

       chroot=pathname (optional)
	      Change the process root directory and working directory  to  the	named  directory.
	      This  happens before switching to the privileges specified with the user attribute,
	      and  before  executing  the  optional  directory=pathname  directive.  Delivery  is
	      deferred in case of failure.

	      This feature is available as of Postfix 2.3.

       directory=pathname (optional)
	      Change to the named directory before executing the external command.  The directory
	      must be accessible for the user specified with the user attribute (see below).  The
	      default  working	directory  is  $queue_directory.  Delivery is deferred in case of
	      failure.

	      This feature is available as of Postfix 2.2.

       eol=string (optional, default: \n)
	      The output record delimiter. Typically one would use either \r\n or \n.  The  usual
	      C-style backslash escape sequences are recognized: \a \b \f \n \r \t \v \ddd (up to
	      three octal digits) and \\.

       flags=BDFORXhqu.> (optional)
	      Optional message processing flags. By default, a message is copied unchanged.

	      B      Append a blank line at the end of each message. This  is  required  by  some
		     mail  user agents that recognize "From " lines only when preceded by a blank
		     line.

	      D      Prepend a "Delivered-To: recipient" message header with the envelope recipi-
		     ent  address.  Note:  for	this  to  work, the transport_destination_recipi-
		     ent_limit must be 1 (see SINGLE-RECIPIENT DELIVERY above for details).

		     The D flag also enforces loop detection (Postfix 2.5 and later): if  a  mes-
		     sage  already  contains  a  Delivered-To:	header	with  the  same recipient
		     address, then the message is returned as undeliverable. The address compari-
		     son is case insensitive.

		     This feature is available as of Postfix 2.0.

	      F      Prepend  a  "From sender time_stamp" envelope header to the message content.
		     This is expected by, for example, UUCP software.

	      O      Prepend an "X-Original-To: recipient"  message  header  with  the	recipient
		     address  as given to Postfix. Note: for this to work, the transport_destina-
		     tion_recipient_limit must be 1  (see  SINGLE-RECIPIENT  DELIVERY  above  for
		     details).

		     This feature is available as of Postfix 2.0.

	      R      Prepend a Return-Path: message header with the envelope sender address.

	      X      Indicate  that  the  external  command  performs  final delivery.	This flag
		     affects the status reported in "success" DSN (delivery status  notification)
		     messages, and changes it from "relayed" into "delivered".

		     This feature is available as of Postfix 2.5.

	      h      Fold the command-line $original_recipient and $recipient address domain part
		     (text to the right of the right-most @ character) to lower  case;	fold  the
		     entire command-line $domain and $nexthop host or domain information to lower
		     case.  This is recommended for delivery via UUCP.

	      q      Quote white space and other special characters in the command-line  $sender,
		     $original_recipient  and  $recipient address localparts (text to the left of
		     the right-most @ character), according to an 8-bit  transparent  version  of
		     RFC 822.  This is recommended for delivery via UUCP or BSMTP.

		     The result is compatible with the address parsing of command-line recipients
		     by the Postfix sendmail(1) mail submission command.

		     The q flag affects only entire addresses, not the partial	address  informa-
		     tion from the $user, $extension or $mailbox command-line macros.

	      u      Fold  the	command-line $original_recipient and $recipient address localpart
		     (text to the left of the right-most @ character) to  lower  case.	 This  is
		     recommended for delivery via UUCP.

	      .      Prepend  "."  to  lines  starting	with ".". This is needed by, for example,
		     BSMTP software.

	      >      Prepend ">" to lines starting with "From ". This is expected by,  for  exam-
		     ple, UUCP software.

       null_sender=replacement (default: MAILER-DAEMON)
	      Replace  the null sender address (typically used for delivery status notifications)
	      with the specified text when expanding the $sender  command-line	macro,	and  when
	      generating a From_ or Return-Path: message header.

	      If  the  null  sender replacement text is a non-empty string then it is affected by
	      the q flag for address quoting in command-line arguments.

	      The null sender replacement text may be empty; this form is recommended for content
	      filters  that feed mail back into Postfix. The empty sender address is not affected
	      by the q flag for address quoting in command-line arguments.

