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.

       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
       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.



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LOCAL(8)                                                 LOCAL(8)


       In order to stop mail forwarding loops early, the software
       adds a 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_user).

       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
       each message, prepends a  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
       a Delivered-To: header with the envelope recipient 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.



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LOCAL(8)                                                 LOCAL(8)


       Assistance  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>.

       When mail is delivered on behalf of a user, the HOME, LOG-
       NAME, and SHELL environment variables are set accordingly.
       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  a  Delivered-To:
       header  with  the  recipient  envelope address, prepends a
       Return-Path: header with the sender envelope address,  and
       appends an 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  a  Delivered-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 destination is a  regu-
       lar 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
       a  Delivered-To:  header  with  the   envelope   recipient
       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



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LOCAL(8)                                                 LOCAL(8)


       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  a  `Delivered-To:
       name+foo' header line.

DELIVERY RIGHTS
       Deliveries  to  external  files  and external commands are
       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.

       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 con-
              tains   no   shell   built-in   commands   or  meta



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LOCAL(8)                                                 LOCAL(8)


              characters.

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

       recipient_delimiter
              Separator between username and address extension.

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 can be any destination that  is
              valid in an alias file.

       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).

       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.

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.





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LOCAL(8)                                                 LOCAL(8)


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.

       default_privs
              Default rights for delivery  to  external  file  or
              command.

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.




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LOCAL(8)                                                 LOCAL(8)


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




















































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