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LOCAL(8)                                                 LOCAL(8)


NAME
       local - Postfix local mail delivery

SYNOPSIS
       local [generic Postfix daemon options]

DESCRIPTION
       The  local  daemon  processes  delivery  requests from the
       Postfix queue manager to deliver mail to local recipients.
       Each  delivery  request  specifies  a queue file, a sender
       address, a domain or host to deliver to, and one  or  more
       recipients.   This program expects to be run from the mas-
       ter(8) process manager.

       The local 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.

SYSTEM-WIDE AND USER-LEVEL ALIASING
       The system adminstrator can set up one or more system-wide
       sendmail-style  alias databases.  Users can have sendmail-
       style ~/.forward files.  Mail for name is delivered to the
       alias  name,  to  destinations  in  ~name/.forward, to the
       mailbox owned by the user name, or  it  is  sent  back  as
       undeliverable.

       The  system  administrator can specify a comma/space sepa-
       rated list of  ~/.forward  like  files  through  the  for-
       ward_path  configuration  parameter.  Upon  delivery,  the
       local delivery agent tries each pathname in the list until
       a file is found.  The forward_path parameter is subject to
       interpolation of $user (recipient username), $home (recip-
       ient home directory), $shell (recipient shell), $recipient
       (complete  recipient   address),   $extension   (recipient
       address  extension),  $domain  (recipient  domain),  local
       (entire recipient address localpart) and $recipient_delim-
       iter.  The  forms  ${name?value}  and ${name:value} expand
       conditionally to value when $name  is  (is  not)  defined.
       Characters  that  may have special meaning to the shell or
       file system are replaced  by  underscores.   The  list  of
       acceptable characters is specified with the forward_expan-
       sion_filter configuration parameter.

       An alias or ~/.forward file may list  any  combination  of
       external   commands,  destination  file  names,  :include:
       directives, or mail addresses.  See aliases(5) for a  pre-
       cise  description. Each line in a user's .forward file has
       the same syntax as the right-hand part of an alias.

       When an address is  found  in  its  own  alias  expansion,
       delivery  is  made  to  the  user  instead. When a user is
       listed in the user's own ~/.forward file, delivery is made



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LOCAL(8)                                                 LOCAL(8)


       to  the  user's mailbox instead.  An empty ~/.forward file
       means do not forward mail.

       In order to prevent the mail system from using  up  unrea-
       sonable   amounts  of  memory,  input  records  read  from
       :include: or from ~/.forward  files  are  broken  up  into
       chunks of length line_length_limit.

       While  expanding aliases, ~/.forward files, and so on, the
       program attempts to avoid duplicate deliveries. The dupli-
       cate_filter_limit  configuration parameter limits the num-
       ber of remembered recipients.

MAIL FORWARDING
       For the sake of reliability, forwarded mail is  re-submit-
       ted  as  a new message, so that each recipient has a sepa-
       rate on-file delivery status record.

       In order to stop mail forwarding loops early, the software
       adds  an  optional  Delivered-To: header with the envelope
       recipient address. If mail arrives for a recipient that is
       already  listed  in a Delivered-To: header, the message is
       bounced.

MAILBOX DELIVERY
       The default per-user mailbox is a file in  the  UNIX  mail
       spool  directory (/var/mail/user or /var/spool/mail/user);
       the location can be specified with  the  mail_spool_direc-
       tory configuration parameter.

       Alternatively,  the  per-user mailbox can be a file in the
       user's home  directory  with  a  name  specified  via  the
       home_mailbox  configuration  parameter. Specify a relative
       path name. Specify a name ending in / for qmail-compatible
       maildir delivery.

       Mailbox  delivery  can be delegated to an external command
       specified with the mailbox_command  configuration  parame-
       ter.  The  command  executes  with  the  privileges of the
       recipient user (exception: in case of  delivery  as  root,
       the    command    executes    with   the   privileges   of
       default_privs).

       Mailbox delivery can be delegated to  alternative  message
       transports  specified  in  the  master.cf file.  The mail-
       box_transport configuration parameter specifies a  message
       transport  that  is  to  be used for all local recipients,
       regardless of whether they are found in  the  UNIX  passwd
       database.   The  fallback_transport  parameter specifies a
       message transport for recipients that are not found in the
       UNIX passwd database.

