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		SENDMAIL CONFIGURATION FILES

This document describes the sendmail configuration files.  It
explains how to create a sendmail.cf file for use with sendmail.
It also describes how to set options for sendmail which are explained
in the Sendmail Installation and Operation guide (doc/op/op.me).

To get started, you may want to look at tcpproto.mc (for TCP-only
sites) and clientproto.mc (for clusters of clients using a single
mail host), or the generic-*.mc files as operating system-specific
examples.

Table of Content:

INTRODUCTION AND EXAMPLE
A BRIEF INTRODUCTION TO M4
FILE LOCATIONS
OSTYPE
DOMAINS
MAILERS
FEATURES
HACKS
SITE CONFIGURATION
USING UUCP MAILERS
TWEAKING RULESETS
MASQUERADING AND RELAYING
USING LDAP FOR ALIASES, MAPS, AND CLASSES
LDAP ROUTING
ANTI-SPAM CONFIGURATION CONTROL
CONNECTION CONTROL
STARTTLS
SMTP AUTHENTICATION
ADDING NEW MAILERS OR RULESETS
ADDING NEW MAIL FILTERS
QUEUE GROUP DEFINITIONS
NON-SMTP BASED CONFIGURATIONS
WHO AM I?
ACCEPTING MAIL FOR MULTIPLE NAMES
USING MAILERTABLES
USING USERDB TO MAP FULL NAMES
MISCELLANEOUS SPECIAL FEATURES
SECURITY NOTES
TWEAKING CONFIGURATION OPTIONS
MESSAGE SUBMISSION PROGRAM
FORMAT OF FILES AND MAPS
DIRECTORY LAYOUT
ADMINISTRATIVE DETAILS


+--------------------------+
| INTRODUCTION AND EXAMPLE |
+--------------------------+

Configuration files are contained in the subdirectory "cf", with a
suffix ".mc".  They must be run through "m4" to produce a ".cf" file.
You must pre-load "cf.m4":

	m4 ${CFDIR}/m4/cf.m4 config.mc > config.cf

Alternatively, you can simply:

	cd ${CFDIR}/cf
	./Build config.cf

where ${CFDIR} is the root of the cf directory and config.mc is the
name of your configuration file.  If you are running a version of M4
that understands the __file__ builtin (versions of GNU m4 >= 0.75 do
this, but the versions distributed with 4.4BSD and derivatives do not)
or the -I flag (ditto), then ${CFDIR} can be in an arbitrary directory.
For "traditional" versions, ${CFDIR} ***MUST*** be "..", or you MUST
use -D_CF_DIR_=/path/to/cf/dir/ -- note the trailing slash!  For example:

	m4 -D_CF_DIR_=${CFDIR}/ ${CFDIR}/m4/cf.m4 config.mc > config.cf

Let's examine a typical .mc file:

	divert(-1)
	#
	# Copyright (c) 1998-2005 Sendmail, Inc. and its suppliers.
	#	All rights reserved.
	# Copyright (c) 1983 Eric P. Allman.  All rights reserved.
	# Copyright (c) 1988, 1993
	#	The Regents of the University of California.  All rights reserved.
	#
	# By using this file, you agree to the terms and conditions set
	# forth in the LICENSE file which can be found at the top level of
	# the sendmail distribution.
	#

	#
	#  This is a Berkeley-specific configuration file for HP-UX 9.x.
	#  It applies only to the Computer Science Division at Berkeley,
	#  and should not be used elsewhere.   It is provided on the sendmail
	#  distribution as a sample only.  To create your own configuration
	#  file, create an appropriate domain file in ../domain, change the
	#  `DOMAIN' macro below to reference that file, and copy the result
	#  to a name of your own choosing.
	#
	divert(0)

The divert(-1) will delete the crud in the resulting output file.
The copyright notice can be replaced by whatever your lawyers require;
our lawyers require the one that is included in these files.  A copyleft
is a copyright by another name.  The divert(0) restores regular output.

	VERSIONID(`<SCCS or RCS version id>')

VERSIONID is a macro that stuffs the version information into the
resulting file.  You could use SCCS, RCS, CVS, something else, or
omit it completely.  This is not the same as the version id included
in SMTP greeting messages -- this is defined in m4/version.m4.

	OSTYPE(`hpux9')dnl

You must specify an OSTYPE to properly configure things such as the
pathname of the help and status files, the flags needed for the local
mailer, and other important things.  If you omit it, you will get an
error when you try to build the configuration.  Look at the ostype
directory for the list of known operating system types.

	DOMAIN(`CS.Berkeley.EDU')dnl

This example is specific to the Computer Science Division at Berkeley.
You can use "DOMAIN(`generic')" to get a sufficiently bland definition
that may well work for you, or you can create a customized domain
definition appropriate for your environment.

	MAILER(`local')
	MAILER(`smtp')

These describe the mailers used at the default CS site.  The local
mailer is always included automatically.  Beware: MAILER declarations
should only be followed by LOCAL_* sections.  The general rules are
that the order should be:

	VERSIONID
	OSTYPE
	DOMAIN
	FEATURE
	local macro definitions
	MAILER
	LOCAL_CONFIG
	LOCAL_RULE_*
	LOCAL_RULESETS

There are a few exceptions to this rule.  Local macro definitions which
influence a FEATURE() should be done before that feature.  For example,
a define(`PROCMAIL_MAILER_PATH', ...) should be done before
FEATURE(`local_procmail').

*******************************************************************
***  BE SURE YOU CUSTOMIZE THESE FILES!  They have some		***
***  Berkeley-specific assumptions built in, such as the name	***
***  of their UUCP-relay.  You'll want to create your own	***
***  domain description, and use that in place of		***
***  domain/Berkeley.EDU.m4.					***
*******************************************************************


+----------------------------+
| A BRIEF INTRODUCTION TO M4 |
+----------------------------+

Sendmail uses the M4 macro processor to ``compile'' the configuration
files.  The most important thing to know is that M4 is stream-based,
that is, it doesn't understand about lines.  For this reason, in some
places you may see the word ``dnl'', which stands for ``delete
through newline''; essentially, it deletes all characters starting
at the ``dnl'' up to and including the next newline character.  In
most cases sendmail uses this only to avoid lots of unnecessary
blank lines in the output.

Other important directives are define(A, B) which defines the macro
``A'' to have value ``B''.  Macros are expanded as they are read, so
one normally quotes both values to prevent expansion.  For example,

	define(`SMART_HOST', `smart.foo.com')

One word of warning:  M4 macros are expanded even in lines that appear
to be comments.  For example, if you have

	# See FEATURE(`foo') above

it will not do what you expect, because the FEATURE(`foo') will be
expanded.  This also applies to

	# And then define the $X macro to be the return address

because ``define'' is an M4 keyword.  If you want to use them, surround
them with directed quotes, `like this'.

Since m4 uses single quotes (opening "`" and closing "'") to quote
arguments, those quotes can't be used in arguments.  For example,
it is not possible to define a rejection message containing a single
quote. Usually there are simple workarounds by changing those
messages; in the worst case it might be ok to change the value
directly in the generated .cf file, which however is not advised.


Notice:
-------

This package requires a post-V7 version of m4; if you are running the
4.2bsd, SysV.2, or 7th Edition version.  SunOS's /usr/5bin/m4 or
BSD-Net/2's m4 both work.  GNU m4 version 1.1 or later also works.
Unfortunately, the M4 on BSDI 1.0 doesn't work -- you'll have to use a
Net/2 or GNU version.  GNU m4 is available from
ftp://ftp.gnu.org/pub/gnu/m4/m4-1.4.tar.gz (check for the latest version).
EXCEPTIONS: DEC's m4 on Digital UNIX 4.x is broken (3.x is fine).  Use GNU
m4 on this platform.


+----------------+
| FILE LOCATIONS |
+----------------+

sendmail 8.9 has introduced a new configuration directory for sendmail
related files, /etc/mail.  The new files available for sendmail 8.9 --
the class {R} /etc/mail/relay-domains and the access database
/etc/mail/access -- take advantage of this new directory.  Beginning with
8.10, all files will use this directory by default (some options may be
set by OSTYPE() files).  This new directory should help to restore
uniformity to sendmail's file locations.

Below is a table of some of the common changes:

Old filename			New filename
------------			------------
/etc/bitdomain			/etc/mail/bitdomain
/etc/domaintable		/etc/mail/domaintable
/etc/genericstable		/etc/mail/genericstable
/etc/uudomain			/etc/mail/uudomain
/etc/virtusertable		/etc/mail/virtusertable
/etc/userdb			/etc/mail/userdb

/etc/aliases			/etc/mail/aliases
/etc/sendmail/aliases		/etc/mail/aliases
/etc/ucbmail/aliases		/etc/mail/aliases
/usr/adm/sendmail/aliases	/etc/mail/aliases
/usr/lib/aliases		/etc/mail/aliases
/usr/lib/mail/aliases		/etc/mail/aliases
/usr/ucblib/aliases		/etc/mail/aliases

/etc/sendmail.cw		/etc/mail/local-host-names
/etc/mail/sendmail.cw		/etc/mail/local-host-names
/etc/sendmail/sendmail.cw	/etc/mail/local-host-names

/etc/sendmail.ct		/etc/mail/trusted-users

/etc/sendmail.oE		/etc/mail/error-header

/etc/sendmail.hf		/etc/mail/helpfile
/etc/mail/sendmail.hf		/etc/mail/helpfile
/usr/ucblib/sendmail.hf		/etc/mail/helpfile
/etc/ucbmail/sendmail.hf	/etc/mail/helpfile
/usr/lib/sendmail.hf		/etc/mail/helpfile
/usr/share/lib/sendmail.hf	/etc/mail/helpfile
/usr/share/misc/sendmail.hf	/etc/mail/helpfile
/share/misc/sendmail.hf		/etc/mail/helpfile

/etc/service.switch		/etc/mail/service.switch

/etc/sendmail.st		/etc/mail/statistics
/etc/mail/sendmail.st		/etc/mail/statistics
/etc/mailer/sendmail.st		/etc/mail/statistics
/etc/sendmail/sendmail.st	/etc/mail/statistics
/usr/lib/sendmail.st		/etc/mail/statistics
/usr/ucblib/sendmail.st		/etc/mail/statistics

Note that all of these paths actually use a new m4 macro MAIL_SETTINGS_DIR
to create the pathnames.  The default value of this variable is
`/etc/mail/'.  If you set this macro to a different value, you MUST include
a trailing slash.

Notice: all filenames used in a .mc (or .cf) file should be absolute
(starting at the root, i.e., with '/').  Relative filenames most
likely cause surprises during operations (unless otherwise noted).


+--------+
| OSTYPE |
+--------+

You MUST define an operating system environment, or the configuration
file build will puke.  There are several environments available; look
at the "ostype" directory for the current list.  This macro changes
things like the location of the alias file and queue directory.  Some
of these files are identical to one another.

It is IMPERATIVE that the OSTYPE occur before any MAILER definitions.
In general, the OSTYPE macro should go immediately after any version
information, and MAILER definitions should always go last.

Operating system definitions are usually easy to write.  They may define
the following variables (everything defaults, so an ostype file may be
empty).  Unfortunately, the list of configuration-supported systems is
not as broad as the list of source-supported systems, since many of
the source contributors do not include corresponding ostype files.

