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LOCAL(8) LOCAL(8)
<b>NAME</b>
local - Postfix local mail delivery
<b>SYNOPSIS</b>
<b>local</b> [generic Postfix daemon options]
<b>DESCRIPTION</b>
The <b>local</b> 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 <a href="master.8.html"><b>mas-</b>
<b>ter</b>(8)</a> process manager.
The <b>local</b> daemon updates queue files and marks recipients
as finished, or it informs the queue manager that delivery
should be tried again at a later time. Delivery problem
reports are sent to the <a href="bounce.8.html"><b>bounce</b>(8)</a> or <a href="defer.8.html"><b>defer</b>(8)</a> daemon as
appropriate.
<b>SYSTEM-WIDE</b> <b>AND</b> <b>USER-LEVEL</b> <b>ALIASING</b>
The system adminstrator can set up one or more system-wide
<b>sendmail</b>-style alias databases. Users can have <b>sendmail</b>-
style ~/.<b>forward</b> files. Mail for <i>name</i> is delivered to the
alias <i>name</i>, to destinations in ~<i>name</i>/.<b>forward</b>, to the
mailbox owned by the user <i>name</i>, or it is sent back as
undeliverable.
The system administrator can specify a comma/space sepa-
rated list of ~/.<b>forward</b> like files through the <b>for-</b>
<b>ward</b><i>_</i><b>path</b> configuration parameter. Upon delivery, the
local delivery agent tries each pathname in the list until
a file is found. The <b>forward</b><i>_</i><b>path</b> parameter is subject to
interpolation of <b>$user</b> (recipient username), <b>$home</b> (recip-
ient home directory), <b>$shell</b> (recipient shell), <b>$recipient</b>
(complete recipient address), <b>$extension</b> (recipient
address extension), <b>$domain</b> (recipient domain), <b>local</b>
(entire recipient address localpart) and <b>$recipient</b><i>_</i><b>delim-</b>
<b>iter.</b> The forms <i>${name?value}</i> and <i>${name:value}</i> expand
conditionally to <i>value</i> when <i>$name</i> 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 <b>forward</b><i>_</i><b>expan-</b>
<b>sion</b><i>_</i><b>filter</b> configuration parameter.
An alias or ~/.<b>forward</b> file may list any combination of
external commands, destination file names, <b>:include:</b>
directives, or mail addresses. See <a href="aliases.5.html"><b>aliases</b>(5)</a> for a pre-
cise description. Each line in a user's .<b>forward</b> 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 ~/.<b>forward</b> file, delivery is made
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LOCAL(8) LOCAL(8)
to the user's mailbox instead. An empty ~/.<b>forward</b> 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
<b>:include:</b> or from ~/.<b>forward</b> files are broken up into
chunks of length <b>line</b><i>_</i><b>length</b><i>_</i><b>limit</b>.
While expanding aliases, ~/.<b>forward</b> files, and so on, the
program attempts to avoid duplicate deliveries. The <b>dupli-</b>
<b>cate</b><i>_</i><b>filter</b><i>_</i><b>limit</b> configuration parameter limits the num-
ber of remembered recipients.
<b>MAIL</b> <b>FORWARDING</b>
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 <b>Delivered-To:</b> header with the envelope
recipient address. If mail arrives for a recipient that is
already listed in a <b>Delivered-To:</b> header, the message is
bounced.
<b>MAILBOX</b> <b>DELIVERY</b>
The default per-user mailbox is a file in the UNIX mail
spool directory (<b>/var/mail/</b><i>user</i> or <b>/var/spool/mail/</b><i>user</i>);
the location can be specified with the <b>mail</b><i>_</i><b>spool</b><i>_</i><b>direc-</b>
<b>tory</b> configuration parameter.
Alternatively, the per-user mailbox can be a file in the
user's home directory with a name specified via the
<b>home</b><i>_</i><b>mailbox</b> configuration parameter. Specify a relative
path name. Specify a name ending in <b>/</b> for <b>qmail</b>-compatible
<b>maildir</b> delivery.
