path: root/upstream/debian-bookworm/man1/maildrop.1

'\" t
.\"<!-- Copyright 1998 - 2009 Double Precision, Inc.  See COPYING for -->
.\"<!-- distribution information. -->
.\"     Title: maildrop
.\"    Author: Sam Varshavchik
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 07/24/2017
.\"    Manual: Double Precision, Inc.
.\"    Source: Courier Mail Server
.\"  Language: English
.\"
.TH "MAILDROP" "1" "07/24/2017" "Courier Mail Server" "Double Precision, Inc\&."
.\" -----------------------------------------------------------------
.\" * Define some portability stuff
.\" -----------------------------------------------------------------
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.\" http://bugs.debian.org/507673
.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
.\" -----------------------------------------------------------------
.\" * set default formatting
.\" -----------------------------------------------------------------
.\" disable hyphenation
.nh
.\" disable justification (adjust text to left margin only)
.ad l
.\" -----------------------------------------------------------------
.\" * MAIN CONTENT STARTS HERE *
.\" -----------------------------------------------------------------
.SH "NAME"
maildrop \- mail delivery filter/agent
.SH "SYNOPSIS"
.HP \w'\fBmaildrop\fR\ 'u
\fBmaildrop\fR [option...] [\-d\ \fIuser\fR] [\fIarg\fR...]
.HP \w'\fBmaildrop\fR\ 'u
\fBmaildrop\fR [option...] [\fIfilename\fR] [\fIarg\fR...]
.SH "DESCRIPTION"
.PP
\fBmaildrop\fR
is a replacement local mail delivery agent that includes a mail filtering language\&. The system administrator can either replace the existing mail delivery agent with
\fBmaildrop\fR, or users may run
\fBmaildrop\fR
using the \*(Aqforward to program\*(Aq mechanism of the existing mail delivery agent\&.
.PP
\fBmaildrop\fR
first reads the E\-mail message on standard input\&. Trailing carriage return characters are automatically stripped\&. An E\-mail message consists of header lines, followed by a blank line, followed by the contents of the message\&.
.PP
\fBmaildrop\fR
does not accept an mbox\-style
From_
line before the first header line\&.
\fBmaildrop\fR
does not accept leading empty lines before the first non\-blank header line\&. If the message can possibly start with empty lines, and a
From_
line, use
\fBreformail \-f0\fR
to remove any initial empty lines, and replace a
From_
line with a proper
\(lqReturn\-Path:\(rq
header; then pipe it to
\fBmaildrop\fR\&.
.PP
If the file
/etc/maildroprc
exists, mail delivery or mail filtering instructions are read from that file\&.
\fBmaildrop\fR\*(Aqs delivery/filtering instructions may direct
\fBmaildrop\fR
to save the message in specific mailbox, discard it, return it to sender, or forward it to a different E\-mail address\&.
.PP
If
/etc/maildroprc
does not exist, or its mail delivery instructions do not completely dispose of this message,
\fBmaildrop\fR
then reads the mail delivery instructions from
$HOME/\&.mailfilter\&. If it doesn\*(Aqt exist, or its mail delivery instructions do not completely dispose of the message,
\fBmaildrop\fR
then saves the E\-mail message in the default mailbox\&.
.PP
\fBmaildrop\fR
knows how to deliver mail to an standard mailbox files; it also knows how to deliver to maildirs\&. A
maildir
is a directory\-based mail format used by the
\m[blue]\fBCourier\fR\m[]\&\s-2\u[1]\d\s+2
and
\m[blue]\fBQmail\fR\m[]\&\s-2\u[2]\d\s+2
mail servers\&. Many other mail servers also know how to read maildirs\&. When delivering to mailbox files,
\fBmaildrop\fR
will lock the mailbox for the duration of the delivery\&.
.PP
This is the general mail delivery behavior\&. There are minor differences in behavior depending on
\fBmaildrop\fR
delivery mode, which is determined based on how
\fBmaildrop\fR
was started\&.
