Provided by: postfix_3.4.5-1ubuntu1_amd64 bug

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
       executed.

       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
       Postfix 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
                     recipient      address.      Note:     for     this     to     work,     the
                     transport_destination_recipient_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
                     message already contains a Delivered-To:  header  with  the  same  recipient
                     address,  then  the  message  is  returned  as  undeliverable.  The  address
                     comparison 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_destination_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
                     information 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
                     example, 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
              username.   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
              characters by a shell command interpreter.

              Specify  "{"  and "}" around command arguments that contain whitespace (Postfix 3.0
              and later). Whitespace after the opening "{" and before the closing "}" is ignored.

              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 the deprecated form $(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
                     example, with an address user+foo@domain the extension is foo.

                     A command-line argument that contains  ${extension}  expands  into  as  many
                     command-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.

              ${queue_id}
                     This macro expands to the queue id.

                     This feature is available as of Postfix 2.11.

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

                     A  command-line  argument  that  contains  ${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.

              ${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
                     Postfix 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
                     example, 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  logged,  and
       reported  in a 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 version 2.3 and later).

       After successful delivery (zero exit status) a limited amount of command output is logged,
       and reported in "success" delivery status notifications (Postfix  3.0  and  later).   This
       command output is not examined for the presence of an enhanced status code.

       Problems  and  transactions  are  logged  to syslogd(8) or postlogd(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
       mechanisms, and 2) to execute external commands as the specified  user.  It  is  therefore
       security 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
       including examples.

RESOURCE AND RATE CONTROLS

       In the text below, transport is the first field in a master.cf entry.

       transport_time_limit ($command_time_limit)
              A  transport-specific  override  for  the command_time_limit parameter value, where
              transport is the master.cf name of the message delivery transport.

       Implemented in the qmgr(8) daemon:

       transport_destination_concurrency_limit ($default_destination_concurrency_limit)
              A  transport-specific  override   for   the   default_destination_concurrency_limit
              parameter  value,  where  transport  is  the master.cf name of the message delivery
              transport.

       transport_destination_recipient_limit ($default_destination_recipient_limit)
              A transport-specific override for the default_destination_recipient_limit parameter
              value, where transport is the master.cf name of the message delivery transport.

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
              processes.

       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.

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

       recipient_delimiter (empty)
              The set of characters that can separate a user name from  its  extension  (example:
              user+foo), or a .forward file name from its extension (example: .forward+foo).

       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".

       Available in Postfix version 3.0 and later:

       pipe_delivery_status_filter ($default_delivery_status_filter)
              Optional filter for the pipe(8) delivery agent to change the delivery  status  code
              or explanatory text of successful or unsuccessful deliveries.

       Available in Postfix version 3.3 and later:

       enable_original_recipient (yes)
              Enable  support for the original recipient address after an address is rewritten to
              a different address (for example with aliasing or with canonical mapping).

       service_name (read-only)
              The master.cf service name of a Postfix daemon process.

SEE ALSO

       qmgr(8), queue manager
       bounce(8), delivery status reports
       postconf(5), configuration parameters
       master(5), generic daemon options
       master(8), process manager
       postlogd(8), Postfix logging
       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

       Wietse Venema
       Google, Inc.
       111 8th Avenue
       New York, NY 10011, USA

                                                                                   PIPE(8postfix)