PIPE(8)                                                   PIPE(8)


NAME
       pipe - Postfix delivery to external command

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

DESCRIPTION
       The  pipe daemon processes requests from the Postfix queue
       manager to deliver messages  to  external  commands.  Each
       delivery request specifies a queue file, a sender address,
       a domain or host to deliver to, and one  or  more  recipi-
       ents.   This  program expects to be run from the master(8)
       process manager.

       The pipe 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  problem
       reports  are  sent  to the bounce(8) or defer(8) daemon as
       appropriate.

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:

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

              F      Prepend  a "From sender time_stamp" envelope
                     header to  the  message  content.   This  is
                     expected by, for example, UUCP software. The
                     F flag also  causes  an  empty  line  to  be
                     appended to the message.

              >      Prepend  >  to  lines starting with "From ".
                     This expected by, for  example,  UUCP  soft-
                     ware.

       user=username (required)
              The external command is executed with the rights of
              the specified username.  The  software  refuses  to
              execute  commands with root privileges, or with the
              privileges of the mail system owner.

       argv=command... (required)
              The command to be executed. This must be  specified
              as the last command attribute.  The command is exe-
              cuted  directly,  i.e.  without  interpretation  of
              shell  meta  characters  by  a shell command inter-
              preter.

              In the command argument vector,  all  instances  of
              the  macros  ${sender}, ${nexthop} and ${recipient}



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PIPE(8)                                                   PIPE(8)


              are replaced by the corresponding information  from
              the Postfix queue manager delivery request.

              In  particular,  a  command-line argument that con-
              tains ${recipient} will be expanded  into  as  many
              command-line arguments as there are recipients.

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

DIAGNOSTICS
       Command  exit status codes are expected to follow the con-
       ventions defined in <sysexits.h>.

       Problems and transactions are logged to syslogd(8).   Cor-
       rupted  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  exe-
       cute external commands as the specified user. It is there-
       fore security sensitive.

CONFIGURATION PARAMETERS
       The following main.cf parameters are  especially  relevant
       to  this  program. See the Postfix main.cf file for syntax
       details and for default values.  Use  the  postfix  reload
       command after a configuration change.

Miscellaneous
       mail_owner
              The  process  privileges  used while not running an
              external command.

Resource controls
       In the text below, transport is the first field in a  mas-
       ter.cf entry.

       transport_destination_concurrency_limit
              Limit the number of parallel deliveries to the same
              destination, for delivery via the named  transport.
              The  default limit is taken from the default_desti-
              nation_concurrency_limit parameter.  The  limit  is
              enforced by the Postfix queue manager.

       transport_destination_recipient_limit
              Limit  the  number of recipients per message deliv-
              ery, for delivery  via  the  named  transport.  The
              default  limit  is  taken from the default_destina-
              tion_recipient_limit  parameter.   The   limit   is
              enforced by the Postfix queue manager.




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PIPE(8)                                                   PIPE(8)


       transport_time_limit
              Limit  the  time  for delivery to external command,
              for delivery via the named transport.  The  default
              limit  is taken from the command_time_limit parame-
              ter.  The limit is enforced by  the  Postfix  queue
              manager.

SEE ALSO
       bounce(8) non-delivery status reports
       master(8) process manager
       qmgr(8) queue 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



































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