ALIAS_FILE		[/etc/mail/aliases] The location of the text version
			of the alias file(s).  It can be a comma-separated
			list of names (but be sure you quote values with
			commas in them -- for example, use
				define(`ALIAS_FILE', `a,b')
			to get "a" and "b" both listed as alias files;
			otherwise the define() primitive only sees "a").
HELP_FILE		[/etc/mail/helpfile] The name of the file
			containing information printed in response to
			the SMTP HELP command.
QUEUE_DIR		[/var/spool/mqueue] The directory containing
			queue files.  To use multiple queues, supply
			a value ending with an asterisk.  For
			example, /var/spool/mqueue/qd* will use all of the
			directories or symbolic links to directories
			beginning with 'qd' in /var/spool/mqueue as queue
			directories.  The names 'qf', 'df', and 'xf' are
			reserved as specific subdirectories for the
			corresponding queue file types as explained in
			doc/op/op.me.  See also QUEUE GROUP DEFINITIONS.
MSP_QUEUE_DIR		[/var/spool/clientmqueue] The directory containing
			queue files for the MSP (Mail Submission Program,
			see sendmail/SECURITY).
STATUS_FILE		[/etc/mail/statistics] The file containing status
			information.
LOCAL_MAILER_PATH	[/bin/mail] The program used to deliver local mail.
LOCAL_MAILER_FLAGS	[Prmn9] The flags used by the local mailer.  The
			flags lsDFMAw5:/|@q are always included.
LOCAL_MAILER_ARGS	[mail -d $u] The arguments passed to deliver local
			mail.
LOCAL_MAILER_MAX	[undefined] If defined, the maximum size of local
			mail that you are willing to accept.
LOCAL_MAILER_MAXMSGS	[undefined] If defined, the maximum number of
			messages to deliver in a single connection.  Only
			useful for LMTP local mailers.
LOCAL_MAILER_CHARSET	[undefined] If defined, messages containing 8-bit data
			that ARRIVE from an address that resolves to the
			local mailer and which are converted to MIME will be
			labeled with this character set.
LOCAL_MAILER_EOL	[undefined] If defined, the string to use as the
			end of line for the local mailer.
LOCAL_MAILER_DSN_DIAGNOSTIC_CODE
			[X-Unix] The DSN Diagnostic-Code value for the
			local mailer.  This should be changed with care.
LOCAL_SHELL_PATH	[/bin/sh] The shell used to deliver piped email.
LOCAL_SHELL_FLAGS	[eu9] The flags used by the shell mailer.  The
			flags lsDFM are always included.
LOCAL_SHELL_ARGS	[sh -c $u] The arguments passed to deliver "prog"
			mail.
LOCAL_SHELL_DIR		[$z:/] The directory search path in which the
			shell should run.
LOCAL_MAILER_QGRP	[undefined] The queue group for the local mailer.
USENET_MAILER_PATH	[/usr/lib/news/inews] The name of the program
			used to submit news.
USENET_MAILER_FLAGS	[rsDFMmn] The mailer flags for the usenet mailer.
USENET_MAILER_ARGS	[-m -h -n] The command line arguments for the
			usenet mailer.  NOTE: Some versions of inews
			(such as those shipped with newer versions of INN)
			use different flags.  Double check the defaults
			against the inews man page.
USENET_MAILER_MAX	[undefined] The maximum size of messages that will
			be accepted by the usenet mailer.
USENET_MAILER_QGRP	[undefined] The queue group for the usenet mailer.
SMTP_MAILER_FLAGS	[undefined] Flags added to SMTP mailer.  Default
			flags are `mDFMuX' for all SMTP-based mailers; the
			"esmtp" mailer adds `a'; "smtp8" adds `8'; and
			"dsmtp" adds `%'.
RELAY_MAILER_FLAGS	[undefined] Flags added to the relay mailer.  Default
			flags are `mDFMuX' for all SMTP-based mailers; the
			relay mailer adds `a8'.  If this is not defined,
			then SMTP_MAILER_FLAGS is used.
SMTP_MAILER_MAX		[undefined] The maximum size of messages that will
			be transported using the smtp, smtp8, esmtp, or dsmtp
			mailers.
SMTP_MAILER_MAXMSGS	[undefined] If defined, the maximum number of
			messages to deliver in a single connection for the
			smtp, smtp8, esmtp, or dsmtp mailers.
SMTP_MAILER_MAXRCPTS	[undefined] If defined, the maximum number of
			recipients to deliver in a single connection for the
			smtp, smtp8, esmtp, or dsmtp mailers.
SMTP_MAILER_ARGS	[TCP $h] The arguments passed to the smtp mailer.
			About the only reason you would want to change this
			would be to change the default port.
ESMTP_MAILER_ARGS	[TCP $h] The arguments passed to the esmtp mailer.
SMTP8_MAILER_ARGS	[TCP $h] The arguments passed to the smtp8 mailer.
DSMTP_MAILER_ARGS	[TCP $h] The arguments passed to the dsmtp mailer.
RELAY_MAILER_ARGS	[TCP $h] The arguments passed to the relay mailer.
SMTP_MAILER_QGRP	[undefined] The queue group for the smtp mailer.
ESMTP_MAILER_QGRP	[undefined] The queue group for the esmtp mailer.
SMTP8_MAILER_QGRP	[undefined] The queue group for the smtp8 mailer.
DSMTP_MAILER_QGRP	[undefined] The queue group for the dsmtp mailer.
RELAY_MAILER_QGRP	[undefined] The queue group for the relay mailer.
RELAY_MAILER_MAXMSGS	[undefined] If defined, the maximum number of
			messages to deliver in a single connection for the
			relay mailer.
SMTP_MAILER_CHARSET	[undefined] If defined, messages containing 8-bit data
			that ARRIVE from an address that resolves to one of
			the SMTP mailers and which are converted to MIME will
			be labeled with this character set.
UUCP_MAILER_PATH	[/usr/bin/uux] The program used to send UUCP mail.
UUCP_MAILER_FLAGS	[undefined] Flags added to UUCP mailer.  Default
			flags are `DFMhuU' (and `m' for uucp-new mailer,
			minus `U' for uucp-dom mailer).
UUCP_MAILER_ARGS	[uux - -r -z -a$g -gC $h!rmail ($u)] The arguments
			passed to the UUCP mailer.
UUCP_MAILER_MAX		[100000] The maximum size message accepted for
			transmission by the UUCP mailers.
UUCP_MAILER_CHARSET	[undefined] If defined, messages containing 8-bit data
			that ARRIVE from an address that resolves to one of
			the UUCP mailers and which are converted to MIME will
			be labeled with this character set.
UUCP_MAILER_QGRP	[undefined] The queue group for the UUCP mailers.
FAX_MAILER_PATH		[/usr/local/lib/fax/mailfax] The program used to
			submit FAX messages.
FAX_MAILER_ARGS		[mailfax $u $h $f] The arguments passed to the FAX
			mailer.
FAX_MAILER_MAX		[100000] The maximum size message accepted for
			transmission by FAX.
POP_MAILER_PATH		[/usr/lib/mh/spop] The pathname of the POP mailer.
POP_MAILER_FLAGS	[Penu] Flags added to POP mailer.  Flags lsDFMq
			are always added.
POP_MAILER_ARGS		[pop $u] The arguments passed to the POP mailer.
POP_MAILER_QGRP		[undefined] The queue group for the pop mailer.
PROCMAIL_MAILER_PATH	[/usr/local/bin/procmail] The path to the procmail
			program.  This is also used by
			FEATURE(`local_procmail').
PROCMAIL_MAILER_FLAGS	[SPhnu9] Flags added to Procmail mailer.  Flags
			DFM are always set.  This is NOT used by
			FEATURE(`local_procmail'); tweak LOCAL_MAILER_FLAGS
			instead.
PROCMAIL_MAILER_ARGS	[procmail -Y -m $h $f $u] The arguments passed to
			the Procmail mailer.  This is NOT used by
			FEATURE(`local_procmail'); tweak LOCAL_MAILER_ARGS
			instead.
PROCMAIL_MAILER_MAX	[undefined] If set, the maximum size message that
			will be accepted by the procmail mailer.
PROCMAIL_MAILER_QGRP	[undefined] The queue group for the procmail mailer.
MAIL11_MAILER_PATH	[/usr/etc/mail11] The path to the mail11 mailer.
MAIL11_MAILER_FLAGS	[nsFx] Flags for the mail11 mailer.
MAIL11_MAILER_ARGS	[mail11 $g $x $h $u] Arguments passed to the mail11
			mailer.
MAIL11_MAILER_QGRP	[undefined] The queue group for the mail11 mailer.
PH_MAILER_PATH		[/usr/local/etc/phquery] The path to the phquery
			program.
PH_MAILER_FLAGS		[ehmu] Flags for the phquery mailer.  Flags nrDFM
			are always set.
PH_MAILER_ARGS		[phquery -- $u] -- arguments to the phquery mailer.
PH_MAILER_QGRP		[undefined] The queue group for the ph mailer.
CYRUS_MAILER_FLAGS	[Ah5@/:|] The flags used by the cyrus mailer.  The
			flags lsDFMnPq are always included.
CYRUS_MAILER_PATH	[/usr/cyrus/bin/deliver] The program used to deliver
			cyrus mail.
CYRUS_MAILER_ARGS	[deliver -e -m $h -- $u] The arguments passed
			to deliver cyrus mail.
CYRUS_MAILER_MAX	[undefined] If set, the maximum size message that
			will be accepted by the cyrus mailer.
CYRUS_MAILER_USER	[cyrus:mail] The user and group to become when
			running the cyrus mailer.
CYRUS_MAILER_QGRP	[undefined] The queue group for the cyrus mailer.
CYRUS_BB_MAILER_FLAGS	[u] The flags used by the cyrusbb mailer.
			The flags lsDFMnP are always included.
CYRUS_BB_MAILER_ARGS	[deliver -e -m $u] The arguments passed
			to deliver cyrusbb mail.
CYRUSV2_MAILER_FLAGS	[A@/:|m] The flags used by the cyrusv2 mailer.  The
			flags lsDFMnqXz are always included.
CYRUSV2_MAILER_MAXMSGS	[undefined] If defined, the maximum number of
			messages to deliver in a single connection for the
			cyrusv2 mailer.
CYRUSV2_MAILER_MAXRCPTS	[undefined] If defined, the maximum number of
			recipients to deliver in a single connection for the
			cyrusv2 mailer.
CYRUSV2_MAILER_ARGS	[FILE /var/imap/socket/lmtp] The arguments passed
			to the cyrusv2 mailer.  This can be used to
			change the name of the Unix domain socket, or
			to switch to delivery via TCP (e.g., `TCP $h lmtp')
CYRUSV2_MAILER_QGRP	[undefined] The queue group for the cyrusv2 mailer.
CYRUSV2_MAILER_CHARSET	[undefined] If defined, messages containing 8-bit data
			that ARRIVE from an address that resolves to one the
			Cyrus mailer and which are converted to MIME will
			be labeled with this character set.
confEBINDIR		[/usr/libexec] The directory for executables.
			Currently used for FEATURE(`local_lmtp') and
			FEATURE(`smrsh').
QPAGE_MAILER_FLAGS	[mDFMs] The flags used by the qpage mailer.
QPAGE_MAILER_PATH	[/usr/local/bin/qpage] The program used to deliver
			qpage mail.
QPAGE_MAILER_ARGS	[qpage -l0 -m -P$u] The arguments passed
			to deliver qpage mail.
QPAGE_MAILER_MAX	[4096] If set, the maximum size message that
			will be accepted by the qpage mailer.
QPAGE_MAILER_QGRP	[undefined] The queue group for the qpage mailer.
LOCAL_PROG_QGRP		[undefined] The queue group for the prog mailer.

Note: to tweak Name_MAILER_FLAGS use the macro MODIFY_MAILER_FLAGS:
MODIFY_MAILER_FLAGS(`Name', `change') where Name is the first part
of the macro Name_MAILER_FLAGS (note: that means Name is entirely in
upper case) and change can be: flags that should be used directly
(thus overriding the default value), or if it starts with `+' (`-')
then those flags are added to (removed from) the default value.
Example:

	MODIFY_MAILER_FLAGS(`LOCAL', `+e')

will add the flag `e' to LOCAL_MAILER_FLAGS.  Notice: there are
several smtp mailers all of which are manipulated individually.
See the section MAILERS for the available mailer names.
WARNING: The FEATUREs local_lmtp and local_procmail set LOCAL_MAILER_FLAGS
unconditionally, i.e., without respecting any definitions in an
OSTYPE setting.


+---------+
| DOMAINS |
+---------+

You will probably want to collect domain-dependent defines into one
file, referenced by the DOMAIN macro.  For example, the Berkeley
domain file includes definitions for several internal distinguished
hosts:

UUCP_RELAY	The host that will accept UUCP-addressed email.
		If not defined, all UUCP sites must be directly
		connected.
BITNET_RELAY	The host that will accept BITNET-addressed email.
		If not defined, the .BITNET pseudo-domain won't work.
DECNET_RELAY	The host that will accept DECNET-addressed email.
		If not defined, the .DECNET pseudo-domain and addresses
		of the form node::user will not work.
FAX_RELAY	The host that will accept mail to the .FAX pseudo-domain.
		The "fax" mailer overrides this value.
LOCAL_RELAY	The site that will handle unqualified names -- that
		is, names without an @domain extension.
		Normally MAIL_HUB is preferred for this function.
		LOCAL_RELAY is mostly useful in conjunction with
		FEATURE(`stickyhost') -- see the discussion of
		stickyhost below.  If not set, they are assumed to
		belong on this machine.  This allows you to have a
		central site to store a company- or department-wide
		alias database.  This only works at small sites,
		and only with some user agents.
LUSER_RELAY	The site that will handle lusers -- that is, apparently
		local names that aren't local accounts or aliases.  To
		specify a local user instead of a site, set this to
		``local:username''.

Any of these can be either ``mailer:hostname'' (in which case the
mailer is the internal mailer name, such as ``uucp-new'' and the hostname
is the name of the host as appropriate for that mailer) or just a
``hostname'', in which case a default mailer type (usually ``relay'',
a variant on SMTP) is used.  WARNING: if you have a wildcard MX
record matching your domain, you probably want to define these to
have a trailing dot so that you won't get the mail diverted back
to yourself.

The domain file can also be used to define a domain name, if needed
(using "DD<domain>") and set certain site-wide features.  If all hosts
at your site masquerade behind one email name, you could also use
MASQUERADE_AS here.

You do not have to define a domain -- in particular, if you are a
single machine sitting off somewhere, it is probably more work than
it's worth.  This is just a mechanism for combining "domain dependent
knowledge" into one place.


