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"http://www.w3.org/TR/html4/loose.dtd"> 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 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)