Mailbox delivery can be delegated to an external command
specified with the <b>mailbox</b><i>_</i><b>command</b> 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
<b>default</b><i>_</i><b>privs</b>).
Mailbox delivery can be delegated to alternative message
transports specified in the <b>master.cf</b> file. The <b>mail-</b>
<b>box</b><i>_</i><b>transport</b> 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 <b>fallback</b><i>_</i><b>transport</b> 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 <b>local</b> dae-
mon prepends a "<b>From</b> <i>sender</i> <i>time_stamp</i>" envelope header to
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LOCAL(8) LOCAL(8)
each message, prepends an optional <b>Delivered-To:</b> header
with the envelope recipient address, prepends a <b>Return-</b>
<b>Path:</b> header with the envelope sender address, prepends a
&gt; character to lines beginning with "<b>From</b> ", 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 <b>maildir</b> delivery, the local daemon prepends
an optional <b>Delivered-To:</b> header with the envelope recipi-
ent address and prepends a <b>Return-Path:</b> header with the
envelope sender address.
<b>EXTERNAL</b> <b>COMMAND</b> <b>DELIVERY</b>
The <b>allow</b><i>_</i><b>mail</b><i>_</i><b>to</b><i>_</i><b>commands</b> configuration parameter
restricts delivery to external commands. The default set-
ting (<b>alias,</b> <b>forward</b>) forbids command destinations in
<b>:include:</b> files.
The command is executed directly where possible. Assis-
tance by the shell (<b>/bin/sh</b> 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 <b>command</b><i>_</i><b>time</b><i>_</i><b>limit</b> seconds.
Command exit status codes are expected to follow the con-
ventions defined in &lt;<b>sysexits.h</b>&gt;.
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 <b>command</b><i>_</i><b>expan-</b>
<b>sion</b><i>_</i><b>filter</b> configuration parameter.
<b>SHELL</b> The recipient user's login shell.
<b>HOME</b> The recipient user's home directory.
<b>USER</b> The bare recipient name.
<b>EXTENSION</b>
The optional recipient address extension.
<b>DOMAIN</b> The recipient address domain part.
<b>LOGNAME</b>
The bare recipient name.
<b>LOCAL</b> The entire recipient address localpart (text to the
left of the rightmost @ character).
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LOCAL(8) LOCAL(8)
<b>RECIPIENT</b>
The entire recipient address.
The <b>PATH</b> environment variable is always reset to a system-
dependent default path, and the <b>TZ</b> (time zone) environment
variable is always passed on without change.
The current working directory is the mail queue directory.
The <b>local</b> daemon prepends a "<b>From</b> <i>sender</i> <i>time_stamp</i>" enve-
lope header to each message, prepends an optional <b>Deliv-</b>
<b>ered-To:</b> header with the recipient envelope address,
prepends a <b>Return-Path:</b> header with the sender envelope
address, and appends an empty line.
<b>EXTERNAL</b> <b>FILE</b> <b>DELIVERY</b>
The <b>allow</b><i>_</i><b>mail</b><i>_</i><b>to</b><i>_</i><b>files</b> configuration parameter restricts
delivery to external files. The default setting (<b>alias,</b>
<b>forward</b>) forbids file destinations in <b>:include:</b> files.
Specify a pathname ending in <b>/</b> for <b>qmail</b>-compatible
<b>maildir</b> delivery.
The <b>local</b> daemon prepends a "<b>From</b> <i>sender</i> <i>time_stamp</i>" enve-
lope header to each message, prepends an optional <b>Deliv-</b>
<b>ered-To:</b> header with the recipient envelope address,
prepends a &gt; character to lines beginning with "<b>From</b> ",
and appends an empty line. The envelope sender address is
available in the <b>Return-Path:</b> header. When the destina-
tion 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 <b>maildir</b> delivery, the local daemon prepends
an optional <b>Delivered-To:</b> header with the envelope recipi-
ent address. The envelope sender address is available in
the <b>Return-Path:</b> header.
<b>ADDRESS</b> <b>EXTENSION</b>
The optional <b>recipient</b><i>_</i><b>delimiter</b> configuration parameter
specifies how to separate address extensions from local
recipient names.