+---------+
| MAILERS |
+---------+

There are fewer mailers supported in this version than the previous
version, owing mostly to a simpler world.  As a general rule, put the
MAILER definitions last in your .mc file.

local		The local and prog mailers.  You will almost always
		need these; the only exception is if you relay ALL
		your mail to another site.  This mailer is included
		automatically.

smtp		The Simple Mail Transport Protocol mailer.  This does
		not hide hosts behind a gateway or another other
		such hack; it assumes a world where everyone is
		running the name server.  This file actually defines
		five mailers: "smtp" for regular (old-style) SMTP to
		other servers, "esmtp" for extended SMTP to other
		servers, "smtp8" to do SMTP to other servers without
		converting 8-bit data to MIME (essentially, this is
		your statement that you know the other end is 8-bit
		clean even if it doesn't say so), "dsmtp" to do on
		demand delivery, and "relay" for transmission to the
		RELAY_HOST, LUSER_RELAY, or MAIL_HUB.

uucp		The UNIX-to-UNIX Copy Program mailer.  Actually, this
		defines two mailers, "uucp-old" (a.k.a. "uucp") and
		"uucp-new" (a.k.a. "suucp").  The latter is for when you
		know that the UUCP mailer at the other end can handle
		multiple recipients in one transfer.  If the smtp mailer
		is included in your configuration, two other mailers
		("uucp-dom" and "uucp-uudom") are also defined [warning: you
		MUST specify MAILER(`smtp') before MAILER(`uucp')].  When you
		include the uucp mailer, sendmail looks for all names in
		class {U} and sends them to the uucp-old mailer; all
		names in class {Y} are sent to uucp-new; and all
		names in class {Z} are sent to uucp-uudom.  Note that
		this is a function of what version of rmail runs on
		the receiving end, and hence may be out of your control.
		See the section below describing UUCP mailers in more
		detail.

usenet		Usenet (network news) delivery.  If this is specified,
		an extra rule is added to ruleset 0 that forwards all
		local email for users named ``group.usenet'' to the
		``inews'' program.  Note that this works for all groups,
		and may be considered a security problem.

fax		Facsimile transmission.  This is experimental and based
		on Sam Leffler's HylaFAX software.  For more information,
		see http://www.hylafax.org/.

pop		Post Office Protocol.

procmail	An interface to procmail (does not come with sendmail).
		This is designed to be used in mailertables.  For example,
		a common question is "how do I forward all mail for a given
		domain to a single person?".  If you have this mailer
		defined, you could set up a mailertable reading:

			host.com	procmail:/etc/procmailrcs/host.com

		with the file /etc/procmailrcs/host.com reading:

			:0	# forward mail for host.com
			! -oi -f $1 person@other.host

		This would arrange for (anything)@host.com to be sent
		to person@other.host.  In a procmail script, $1 is the
		name of the sender and $2 is the name of the recipient.
		If you use this with FEATURE(`local_procmail'), the FEATURE
		should be listed first.

		Of course there are other ways to solve this particular
		problem, e.g., a catch-all entry in a virtusertable.

mail11		The DECnet mail11 mailer, useful only if you have the mail11
		program from gatekeeper.dec.com:/pub/DEC/gwtools (and
		DECnet, of course).  This is for Phase IV DECnet support;
		if you have Phase V at your site you may have additional
		problems.

phquery		The phquery program.  This is somewhat counterintuitively
		referenced as the "ph" mailer internally.  It can be used
		to do CCSO name server lookups.  The phquery program, which
		this mailer uses, is distributed with the ph client.

cyrus		The cyrus and cyrusbb mailers.  The cyrus mailer delivers to
		a local cyrus user.  this mailer can make use of the
		"user+detail@local.host" syntax (see
		FEATURE(`preserve_local_plus_detail')); it will deliver the
		mail to the user's "detail" mailbox if the mailbox's ACL
		permits.  The cyrusbb mailer delivers to a system-wide
		cyrus mailbox if the mailbox's ACL permits.  The cyrus
		mailer must be defined after the local mailer.

cyrusv2		The mailer for Cyrus v2.x.  The cyrusv2 mailer delivers to
		local cyrus users via LMTP.  This mailer can make use of the
		"user+detail@local.host" syntax (see
		FEATURE(`preserve_local_plus_detail')); it will deliver the
		mail to the user's "detail" mailbox if the mailbox's ACL
		permits.  The cyrusv2 mailer must be defined after the
		local mailer.

qpage		A mailer for QuickPage, a pager interface.  See
		http://www.qpage.org/ for further information.

The local mailer accepts addresses of the form "user+detail", where
the "+detail" is not used for mailbox matching but is available
to certain local mail programs (in particular, see
FEATURE(`local_procmail')).  For example, "eric", "eric+sendmail", and
"eric+sww" all indicate the same user, but additional arguments <null>,
"sendmail", and "sww" may be provided for use in sorting mail.


+----------+
| FEATURES |
+----------+

Special features can be requested using the "FEATURE" macro.  For
example, the .mc line:

	FEATURE(`use_cw_file')

tells sendmail that you want to have it read an /etc/mail/local-host-names
file to get values for class {w}.  A FEATURE may contain up to 9
optional parameters -- for example:

	FEATURE(`mailertable', `dbm /usr/lib/mailertable')

The default database map type for the table features can be set with

	define(`DATABASE_MAP_TYPE', `dbm')

which would set it to use ndbm databases.  The default is the Berkeley DB
hash database format.  Note that you must still declare a database map type
if you specify an argument to a FEATURE.  DATABASE_MAP_TYPE is only used
if no argument is given for the FEATURE.  It must be specified before any
feature that uses a map.

Also, features which can take a map definition as an argument can also take
the special keyword `LDAP'.  If that keyword is used, the map will use the
LDAP definition described in the ``USING LDAP FOR ALIASES, MAPS, AND
CLASSES'' section below.

Available features are:

use_cw_file	Read the file /etc/mail/local-host-names file to get
		alternate names for this host.  This might be used if you
		were on a host that MXed for a dynamic set of other hosts.
		If the set is static, just including the line "Cw<name1>
		<name2> ..." (where the names are fully qualified domain
		names) is probably superior.  The actual filename can be
		overridden by redefining confCW_FILE.

use_ct_file	Read the file /etc/mail/trusted-users file to get the
		names of users that will be ``trusted'', that is, able to
		set their envelope from address using -f without generating
		a warning message.  The actual filename can be overridden
		by redefining confCT_FILE.

redirect	Reject all mail addressed to "address.REDIRECT" with
		a ``551 User has moved; please try <address>'' message.
		If this is set, you can alias people who have left
		to their new address with ".REDIRECT" appended.

nouucp		Don't route UUCP addresses.  This feature takes one
		parameter:
		`reject': reject addresses which have "!" in the local
			part unless it originates from a system
			that is allowed to relay.
		`nospecial': don't do anything special with "!".
		Warnings: 1. See the notice in the anti-spam section.
		2. don't remove "!" from OperatorChars if `reject' is
		given as parameter.

nocanonify	Don't pass addresses to $[ ... $] for canonification
		by default, i.e., host/domain names are considered canonical,
		except for unqualified names, which must not be used in this
		mode (violation of the standard).  It can be changed by
		setting the DaemonPortOptions modifiers (M=).  That is,
		FEATURE(`nocanonify') will be overridden by setting the
		'c' flag.  Conversely, if FEATURE(`nocanonify') is not used,
		it can be emulated by setting the 'C' flag
		(DaemonPortOptions=Modifiers=C).  This would generally only
		be used by sites that only act as mail gateways or which have
		user agents that do full canonification themselves.  You may
		also want to use
		"define(`confBIND_OPTS', `-DNSRCH -DEFNAMES')" to turn off
		the usual resolver options that do a similar thing.

		An exception list for FEATURE(`nocanonify') can be
		specified with CANONIFY_DOMAIN or CANONIFY_DOMAIN_FILE,
		i.e., a list of domains which are nevertheless passed to
		$[ ... $] for canonification.  This is useful to turn on
		canonification for local domains, e.g., use
		CANONIFY_DOMAIN(`my.domain my') to canonify addresses
		which end in "my.domain" or "my".
		Another way to require canonification in the local
		domain is CANONIFY_DOMAIN(`$=m').

		A trailing dot is added to addresses with more than
		one component in it such that other features which
		expect a trailing dot (e.g., virtusertable) will
		still work.

		If `canonify_hosts' is specified as parameter, i.e.,
		FEATURE(`nocanonify', `canonify_hosts'), then
		addresses which have only a hostname, e.g.,
		<user@host>, will be canonified (and hopefully fully
		qualified), too.

stickyhost	This feature is sometimes used with LOCAL_RELAY,
		although it can be used for a different effect with
		MAIL_HUB.

		When used without MAIL_HUB, email sent to
		"user@local.host" are marked as "sticky" -- that
		is, the local addresses aren't matched against UDB,
		don't go through ruleset 5, and are not forwarded to
		the LOCAL_RELAY (if defined).

		With MAIL_HUB, mail addressed to "user@local.host"
		is forwarded to the mail hub, with the envelope
		address still remaining "user@local.host".
		Without stickyhost, the envelope would be changed
		to "user@mail_hub", in order to protect against
		mailing loops.

mailertable	Include a "mailer table" which can be used to override
		routing for particular domains (which are not in class {w},
		i.e.  local host names).  The argument of the FEATURE may be
		the key definition.  If none is specified, the definition
		used is:

			hash /etc/mail/mailertable

		Keys in this database are fully qualified domain names
		or partial domains preceded by a dot -- for example,
		"vangogh.CS.Berkeley.EDU" or ".CS.Berkeley.EDU".  As a
		special case of the latter, "." matches any domain not
		covered by other keys.  Values must be of the form:
			mailer:domain
		where "mailer" is the internal mailer name, and "domain"
		is where to send the message.  These maps are not
		reflected into the message header.  As a special case,
		the forms:
			local:user
		will forward to the indicated user using the local mailer,
			local:
		will forward to the original user in the e-mail address
		using the local mailer, and
			error:code message
			error:D.S.N:code message
		will give an error message with the indicated SMTP reply
		code and message, where D.S.N is an RFC 1893 compliant
		error code.

domaintable	Include a "domain table" which can be used to provide
		domain name mapping.  Use of this should really be
		limited to your own domains.  It may be useful if you
		change names (e.g., your company changes names from
		oldname.com to newname.com).  The argument of the
		FEATURE may be the key definition.  If none is specified,
		the definition used is:

			hash /etc/mail/domaintable

		The key in this table is the domain name; the value is
		the new (fully qualified) domain.  Anything in the
		domaintable is reflected into headers; that is, this
		is done in ruleset 3.

bitdomain	Look up bitnet hosts in a table to try to turn them into
		internet addresses.  The table can be built using the
		bitdomain program contributed by John Gardiner Myers.
		The argument of the FEATURE may be the key definition; if
		none is specified, the definition used is:

			hash /etc/mail/bitdomain

		Keys are the bitnet hostname; values are the corresponding
		internet hostname.

uucpdomain	Similar feature for UUCP hosts.  The default map definition
		is:

			hash /etc/mail/uudomain

		At the moment there is no automagic tool to build this
		database.

always_add_domain
		Include the local host domain even on locally delivered
		mail.  Normally it is not added on unqualified names.
		However, if you use a shared message store but do not use
		the same user name space everywhere, you may need the host
		name on local names.  An optional argument specifies
		another domain to be added than the local.

allmasquerade	If masquerading is enabled (using MASQUERADE_AS), this
		feature will cause recipient addresses to also masquerade
		as being from the masquerade host.  Normally they get
		the local hostname.  Although this may be right for
		ordinary users, it can break local aliases.  For example,
		if you send to "localalias", the originating sendmail will
		find that alias and send to all members, but send the
		message with "To: localalias@masqueradehost".  Since that
		alias likely does not exist, replies will fail.  Use this
		feature ONLY if you can guarantee that the ENTIRE
		namespace on your masquerade host supersets all the
		local entries.

limited_masquerade
		Normally, any hosts listed in class {w} are masqueraded.  If
		this feature is given, only the hosts listed in class {M} (see
		below:  MASQUERADE_DOMAIN) are masqueraded.  This is useful
		if you have several domains with disjoint namespaces hosted
		on the same machine.

masquerade_entire_domain
		If masquerading is enabled (using MASQUERADE_AS) and
		MASQUERADE_DOMAIN (see below) is set, this feature will
		cause addresses to be rewritten such that the masquerading
		domains are actually entire domains to be hidden.  All
		hosts within the masquerading domains will be rewritten
		to the masquerade name (used in MASQUERADE_AS).  For example,
		if you have:

			MASQUERADE_AS(`masq.com')
			MASQUERADE_DOMAIN(`foo.org')
			MASQUERADE_DOMAIN(`bar.com')

		then *foo.org and *bar.com are converted to masq.com.  Without
		this feature, only foo.org and bar.com are masqueraded.

		    NOTE: only domains within your jurisdiction and
		    current hierarchy should be masqueraded using this.

local_no_masquerade
		This feature prevents the local mailer from masquerading even
		if MASQUERADE_AS is used.  MASQUERADE_AS will only have effect
		on addresses of mail going outside the local domain.

masquerade_envelope
		If masquerading is enabled (using MASQUERADE_AS) or the
		genericstable is in use, this feature will cause envelope
		addresses to also masquerade as being from the masquerade
		host.  Normally only the header addresses are masqueraded.

genericstable	This feature will cause unqualified addresses (i.e., without
		a domain) and addresses with a domain listed in class {G}
		to be looked up in a map and turned into another ("generic")
		form, which can change both the domain name and the user name.
		Notice: if you use an MSP (as it is default starting with
		8.12), the MTA will only receive qualified addresses from the
		MSP (as required by the RFCs).  Hence you need to add your
		domain to class {G}.  This feature is similar to the userdb
		functionality.  The same types of addresses as for
		masquerading are looked up, i.e., only header sender
		addresses unless the allmasquerade and/or masquerade_envelope
		features are given.  Qualified addresses must have the domain
		part in class {G}; entries can be added to this class by the
		macros GENERICS_DOMAIN or GENERICS_DOMAIN_FILE (analogously
		to MASQUERADE_DOMAIN and MASQUERADE_DOMAIN_FILE, see below).

