Postfix manual - local(8)

    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  status
           reports  are  sent  to the bounce(8), defer(8) or trace(8)
           daemon as appropriate.

    SYSTEM-WIDE AND USER-LEVEL ALIASING
           The system administrator can set up one  or  more  system-
           wide sendmail-style alias databases.  Users can have send-
           mail-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
           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 final enve-
           lope recipient address. If mail arrives  for  a  recipient
           that is already listed in a Delivered-To: header, the mes-
           sage 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. 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_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
           each message, prepends an X-Original-To: header  with  the
           recipient   address  as  given  to  Postfix,  prepends  an
           optional Delivered-To:  header  with  the  final  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 final envelope
           recipient address, prepends an X-Original-To: header  with
           the  recipient address as given to Postfix, 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).

           RECIPIENT
                  The entire recipient address.

           SENDER The entire sender address.

           The PATH environment variable is always reset to a system-
           dependent  default  path,  and environment variables whose
           names are blessed by the export_environment  configuration
           parameter are exported unchanged.

           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 X-Original-To:
           header with the recipient address  as  given  to  Postfix,
           prepends  an  optional Delivered-To: header with the final
           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
           delivery.

           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 dae-
           mon prepends a "From sender time_stamp" envelope header to
           each  message,  prepends an X-Original-To: header with the
           recipient  address  as  given  to  Postfix,  prepends   an
           optional  Delivered-To:  header  with  the final recipient
           envelope address, prepends a > character to  lines  begin-
           ning  with  "From ", and appends an empty line.  The enve-
           lope 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 reg-
           ular file to its original length.

           In the case of maildir delivery, the local daemon prepends
           an  optional  Delivered-To: header with the final envelope
           recipient address, and prepends an  X-Original-To:  header
           with the recipient address as given to Postfix.  The enve-
           lope 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: header line with the final recipient address.

    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
           Changes  to  main.cf  are  picked  up  automatically,   as
           local(8)  processes run for only a limited amount of time.
           Use the command "postfix reload" to speed up a change.

           The text below provides  only  a  parameter  summary.  See
           postconf(5) for more details including examples.

    COMPATIBILITY CONTROLS
           biff (yes)
                  Whether or not to use the local biff service.

           expand_owner_alias (no)
                  When delivering to an alias "aliasname" that has an
                  "owner-aliasname" companion alias, set the envelope
                  sender  address  to  the  expansion  of the "owner-
                  aliasname" alias.

           owner_request_special (yes)
                  Give special treatment to owner-listname and  list-
                  name-request  address  localparts: don't split such
                  addresses when the recipient_delimiter  is  set  to
                  "-".

           sun_mailtool_compatibility (no)
                  Obsolete SUN mailtool compatibility feature.

    DELIVERY METHOD CONTROLS
           The  precedence  of local(8) delivery methods from high to
           low is: aliases, .forward files, mailbox_transport,  mail-
           box_command_maps,      mailbox_command,      home_mailbox,
           mail_spool_directory, fallback_transport and  luser_relay.

           alias_maps (see 'postconf -d' output)
                  The  alias  databases  that  are  used for local(8)
                  delivery.

           forward_path (see 'postconf -d' output)
                  The local(8) delivery agent search list for finding
                  a  .forward file with user-specified delivery meth-
                  ods.

           mailbox_transport (empty)
                  Optional  message  delivery  transport   that   the
                  local(8)  delivery  agent  should  use  for mailbox
                  delivery to all local recipients,  whether  or  not
                  they are found in the UNIX passwd database.

           mailbox_command_maps (empty)
                  Optional  lookup tables with per-recipient external
                  commands to use for local(8) mailbox delivery.

           mailbox_command (empty)
                  Optional external command that the local(8)  deliv-
                  ery agent should use for mailbox delivery.

           home_mailbox (empty)
                  Optional  pathname  of a mailbox file relative to a
                  local(8) user's home directory.

           mail_spool_directory (see 'postconf -d' output)
                  The directory where local(8)  UNIX-style  mailboxes
                  are kept.

           fallback_transport (empty)
                  Optional   message   delivery  transport  that  the
                  local(8) delivery agent should use for  names  that
                  are  not found in the aliases(5) database or in the
                  UNIX passwd database.

           luser_relay (empty)
                  Optional catch-all destination for unknown local(8)
                  recipients.

    MAILBOX LOCKING CONTROLS
           deliver_lock_attempts (20)
                  The maximal number of attempts to acquire an exclu-
                  sive lock on a mailbox file or bounce(8) logfile.

           deliver_lock_delay (1s)
                  The time between attempts to acquire  an  exclusive
                  lock on a mailbox file or bounce(8) logfile.

           stale_lock_time (500s)
                  The  time  after  which  a  stale exclusive mailbox
                  lockfile is removed.

           mailbox_delivery_lock (see 'postconf -d' output)
                  How to lock a UNIX-style  local(8)  mailbox  before
                  attempting delivery.