\fBmaildrop\fR
uses three different primary operating modes:
.PP
Manual mode
.RS 4
A file containing filtering instructions \-
\fIfilename\fR
is specified as an argument to the
\fBmaildrop\fR
command\&.
\fBmaildrop\fR
reads this
\fIfilename\fR
(after
/etc/maildroprc) and follows the instructions in it\&. Unless the message is explicitly forwarded, bounced, deleted, or delivered to a specific mailbox, it will be delivered to the user\*(Aqs system mailbox\&.
.RE
.PP
Delivery mode
.RS 4
\fBmaildrop\fR
is the mail server\*(Aqs mail delivery agent\&.
\fBmaildrop\fR
runs in delivery mode when no
\fIfilename\fR
is specified on the command line\&.
\fBmaildrop\fR
changes the current directory to the user\*(Aqs home directory, then reads
/etc/maildroprc, then
$HOME/\&.mailfilter\&.
.RE
.PP
Embedded mode
.RS 4
\fBmaildrop\fR
functions as a part of another application\&. The embedded mode is used by the
\m[blue]\fBCourier\fR\m[]\&\s-2\u[1]\d\s+2
mail server to integrate mail filtering directly into the process of receiving mail from a remote mail relay, thus rejecting unwanted mail before it is even accepted for local mail delivery\&. Embedded mode is used when either the \-m, or the \-M, option is specified, and is described below\&. See below for a more extensive description of the embedded mode\&.
.RE
.SH "SECURITY"
.PP
It is safe to install
\fBmaildrop\fR
as a root setuid program\&.
\m[blue]\fBThe Courier mail server\fR\m[]\&\s-2\u[1]\d\s+2
installs
\fBmaildrop\fR
as a root setuid program by default, in order to be able to use
\fBmaildrop\fR
in embedded mode\&. If root runs
\fBmaildrop\fR
(or it is setuided to root) the
\fB\-d\fR
option may be used to specify the message\*(Aqs recipient\&.
\fBmaildrop\fR
immediately resets its userid to the one specified by the
\fB\-d\fR
option\&. The user\*(Aqs
$HOME/\&.mailfilter
is read (if it exists), and the message is delivered to the indicated user\&.
.PP
The system administrator can configure
\fBmaildrop\fR
to restrict the
\fB\-d\fR
option for everyone except the mail system itself\&.
.PP
If in delivery mode the user\*(Aqs home directory has the sticky bit set,
\fBmaildrop\fR
immediately terminates with an exit code of
\fBEX_TEMPFAIL\fR, without doing anything\&. Mail servers interpret the
\fBEX_TEMPFAIL\fR
exit code as a request to reschedule the message for another delivery attempt later\&. Setting the sticky bit allows
$HOME/\&.mailfilter
to be edited while temporarily holding all incoming mail\&.
.PP
\fBmaildrop\fR
also terminates with
\fBEX_TEMPFAIL\fR
if the user\*(Aqs home directory has world write permissions\&.
.PP
\fBmaildrop\fR
immediately terminates with
\fBEX_TEMPFAIL\fR
if the
filename
is not owned by the user, or if it has any group or world permissions\&. This includes read permissions\&. The permissions on
$HOME/\&.mailfilter
may only include read and write privileges to the user\&.
.PP
When using the special embedded mode (see below)
\fBmaildrop\fR
immediately terminates with the exit code set to
\fBEX_TEMPFAIL\fR
if
$HOME/\&.mailfilters
is not owned by the user, or if it has any group or world permissions\&.
.SH "TEMPORARY FILES"
.PP
\fBmaildrop\fR
is heavily optimized and tries to use as little resources as possible\&.
\fBmaildrop\fR
reads small messages into memory, then filters and/or delivers the message directly from memory\&. For larger messages,
\fBmaildrop\fR
accesses the message directly from the file\&. If the standard input is not a file,
\fBmaildrop\fR
writes the message to a temporary file, then accesses the message from the temporary file\&. The temporary file is automatically removed when the message is delivered\&.