	      Caution: a null sender address is easily mis-parsed by naive software. For example,
	      when the pipe(8) daemon executes a command such as:

		  Wrong: command -f$sender -- $recipient

	      the  command  will  mis-parse the -f option value when the sender address is a null
	      string.  For correct parsing, specify $sender as an argument by itself:

		  Right: command -f $sender -- $recipient

	      This feature is available as of Postfix 2.3.

       size=size_limit (optional)
	      Don't deliver messages that exceed this size limit (in bytes); return them  to  the
	      sender instead.

       user=username (required)

       user=username:groupname
	      Execute  the  external command with the user ID and group ID of the specified user-
	      name.  The software refuses to execute commands with root privileges, or	with  the
	      privileges  of  the mail system owner. If groupname is specified, the corresponding
	      group ID is used instead of the group ID of username.

       argv=command... (required)
	      The command to be executed. This must be specified as the last  command  attribute.
	      The command is executed directly, i.e. without interpretation of shell meta charac-
	      ters by a shell command interpreter.

	      In the command argument vector, the following macros are	recognized  and  replaced
	      with corresponding information from the Postfix queue manager delivery request.

	      In  addition  to the form ${name}, the forms $name and $(name) are also recognized.
	      Specify $$ where a single $ is wanted.

	      ${client_address}
		     This macro expands to the remote client network address.

		     This feature is available as of Postfix 2.2.

	      ${client_helo}
		     This macro expands to the remote client HELO command parameter.

		     This feature is available as of Postfix 2.2.

	      ${client_hostname}
		     This macro expands to the remote client hostname.

		     This feature is available as of Postfix 2.2.

	      ${client_port}
		     This macro expands to the remote client TCP port number.

		     This feature is available as of Postfix 2.5.

	      ${client_protocol}
		     This macro expands to the remote client protocol.

		     This feature is available as of Postfix 2.2.

	      ${domain}
		     This macro expands to the domain portion  of  the	recipient  address.   For
		     example, with an address user+foo@domain the domain is domain.

		     This information is modified by the h flag for case folding.

		     This feature is available as of Postfix 2.5.

	      ${extension}
		     This  macro expands to the extension part of a recipient address.	For exam-
		     ple, with an address user+foo@domain the extension is foo.

		     A command-line argument that contains ${extension} expands into as many com-
		     mand-line arguments as there are recipients.

		     This information is modified by the u flag for case folding.

	      ${mailbox}
		     This  macro  expands to the complete local part of a recipient address.  For
		     example, with an address user+foo@domain the mailbox is user+foo.

		     A command-line argument that contains ${mailbox} expands to as many command-
		     line arguments as there are recipients.

		     This information is modified by the u flag for case folding.

	      ${nexthop}
		     This macro expands to the next-hop hostname.

		     This information is modified by the h flag for case folding.

	      ${original_recipient}
		     This  macro  expands  to  the  complete recipient address before any address
		     rewriting or aliasing.

		     A command-line argument that contains ${original_recipient}  expands  to  as
		     many command-line arguments as there are recipients.

		     This information is modified by the hqu flags for quoting and case folding.

		     This feature is available as of Postfix 2.5.

	      ${recipient}
		     This macro expands to the complete recipient address.

		     A	command-line  argument that contains ${recipient} expands to as many com-
		     mand-line arguments as there are recipients.

		     This information is modified by the hqu flags for quoting and case folding.

	      ${sasl_method}
		     This macro expands to the name of the SASL authentication mechanism  in  the
		     AUTH command when the Postfix SMTP server received the message.

		     This feature is available as of Postfix 2.2.

	      ${sasl_sender}
		     This  macro  expands to the SASL sender name (i.e. the original submitter as
		     per RFC 4954) in the MAIL FROM command when the Postfix SMTP server received
		     the message.

		     This feature is available as of Postfix 2.2.

	      ${sasl_username}
		     This  macro expands to the SASL user name in the AUTH command when the Post-
		     fix SMTP server received the message.