		The argument of FEATURE(`genericstable') may be the map
		definition; the default map definition is:

			hash /etc/mail/genericstable

		The key for this table is either the full address, the domain
		(with a leading @; the localpart is passed as first argument)
		or the unqualified username (tried in the order mentioned);
		the value is the new user address.  If the new user address
		does not include a domain, it will be qualified in the standard
		manner, i.e., using $j or the masquerade name.  Note that the
		address being looked up must be fully qualified.  For local
		mail, it is necessary to use FEATURE(`always_add_domain')
		for the addresses to be qualified.
		The "+detail" of an address is passed as %1, so entries like

			old+*@foo.org	new+%1@example.com
			gen+*@foo.org	%1@example.com

		and other forms are possible.

generics_entire_domain
		If the genericstable is enabled and GENERICS_DOMAIN or
		GENERICS_DOMAIN_FILE is used, this feature will cause
		addresses to be searched in the map if their domain
		parts are subdomains of elements in class {G}.

virtusertable	A domain-specific form of aliasing, allowing multiple
		virtual domains to be hosted on one machine.  For example,
		if the virtuser table contains:

			info@foo.com	foo-info
			info@bar.com	bar-info
			joe@bar.com	error:nouser 550 No such user here
			jax@bar.com	error:5.7.0:550 Address invalid
			@baz.org	jane@example.net

		then mail addressed to info@foo.com will be sent to the
		address foo-info, mail addressed to info@bar.com will be
		delivered to bar-info, and mail addressed to anyone at baz.org
		will be sent to jane@example.net, mail to joe@bar.com will
		be rejected with the specified error message, and mail to
		jax@bar.com will also have a RFC 1893 compliant error code
		5.7.0.

		The username from the original address is passed
		as %1 allowing:

			@foo.org	%1@example.com

		meaning someone@foo.org will be sent to someone@example.com.
		Additionally, if the local part consists of "user+detail"
		then "detail" is passed as %2 and "+detail" is passed as %3
		when a match against user+* is attempted, so entries like

			old+*@foo.org	new+%2@example.com
			gen+*@foo.org	%2@example.com
			+*@foo.org	%1%3@example.com
			X++@foo.org	Z%3@example.com
			@bar.org	%1%3

		and other forms are possible.  Note: to preserve "+detail"
		for a default case (@domain) %1%3 must be used as RHS.
		There are two wildcards after "+": "+" matches only a non-empty
		detail, "*" matches also empty details, e.g., user+@foo.org
		matches +*@foo.org but not ++@foo.org.  This can be used
		to ensure that the parameters %2 and %3 are not empty.

		All the host names on the left hand side (foo.com, bar.com,
		and baz.org) must be in class {w} or class {VirtHost}.  The
		latter can be defined by the macros VIRTUSER_DOMAIN or
		VIRTUSER_DOMAIN_FILE (analogously to MASQUERADE_DOMAIN and
		MASQUERADE_DOMAIN_FILE, see below).  If VIRTUSER_DOMAIN or
		VIRTUSER_DOMAIN_FILE is used, then the entries of class
		{VirtHost} are added to class {R}, i.e., relaying is allowed
		to (and from) those domains.  The default map definition is:

			hash /etc/mail/virtusertable

		A new definition can be specified as the second argument of
		the FEATURE macro, such as

			FEATURE(`virtusertable', `dbm /etc/mail/virtusers')

virtuser_entire_domain
		If the virtusertable is enabled and VIRTUSER_DOMAIN or
		VIRTUSER_DOMAIN_FILE is used, this feature will cause
		addresses to be searched in the map if their domain
		parts are subdomains of elements in class {VirtHost}.

ldap_routing	Implement LDAP-based e-mail recipient routing according to
		the Internet Draft draft-lachman-laser-ldap-mail-routing-01.
		This provides a method to re-route addresses with a
		domain portion in class {LDAPRoute} to either a
		different mail host or a different address.  Hosts can
		be added to this class using LDAPROUTE_DOMAIN and
		LDAPROUTE_DOMAIN_FILE (analogously to MASQUERADE_DOMAIN and
		MASQUERADE_DOMAIN_FILE, see below).

		See the LDAP ROUTING section below for more information.

nodns		If you aren't running DNS at your site (for example,
		you are UUCP-only connected).  It's hard to consider
		this a "feature", but hey, it had to go somewhere.
		Actually, as of 8.7 this is a no-op -- remove "dns" from
		the hosts service switch entry instead.

nullclient	This is a special case -- it creates a configuration file
		containing nothing but support for forwarding all mail to a
		central hub via a local SMTP-based network.  The argument
		is the name of that hub.

		The only other feature that should be used in conjunction
		with this one is FEATURE(`nocanonify').  No mailers
		should be defined.  No aliasing or forwarding is done.

local_lmtp	Use an LMTP capable local mailer.  The argument to this
		feature is the pathname of an LMTP capable mailer.  By
		default, mail.local is used.  This is expected to be the
		mail.local which came with the 8.9 distribution which is
		LMTP capable.  The path to mail.local is set by the
		confEBINDIR m4 variable -- making the default
		LOCAL_MAILER_PATH /usr/libexec/mail.local.
		If a different LMTP capable mailer is used, its pathname
		can be specified as second parameter and the arguments
		passed to it (A=) as third parameter, e.g.,

			FEATURE(`local_lmtp', `/usr/local/bin/lmtp', `lmtp')

		WARNING: This feature sets LOCAL_MAILER_FLAGS unconditionally,
		i.e., without respecting any definitions in an OSTYPE setting.

local_procmail	Use procmail or another delivery agent as the local mailer.
		The argument to this feature is the pathname of the
		delivery agent, which defaults to PROCMAIL_MAILER_PATH.
		Note that this does NOT use PROCMAIL_MAILER_FLAGS or
		PROCMAIL_MAILER_ARGS for the local mailer; tweak
		LOCAL_MAILER_FLAGS and LOCAL_MAILER_ARGS instead, or
		specify the appropriate parameters.  When procmail is used,
		the local mailer can make use of the
		"user+indicator@local.host" syntax; normally the +indicator
		is just tossed, but by default it is passed as the -a
		argument to procmail.

		This feature can take up to three arguments:

		1. Path to the mailer program
		   [default: /usr/local/bin/procmail]
		2. Argument vector including name of the program
		   [default: procmail -Y -a $h -d $u]
		3. Flags for the mailer [default: SPfhn9]

		Empty arguments cause the defaults to be taken.
		Note that if you are on a system with a broken
		setreuid() call, you may need to add -f $f to the procmail
		argument vector to pass the proper sender to procmail.

		For example, this allows it to use the maildrop
		(http://www.flounder.net/~mrsam/maildrop/) mailer instead
		by specifying:

		FEATURE(`local_procmail', `/usr/local/bin/maildrop',
		 `maildrop -d $u')

		or scanmails using:

		FEATURE(`local_procmail', `/usr/local/bin/scanmails')

		WARNING: This feature sets LOCAL_MAILER_FLAGS unconditionally,
		i.e.,  without respecting any definitions in an OSTYPE setting.

bestmx_is_local	Accept mail as though locally addressed for any host that
		lists us as the best possible MX record.  This generates
		additional DNS traffic, but should be OK for low to
		medium traffic hosts.  The argument may be a set of
		domains, which will limit the feature to only apply to
		these domains -- this will reduce unnecessary DNS
		traffic.  THIS FEATURE IS FUNDAMENTALLY INCOMPATIBLE WITH
		WILDCARD MX RECORDS!!!  If you have a wildcard MX record
		that matches your domain, you cannot use this feature.

smrsh		Use the SendMail Restricted SHell (smrsh) provided
		with the distribution instead of /bin/sh for mailing
		to programs.  This improves the ability of the local
		system administrator to control what gets run via
		e-mail.  If an argument is provided it is used as the
		pathname to smrsh; otherwise, the path defined by
		confEBINDIR is used for the smrsh binary -- by default,
		/usr/libexec/smrsh is assumed.

promiscuous_relay
		By default, the sendmail configuration files do not permit
		mail relaying (that is, accepting mail from outside your
		local host (class {w}) and sending it to another host than
		your local host).  This option sets your site to allow
		mail relaying from any site to any site.  In almost all
		cases, it is better to control relaying more carefully
		with the access map, class {R}, or authentication.  Domains
		can be added to class {R} by the macros RELAY_DOMAIN or
		RELAY_DOMAIN_FILE (analogously to MASQUERADE_DOMAIN and
		MASQUERADE_DOMAIN_FILE, see below).

relay_entire_domain
		This option allows any host in your domain as defined by
		class {m} to use your server for relaying.  Notice: make
		sure that your domain is not just a top level domain,
		e.g., com.  This can happen if you give your host a name
		like example.com instead of host.example.com.

relay_hosts_only
		By default, names that are listed as RELAY in the access
		db and class {R} are treated as domain names, not host names.
		For example, if you specify ``foo.com'', then mail to or
		from foo.com, abc.foo.com, or a.very.deep.domain.foo.com
		will all be accepted for relaying.  This feature changes
		the behaviour to lookup individual host names only.

relay_based_on_MX
		Turns on the ability to allow relaying based on the MX
		records of the host portion of an incoming recipient; that
		is, if an MX record for host foo.com points to your site,
		you will accept and relay mail addressed to foo.com.  See
		description below for more information before using this
		feature.  Also, see the KNOWNBUGS entry regarding bestmx
		map lookups.

		FEATURE(`relay_based_on_MX') does not necessarily allow
		routing of these messages which you expect to be allowed,
		if route address syntax (or %-hack syntax) is used.  If
		this is a problem, add entries to the access-table or use
		FEATURE(`loose_relay_check').

relay_mail_from
		Allows relaying if the mail sender is listed as RELAY in
		the access map.  If an optional argument `domain' (this
		is the literal word `domain', not a placeholder) is given,
		relaying can be allowed just based on the domain portion
		of the sender address.  This feature should only be used if
		absolutely necessary as the sender address can be easily
		forged.  Use of this feature requires the "From:" tag to
		be used for the key in the access map; see the discussion
		of tags and FEATURE(`relay_mail_from') in the section on
		anti-spam configuration control.

relay_local_from
		Allows relaying if the domain portion of the mail sender
		is a local host.  This should only be used if absolutely
		necessary as it opens a window for spammers.  Specifically,
		they can send mail to your mail server that claims to be
		from your domain (either directly or via a routed address),
		and you will go ahead and relay it out to arbitrary hosts
		on the Internet.

accept_unqualified_senders
		Normally, MAIL FROM: commands in the SMTP session will be
		refused if the connection is a network connection and the
		sender address does not include a domain name.  If your
		setup sends local mail unqualified (i.e., MAIL FROM:<joe>),
		you will need to use this feature to accept unqualified
		sender addresses.  Setting the DaemonPortOptions modifier
		'u' overrides the default behavior, i.e., unqualified
		addresses are accepted even without this FEATURE.
		If this FEATURE is not used, the DaemonPortOptions modifier
		'f' can be used to enforce fully qualified addresses.

accept_unresolvable_domains
		Normally, MAIL FROM: commands in the SMTP session will be
		refused if the host part of the argument to MAIL FROM:
		cannot be located in the host name service (e.g., an A or
		MX record in DNS).  If you are inside a firewall that has
		only a limited view of the Internet host name space, this
		could cause problems.  In this case you probably want to
		use this feature to accept all domains on input, even if
		they are unresolvable.

access_db	Turns on the access database feature.  The access db gives
		you the ability to allow or refuse to accept mail from
		specified domains for administrative reasons.  Moreover,
		it can control the behavior of sendmail in various situations.
		By default, the access database specification is:

			hash -T<TMPF> /etc/mail/access

		See the anti-spam configuration control section for further
		important information about this feature.  Notice:
		"-T<TMPF>" is meant literal, do not replace it by anything.

blacklist_recipients
		Turns on the ability to block incoming mail for certain
		recipient usernames, hostnames, or addresses.  For
		example, you can block incoming mail to user nobody,
		host foo.mydomain.com, or guest@bar.mydomain.com.
		These specifications are put in the access db as
		described in the anti-spam configuration control section
		later in this document.

delay_checks	The rulesets check_mail and check_relay will not be called
		when a client connects or issues a MAIL command, respectively.
		Instead, those rulesets will be called by the check_rcpt
		ruleset; they will be skipped under certain circumstances.
		See "Delay all checks" in the anti-spam configuration control
		section.  Note: this feature is incompatible to the versions
		in 8.10 and 8.11.

use_client_ptr	If this feature is enabled then check_relay will override
		its first argument with $&{client_ptr}.  This is useful for
		rejections based on the unverified hostname of client,
		which turns on the same behavior as in earlier sendmail
		versions when delay_checks was not in use.  See doc/op/op.*
		about check_relay, {client_name}, and {client_ptr}.

dnsbl		Turns on rejection of hosts found in an DNS based rejection
		list.  The first is used as the domain in which blocked
		hosts are listed.  A second argument can be used to change
		the default error message.  Without that second argument,
		the error message will be
			Rejected: IP-ADDRESS listed at SERVER
		where IP-ADDRESS and SERVER are replaced by the appropriate
		information.  By default, temporary lookup failures are
		ignored.  This behavior can be changed by specifying a
		third argument, which must be either `t' or a full error
		message.  See the anti-spam configuration control section for
		an example.  The dnsbl feature can be included several times
		to query different DNS based rejection lists.  See also
		enhdnsbl for an enhanced version.

		Set the DNSBL_MAP mc option to change the default map
		definition from `host'.  Set the DNSBL_MAP_OPT mc option
		to add additional options to the map specification used.

		Some DNS based rejection lists cause failures if asked
		for AAAA records. If your sendmail version is compiled
		with IPv6 support (NETINET6) and you experience this
		problem, add

			define(`DNSBL_MAP', `dns -R A')

		before the first use of this feature.  Alternatively you
		can use enhdnsbl instead (see below).  Moreover, this
		statement can be used to reduce the number of DNS retries,
		e.g.,

			define(`DNSBL_MAP', `dns -R A -r2')

		See below (EDNSBL_TO) for an explanation.

enhdnsbl	Enhanced version of dnsbl (see above).  Further arguments
		(up to 5) can be used to specify specific return values
		from lookups.  Temporary lookup failures are ignored unless
		a third argument is given, which must be either `t' or a full
		error message.  By default, any successful lookup will
		generate an error.  Otherwise the result of the lookup is
		compared with the supplied argument(s), and only if a match
		occurs an error is generated.  For example,

		FEATURE(`enhdnsbl', `dnsbl.example.com', `', `t', `127.0.0.2.')

		will reject the e-mail if the lookup returns the value
		``127.0.0.2.'', or generate a 451 response if the lookup
		temporarily failed.  The arguments can contain metasymbols
		as they are allowed in the LHS of rules.  As the example
		shows, the default values are also used if an empty argument,
		i.e., `', is specified.  This feature requires that sendmail
		has been compiled with the flag DNSMAP (see sendmail/README).