.SH "OPTIONS"
.PP
\-a
.RS 4
Makes the
Courier
Authentication Library usage mandatory, i\&.e\&. maildrop will throw a temporary error code if the call to the authlib mechanism fails for some reason, such as authdaemon being inaccessible\&.
.if n \{\
.sp
.\}
.RS 4
.it 1 an-trap
.nr an-no-space-flag 1
.nr an-break-flag 1
.br
.ps +1
\fBNote\fR
.ps -1
.br
This setting may already be the default, depending on maildrop\*(Aqs configuration\&.
.sp .5v
.RE
.RE
.PP
\-A "\fIHeader: value\fR"
.RS 4
Adds an additional header to the message\&. Specifying
\fI\-A "Foo: Bar"\fR
effectively adds this header to the message being delivered\&.
.sp
The mail transport agent usually adds additional headers when delivering a message to a local mailbox\&. The way it\*(Aqs usually done is by the mail transport agent sending the message using a pipe to the local delivery agent \- such as
\fBmaildrop\fR
\- and adding some additional headers in the process\&. Because
\fBmaildrop\fR
receives the message from a pipe,
\fBmaildrop\fR
must either save the message in memory or write the message into a temporary file\&.
.sp
The
\fB\-A\fR
option enables the file containing the message to be provided to
\fBmaildrop\fR
directly, as standard input, and the additional headers specified on the command line\&. Because the standard input is a file,
\fBmaildrop\fR
will not need a temporary file\&. Multiple
\fB\-A\fR
options may be specified\&.
.RE
.PP
\-d \fIuser\fR
.RS 4
Run
\fBmaildrop\fR
in delivery mode for this user ID\&.
.sp
The system administrator may optionally restrict the
\fB\-d\fR
option to be available to the mail system only, so it may not be available to you\&. In all cases, the
\fB\-d\fR
option is allowed if
\fIuser\fR
is the same user who is running
\fBmaildrop\fR\&. Also, for the
\fB\-d\fR
option to work at all,
\fBmaildrop\fR
must be executed by root, or
\fBmaildrop\fR
must be a root\-owned program with the setuid bit set\&. Absence of a
filename
on
\fBmaildrop\fR\*(Aqs command line implies the
\fB\-d\fR
option for the user running
\fBmaildrop\fR\&.
.sp
If
\fB\-d\fR
is not specified, the first argument following all the options is a name of the file containing filtering instructions\&. The remaining arguments, if any, are assigned to the variables
\fI$1\fR,
\fI$2\fR, and so on (see
\m[blue]\fB"Environment"\fR\m[]\&\s-2\u[3]\d\s+2
and
\m[blue]\fB"Variable substitution"\fR\m[]\&\s-2\u[4]\d\s+2)\&.
.RE
.PP
\-f \fIaddress\fR
.RS 4
Sets the FROM variable (message envelope sender) to
\fIaddress\fR\&. The system administrator may optionally disable the
\fB\-f\fR
option for users, so it may not be available to you\&.
.RE
.PP
\-m
.RS 4
Run
\fBmaildrop\fR
in embedded mode\&. It\*(Aqs possible to use both the
\fB\-m\fR, and the
\fB\-d\fR
options, but it doesn\*(Aqt make much sense to do so\&. Even if you really wanted to run your message through someone else\*(Aqs
\&.mailfilter, that
\&.mailfilter
probably has at least one instruction which is not allowed in the embedded mode\&.
.sp
The
filename
argument to
\fBmaildrop\fR
should be specified\&.
filename
is a file that includes filtering instructions to be processed in embedded mode\&. The
\-m
option is used for debugging filter files which are later placed in
$HOME/\&.mailfilters, and used with the
\fB\-M\fR
option\&.
.RE
.PP
\-M \fIfilterfile\fR
.RS 4
Run
\fBmaildrop\fR
in a special embedded mode\&. The
\fB\-d\fR
option is implied when
\fB\-M\fR
is used, and if absent it defaults to the userid running
\fBmaildrop\fR\&.
.sp
All the requirements for the
\fB\-d\fR
option apply\&.