    RESOURCE AND RATE CONTROLS
           command_time_limit (1000s)
                  Time limit for delivery to external commands.

           duplicate_filter_limit (1000)
                  The  maximal  number of addresses remembered by the
                  address duplicate filter  for  aliases(5)  or  vir-
                  tual(5) alias expansion, or for showq(8) queue dis-
                  plays.

           local_destination_concurrency_limit (2)
                  The maximal number of parallel deliveries  via  the
                  local mail delivery transport to the same recipient
                  (when "local_destination_recipient_limit =  1")  or
                  the  maximal  number  of parallel deliveries to the
                  same local domain (when  "local_destination_recipi-
                  ent_limit > 1").

           local_destination_recipient_limit (1)
                  The maximal number of recipients per message deliv-
                  ery via the local mail delivery transport.

           mailbox_size_limit (51200000)
                  The maximal size of any local(8) individual mailbox
                  or maildir file, or zero (no limit).

    SECURITY CONTROLS
           allow_mail_to_commands (alias, forward)
                  Restrict  local(8)  mail  delivery to external com-
                  mands.

           allow_mail_to_files (alias, forward)
                  Restrict local(8) mail delivery to external  files.

           command_expansion_filter (see 'postconf -d' output)
                  Restrict  the characters that the local(8) delivery
                  agent allows in $name expansions  of  $mailbox_com-
                  mand.

           default_privs (nobody)
                  The  default  rights  used by the local(8) delivery
                  agent for delivery to external file or command.

           forward_expansion_filter (see 'postconf -d' output)
                  Restrict the characters that the local(8)  delivery
                  agent  allows in $name expansions of $forward_path.

    MISCELLANEOUS CONTROLS
           config_directory (see 'postconf -d' output)
                  The default location of  the  Postfix  main.cf  and
                  master.cf configuration files.

           daemon_timeout (18000s)
                  How  much time a Postfix daemon process may take to
                  handle a request  before  it  is  terminated  by  a
                  built-in watchdog timer.

           export_environment (see 'postconf -d' output)
                  The  list  of  environment variables that a Postfix
                  process will export to non-Postfix processes.

           ipc_timeout (3600s)
                  The time limit for sending or receiving information
                  over an internal communication channel.

           local_command_shell (empty)
                  Optional  shell  program  for  local(8) delivery to
                  non-Postfix command.

           max_idle (100s)
                  The maximum amount of time  that  an  idle  Postfix
                  daemon  process  waits for the next service request
                  before exiting.

           max_use (100)
                  The maximal number of connection requests before  a
                  Postfix daemon process terminates.

           prepend_delivered_header (command, file, forward)
                  The  message  delivery  contexts  where the Postfix
                  local(8) delivery agent  prepends  a  Delivered-To:
                  message header.

           process_id (read-only)
                  The  process ID of a Postfix command or daemon pro-
                  cess.

           process_name (read-only)
                  The process name of a  Postfix  command  or  daemon
                  process.

           propagate_unmatched_extensions (canonical, virtual)
                  What  address  lookup tables copy an address exten-
                  sion from the lookup key to the lookup result.

           queue_directory (see 'postconf -d' output)
                  The location of the Postfix top-level queue  direc-
                  tory.

           recipient_delimiter (empty)
                  The separator between user names and address exten-
                  sions (user+foo).

           require_home_directory (no)
                  Whether or not a local(8) recipient's  home  direc-
                  tory  must exist before mail delivery is attempted.

           syslog_facility (mail)
                  The syslog facility of Postfix logging.

           syslog_name (postfix)
                  The mail system name that is prepended to the  pro-
                  cess  name  in  syslog  records,  so  that  "smtpd"
                  becomes, for example, "postfix/smtpd".

    FILES
           The following are examples; details differ between systems.
           $HOME/.forward, per-user aliasing
           /etc/aliases, sytem-wide alias database
           /var/spool/mail, system mailboxes

    SEE ALSO
           qmgr(8), queue manager
           bounce(8), delivery status reports
           newaliases(1), create/update alias database
           postalias(1), create/update alias database
           aliases(5), format of alias database
           postconf(5), configuration parameters
           syslogd(8), system logging

    LICENSE
           The Secure Mailer license must be  distributed  with  this
           software.

    HISTORY
           The Delivered-To: message header appears in the qmail sys-
           tem by Daniel Bernstein.

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

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

                                                             LOCAL(8)