For example, with "<b>recipient</b><i>_</i><b>delimiter</b> <b>=</b> <b>+</b>", mail for
<i>name</i>+<i>foo</i> is delivered to the alias <i>name</i>+<i>foo</i> or to the
alias <i>name</i>, to the destinations listed in ~<i>name</i>/.<b>for-</b>
<b>ward</b>+<i>foo</i> or in ~<i>name</i>/.<b>forward</b>, to the mailbox owned by the
user <i>name</i>, or it is sent back as undeliverable.
In all cases the <b>local</b> daemon prepends an opional `<b>Deliv-</b>
<b>ered-To:</b> <i>name</i>+<i>foo</i>' header line.
<b>DELIVERY</b> <b>RIGHTS</b>
Deliveries to external files and external commands are
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made with the rights of the receiving user on whose behalf
the delivery is made. In the absence of a user context,
the <b>local</b> daemon uses the owner rights of the <b>:include:</b>
file or alias database. When those files are owned by the
superuser, delivery is made with the rights specified with
the <b>default</b><i>_</i><b>privs</b> configuration parameter.
<b>STANDARDS</b>
RFC 822 (ARPA Internet Text Messages)
<b>DIAGNOSTICS</b>
Problems and transactions are logged to <b>syslogd</b>(8). Cor-
rupted message files are marked so that the queue manager
can move them to the <b>corrupt</b> queue afterwards.
Depending on the setting of the <b>notify</b><i>_</i><b>classes</b> parameter,
the postmaster is notified of bounces and of other trou-
ble.
<b>BUGS</b>
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 ~/.<b>forward</b> files are not
detected early. The resulting mail forwarding loop is
broken by the use of the <b>Delivered-To:</b> message header.
<b>CONFIGURATION</b> <b>PARAMETERS</b>
The following <b>main.cf</b> parameters are especially relevant
to this program. See the Postfix <b>main.cf</b> file for syntax
details and for default values. Use the <b>postfix</b> <b>reload</b>
command after a configuration change.
<b>Miscellaneous</b>
<b>alias</b><i>_</i><b>maps</b>
List of alias databases.
<b>expand</b><i>_</i><b>owner</b><i>_</i><b>alias</b>
When delivering to an alias that has an owner- com-
panion alias, set the envelope sender address to
the right-hand side of the owner alias, instead
using of the left-hand side address.
<b>forward</b><i>_</i><b>path</b>
Search list for .forward files. The names are sub-
ject to <i>$name</i> expansion.
<b>local</b><i>_</i><b>command</b><i>_</i><b>shell</b>
Shell to use for external command execution (for
example, /some/where/smrsh -c). When a shell is
specified, it is invoked even when the command
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contains no shell built-in commands or meta charac-
ters.
<b>owner</b><i>_</i><b>request</b><i>_</i><b>special</b>
Give special treatment to <b>owner-</b><i>xxx</i> and <i>xxx</i><b>-request</b>
addresses.
<b>prepend</b><i>_</i><b>delivered</b><i>_</i><b>header</b>
Prepend an optional <b>Delivered-To:</b> header upon
external forwarding, delivery to command or file.
Specify zero or more of: <b>command,</b> <b>file,</b> <b>forward</b>.
Turning off <b>Delivered-To:</b> when forwarding mail is
not recommended.
<b>recipient</b><i>_</i><b>delimiter</b>
Separator between username and address extension.
<b>Mailbox</b> <b>delivery</b>
<b>fallback</b><i>_</i><b>transport</b>
Message transport for recipients that are not found
in the UNIX passwd database. This parameter over-
rides <b>luser</b><i>_</i><b>relay</b>.
<b>home</b><i>_</i><b>mailbox</b>
Pathname of a mailbox relative to a user's home
directory. Specify a path ending in <b>/</b> for maildir-
style delivery.
<b>luser</b><i>_</i><b>relay</b>
Destination (<i>@domain</i> or <i>address</i>) for non-existent
users. The <i>address</i> is subjected to <i>$name</i> expan-
sion.