\fBmaildrop\fR
must either be executed by root, or the
\fBmaildrop\fR
program must be owned by root with the setuid bit set\&.
\fBmaildrop\fR
immediately gives up root privileges by changing its user ID to the one specified by
\fB\-d\fR, then reads
$HOME/\&.mailfilters/\fIfilterfile\fR\&. For security reasons the name of the file may not begin with a slash or include periods\&.
\fBmaildrop\fR
is very paranoid: both
$HOME/\&.mailfilters, and
$HOME/\&.mailfilters/\fIfilterfile\fR
must be owned by the user, and may not have any group or world permissions\&.
.sp
The
\fB\-M\fR
option allows for some friendly cooperation between the user running the application, and the user who provides a filter for the embedded mode\&. The user running the application can use someone else\*(Aqs canned filter and be assured that the filter is not going to run amok and start sending mail or create files all over the place\&. The user who provides the filter can be assured that the environment variables are clean, and that there are no surprises\&.
.sp
\fBmaildrop\fR
supports the concept of "default" filter files\&. If the file specified by the
\fB\-M\fR
option cannot be found in
$HOME/\&.mailfilters,
\fBmaildrop\fR
will try to open
$HOME/\&.mailfilters/\fIfilterfileprefix\fR\-default\&.
\fIfilterfileprefix\fR
is the initial part of
\fIfilterfile\fR
up until the last \*(Aq\-\*(Aq character in
\fIfilterfile\fR\&.
.sp
If
$HOME/\&.mailfilters/\fIfilterfileprefix\fR\-default
does not exist, and there are any other dashes left in
\fIfilterfileprefix\fR, maildrop removes the last dash and everything following it, then tries again\&.
.sp
As a last resort
\fBmaildrop\fR
tries to open
$HOME/\&.mailfilters/default\&.
.sp
For example, if the parameter to the
\fB\-M\fR
option is
\fImailfilter\-lists\-maildrop\fR,
\fBmaildrop\fR
will try to open the following files, in order:
.sp .if n \{\ .RS 4 .\} .nf $HOME/\&.mailfilters/mailfilter\-lists\-maildrop $HOME/\&.mailfilters/mailfilter\-lists\-maildrop\-default $HOME/\&.mailfilters/mailfilter\-lists\-default $HOME/\&.mailfilters/mailfilter\-default $HOME/\&.mailfilters/default .fi .if n \{\ .RE .\}
.sp
Note that
\fBmaildrop\fR
looks for \-default files ONLY if
\fB\-M\fR
is used\&.
.RE
.PP
\-D \fIuuu/ggg\fR
.RS 4
This option is reserved for use by the version of
\fBmaildrop\fR
that comes integrated with the
\m[blue]\fBCourier mail server\fR\m[]\&\s-2\u[1]\d\s+2\&.
.RE
.PP
\-V \fIlevel\fR
.RS 4
Initialize the
\fIVERBOSE\fR
variable to
\fIlevel\fR\&. Because
\fBmaildrop\fR
parses the entire file before running it, this option is used to produce debugging output in the parsing phase\&. Otherwise, if
filename
has syntax errors, then no debugging output is possible because the
\fIVERBOSE\fR
variable is not yet set\&.
.sp
\fB\-V\fR
is ignored when
\fBmaildrop\fR
runs in delivery mode\&.
.RE
.PP
\-w \fIN\fR
.RS 4
The
\fB\-w N\fR
option places a warning message into the maildir if the maildir has a quota setting, and after the message was successfully delivered the maildir was at least
\fIN\fR
percent full\&.
.RE
.PP
\-W \fIfilename\fR
.RS 4
Copy the warning message from
\fIfilename\fR, or from
/etc/quotawarnmsg
if this option is not specified, with the addition of the "Date:" and "Message\-Id:" headers\&. The warning is repeated every 24 hours (at least), until the maildir drops below
\fIN\fR
percent full\&.
.RE
.PP
\-t \fIsocket\fR
.RS 4
This option is available if maildrop is compiled with optional Dovecot authentication support\&.