		Set the EDNSBL_TO mc option to change the DNS retry count
		from the default value of 5, this can be very useful when
		a DNS server is not responding, which in turn may cause
		clients to time out (an entry stating

			did not issue MAIL/EXPN/VRFY/ETRN

		will be logged).

ratecontrol	Enable simple ruleset to do connection rate control
		checking.  This requires entries in access_db of the form

			ClientRate:IP.ADD.RE.SS		LIMIT

		The RHS specifies the maximum number of connections
		(an integer number) over the time interval defined
		by ConnectionRateWindowSize, where 0 means unlimited.

		Take the following example:

			ClientRate:10.1.2.3		4
			ClientRate:127.0.0.1		0
			ClientRate:			10

		10.1.2.3 can only make up to 4 connections, the
		general limit it 10, and 127.0.0.1 can make an unlimited
		number of connections per ConnectionRateWindowSize.

		See also CONNECTION CONTROL.

conncontrol	Enable a simple check of the number of incoming SMTP
		connections.  This requires entries in access_db of the
		form

			ClientConn:IP.ADD.RE.SS		LIMIT

		The RHS specifies the maximum number of open connections
		(an integer number).

		Take the following example:

			ClientConn:10.1.2.3		4
			ClientConn:127.0.0.1		0
			ClientConn:			10

		10.1.2.3 can only have up to 4 open connections, the
		general limit it 10, and 127.0.0.1 does not have any
		explicit limit.

		See also CONNECTION CONTROL.

mtamark		Experimental support for "Marking Mail Transfer Agents in
		Reverse DNS with TXT RRs" (MTAMark), see
		draft-stumpf-dns-mtamark-01.  Optional arguments are:

		1. Error message, default:

			550 Rejected: $&{client_addr} not listed as MTA

		2. Temporary lookup failures are ignored unless a second
		argument is given, which must be either `t' or a full
		error message.

		3. Lookup prefix, default: _perm._smtp._srv.  This should
		not be changed unless the draft changes it.

		Example:

			FEATURE(`mtamark', `', `t')

lookupdotdomain	Look up also .domain in the access map.  This allows to
		match only subdomains.  It does not work well with
		FEATURE(`relay_hosts_only'), because most lookups for
		subdomains are suppressed by the latter feature.

loose_relay_check
		Normally, if % addressing is used for a recipient, e.g.
		user%site@othersite, and othersite is in class {R}, the
		check_rcpt ruleset will strip @othersite and recheck
		user@site for relaying.  This feature changes that
		behavior.  It should not be needed for most installations.

authinfo	Provide a separate map for client side authentication
		information.  See SMTP AUTHENTICATION for details.
		By default, the authinfo database specification is:

			hash /etc/mail/authinfo

preserve_luser_host
		Preserve the name of the recipient host if LUSER_RELAY is
		used.  Without this option, the domain part of the
		recipient address will be replaced by the host specified as
		LUSER_RELAY.  This feature only works if the hostname is
		passed to the mailer (see mailer triple in op.me).  Note
		that in the default configuration the local mailer does not
		receive the hostname, i.e., the mailer triple has an empty
		hostname.

preserve_local_plus_detail
		Preserve the +detail portion of the address when passing
		address to local delivery agent.  Disables alias and
		.forward +detail stripping (e.g., given user+detail, only
		that address will be looked up in the alias file; user+* and
		user will not be looked up).  Only use if the local
		delivery agent in use supports +detail addressing.

compat_check	Enable ruleset check_compat to look up pairs of addresses
		with the Compat: tag --	Compat:sender<@>recipient -- in the
		access map.  Valid values for the RHS include
			DISCARD	silently discard recipient
			TEMP:	return a temporary error
			ERROR:	return a permanent error
		In the last two cases, a 4xy/5xy SMTP reply code should
		follow the colon.

no_default_msa	Don't generate the default MSA daemon, i.e.,
		DAEMON_OPTIONS(`Port=587,Name=MSA,M=E')
		To define a MSA daemon with other parameters, use this
		FEATURE and introduce new settings via DAEMON_OPTIONS().

msp		Defines config file for Message Submission Program.
		See sendmail/SECURITY for details and cf/cf/submit.mc how
		to use it.  An optional argument can be used to override
		the default of `[localhost]' to use as host to send all
		e-mails to.  Note that MX records will be used if the
		specified hostname is not in square brackets (e.g.,
		[hostname]).  If `MSA' is specified as second argument then
		port 587 is used to contact the server.  Example:

			FEATURE(`msp', `', `MSA')

		Some more hints about possible changes can be found below
		in the section MESSAGE SUBMISSION PROGRAM.

		Note: Due to many problems, submit.mc uses

			FEATURE(`msp', `[127.0.0.1]')

		by default.  If you have a machine with IPv6 only,
		change it to

			FEATURE(`msp', `[IPv6:::1]')

		If you want to continue using '[localhost]', (the behavior
		up to 8.12.6), use

			FEATURE(`msp')

queuegroup	A simple example how to select a queue group based
		on the full e-mail address or the domain of the
		recipient.  Selection is done via entries in the
		access map using the tag QGRP:, for example:

			QGRP:example.com	main
			QGRP:friend@some.org	others
			QGRP:my.domain		local

		where "main", "others", and "local" are names of
		queue groups.  If an argument is specified, it is used
		as default queue group.

		Note: please read the warning in doc/op/op.me about
		queue groups and possible queue manipulations.

greet_pause	Adds the greet_pause ruleset which enables open proxy
		and SMTP slamming protection.  The feature can take an
		argument specifying the milliseconds to wait:

			FEATURE(`greet_pause', `5000')  dnl 5 seconds

		If FEATURE(`access_db') is enabled, an access database
		lookup with the GreetPause tag is done using client
		hostname, domain, IP address, or subnet to determine the
		pause time:

			GreetPause:my.domain	0
			GreetPause:example.com	5000
			GreetPause:10.1.2	2000
			GreetPause:127.0.0.1	0

		When using FEATURE(`access_db'), the optional
		FEATURE(`greet_pause') argument becomes the default if
		nothing is found in the access database.  A ruleset called
		Local_greet_pause can be used for local modifications, e.g.,

			LOCAL_RULESETS
			SLocal_greet_pause
			R$*		$: $&{daemon_flags}
			R$* a $*	$# 0

+-------+
| HACKS |
+-------+

Some things just can't be called features.  To make this clear,
they go in the hack subdirectory and are referenced using the HACK
macro.  These will tend to be site-dependent.  The release
includes the Berkeley-dependent "cssubdomain" hack (that makes
sendmail accept local names in either Berkeley.EDU or CS.Berkeley.EDU;
this is intended as a short-term aid while moving hosts into
subdomains.


+--------------------+
| SITE CONFIGURATION |
+--------------------+

    *****************************************************
    * This section is really obsolete, and is preserved	*
    * only for back compatibility.  You should plan on	*
    * using mailertables for new installations.  In	*
    * particular, it doesn't work for the newer forms	*
    * of UUCP mailers, such as uucp-uudom.		*
    *****************************************************

Complex sites will need more local configuration information, such as
lists of UUCP hosts they speak with directly.  This can get a bit more
tricky.  For an example of a "complex" site, see cf/ucbvax.mc.

The SITECONFIG macro allows you to indirectly reference site-dependent
configuration information stored in the siteconfig subdirectory.  For
example, the line

	SITECONFIG(`uucp.ucbvax', `ucbvax', `U')

reads the file uucp.ucbvax for local connection information.  The
second parameter is the local name (in this case just "ucbvax" since
it is locally connected, and hence a UUCP hostname).  The third
parameter is the name of both a macro to store the local name (in
this case, {U}) and the name of the class (e.g., {U}) in which to store
the host information read from the file.  Another SITECONFIG line reads

	SITECONFIG(`uucp.ucbarpa', `ucbarpa.Berkeley.EDU', `W')

This says that the file uucp.ucbarpa contains the list of UUCP sites
connected to ucbarpa.Berkeley.EDU.  Class {W} will be used to
store this list, and $W is defined to be ucbarpa.Berkeley.EDU, that
is, the name of the relay to which the hosts listed in uucp.ucbarpa
are connected.  [The machine ucbarpa is gone now, but this
out-of-date configuration file has been left around to demonstrate
how you might do this.]

Note that the case of SITECONFIG with a third parameter of ``U'' is
special; the second parameter is assumed to be the UUCP name of the
local site, rather than the name of a remote site, and the UUCP name
is entered into class {w} (the list of local hostnames) as $U.UUCP.

The siteconfig file (e.g., siteconfig/uucp.ucbvax.m4) contains nothing
more than a sequence of SITE macros describing connectivity.  For
example:

	SITE(`cnmat')
	SITE(`sgi olympus')

The second example demonstrates that you can use two names on the
same line; these are usually aliases for the same host (or are at
least in the same company).

The macro LOCAL_UUCP can be used to add rules into the generated
cf file at the place where MAILER(`uucp') inserts its rules.  This
should only be used if really necessary.

+--------------------+
| USING UUCP MAILERS |
+--------------------+

It's hard to get UUCP mailers right because of the extremely ad hoc
nature of UUCP addressing.  These config files are really designed
for domain-based addressing, even for UUCP sites.

There are four UUCP mailers available.  The choice of which one to
use is partly a matter of local preferences and what is running at
the other end of your UUCP connection.  Unlike good protocols that
define what will go over the wire, UUCP uses the policy that you
should do what is right for the other end; if they change, you have
to change.  This makes it hard to do the right thing, and discourages
people from updating their software.  In general, if you can avoid
UUCP, please do.

The major choice is whether to go for a domainized scheme or a
non-domainized scheme.  This depends entirely on what the other
end will recognize.  If at all possible, you should encourage the
other end to go to a domain-based system -- non-domainized addresses
don't work entirely properly.

The four mailers are:

    uucp-old (obsolete name: "uucp")
	This is the oldest, the worst (but the closest to UUCP) way of
	sending messages across UUCP connections.  It does bangify
	everything and prepends $U (your UUCP name) to the sender's
	address (which can already be a bang path itself).  It can
	only send to one address at a time, so it spends a lot of
	time copying duplicates of messages.  Avoid this if at all
	possible.

    uucp-new (obsolete name: "suucp")
	The same as above, except that it assumes that in one rmail
	command you can specify several recipients.  It still has a
	lot of other problems.

    uucp-dom
	This UUCP mailer keeps everything as domain addresses.
	Basically, it uses the SMTP mailer rewriting rules.  This mailer
	is only included if MAILER(`smtp') is specified before
	MAILER(`uucp').

	Unfortunately, a lot of UUCP mailer transport agents require
	bangified addresses in the envelope, although you can use
	domain-based addresses in the message header.  (The envelope
	shows up as the From_ line on UNIX mail.)  So....

    uucp-uudom
	This is a cross between uucp-new (for the envelope addresses)
	and uucp-dom (for the header addresses).  It bangifies the
	envelope sender (From_ line in messages) without adding the
	local hostname, unless there is no host name on the address
	at all (e.g., "wolf") or the host component is a UUCP host name
	instead of a domain name ("somehost!wolf" instead of
	"some.dom.ain!wolf").  This is also included only if MAILER(`smtp')
	is also specified earlier.

Examples:

On host grasp.insa-lyon.fr (UUCP host name "grasp"), the following
summarizes the sender rewriting for various mailers.

Mailer		sender		rewriting in the envelope
------		------		-------------------------
uucp-{old,new}	wolf		grasp!wolf
uucp-dom	wolf		wolf@grasp.insa-lyon.fr
uucp-uudom	wolf		grasp.insa-lyon.fr!wolf

uucp-{old,new}	wolf@fr.net	grasp!fr.net!wolf
uucp-dom	wolf@fr.net	wolf@fr.net
uucp-uudom	wolf@fr.net	fr.net!wolf

uucp-{old,new}	somehost!wolf	grasp!somehost!wolf
uucp-dom	somehost!wolf	somehost!wolf@grasp.insa-lyon.fr
uucp-uudom	somehost!wolf	grasp.insa-lyon.fr!somehost!wolf

If you are using one of the domainized UUCP mailers, you really want
to convert all UUCP addresses to domain format -- otherwise, it will
do it for you (and probably not the way you expected).  For example,
if you have the address foo!bar!baz (and you are not sending to foo),
the heuristics will add the @uucp.relay.name or @local.host.name to
this address.  However, if you map foo to foo.host.name first, it
will not add the local hostname.  You can do this using the uucpdomain
feature.


+-------------------+
| TWEAKING RULESETS |
+-------------------+

For more complex configurations, you can define special rules.
The macro LOCAL_RULE_3 introduces rules that are used in canonicalizing
the names.  Any modifications made here are reflected in the header.

A common use is to convert old UUCP addresses to SMTP addresses using
the UUCPSMTP macro.  For example:

	LOCAL_RULE_3
	UUCPSMTP(`decvax',	`decvax.dec.com')
	UUCPSMTP(`research',	`research.att.com')

will cause addresses of the form "decvax!user" and "research!user"
to be converted to "user@decvax.dec.com" and "user@research.att.com"
respectively.