<b>mail</b><i>_</i><b>spool</b><i>_</i><b>directory</b>
Directory with UNIX-style mailboxes. The default
pathname is system dependent.
<b>mailbox</b><i>_</i><b>command</b>
External command to use for mailbox delivery. The
command executes with the recipient privileges
(exception: root). The string is subject to $name
expansions.
<b>mailbox</b><i>_</i><b>transport</b>
Message transport to use for mailbox delivery to
all local recipients, whether or not they are found
in the UNIX passwd database. This parameter over-
rides all other configuration parameters that con-
trol mailbox delivery, including <b>luser</b><i>_</i><b>relay</b>.
<b>Locking</b> <b>controls</b>
<b>deliver</b><i>_</i><b>lock</b><i>_</i><b>attempts</b>
Limit the number of attempts to acquire an exclu-
sive lock on a mailbox or external file.
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<b>deliver</b><i>_</i><b>lock</b><i>_</i><b>delay</b>
Time in seconds between successive attempts to
acquire an exclusive lock.
<b>stale</b><i>_</i><b>lock</b><i>_</i><b>time</b>
Limit the time after which a stale lock is removed.
<b>Resource</b> <b>controls</b>
<b>command</b><i>_</i><b>time</b><i>_</i><b>limit</b>
Limit the amount of time for delivery to external
command.
<b>duplicate</b><i>_</i><b>filter</b><i>_</i><b>limit</b>
Limit the size of the duplicate filter for results
from alias etc. expansion.
<b>line</b><i>_</i><b>length</b><i>_</i><b>limit</b>
Limit the amount of memory used for processing a
partial input line.
<b>local</b><i>_</i><b>destination</b><i>_</i><b>concurrency</b><i>_</i><b>limit</b>
Limit the number of parallel deliveries to the same
user. The default limit is taken from the
<b>default</b><i>_</i><b>destination</b><i>_</i><b>concurrency</b><i>_</i><b>limit</b> parameter.
<b>local</b><i>_</i><b>destination</b><i>_</i><b>recipient</b><i>_</i><b>limit</b>
Limit the number of recipients per message deliv-
ery. The default limit is taken from the
<b>default</b><i>_</i><b>destination</b><i>_</i><b>recipient</b><i>_</i><b>limit</b> parameter.
<b>Security</b> <b>controls</b>
<b>allow</b><i>_</i><b>mail</b><i>_</i><b>to</b><i>_</i><b>commands</b>
Restrict the usage of mail delivery to external
command.
<b>allow</b><i>_</i><b>mail</b><i>_</i><b>to</b><i>_</i><b>files</b>
Restrict the usage of mail delivery to external
file.
<b>command</b><i>_</i><b>expansion</b><i>_</i><b>filter</b>
What characters are allowed to appear in $name
expansions of mailbox_command. Illegal characters
are replaced by underscores.
<b>default</b><i>_</i><b>privs</b>
Default rights for delivery to external file or
command.
<b>forward</b><i>_</i><b>expansion</b><i>_</i><b>filter</b>
What characters are allowed to appear in $name
expansions of forward_path. Illegal characters are
replaced by underscores.
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LOCAL(8) LOCAL(8)
<b>HISTORY</b>
The <b>Delivered-To:</b> header appears in the <b>qmail</b> system by
Daniel Bernstein.
The <i>maildir</i> structure appears in the <b>qmail</b> system by
Daniel Bernstein.
<b>SEE</b> <b>ALSO</b>
<a href="aliases.5.html">aliases(5)</a> format of alias database
<a href="bounce.8.html">bounce(8)</a> non-delivery status reports
<a href="postalias.1.html">postalias(1)</a> create/update alias database
syslogd(8) system logging
<a href="qmgr.8.html">qmgr(8)</a> queue manager
<b>LICENSE</b>
The Secure Mailer license must be distributed with this
software.
<b>AUTHOR(S)</b>
Wietse Venema
IBM T.J. Watson Research
P.O. Box 704
Yorktown Heights, NY 10598, USA
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