\fIsocket\fR
specifies the location of Dovecot master authentication socket, for example
/var/run/dovecot/auth\-master\&.
.RE
.SH "DELIVERY MODE"
.PP
If a
filename
is not specified on the command line, or if the
\fB\-d\fR
option is used,
\fBmaildrop\fR
will run in delivery mode\&. In delivery mode,
\fBmaildrop\fR
changes to the home directory of the user specified by the
\fB\-d\fR
option (or the user who is running
\fBmaildrop\fR
if the
\fB\-d\fR
option was not given) and reads
$HOME/\&.mailfilter
for filtering instructions\&.
$HOME/\&.mailfilter
must be owned by the user, and have no group or global permissions (\fBmaildrop\fR
terminates if it does)\&.
.PP
If
$HOME/\&.mailfilter
does not exist,
\fBmaildrop\fR
will simply deliver the message to the user\*(Aqs mailbox\&.
.PP
If the file
/etc/maildroprc
exists,
\fBmaildrop\fR
reads filtering instructions from this file first, before reading
$HOME/\&.mailfilter\&. This allows the system administrator to provide global filtering instructions for all users\&.
.if n \{\
.sp
.\}
.RS 4
.it 1 an-trap
.nr an-no-space-flag 1
.nr an-break-flag 1
.br
.ps +1
\fBNote\fR
.ps -1
.br
.PP
/etc/maildroprc
is read only in delivery mode\&.
.sp .5v
.RE
.SH "VIRTUAL ACCOUNTS"
.PP
The
\fB\-d\fR
option can also specify a name of a virtual account or mailbox\&. See the
\fBmakeuserdb\fR(1)
manual page in the
Courier
Authentication library\*(Aqs documentation for more information\&.
.SH "EMBEDDED MODE"
.PP
The embedded mode is used when
\fBmaildrop\fR\*(Aqs filtering abilities are desired, but no actual mail delivery is needed\&. In embedded mode
\fBmaildrop\fR
is executed by another application, and
\m[blue]\fBis passed the \(hym or the \(hyM option\&.\fR\m[]\&\s-2\u[5]\d\s+2
\fBmaildrop\fR
reads the message, then runs the filtering rules specified in
filename\&.
.PP
filename
may contain any filtering instructions EXCEPT the following:
.PP
` \&.\&.\&. `
.RS 4
Text strings delimited by back\-tick characters (run shell command) are not allowed\&.
.RE
.PP
\m[blue]\fBcc\fR\m[]\&\s-2\u[6]\d\s+2
.RS 4
The
\fBcc\fR
command is not allowed in embedded mode\&.
.RE
.PP
\m[blue]\fBdotlock\fR\m[]\&\s-2\u[7]\d\s+2
.RS 4
The
\fBdotlock\fR
command is not allowed in embedded mode\&.
.RE
.PP
\m[blue]\fBflock\fR\m[]\&\s-2\u[8]\d\s+2
.RS 4
The
\fBflock\fR
command is not allowed in embedded mode\&.
.RE
.PP
\m[blue]\fBgdbmopen\fR\m[]\&\s-2\u[9]\d\s+2
.RS 4
In embedded mode, GDBM databases may be opened only for reading\&.
.RE
.PP
\m[blue]\fBlog\fR\m[]\&\s-2\u[10]\d\s+2
.RS 4
The
\fBlog\fR
command is not allowed in embedded mode\&.
.RE
.PP
\m[blue]\fBlogfile\fR\m[]\&\s-2\u[10]\d\s+2
.RS 4
The
\fBlogfile\fR
command is not allowed in embedded mode\&.
.RE
.PP
\m[blue]\fBsystem\fR\m[]\&\s-2\u[11]\d\s+2
.RS 4
The
\fBsystem\fR
command is not allowed in embedded mode\&.
.RE
.PP
\m[blue]\fBto\fR\m[]\&\s-2\u[12]\d\s+2
.RS 4
The
\fBto\fR
command is not allowed in embedded mode\&.
