Postfix manual - local(8)

    LOCAL(8)                                                              LOCAL(8)

    NAME
           local - Postfix local mail delivery

    SYNOPSIS
           local [generic Postfix daemon options]

    DESCRIPTION
           The  local(8)  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(8) daemon updates queue files and marks  recipi-
           ents  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.

    CASE FOLDING
           All delivery decisions are made using the  bare  recipient
           name  (i.e.  the address localpart), folded to lower case.
           See also under ADDRESS EXTENSION below for  a  few  excep-
           tions.

    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.

           Delivery via ~/.forward files is done with the  privileges
           of  the  recipient.   Thus,  ~/.forward like files must be
           readable by the  recipient,  and  their  parent  directory
           needs to have "execute" permission for the recipient.

           The  forward_path parameter is subject to interpolation of
           $user (recipient username), $home (recipient  home  direc-
           tory),  $shell  (recipient  shell),  $recipient  (complete
           recipient address), $extension (recipient  address  exten-
           sion),  $domain (recipient domain), $local (entire recipi-
           ent 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  charac-
           ters  is  specified with the forward_expansion_filter con-
           figuration 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_maps and mailbox_com-
           mand configuration parameters. The command  executes  with
           the  privileges  of  the  recipient user (exceptions: sec-
           ondary groups are not enabled;  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_maps  and  mailbox_transport   configuration
           parameters  specify  an optional message transport that is
           to be used for all local recipients, regardless of whether
           they  are  found  in  the UNIX passwd database.  The fall-
           back_transport_maps  and   fallback_transport   parameters
           specify  an optional message transport for recipients that
           are not found in the aliases(5) or UNIX passwd database.

           In the case of UNIX-style mailbox delivery,  the  local(8)
           daemon 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.

           Optionally,  the  process  working directory is changed to
           the path specified with command_execution_directory (Post-
           fix  2.2  and  later).  Failure to change directory causes
           mail to be deferred.

           The command_execution_directory parameter value is subject
           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 $recipi-
           ent_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 execu-
           tion_directory_expansion_filter configuration parameter.

           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>.   Exit status 0 means
           normal successful completion.

           Postfix version  2.3  and  later  support  RFC  3463-style
           enhanced  status  codes.   If  a command terminates with a
           non-zero exit status, and the command output  begins  with
           an enhanced status code, this status code takes precedence
           over the non-zero exit status.

           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).

           ORIGINAL_RECIPIENT
                  The  entire  recipient  address, before any address
                  rewriting or aliasing (Postfix 2.5 and later).

           RECIPIENT
                  The entire recipient address.

           SENDER The entire sender address.

           Additional remote client information is made available via
           the following environment variables:

           CLIENT_ADDRESS
                  Remote  client  network  address.  Available  as of
                  Postfix 2.2.

           CLIENT_HELO
                  Remote client EHLO command parameter. Available  as
                  of Postfix 2.2.

           CLIENT_HOSTNAME
                  Remote  client  hostname.  Available  as of Postfix
                  2.2.

           CLIENT_PROTOCOL
                  Remote client protocol.  Available  as  of  Postfix
                  2.2.

           SASL_METHOD
                  SASL  authentication method specified in the remote
                  client AUTH command. Available as of Postfix 2.2.

           SASL_SENDER
                  SASL sender address specified in the remote  client
                  MAIL FROM command. Available as of Postfix 2.2.

           SASL_USERNAME
                  SASL  username  specified in the remote client AUTH
                  command.  Available as of Postfix 2.2.

           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(8) daemon 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 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(8)
           daemon 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.

    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(8) 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)
           RFC 3463 (Enhanced status codes)

    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.

    SECURITY
           The local(8) delivery agent needs a dual personality 1) to
           access the private Postfix queue and IPC mechanisms, 2) to
           impersonate  the recipient and deliver to recipient-speci-
           fied files or commands. It is  therefore  security  sensi-
           tive.

           The  local(8)  delivery agent disallows regular expression
           substitution of $1 etc. in alias_maps, because that  would
           open a security hole.

           The  local(8) delivery agent will silently ignore requests
           to use the proxymap(8) server within  alias_maps.  Instead
           it  will  open the table directly.  Before Postfix version
           2.2, the local(8) delivery agent  will  terminate  with  a
           fatal error.

    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.

           Available in Postfix version 2.3 and later:

           frozen_delivered_to (yes)
                  Update the local(8) delivery agent's  idea  of  the
                  Delivered-To:     address    (see    prepend_deliv-
                  ered_header) only once, at the start of a  delivery
                  attempt;  do  not  update the Delivered-To: address
                  while expanding aliases or .forward files.

           Available in Postfix version 2.5.3 and later:

           strict_mailbox_ownership (yes)
                  Defer delivery when a mailbox file is not owned  by
                  its recipient.

    DELIVERY METHOD CONTROLS
           The  precedence  of local(8) delivery methods from high to
           low is: aliases, .forward  files,  mailbox_transport_maps,
           mailbox_transport,  mailbox_command_maps, mailbox_command,
           home_mailbox,    mail_spool_directory,     fallback_trans-
           port_maps, 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_maps (empty)
                  Optional lookup tables with  per-recipient  message
                  delivery  transports  to  use  for local(8) mailbox
                  delivery, whether or not the recipients  are  found
                  in the UNIX passwd database.

           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_maps (empty)
                  Optional lookup tables with  per-recipient  message
                  delivery   transports   for   recipients  that  the
                  local(8) delivery  agent  could  not  find  in  the
                  aliases(5) or UNIX password database.

           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) or UNIX password
                  database.

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

           Available in Postfix version 2.2 and later:

           command_execution_directory (empty)
                  The  local(8)  delivery agent working directory for
                  delivery to external command.

    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 and $command_execution_directory.

           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.

           Available in Postfix version 2.2 and later:

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

           Available in Postfix version 2.5.3 and later:

           strict_mailbox_ownership (yes)
                  Defer  delivery when a mailbox file is not owned by
                  its recipient.

    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.

           delay_logging_resolution_limit (2)
                  The  maximal  number  of  digits  after the decimal
                  point when logging sub-second delay values.

           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  an  incoming  connection
                  before terminating voluntarily.

           max_use (100)
                  The  maximal  number of incoming connections that a
                  Postfix daemon process will service  before  termi-
                  nating voluntarily.

           prepend_delivered_header (command, file, forward)
                  The  message  delivery  contexts  where the Postfix
                  local(8) delivery agent  prepends  a  Delivered-To:
                  message  header  with the address that the mail was
                  delivered to.

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

           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 (see 'postconf -d' output)
                  The  mail  system  name  that  is  prepended to the
                  process 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, system-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
           master(5), generic daemon options
           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)