       In the case of UNIX-style mailbox delivery, the local dae-
       mon prepends a "From sender time_stamp" envelope header to



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LOCAL(8)                                                 LOCAL(8)


       each  message,  prepends  an optional Delivered-To: header
       with the envelope recipient address,  prepends  a  Return-
       Path:  header with the envelope sender address, prepends a
       > character to lines beginning with "From ",  and  appends
       an empty line.  The mailbox is locked for exclusive access
       while delivery is in progress. In  case  of  problems,  an
       attempt  is  made  to truncate the mailbox to its original
       length.

       In the case of maildir delivery, the local daemon prepends
       an optional Delivered-To: header with the envelope recipi-
       ent address and prepends a Return-Path:  header  with  the
       envelope sender address.

EXTERNAL COMMAND DELIVERY
       The    allow_mail_to_commands    configuration   parameter
       restricts delivery to external commands. The default  set-
       ting  (alias,  forward)  forbids  command  destinations in
       :include: files.

       The command is executed directly  where  possible.  Assis-
       tance  by the shell (/bin/sh on UNIX systems) is used only
       when the command contains shell magic characters, or  when
       the command invokes a shell built-in command.

       A  limited  amount  of command output (standard output and
       standard error) is captured for inclusion with  non-deliv-
       ery  status  reports.  A command is forcibly terminated if
       it does not complete  within  command_time_limit  seconds.
       Command  exit status codes are expected to follow the con-
       ventions defined in <sysexits.h>.

       A limited amount of message context is exported via  envi-
       ronment  variables. Characters that may have special mean-
       ing to the shell are replaced by underscores.  The list of
       acceptable characters is specified with the command_expan-
       sion_filter configuration parameter.

       SHELL  The recipient user's login shell.

       HOME   The recipient user's home directory.

       USER   The bare recipient name.

       EXTENSION
              The optional recipient address extension.

       DOMAIN The recipient address domain part.

       LOGNAME
              The bare recipient name.

       LOCAL  The entire recipient address localpart (text to the
              left of the rightmost @ character).



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LOCAL(8)                                                 LOCAL(8)


       RECIPIENT
              The entire recipient address.

       The PATH environment variable is always reset to a system-
       dependent default path, and the TZ (time zone) environment
       variable is always passed on without change.

       The current working directory is the mail queue directory.

       The local daemon prepends a "From sender time_stamp" enve-
       lope  header  to each message, prepends an optional Deliv-
       ered-To:  header  with  the  recipient  envelope  address,
       prepends  a  Return-Path:  header with the sender envelope
       address, and appends no empty line.

EXTERNAL FILE DELIVERY
       The allow_mail_to_files configuration parameter  restricts
       delivery  to  external  files. The default setting (alias,
       forward) forbids file  destinations  in  :include:  files.
       Specify  a  pathname  ending  in  /  for  qmail-compatible
       maildir delivery.

       The local daemon prepends a "From sender time_stamp" enve-
       lope  header  to each message, prepends an optional Deliv-
       ered-To:  header  with  the  recipient  envelope  address,
       prepends  a  >  character to lines beginning with "From ",
       and appends an empty line.  The envelope sender address is
       available  in  the Return-Path: header.  When the destina-
       tion is a regular file, it is locked for exclusive  access
       while  delivery  is  in  progress. In case of problems, an
       attempt is made to truncate a regular file to its original
       length.

       In the case of maildir delivery, the local daemon prepends
       an optional Delivered-To: header with the envelope recipi-
       ent  address.  The envelope sender address is available in
       the Return-Path: header.

ADDRESS EXTENSION
       The optional recipient_delimiter  configuration  parameter
       specifies  how  to  separate address extensions from local
       recipient names.

       For example, with  "recipient_delimiter  =  +",  mail  for
       name+foo  is  delivered  to  the  alias name+foo or to the
       alias name, to  the  destinations  listed  in  ~name/.for-
       ward+foo or in ~name/.forward, to the mailbox owned by the
       user name, or it is sent back as undeliverable.

       In all cases the local daemon prepends an optional `Deliv-
       ered-To: name+foo' header line.

DELIVERY RIGHTS
       Deliveries  to  external  files  and external commands are



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LOCAL(8)                                                 LOCAL(8)


       made with the rights of the receiving user on whose behalf
       the  delivery  is made.  In the absence of a user context,
       the local daemon uses the owner rights  of  the  :include:
       file or alias database.  When those files are owned by the
       superuser, delivery is made with the rights specified with
       the default_privs configuration parameter.

STANDARDS
       RFC 822 (ARPA Internet Text Messages)

DIAGNOSTICS
       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 afterwards.

       Depending  on the setting of the notify_classes parameter,
       the postmaster is notified of bounces and of  other  trou-
       ble.