.RE
.PP
\m[blue]\fBxfilter\fR\m[]\&\s-2\u[13]\d\s+2
.RS 4
The
\fBxfilter\fR
command is not allowed in embedded mode\&.
.RE
.PP
Normally when the
filename
does not explicitly delivers a message,
\fBmaildrop\fR
will deliver the message to the user\*(Aqs default mailbox\&. This is also disabled in embedded mode\&.
.PP
The
filename
may communicate with the parent application by using the
\m[blue]\fBecho\fR\m[]\&\s-2\u[14]\d\s+2
statement and the
\fIEXITCODE\fR
environment variable\&.
.SS "/etc/maildroprcs"
.PP
If
\fBmaildrop\fR
encounters an
\m[blue]\fBinclude\fR\m[]\&\s-2\u[15]\d\s+2
statement where the filename starts with
/etc/maildroprcs/, the normal restrictions for the embedded mode are suspended while executing the filter file in the
/etc/maildroprcs
directory\&. The restrictions are also suspended for any additional filter files that are included from
/etc/maildroprcs\&. The restrictions resume once
\fBmaildrop\fR
finishes executing the file from
/etc/maildroprcs\&.
.PP
This allows the system administrator to have a controlled environment for running external commands (via the backticks, the
\m[blue]\fBsystem\fR\m[]\&\s-2\u[11]\d\s+2
or the
\m[blue]\fBxfilter\fR\m[]\&\s-2\u[13]\d\s+2
commands)\&.
.PP
The name of the file may not contain any periods (so that a creative individual can\*(Aqt write
\fIinclude "/etc/maildroprcs/\&.\&./\&.\&./home/user/recipe"\fR)\&.
.PP
Before executing the commands in the
/etc/maildroprcs
file,
\fBmaildrop\fR
automatically resets the following variables to their initial values:
\fIDEFAULT\fR,
\fIHOME\fR,
\fILOCKEXT\fR,
\fILOCKSLEEP\fR,
\fILOCKTIMEOUT\fR,
\fILOCKREFRESH\fR,
\fILOGNAME\fR,
\fIPATH\fR,
\fISENDMAIL\fR, and
\fISHELL\fR\&. Please note that the previous values of these variables (if they were changed) will NOT be restored once
\fBmaildrop\fR
finishes executing the commands from
/etc/maildroprcs\&.
.SH "WATCHDOG TIMER"
.PP
\fBmaildrop\fR
has a watchdog timer that attempts to abort runaway filtering\&. If filtering is not complete within a predefined time interval (defined by the system administrator, usually five minutes),
\fBmaildrop\fR
terminates\&.
.SH "FILES"
.PP
/etc/passwd
.RS 4
Sets user\*(Aqs home directory, and related variables\&. If NIS/YP is install, that will be used as well\&.
.RE
.PP
/etc/maildroprc
.RS 4
Global filtering instructions for delivery mode\&.
.RE
.PP
/var/mail
.RS 4
System mailbox (actual directory defined by the system administrator)\&.
.RE
.PP
/usr/sbin/sendmail
.RS 4
Program to forward mail (exact program defined by the system administrator)\&.
.RE
.PP
$HOME/\&.mailfilter
.RS 4
Filtering instructions in delivery mode\&.
.RE
.PP
$HOME/\&.mailfilters
.RS 4
Directory containing files used in special embedded mode\&.