		     This feature is available as of Postfix 2.2.

	      ${sender}
		     This macro expands to the envelope sender	address.  By  default,	the  null
		     sender  address  expands  to  MAILER-DAEMON;  this  can  be changed with the
		     null_sender attribute, as described above.

		     This information is modified by the q flag for quoting.

	      ${size}
		     This macro expands to Postfix's idea  of  the  message  size,  which  is  an
		     approximation of the size of the message as delivered.

	      ${user}
		     This  macro  expands to the username part of a recipient address.	For exam-
		     ple, with an address user+foo@domain the username part is user.

		     A command-line argument that contains ${user} expands into as many  command-
		     line arguments as there are recipients.

		     This information is modified by the u flag for case folding.

STANDARDS
       RFC 3463 (Enhanced status codes)

DIAGNOSTICS
       Command	exit status codes are expected to follow the conventions defined in <sysexits.h>.
       Exit status 0 means normal successful completion.

       In the case of a non-zero exit status, a limited amount of command output is  reported  in
       an  delivery  status  notification.  When the output begins with a 4.X.X or 5.X.X enhanced
       status code, the status code takes precedence over the non-zero exit status (Postfix  ver-
       sion 2.3 and later).

       Problems and transactions are logged to syslogd(8).  Corrupted message files are marked so
       that the queue manager can move them to the corrupt queue for further inspection.

SECURITY
       This program needs a dual personality 1) to access the private Postfix queue and IPC mech-
       anisms,	and  2) to execute external commands as the specified user. It is therefore secu-
       rity sensitive.

CONFIGURATION PARAMETERS
       Changes to main.cf are picked up automatically as pipe(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 includ-
       ing examples.

RESOURCE AND RATE CONTROLS
       In the text below, transport is the first field in a master.cf entry.

       transport_destination_concurrency_limit ($default_destination_concurrency_limit)
	      Limit the number of parallel deliveries to the same destination, for  delivery  via
	      the named transport.  The limit is enforced by the Postfix queue manager.

       transport_destination_recipient_limit ($default_destination_recipient_limit)
	      Limit  the  number  of  recipients per message delivery, for delivery via the named
	      transport.  The limit is enforced by the Postfix queue manager.

       transport_time_limit ($command_time_limit)
	      Limit the time for delivery to external command, for delivery via the named  trans-
	      port.  The limit is enforced by the pipe delivery agent.

	      Postfix 2.4 and later support a suffix that specifies the time unit: s (seconds), m
	      (minutes), h (hours), d (days), w (weeks). The default time unit is seconds.

MISCELLANEOUS CONTROLS
       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.

       delay_logging_resolution_limit(2)
	      The  maximal number of digits after the decimal point when logging sub-second delay
	      values.

       export_environment (see 'postconf -d' output)
	      The list of environment variables that a Postfix process will export to non-Postfix
	      processes.

       ipc_timeout(3600s)
	      The  time limit for sending or receiving information over an internal communication
	      channel.

       mail_owner (postfix)
	      The UNIX system account that owns the Postfix queue and most  Postfix  daemon  pro-
	      cesses.

       max_idle(100s)
	      The  maximum amount of time that an idle Postfix daemon process waits for an incom-
	      ing connection before terminating voluntarily.

       max_use(100)
	      The maximal number of incoming connections that a Postfix daemon process will  ser-
	      vice 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.

       queue_directory (see 'postconf -d' output)
	      The location of the Postfix top-level queue directory.

       recipient_delimiter (empty)
	      The separator between user names and address extensions (user+foo).

       syslog_facility (mail)
	      The syslog facility of Postfix logging.

       syslog_name (see 'postconf -d' output)
	      The  mail  system  name that is prepended to the process name in syslog records, so
	      that "smtpd" becomes, for example, "postfix/smtpd".

SEE ALSO
       qmgr(8), queue manager
       bounce(8), delivery status reports
       postconf(5), configuration parameters
       master(5), generic daemon options
       master(8), process manager
       syslogd(8), system logging

LICENSE
       The Secure Mailer license must be distributed with this software.

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

										   PIPE(8postfix)


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