Provided by: postfix_3.1.0-3_amd64 bug

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 master(8) process manager.

       The local(8) 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.

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
       exceptions.

SYSTEM-WIDE AND USER-LEVEL ALIASING

       The system  administrator  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.

       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 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
       duplicate 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 final 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
       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_command  configuration parameters. The command executes
       with the privileges of the recipient user (exceptions: secondary 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 mailbox_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
       fallback_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 setting (alias, forward) forbids command destinations  in  :include:
       files.

       Optionally,  the  process  working  directory  is  changed  to  the  path  specified  with
       command_execution_directory (Postfix 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  $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
       execution_directory_expansion_filter configuration parameter.

       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
       command 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>.  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 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  @
              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 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  regular
       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 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
       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).  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.

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-specified files or commands. It is therefore security sensitive.

       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 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

       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 listname-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_delivered_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.

       reset_owner_alias (no)
              Reset  the  local(8)  delivery  agent's  idea  of  the  owner-alias attribute, when
              delivering mail to a child alias that does not have its own owner alias.

       Available in Postfix version 3.0 and later:

       local_delivery_status_filter ($default_delivery_status_filter)
              Optional filter for the local(8) delivery  agent  to  change  the  status  code  or
              explanatory text of successful or unsuccessful deliveries.

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_transport_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 methods.

       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) delivery 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 exclusive 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 virtual(5) alias expansion, or for showq(8) queue displays.

       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_recipient_limit > 1").

       local_destination_recipient_limit (1)
              The maximal number of recipients per message delivery 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 commands.

       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_command 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_execution_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 terminating 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 extension from the lookup key to the
              lookup result.

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

       recipient_delimiter (empty)
              The set of characters that can separate a user name from  its  extension  (example:
              user+foo), or a .forward file name from its extension (example: .forward+foo).

       require_home_directory (no)
              Require  that  a local(8) recipient's home directory exists 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 system 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

       Wietse Venema
       Google, Inc.
       111 8th Avenue
       New York, NY 10011, USA

                                                                                  LOCAL(8postfix)