.RE
.SH "SEE ALSO"
.PP
\m[blue]\fB\fBlockmail\fR(1)\fR\m[]\&\s-2\u[16]\d\s+2,
\m[blue]\fB\fBmaildropfilter\fR(7)\fR\m[]\&\s-2\u[17]\d\s+2,
\m[blue]\fB\fBmakedat\fR(1)\fR\m[]\&\s-2\u[18]\d\s+2,
\m[blue]\fB\fBmaildropgdbm\fR(7)\fR\m[]\&\s-2\u[9]\d\s+2,
\m[blue]\fB\fBmaildropex\fR(7)\fR\m[]\&\s-2\u[19]\d\s+2,
\m[blue]\fB\fBreformail\fR(1)\fR\m[]\&\s-2\u[20]\d\s+2,
\m[blue]\fB\fBmakemime\fR(1)\fR\m[]\&\s-2\u[21]\d\s+2,
\m[blue]\fB\fBreformime\fR(1)\fR\m[]\&\s-2\u[22]\d\s+2,
\fBegrep\fR(1),
\fBgrep\fR(1), ,
\m[blue]\fB\fBcourier\fR(8)\fR\m[]\&\s-2\u[23]\d\s+2,
\fBsendmail\fR(8),
\m[blue]\fBhttp://www\&.qmail\&.org\fR\m[]\&.
.SH "AUTHOR"
.PP
\fBSam Varshavchik\fR
.RS 4
Author
.RE
.SH "NOTES"
.IP " 1." 4
Courier
.RS 4
\%http://www.courier-mta.org
.RE
.IP " 2." 4
Qmail
.RS 4
\%http://www.qmail.org
.RE
.IP " 3." 4
"Environment"
.RS 4
\%http://www.courier-mta.org/maildrop/maildropfilter.html#environment
.RE
.IP " 4." 4
"Variable substitution"
.RS 4
\%http://www.courier-mta.org/maildrop/maildropfilter.html#varsubst
.RE
.IP " 5." 4
is passed the \(hym or the \(hyM option.
.RS 4
\%http://www.courier-mta.org/maildrop/#options
.RE
.IP " 6." 4
cc
.RS 4
\%http://www.courier-mta.org/maildrop/maildropfilter.html#cc
.RE
.IP " 7." 4
dotlock
.RS 4
\%http://www.courier-mta.org/maildrop/maildropfilter.html#dotlock
.RE
.IP " 8." 4
flock
.RS 4
\%http://www.courier-mta.org/maildrop/maildropfilter.html#flock
.RE
.IP " 9." 4
gdbmopen
.RS 4
\%http://www.courier-mta.org/maildrop/maildropgdbm.html
.RE
.IP "10." 4
log
.RS 4
\%http://www.courier-mta.org/maildrop/maildropfilter.html#log
.RE
.IP "11." 4
system
.RS 4
\%http://www.courier-mta.org/maildrop/maildropfilter.html#system
.RE
.IP "12." 4
to
.RS 4
\%http://www.courier-mta.org/maildrop/maildropfilter.html#to
.RE
.IP "13." 4
xfilter
.RS 4
\%http://www.courier-mta.org/maildrop/maildropfilter.html#xfilter
.RE
.IP "14." 4
echo
.RS 4
\%http://www.courier-mta.org/maildrop/maildropfilter.html#echo
.RE
.IP "15." 4
include
.RS 4
\%http://www.courier-mta.org/maildrop/maildropfilter.html#include
.RE
.IP "16." 4
\fBlockmail\fR(1)
.RS 4
\%http://www.courier-mta.org/maildrop/lockmail.html
.RE
.IP "17." 4
\fBmaildropfilter\fR(7)
.RS 4
\%http://www.courier-mta.org/maildrop/maildropfilter.html
.RE
.IP "18." 4
\fBmakedat\fR(1)
.RS 4
\%http://www.courier-mta.org/maildrop/makedat.html
.RE
.IP "19." 4
\fBmaildropex\fR(7)
.RS 4
\%http://www.courier-mta.org/maildrop/maildropex.html
.RE
.IP "20." 4
\fBreformail\fR(1)
.RS 4
\%http://www.courier-mta.org/maildrop/reformail.html
.RE
.IP "21." 4
\fBmakemime\fR(1)
.RS 4
\%http://www.courier-mta.org/maildrop/makemime.html
.RE
.IP "22." 4
\fBreformime\fR(1)
.RS 4
\%http://www.courier-mta.org/maildrop/reformime.html
.RE
.IP "23." 4
\fBcourier\fR(8)
.RS 4
\%http://www.courier-mta.org/maildrop/courier.html
.RE