BUGS
       For  security  reasons,  the  message  delivery  status of
       external commands or of external  files  is  never  check-
       pointed to file. As a result, the program may occasionally
       deliver more than once to a command or external file. Bet-
       ter safe than sorry.

       Mutually-recursive  aliases  or  ~/.forward  files are not
       detected early.  The resulting  mail  forwarding  loop  is
       broken by the use of the Delivered-To: message header.

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
       alias_maps
              List of alias databases.

       expand_owner_alias
              When delivering to an alias that has an owner- com-
              panion  alias,  set  the envelope sender address to
              the right-hand side of  the  owner  alias,  instead
              using of the left-hand side address.

       forward_path
              Search list for .forward files.  The names are sub-
              ject to $name expansion.

       local_command_shell
              Shell to use for external  command  execution  (for
              example,  /some/where/smrsh  -c).   When a shell is
              specified, it is  invoked  even  when  the  command



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LOCAL(8)                                                 LOCAL(8)


              contains no shell built-in commands or meta charac-
              ters.

       owner_request_special
              Give special treatment to owner-xxx and xxx-request
              addresses.

       prepend_delivered_header
              Prepend   an  optional  Delivered-To:  header  upon
              external forwarding, delivery to command  or  file.
              Specify  zero  or  more of: command, file, forward.
              Turning off Delivered-To: when forwarding  mail  is
              not recommended.

       recipient_delimiter
              Separator between username and address extension.

       test_home_directory
              Require that a recipient's home directory is acces-
              sible by the recipient before attempting  delivery.

Mailbox delivery
       fallback_transport
              Message transport for recipients that are not found
              in the UNIX passwd database.  This parameter  over-
              rides luser_relay.

       home_mailbox
              Pathname  of  a  mailbox  relative to a user's home
              directory.  Specify a path ending in / for maildir-
              style delivery.

       luser_relay
              Destination  (@domain  or address) for non-existent
              users.  The address is subjected  to  $name  expan-
              sion.

       mail_spool_directory
              Directory  with  UNIX-style  mailboxes. The default
              pathname is system dependent.

       mailbox_command
              External command to use for mailbox  delivery.  The
              command  executes  with  the  recipient  privileges
              (exception: root). The string is subject  to  $name
              expansions.

       mailbox_transport
              Message  transport  to  use for mailbox delivery to
              all local recipients, whether or not they are found
              in  the UNIX passwd database.  This parameter over-
              rides all other configuration parameters that  con-
              trol mailbox delivery, including luser_relay.




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LOCAL(8)                                                 LOCAL(8)


Locking controls
       deliver_lock_attempts
              Limit  the  number of attempts to acquire an exclu-
              sive lock on a mailbox or external file.

       deliver_lock_delay
              Time in  seconds  between  successive  attempts  to
              acquire an exclusive lock.

       stale_lock_time
              Limit the time after which a stale lock is removed.

Resource controls
       command_time_limit
              Limit the amount of time for delivery  to  external
              command.

       duplicate_filter_limit
              Limit  the size of the duplicate filter for results
              from alias etc. expansion.

       line_length_limit
              Limit the amount of memory used  for  processing  a
              partial input line.

       local_destination_concurrency_limit
              Limit the number of parallel deliveries to the same
              user.   The  default  limit  is  taken   from   the
              default_destination_concurrency_limit parameter.

       local_destination_recipient_limit
              Limit  the  number of recipients per message deliv-
              ery.   The  default  limit  is   taken   from   the
              default_destination_recipient_limit parameter.

Security controls
       allow_mail_to_commands
              Restrict  the  usage  of  mail delivery to external
              command.

       allow_mail_to_files
              Restrict the usage of  mail  delivery  to  external
              file.

       command_expansion_filter
              What  characters  are  allowed  to  appear in $name
              expansions of mailbox_command.  Illegal  characters
              are replaced by underscores.

       default_privs
              Default  rights  for  delivery  to external file or
              command.





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LOCAL(8)                                                 LOCAL(8)


       forward_expansion_filter
              What characters are  allowed  to  appear  in  $name
              expansions  of forward_path. Illegal characters are
              replaced by underscores.

HISTORY
       The Delivered-To: header appears in the  qmail  system  by
       Daniel Bernstein.

       The  maildir  structure  appears  in  the  qmail system by
       Daniel Bernstein.

SEE ALSO
       aliases(5) format of alias database
       bounce(8) non-delivery status reports
       postalias(1) create/update alias database
       syslogd(8) system logging
       qmgr(8) queue manager

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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