    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).

                                                                    3

    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.

           biff   Enable or disable notification of new mail via  the
                  comsat network service.

           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.

           export_environment
                  List of names of environment parameters that can be
                  exported to non-Postfix processes.

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    LOCAL(8)                                                 LOCAL(8)

           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 con-
                  tains  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.

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

    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

                                                                    6

    LOCAL(8)                                                 LOCAL(8)

                  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.

    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.

           mailbox_delivery_lock
                  What file locking method(s) to use when  delivering
                  to  a  UNIX-style  mailbox.  The default setting is
                  system dependent.  For a  list  of  available  file
                  locking methods, use the postconf -l command.

    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.

           mailbox_size_limit
                  Limit the size of a mailbox  etc.  file  (any  file
                  that  is written to upon delivery).  Set to zero to
                  disable the limit.

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    LOCAL(8)                                                 LOCAL(8)

    Security controls
           allow_mail_to_commands
                  Restrict the usage of  mail  delivery  to  external
                  command.   Specify zero or more of: alias, forward,
                  include.

           allow_mail_to_files
                  Restrict the usage of  mail  delivery  to  external
                  file.   Specify  zero  or  more of: alias, forward,
                  include.

           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.

           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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