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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 master(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 separated list of ~/.forward like files
       through the forward_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 sub-
       ject to interpolation of $user (recipient username),  $home  (recipient	home  directory),
       $shell  (recipient  shell), $recipient (complete recipient address), $extension (recipient
       address extension), $domain (recipient domain), local (entire recipient address localpart)
       and  $recipient_delimiter.  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_expansion_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 precise
       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 unreasonable 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 dupli-
       cate deliveries. The duplicate_filter_limit configuration parameter limits the  number  of
       remembered recipients.

MAIL FORWARDING
       For the sake of reliability, forwarded mail is re-submitted as a new message, so that each
       recipient has a separate 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_directory config-
       uration parameter. Specify a name ending in / for qmail-compatible maildir delivery.

       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_com-
       mand  configuration  parameter.	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 mas-
       ter.cf file.  The mailbox_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 daemon prepends a "From sender
       time_stamp" envelope header to 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  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  com-
       mands.  The  default  setting  (alias,  forward) forbids command destinations in :include:
       files.

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

       A limited amount of command output (standard output and standard error)	is  captured  for
       inclusion  with	non-delivery 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 conventions defined in <sysexits.h>.

       A limited amount of message context is exported via environment variables. Characters that
       may have special meaning to the shell are replaced by underscores.  The list of acceptable
       characters is specified with the command_expansion_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 @ charac-
	      ter).

       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" envelope header to each message,
       prepends an optional Delivered-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  delivery  format  depends  on the destination filename syntax.  The default is to use
       UNIX-style mailbox format.  Specify a name ending in / for qmail-compatible maildir deliv-
       ery.

       The  allow_mail_to_files configuration parameter restricts delivery to external files. The
       default setting (alias, forward) forbids file destinations in :include: files.

       In the case of UNIX-style mailbox delivery, the	local  daemon  prepends  a  "From  sender
       time_stamp"  envelope  header  to  each message, prepends an optional 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 regular file, it is locked for	exclusive  access
       while delivery is in progress. In case of problems, an attempt is made to truncate a regu-
       lar file to its original length.

       In the case of maildir delivery, the  local  daemon  prepends  an  optional  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 alias name, to the destinations  listed  in  ~name/.forward+foo  or  in
       ~name/.forward,	to  the  mailbox owned by the user name, or it is sent back as undeliver-
       able.

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

DELIVERY RIGHTS
       Deliveries to external files and external commands are made with the rights of the receiv-
       ing  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).  Corrupted 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 trouble.

BUGS
       For security reasons, the message delivery status of  external  commands  or  of  external
       files  is  never  checkpointed  to file. As a result, the program may occasionally deliver
       more than once to a command or external file. Better 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- companion 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 pro-
	      cesses.

       forward_path
	      Search list for .forward files.  The names are subject 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 contains no shell
	      built-in commands or meta characters.

       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 com-
	      mand  or	file. Specify zero or more of: command, file, forward. Turning off Deliv-
	      ered-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 accessible  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 overrides 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 expansion.

       mail_spool_directory
	      Directory with UNIX-style mailboxes. The	default  pathname  is  system  dependent.
	      Specify a path ending in / for maildir-style delivery.

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

       mailbox_command_maps
	      Lookup tables with per-recipient external commands to  use  for  mailbox	delivery.
	      Behavior is as with mailbox_command.

       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 overrides all other
	      configuration parameters that control mailbox delivery, including luser_relay.

Locking controls
       deliver_lock_attempts
	      Limit  the number of attempts to acquire an exclusive 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 delivery.  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.

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. Ille-
	      gal 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

											 LOCAL(8)
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