This could also be used to look up hosts in a database map:

	LOCAL_RULE_3
	R$* < @ $+ > $*		$: $1 < @ $(hostmap $2 $) > $3

This map would be defined in the LOCAL_CONFIG portion, as shown below.

Similarly, LOCAL_RULE_0 can be used to introduce new parsing rules.
For example, new rules are needed to parse hostnames that you accept
via MX records.  For example, you might have:

	LOCAL_RULE_0
	R$+ <@ host.dom.ain.>	$#uucp $@ cnmat $: $1 < @ host.dom.ain.>

You would use this if you had installed an MX record for cnmat.Berkeley.EDU
pointing at this host; this rule catches the message and forwards it on
using UUCP.

You can also tweak rulesets 1 and 2 using LOCAL_RULE_1 and LOCAL_RULE_2.
These rulesets are normally empty.

A similar macro is LOCAL_CONFIG.  This introduces lines added after the
boilerplate option setting but before rulesets.  Do not declare rulesets in
the LOCAL_CONFIG section.  It can be used to declare local database maps or
whatever.  For example:

	LOCAL_CONFIG
	Khostmap hash /etc/mail/hostmap
	Kyplocal nis -m hosts.byname


+---------------------------+
| MASQUERADING AND RELAYING |
+---------------------------+

You can have your host masquerade as another using

	MASQUERADE_AS(`host.domain')

This causes mail being sent to be labeled as coming from the
indicated host.domain, rather than $j.  One normally masquerades as
one of one's own subdomains (for example, it's unlikely that
Berkeley would choose to masquerade as an MIT site).  This
behaviour is modified by a plethora of FEATUREs; in particular, see
masquerade_envelope, allmasquerade, limited_masquerade, and
masquerade_entire_domain.

The masquerade name is not normally canonified, so it is important
that it be your One True Name, that is, fully qualified and not a
CNAME.  However, if you use a CNAME, the receiving side may canonify
it for you, so don't think you can cheat CNAME mapping this way.

Normally the only addresses that are masqueraded are those that come
from this host (that is, are either unqualified or in class {w}, the list
of local domain names).  You can augment this list, which is realized
by class {M} using

	MASQUERADE_DOMAIN(`otherhost.domain')

The effect of this is that although mail to user@otherhost.domain
will not be delivered locally, any mail including any user@otherhost.domain
will, when relayed, be rewritten to have the MASQUERADE_AS address.
This can be a space-separated list of names.

If these names are in a file, you can use

	MASQUERADE_DOMAIN_FILE(`filename')

to read the list of names from the indicated file (i.e., to add
elements to class {M}).

To exempt hosts or subdomains from being masqueraded, you can use

	MASQUERADE_EXCEPTION(`host.domain')

This can come handy if you want to masquerade a whole domain
except for one (or a few) host(s).  If these names are in a file,
you can use

	MASQUERADE_EXCEPTION_FILE(`filename')

Normally only header addresses are masqueraded.  If you want to
masquerade the envelope as well, use

	FEATURE(`masquerade_envelope')

There are always users that need to be "exposed" -- that is, their
internal site name should be displayed instead of the masquerade name.
Root is an example (which has been "exposed" by default prior to 8.10).
You can add users to this list using

	EXPOSED_USER(`usernames')

This adds users to class {E}; you could also use

	EXPOSED_USER_FILE(`filename')

You can also arrange to relay all unqualified names (that is, names
without @host) to a relay host.  For example, if you have a central
email server, you might relay to that host so that users don't have
to have .forward files or aliases.  You can do this using

	define(`LOCAL_RELAY', `mailer:hostname')

The ``mailer:'' can be omitted, in which case the mailer defaults to
"relay".  There are some user names that you don't want relayed, perhaps
because of local aliases.  A common example is root, which may be
locally aliased.  You can add entries to this list using

	LOCAL_USER(`usernames')

This adds users to class {L}; you could also use

	LOCAL_USER_FILE(`filename')

If you want all incoming mail sent to a centralized hub, as for a
shared /var/spool/mail scheme, use

	define(`MAIL_HUB', `mailer:hostname')

Again, ``mailer:'' defaults to "relay".  If you define both LOCAL_RELAY
and MAIL_HUB _AND_ you have FEATURE(`stickyhost'), unqualified names will
be sent to the LOCAL_RELAY and other local names will be sent to MAIL_HUB.
Note: there is a (long standing) bug which keeps this combination from
working for addresses of the form user+detail.
Names in class {L} will be delivered locally, so you MUST have aliases or
.forward files for them.

For example, if you are on machine mastodon.CS.Berkeley.EDU and you have
FEATURE(`stickyhost'), the following combinations of settings will have the
indicated effects:

email sent to....	eric			  eric@mastodon.CS.Berkeley.EDU

LOCAL_RELAY set to	mail.CS.Berkeley.EDU	  (delivered locally)
mail.CS.Berkeley.EDU	  (no local aliasing)	    (aliasing done)

MAIL_HUB set to		mammoth.CS.Berkeley.EDU	  mammoth.CS.Berkeley.EDU
mammoth.CS.Berkeley.EDU	  (aliasing done)	    (aliasing done)

Both LOCAL_RELAY and	mail.CS.Berkeley.EDU	  mammoth.CS.Berkeley.EDU
MAIL_HUB set as above	  (no local aliasing)	    (aliasing done)

If you do not have FEATURE(`stickyhost') set, then LOCAL_RELAY and
MAIL_HUB act identically, with MAIL_HUB taking precedence.

If you want all outgoing mail to go to a central relay site, define
SMART_HOST as well.  Briefly:

	LOCAL_RELAY applies to unqualified names (e.g., "eric").
	MAIL_HUB applies to names qualified with the name of the
		local host (e.g., "eric@mastodon.CS.Berkeley.EDU").
	SMART_HOST applies to names qualified with other hosts or
		bracketed addresses (e.g., "eric@mastodon.CS.Berkeley.EDU"
		or "eric@[127.0.0.1]").

However, beware that other relays (e.g., UUCP_RELAY, BITNET_RELAY,
DECNET_RELAY, and FAX_RELAY) take precedence over SMART_HOST, so if you
really want absolutely everything to go to a single central site you will
need to unset all the other relays -- or better yet, find or build a
minimal config file that does this.

For duplicate suppression to work properly, the host name is best
specified with a terminal dot:

	define(`MAIL_HUB', `host.domain.')
	      note the trailing dot ---^


+-------------------------------------------+
| USING LDAP FOR ALIASES, MAPS, AND CLASSES |
+-------------------------------------------+

LDAP can be used for aliases, maps, and classes by either specifying your
own LDAP map specification or using the built-in default LDAP map
specification.  The built-in default specifications all provide lookups
which match against either the machine's fully qualified hostname (${j}) or
a "cluster".  The cluster allows you to share LDAP entries among a large
number of machines without having to enter each of the machine names into
each LDAP entry.  To set the LDAP cluster name to use for a particular
machine or set of machines, set the confLDAP_CLUSTER m4 variable to a
unique name.  For example:

	define(`confLDAP_CLUSTER', `Servers')

Here, the word `Servers' will be the cluster name.  As an example, assume
that smtp.sendmail.org, etrn.sendmail.org, and mx.sendmail.org all belong
to the Servers cluster.

Some of the LDAP LDIF examples below show use of the Servers cluster.
Every entry must have either a sendmailMTAHost or sendmailMTACluster
attribute or it will be ignored.  Be careful as mixing clusters and
individual host records can have surprising results (see the CAUTION
sections below).

See the file cf/sendmail.schema for the actual LDAP schemas.  Note that
this schema (and therefore the lookups and examples below) is experimental
at this point as it has had little public review.  Therefore, it may change
in future versions.  Feedback via sendmail-YYYY@support.sendmail.org is
encouraged (replace YYYY with the current year, e.g., 2005).

-------
Aliases
-------

The ALIAS_FILE (O AliasFile) option can be set to use LDAP for alias
lookups.  To use the default schema, simply use:

	define(`ALIAS_FILE', `ldap:')

By doing so, you will use the default schema which expands to a map
declared as follows:

	ldap -k (&(objectClass=sendmailMTAAliasObject)
		  (sendmailMTAAliasGrouping=aliases)
		  (|(sendmailMTACluster=${sendmailMTACluster})
		    (sendmailMTAHost=$j))
		  (sendmailMTAKey=%0))
	     -v sendmailMTAAliasValue,sendmailMTAAliasSearch:FILTER:sendmailMTAAliasObject,sendmailMTAAliasURL:URL:sendmailMTAAliasObject


NOTE: The macros shown above ${sendmailMTACluster} and $j are not actually
used when the binary expands the `ldap:' token as the AliasFile option is
not actually macro-expanded when read from the sendmail.cf file.

Example LDAP LDIF entries might be:

	dn: sendmailMTAKey=sendmail-list, dc=sendmail, dc=org
	objectClass: sendmailMTA
	objectClass: sendmailMTAAlias
	objectClass: sendmailMTAAliasObject
	sendmailMTAAliasGrouping: aliases
	sendmailMTAHost: etrn.sendmail.org
	sendmailMTAKey: sendmail-list
	sendmailMTAAliasValue: ca@example.org
	sendmailMTAAliasValue: eric
	sendmailMTAAliasValue: gshapiro@example.com

	dn: sendmailMTAKey=owner-sendmail-list, dc=sendmail, dc=org
	objectClass: sendmailMTA
	objectClass: sendmailMTAAlias
	objectClass: sendmailMTAAliasObject
	sendmailMTAAliasGrouping: aliases
	sendmailMTAHost: etrn.sendmail.org
	sendmailMTAKey: owner-sendmail-list
	sendmailMTAAliasValue: eric

	dn: sendmailMTAKey=postmaster, dc=sendmail, dc=org
	objectClass: sendmailMTA
	objectClass: sendmailMTAAlias
	objectClass: sendmailMTAAliasObject
	sendmailMTAAliasGrouping: aliases
	sendmailMTACluster: Servers
	sendmailMTAKey: postmaster
	sendmailMTAAliasValue: eric

Here, the aliases sendmail-list and owner-sendmail-list will be available
only on etrn.sendmail.org but the postmaster alias will be available on
every machine in the Servers cluster (including etrn.sendmail.org).

CAUTION: aliases are additive so that entries like these:

	dn: sendmailMTAKey=bob, dc=sendmail, dc=org
	objectClass: sendmailMTA
	objectClass: sendmailMTAAlias
	objectClass: sendmailMTAAliasObject
	sendmailMTAAliasGrouping: aliases
	sendmailMTACluster: Servers
	sendmailMTAKey: bob
	sendmailMTAAliasValue: eric

	dn: sendmailMTAKey=bobetrn, dc=sendmail, dc=org
	objectClass: sendmailMTA
	objectClass: sendmailMTAAlias
	objectClass: sendmailMTAAliasObject
	sendmailMTAAliasGrouping: aliases
	sendmailMTAHost: etrn.sendmail.org
	sendmailMTAKey: bob
	sendmailMTAAliasValue: gshapiro

would mean that on all of the hosts in the cluster, mail to bob would go to
eric EXCEPT on etrn.sendmail.org in which case it would go to BOTH eric and
gshapiro.

If you prefer not to use the default LDAP schema for your aliases, you can
specify the map parameters when setting ALIAS_FILE.  For example:

	define(`ALIAS_FILE', `ldap:-k (&(objectClass=mailGroup)(mail=%0)) -v mgrpRFC822MailMember')

----
Maps
----

FEATURE()'s which take an optional map definition argument (e.g., access,
mailertable, virtusertable, etc.) can instead take the special keyword
`LDAP', e.g.:

	FEATURE(`access_db', `LDAP')
	FEATURE(`virtusertable', `LDAP')

When this keyword is given, that map will use LDAP lookups consisting of
the objectClass sendmailMTAClassObject, the attribute sendmailMTAMapName
with the map name, a search attribute of sendmailMTAKey, and the value
attribute sendmailMTAMapValue.

The values for sendmailMTAMapName are:

	FEATURE()		sendmailMTAMapName
	---------		------------------
	access_db		access
	authinfo		authinfo
	bitdomain		bitdomain
	domaintable		domain
	genericstable		generics
	mailertable		mailer
	uucpdomain		uucpdomain
	virtusertable		virtuser

For example, FEATURE(`mailertable', `LDAP') would use the map definition:

	Kmailertable ldap -k (&(objectClass=sendmailMTAMapObject)
			       (sendmailMTAMapName=mailer)
			       (|(sendmailMTACluster=${sendmailMTACluster})
				 (sendmailMTAHost=$j))
			       (sendmailMTAKey=%0))
			  -1 -v sendmailMTAMapValue,sendmailMTAMapSearch:FILTER:sendmailMTAMapObject,sendmailMTAMapURL:URL:sendmailMTAMapObject

An example LDAP LDIF entry using this map might be:

	dn: sendmailMTAMapName=mailer, dc=sendmail, dc=org
	objectClass: sendmailMTA
	objectClass: sendmailMTAMap
	sendmailMTACluster: Servers
	sendmailMTAMapName: mailer

	dn: sendmailMTAKey=example.com, sendmailMTAMapName=mailer, dc=sendmail, dc=org
	objectClass: sendmailMTA
	objectClass: sendmailMTAMap
	objectClass: sendmailMTAMapObject
	sendmailMTAMapName: mailer
	sendmailMTACluster: Servers
	sendmailMTAKey: example.com
	sendmailMTAMapValue: relay:[smtp.example.com]

CAUTION: If your LDAP database contains the record above and *ALSO* a host
specific record such as:

	dn: sendmailMTAKey=example.com@etrn, sendmailMTAMapName=mailer, dc=sendmail, dc=org
	objectClass: sendmailMTA
	objectClass: sendmailMTAMap
	objectClass: sendmailMTAMapObject
	sendmailMTAMapName: mailer
	sendmailMTAHost: etrn.sendmail.org
	sendmailMTAKey: example.com
	sendmailMTAMapValue: relay:[mx.example.com]

then these entries will give unexpected results.  When the lookup is done
on etrn.sendmail.org, the effect is that there is *NO* match at all as maps
require a single match.  Since the host etrn.sendmail.org is also in the
Servers cluster, LDAP would return two answers for the example.com map key
in which case sendmail would treat this as no match at all.

If you prefer not to use the default LDAP schema for your maps, you can
specify the map parameters when using the FEATURE().  For example:

	FEATURE(`access_db', `ldap:-1 -k (&(objectClass=mapDatabase)(key=%0)) -v value')

-------
Classes
-------

Normally, classes can be filled via files or programs.  As of 8.12, they
can also be filled via map lookups using a new syntax:

	F{ClassName}mapkey@mapclass:mapspec

mapkey is optional and if not provided the map key will be empty.  This can
be used with LDAP to read classes from LDAP.  Note that the lookup is only
done when sendmail is initially started.  Use the special value `@LDAP' to
use the default LDAP schema.  For example:

	RELAY_DOMAIN_FILE(`@LDAP')

would put all of the attribute sendmailMTAClassValue values of LDAP records
with objectClass sendmailMTAClass and an attribute sendmailMTAClassName of
'R' into class $={R}.  In other words, it is equivalent to the LDAP map
specification:

	F{R}@ldap:-k (&(objectClass=sendmailMTAClass)
		       (sendmailMTAClassName=R)
		       (|(sendmailMTACluster=${sendmailMTACluster})
			 (sendmailMTAHost=$j)))
		  -v sendmailMTAClassValue,sendmailMTAClassSearch:FILTER:sendmailMTAClass,sendmailMTAClassURL:URL:sendmailMTAClass

NOTE: The macros shown above ${sendmailMTACluster} and $j are not actually
used when the binary expands the `@LDAP' token as class declarations are
not actually macro-expanded when read from the sendmail.cf file.

This can be used with class related commands such as RELAY_DOMAIN_FILE(),
MASQUERADE_DOMAIN_FILE(), etc:

	Command				sendmailMTAClassName
	-------				--------------------
	CANONIFY_DOMAIN_FILE()		Canonify
	EXPOSED_USER_FILE()		E
	GENERICS_DOMAIN_FILE()		G
	LDAPROUTE_DOMAIN_FILE()		LDAPRoute
	LDAPROUTE_EQUIVALENT_FILE()	LDAPRouteEquiv
	LOCAL_USER_FILE()		L
	MASQUERADE_DOMAIN_FILE()	M
	MASQUERADE_EXCEPTION_FILE()	N
	RELAY_DOMAIN_FILE()		R
	VIRTUSER_DOMAIN_FILE()		VirtHost

You can also add your own as any 'F'ile class of the form:

	F{ClassName}@LDAP
	  ^^^^^^^^^
will use "ClassName" for the sendmailMTAClassName.

An example LDAP LDIF entry would look like:

	dn: sendmailMTAClassName=R, dc=sendmail, dc=org
	objectClass: sendmailMTA
	objectClass: sendmailMTAClass
	sendmailMTACluster: Servers
	sendmailMTAClassName: R
	sendmailMTAClassValue: sendmail.org
	sendmailMTAClassValue: example.com
	sendmailMTAClassValue: 10.56.23

CAUTION: If your LDAP database contains the record above and *ALSO* a host
specific record such as:

	dn: sendmailMTAClassName=R@etrn.sendmail.org, dc=sendmail, dc=org
	objectClass: sendmailMTA
	objectClass: sendmailMTAClass
	sendmailMTAHost: etrn.sendmail.org
	sendmailMTAClassName: R
	sendmailMTAClassValue: example.com

the result will be similar to the aliases caution above.  When the lookup
is done on etrn.sendmail.org, $={R} would contain all of the entries (from
both the cluster match and the host match).  In other words, the effective
is additive.

If you prefer not to use the default LDAP schema for your classes, you can
specify the map parameters when using the class command.  For example:

	VIRTUSER_DOMAIN_FILE(`@ldap:-k (&(objectClass=virtHosts)(host=*)) -v host')

Remember, macros can not be used in a class declaration as the binary does
not expand them.


+--------------+
| LDAP ROUTING |
+--------------+

FEATURE(`ldap_routing') can be used to implement the IETF Internet Draft
LDAP Schema for Intranet Mail Routing
(draft-lachman-laser-ldap-mail-routing-01).  This feature enables
LDAP-based rerouting of a particular address to either a different host
or a different address.  The LDAP lookup is first attempted on the full
address (e.g., user@example.com) and then on the domain portion
(e.g., @example.com).  Be sure to setup your domain for LDAP routing using
LDAPROUTE_DOMAIN(), e.g.:

	LDAPROUTE_DOMAIN(`example.com')

Additionally, you can specify equivalent domains for LDAP routing using
LDAPROUTE_EQUIVALENT() and LDAPROUTE_EQUIVALENT_FILE().  'Equivalent'
hostnames are mapped to $M (the masqueraded hostname for the server) before
the LDAP query.  For example, if the mail is addressed to
user@host1.example.com, normally the LDAP lookup would only be done for
'user@host1.example.com' and '@host1.example.com'.   However, if
LDAPROUTE_EQUIVALENT(`host1.example.com') is used, the lookups would also be
done on 'user@example.com' and '@example.com' after attempting the
host1.example.com lookups.

By default, the feature will use the schemas as specified in the draft
and will not reject addresses not found by the LDAP lookup.  However,
this behavior can be changed by giving additional arguments to the FEATURE()
command:

 FEATURE(`ldap_routing', <mailHost>, <mailRoutingAddress>, <bounce>,
		 <detail>, <nodomain>, <tempfail>)

where <mailHost> is a map definition describing how to lookup an alternative
mail host for a particular address; <mailRoutingAddress> is a map definition
describing how to lookup an alternative address for a particular address;
the <bounce> argument, if present and not the word "passthru", dictates
that mail should be bounced if neither a mailHost nor mailRoutingAddress
is found, if set to "sendertoo", the sender will be rejected if not
found in LDAP; and <detail> indicates what actions to take if the address
contains +detail information -- `strip' tries the lookup with the +detail
and if no matches are found, strips the +detail and tries the lookup again;
`preserve', does the same as `strip' but if a mailRoutingAddress match is
found, the +detail information is copied to the new address; the <nodomain>
argument, if present, will prevent the @domain lookup if the full
address is not found in LDAP; the <tempfail> argument, if set to
"tempfail", instructs the rules to give an SMTP 4XX temporary
error if the LDAP server gives the MTA a temporary failure, or if set to
"queue" (the default), the MTA will locally queue the mail.

The default <mailHost> map definition is:

	ldap -1 -T<TMPF> -v mailHost -k (&(objectClass=inetLocalMailRecipient)
				 (mailLocalAddress=%0))

The default <mailRoutingAddress> map definition is:

	ldap -1 -T<TMPF> -v mailRoutingAddress
			 -k (&(objectClass=inetLocalMailRecipient)
			      (mailLocalAddress=%0))

Note that neither includes the LDAP server hostname (-h server) or base DN
(-b o=org,c=COUNTRY), both necessary for LDAP queries.  It is presumed that
your .mc file contains a setting for the confLDAP_DEFAULT_SPEC option with
these settings.  If this is not the case, the map definitions should be
changed as described above.  The "-T<TMPF>" is required in any user
specified map definition to catch temporary errors.

The following possibilities exist as a result of an LDAP lookup on an
address:

	mailHost is	mailRoutingAddress is	Results in
	-----------	---------------------	----------
	set to a	set			mail delivered to
	"local" host				mailRoutingAddress

	set to a	not set			delivered to
	"local" host				original address

	set to a	set			mailRoutingAddress
	remote host				relayed to mailHost

	set to a	not set			original address
	remote host				relayed to mailHost

	not set		set			mail delivered to
						mailRoutingAddress

	not set		not set			delivered to
						original address *OR*
						bounced as unknown user

The term "local" host above means the host specified is in class {w}.  If
the result would mean sending the mail to a different host, that host is
looked up in the mailertable before delivery.

Note that the last case depends on whether the third argument is given
to the FEATURE() command.  The default is to deliver the message to the
original address.

The LDAP entries should be set up with an objectClass of
inetLocalMailRecipient and the address be listed in a mailLocalAddress
attribute.  If present, there must be only one mailHost attribute and it
must contain a fully qualified host name as its value.  Similarly, if
present, there must be only one mailRoutingAddress attribute and it must
contain an RFC 822 compliant address.  Some example LDAP records (in LDIF
format):

	dn: uid=tom, o=example.com, c=US
	objectClass: inetLocalMailRecipient
	mailLocalAddress: tom@example.com
	mailRoutingAddress: thomas@mailhost.example.com

This would deliver mail for tom@example.com to thomas@mailhost.example.com.

	dn: uid=dick, o=example.com, c=US
	objectClass: inetLocalMailRecipient
	mailLocalAddress: dick@example.com
	mailHost: eng.example.com

This would relay mail for dick@example.com to the same address but redirect
the mail to MX records listed for the host eng.example.com (unless the
mailertable overrides).

	dn: uid=harry, o=example.com, c=US
	objectClass: inetLocalMailRecipient
	mailLocalAddress: harry@example.com
	mailHost: mktmail.example.com
	mailRoutingAddress: harry@mkt.example.com

This would relay mail for harry@example.com to the MX records listed for
the host mktmail.example.com using the new address harry@mkt.example.com
when talking to that host.

	dn: uid=virtual.example.com, o=example.com, c=US
	objectClass: inetLocalMailRecipient
	mailLocalAddress: @virtual.example.com
	mailHost: server.example.com
	mailRoutingAddress: virtual@example.com

This would send all mail destined for any username @virtual.example.com to
the machine server.example.com's MX servers and deliver to the address
virtual@example.com on that relay machine.


+---------------------------------+
| ANTI-SPAM CONFIGURATION CONTROL |
+---------------------------------+

The primary anti-spam features available in sendmail are:

* Relaying is denied by default.
* Better checking on sender information.
* Access database.
* Header checks.

Relaying (transmission of messages from a site outside your host (class
{w}) to another site except yours) is denied by default.  Note that this
changed in sendmail 8.9; previous versions allowed relaying by default.
If you really want to revert to the old behaviour, you will need to use
FEATURE(`promiscuous_relay').  You can allow certain domains to relay
through your server by adding their domain name or IP address to class
{R} using RELAY_DOMAIN() and RELAY_DOMAIN_FILE() or via the access database
(described below).  Note that IPv6 addresses must be prefaced with "IPv6:".
The file consists (like any other file based class) of entries listed on
separate lines, e.g.,

	sendmail.org
	128.32
	IPv6:2002:c0a8:02c7
	IPv6:2002:c0a8:51d2::23f4
	host.mydomain.com
	[UNIX:localhost]

Notice: the last entry allows relaying for connections via a UNIX
socket to the MTA/MSP.  This might be necessary if your configuration
doesn't allow relaying by other means in that case, e.g., by having
localhost.$m in class {R} (make sure $m is not just a top level
domain).

If you use

	FEATURE(`relay_entire_domain')

then any host in any of your local domains (that is, class {m})
will be relayed (that is, you will accept mail either to or from any
host in your domain).

You can also allow relaying based on the MX records of the host
portion of an incoming recipient address by using

	FEATURE(`relay_based_on_MX')

For example, if your server receives a recipient of user@domain.com
and domain.com lists your server in its MX records, the mail will be
accepted for relay to domain.com.  This feature may cause problems
if MX lookups for the recipient domain are slow or time out.  In that
case, mail will be temporarily rejected.  It is usually better to
maintain a list of hosts/domains for which the server acts as relay.
Note also that this feature will stop spammers from using your host
to relay spam but it will not stop outsiders from using your server
as a relay for their site (that is, they set up an MX record pointing
to your mail server, and you will relay mail addressed to them
without any prior arrangement).  Along the same lines,

	FEATURE(`relay_local_from')

will allow relaying if the sender specifies a return path (i.e.
MAIL FROM:<user@domain>) domain which is a local domain.  This is a
dangerous feature as it will allow spammers to spam using your mail
server by simply specifying a return address of user@your.domain.com.
It should not be used unless absolutely necessary.
A slightly better solution is

	FEATURE(`relay_mail_from')

which allows relaying if the mail sender is listed as RELAY in the
access map.  If an optional argument `domain' (this is the literal
word `domain', not a placeholder) is given, the domain portion of
the mail sender is also checked to allowing relaying.  This option
only works together with the tag From: for the LHS of the access
map entries.  This feature allows spammers to abuse your mail server
by specifying a return address that you enabled in your access file.
This may be harder to figure out for spammers, but it should not
be used unless necessary.  Instead use SMTP AUTH or STARTTLS to
allow relaying for roaming users.


If source routing is used in the recipient address (e.g.,
RCPT TO:<user%site.com@othersite.com>), sendmail will check
user@site.com for relaying if othersite.com is an allowed relay host
in either class {R}, class {m} if FEATURE(`relay_entire_domain') is used,
or the access database if FEATURE(`access_db') is used.  To prevent
the address from being stripped down, use:

	FEATURE(`loose_relay_check')

If you think you need to use this feature, you probably do not.  This
should only be used for sites which have no control over the addresses
that they provide a gateway for.  Use this FEATURE with caution as it
can allow spammers to relay through your server if not setup properly.

NOTICE: It is possible to relay mail through a system which the anti-relay
rules do not prevent: the case of a system that does use FEATURE(`nouucp',
`nospecial') (system A) and relays local messages to a mail hub (e.g., via
LOCAL_RELAY or LUSER_RELAY) (system B).  If system B doesn't use
FEATURE(`nouucp') at all, addresses of the form
<example.net!user@local.host> would be relayed to <user@example.net>.
System A doesn't recognize `!' as an address separator and therefore
forwards it to the mail hub which in turns relays it because it came from
a trusted local host.  So if a mailserver allows UUCP (bang-format)
addresses, all systems from which it allows relaying should do the same
or reject those addresses.

As of 8.9, sendmail will refuse mail if the MAIL FROM: parameter has
an unresolvable domain (i.e., one that DNS, your local name service,
or special case rules in ruleset 3 cannot locate).  This also applies
to addresses that use domain literals, e.g., <user@[1.2.3.4]>, if the
IP address can't be mapped to a host name.  If you want to continue
to accept such domains, e.g., because you are inside a firewall that
has only a limited view of the Internet host name space (note that you
will not be able to return mail to them unless you have some "smart
host" forwarder), use

	FEATURE(`accept_unresolvable_domains')

Alternatively, you can allow specific addresses by adding them to
the access map, e.g.,

	From:unresolvable.domain	OK
	From:[1.2.3.4]			OK
	From:[1.2.4]			OK

Notice: domains which are temporarily unresolvable are (temporarily)
rejected with a 451 reply code.  If those domains should be accepted
(which is discouraged) then you can use

	LOCAL_CONFIG
	C{ResOk}TEMP

sendmail will also refuse mail if the MAIL FROM: parameter is not
fully qualified (i.e., contains a domain as well as a user).  If you
want to continue to accept such senders, use

	FEATURE(`accept_unqualified_senders')

Setting the DaemonPortOptions modifier 'u' overrides the default behavior,
i.e., unqualified addresses are accepted even without this FEATURE.  If
this FEATURE is not used, the DaemonPortOptions modifier 'f' can be used
to enforce fully qualified domain names.

An ``access'' database can be created to accept or reject mail from
selected domains.  For example, you may choose to reject all mail
originating from known spammers.  To enable such a database, use

	FEATURE(`access_db')

Notice: the access database is applied to the envelope addresses
and the connection information, not to the header.

The FEATURE macro can accept as second parameter the key file
definition for the database; for example

	FEATURE(`access_db', `hash -T<TMPF> /etc/mail/access_map')

Notice: If a second argument is specified it must contain the option
`-T<TMPF>' as shown above.  The optional third and fourth parameters
may be `skip' or `lookupdotdomain'.  The former enables SKIP as
value part (see below), the latter is another way to enable the
feature of the same name (see above).

Remember, since /etc/mail/access is a database, after creating the text
file as described below, you must use makemap to create the database
map.  For example:

	makemap hash /etc/mail/access < /etc/mail/access

The table itself uses e-mail addresses, domain names, and network
numbers as keys.  Note that IPv6 addresses must be prefaced with "IPv6:".
For example,

	From:spammer@aol.com			REJECT
	From:cyberspammer.com			REJECT
	Connect:cyberspammer.com		REJECT
	Connect:TLD				REJECT
	Connect:192.168.212			REJECT
	Connect:IPv6:2002:c0a8:02c7		RELAY
	Connect:IPv6:2002:c0a8:51d2::23f4	REJECT

would refuse mail from spammer@aol.com, any user from cyberspammer.com
(or any host within the cyberspammer.com domain), any host in the entire
top level domain TLD, 192.168.212.* network, and the IPv6 address
2002:c0a8:51d2::23f4.  It would allow relay for the IPv6 network
2002:c0a8:02c7::/48.

Entries in the access map should be tagged according to their type.
Three tags are available:

	Connect:	connection information (${client_addr}, ${client_name})
	From:		envelope sender
	To:		envelope recipient

Notice: untagged entries are deprecated.

If the required item is looked up in a map, it will be tried first
with the corresponding tag in front, then (as fallback to enable
backward compatibility) without any tag, unless the specific feature
requires a tag.  For example,

	From:spammer@some.dom	REJECT
	To:friend.domain	RELAY
	Connect:friend.domain	OK
	Connect:from.domain	RELAY
	From:good@another.dom	OK
	From:another.dom	REJECT

This would deny mails from spammer@some.dom but you could still
send mail to that address even if FEATURE(`blacklist_recipients')
is enabled.  Your system will allow relaying to friend.domain, but
not from it (unless enabled by other means).  Connections from that
domain will be allowed even if it ends up in one of the DNS based
rejection lists.  Relaying is enabled from from.domain but not to
it (since relaying is based on the connection information for
outgoing relaying, the tag Connect: must be used; for incoming
relaying, which is based on the recipient address, To: must be
used).  The last two entries allow mails from good@another.dom but
reject mail from all other addresses with another.dom as domain
part.


The value part of the map can contain:

	OK		Accept mail even if other rules in the running
			ruleset would reject it, for example, if the domain
			name is unresolvable.  "Accept" does not mean
			"relay", but at most acceptance for local
			recipients.  That is, OK allows less than RELAY.
	RELAY		Accept mail addressed to the indicated domain or
			received from the indicated domain for relaying
			through your SMTP server.  RELAY also serves as
			an implicit OK for the other checks.
	REJECT		Reject the sender or recipient with a general
			purpose message.
	DISCARD		Discard the message completely using the
			$#discard mailer.  If it is used in check_compat,
			it affects only the designated recipient, not
			the whole message as it does in all other cases.
			This should only be used if really necessary.
	SKIP		This can only be used for host/domain names
			and IP addresses/nets.  It will abort the current
			search for this entry without accepting or rejecting
			it but causing the default action.
	### any text	where ### is an RFC 821 compliant error code and
			"any text" is a message to return for the command.
			The entire string should be quoted to avoid
			surprises:

				"### any text"

			Otherwise sendmail formats the text as email
			addresses, e.g., it may remove spaces.
			This type is deprecated, use one of the two
			ERROR:  entries below instead.
	ERROR:### any text
			as above, but useful to mark error messages as such.
			If quotes need to be used to avoid modifications
			(see above), they should be placed like this:

				ERROR:"### any text"

	ERROR:D.S.N:### any text
			where D.S.N is an RFC 1893 compliant error code
			and the rest as above.  If quotes need to be used
			to avoid modifications, they should be placed
			like this:

				ERROR:D.S.N:"### any text"

	QUARANTINE:any text
			Quarantine the message using the given text as the
			quarantining reason.

For example:

	From:cyberspammer.com	ERROR:"550 We don't accept mail from spammers"
	From:okay.cyberspammer.com	OK
	Connect:sendmail.org		RELAY
	To:sendmail.org			RELAY
	Connect:128.32			RELAY
	Connect:128.32.2		SKIP
	Connect:IPv6:1:2:3:4:5:6:7	RELAY
	Connect:suspicious.example.com	QUARANTINE:Mail from suspicious host
	Connect:[127.0.0.3]		OK
	Connect:[IPv6:1:2:3:4:5:6:7:8]	OK

would accept mail from okay.cyberspammer.com, but would reject mail
from all other hosts at cyberspammer.com with the indicated message.
It would allow relaying mail from and to any hosts in the sendmail.org
domain, and allow relaying from the IPv6 1:2:3:4:5:6:7:* network
and from the 128.32.*.* network except for the 128.32.2.* network,
which shows how SKIP is useful to exempt subnets/subdomains.  The
last two entries are for checks against ${client_name} if the IP
address doesn't resolve to a hostname (or is considered as "may be
forged").  That is, using square brackets means these are host
names, not network numbers.

Warning: if you change the RFC 821 compliant error code from the default
value of 550, then you should probably also change the RFC 1893 compliant
error code to match it.  For example, if you use

	To:user@example.com	ERROR:450 mailbox full

the error returned would be "450 5.0.0 mailbox full" which is wrong.
Use "ERROR:4.2.2:450 mailbox full" instead.

Note, UUCP users may need to add hostname.UUCP to the access database
or class {R}.

If you also use:

	FEATURE(`relay_hosts_only')

then the above example will allow relaying for sendmail.org, but not
hosts within the sendmail.org domain.  Note that this will also require
hosts listed in class {R} to be fully qualified host names.

You can also use the access database to block sender addresses based on
the username portion of the address.  For example:

	From:FREE.STEALTH.MAILER@	ERROR:550 Spam not accepted

Note that you must include the @ after the username to signify that
this database entry is for checking only the username portion of the
sender address.

If you use:

	FEATURE(`blacklist_recipients')

then you can add entries to the map for local users, hosts in your
domains, or addresses in your domain which should not receive mail:

	To:badlocaluser@	ERROR:550 Mailbox disabled for badlocaluser
	To:host.my.TLD		ERROR:550 That host does not accept mail
	To:user@other.my.TLD	ERROR:550 Mailbox disabled for this recipient

This would prevent a recipient of badlocaluser in any of the local
domains (class {w}), any user at host.my.TLD, and the single address
user@other.my.TLD from receiving mail.  Please note: a local username
must be now tagged with an @ (this is consistent with the check of
the sender address, and hence it is possible to distinguish between
hostnames and usernames).  Enabling this feature will keep you from
sending mails to all addresses that have an error message or REJECT
as value part in the access map.  Taking the example from above:

	spammer@aol.com		REJECT
	cyberspammer.com	REJECT

Mail can't be sent to spammer@aol.com or anyone at cyberspammer.com.
That's why tagged entries should be used.

There are several DNS based blacklists which can be found by
querying a search engine.  These are databases of spammers
maintained in DNS.  To use such a database, specify

	FEATURE(`dnsbl', `dnsbl.example.com')

This will cause sendmail to reject mail from any site listed in the
DNS based blacklist.  You must select an DNSB based blacklist domain
to check by specifying an argument to the FEATURE.  The default
error message is

	Rejected: IP-ADDRESS listed at SERVER

where IP-ADDRESS and SERVER are replaced by the appropriate
information.  A second argument can be used to specify a different
text.  By default, temporary lookup failures are ignored and hence
cause the connection not to be rejected by the DNS based rejection
list.  This behavior can be changed by specifying a third argument,
which must be either `t' or a full error message.  For example:

	FEATURE(`dnsbl', `dnsbl.example.com', `',
	`"451 Temporary lookup failure for " $&{client_addr} " in dnsbl.example.com"')

If `t' is used, the error message is:

	451 Temporary lookup failure of IP-ADDRESS at SERVER

where IP-ADDRESS and SERVER are replaced by the appropriate
information.

This FEATURE can be included several times to query different
DNS based rejection lists.

Notice: to avoid checking your own local domains against those
blacklists, use the access_db feature and add:

	Connect:10.1		OK
	Connect:127.0.0.1	RELAY

to the access map, where 10.1 is your local network.  You may
want to use "RELAY" instead of "OK" to allow also relaying
instead of just disabling the DNS lookups in the blacklists.


The features described above make use of the check_relay, check_mail,
and check_rcpt rulesets.  Note that check_relay checks the SMTP
client hostname and IP address when the connection is made to your
server.  It does not check if a mail message is being relayed to
another server.  That check is done in check_rcpt.  If you wish to
include your own checks, you can put your checks in the rulesets
Local_check_relay, Local_check_mail, and Local_check_rcpt.  For
example if you wanted to block senders with all numeric usernames
(i.e. 2312343@bigisp.com), you would use Local_check_mail and the
regex map:

	LOCAL_CONFIG
	Kallnumbers regex -a@MATCH ^[0-9]+$

	LOCAL_RULESETS
	SLocal_check_mail
	# check address against various regex checks
	R$*				$: $>Parse0 $>3 $1
	R$+ < @ bigisp.com. > $*	$: $(allnumbers $1 $)
	R@MATCH				$#error $: 553 Header Error

These rules are called with the original arguments of the corresponding
check_* ruleset.  If the local ruleset returns $#OK, no further checking
is done by the features described above and the mail is accepted.  If
the local ruleset resolves to a mailer (such as $#error or $#discard),
the appropriate action is taken.  Other results starting with $# are
interpreted by sendmail and may lead to unspecified behavior.  Note: do
NOT create a mailer with the name OK.  Return values that do not start
with $# are ignored, i.e., normal processing continues.

Delay all checks
----------------

By using FEATURE(`delay_checks') the rulesets check_mail and check_relay
will not be called when a client connects or issues a MAIL command,
respectively.  Instead, those rulesets will be called by the check_rcpt
ruleset; they will be skipped if a sender has been authenticated using
a "trusted" mechanism, i.e., one that is defined via TRUST_AUTH_MECH().
If check_mail returns an error then the RCPT TO command will be rejected
with that error.  If it returns some other result starting with $# then
check_relay will be skipped.  If the sender address (or a part of it) is
listed in the access map and it has a RHS of OK or RELAY, then check_relay
will be skipped.  This has an interesting side effect: if your domain is
my.domain and you have

	my.domain	RELAY

in the access map, then any e-mail with a sender address of
<user@my.domain> will not be rejected by check_relay even though
it would match the hostname or IP address.  This allows spammers
to get around DNS based blacklist by faking the sender address.  To
avoid this problem you have to use tagged entries:

	To:my.domain		RELAY
	Connect:my.domain	RELAY

if you need those entries at all (class {R} may take care of them).

FEATURE(`delay_checks') can take an optional argument:

	FEATURE(`delay_checks', `friend')
		 enables spamfriend test
	FEATURE(`delay_checks', `hater')
		 enables spamhater test

If such an argument is given, the recipient will be looked up in the
access map (using the tag Spam:).  If the argument is `friend', then
the default behavior is to apply the other rulesets and make a SPAM
friend the exception.  The rulesets check_mail and check_relay will be
skipped only if the recipient address is found and has RHS FRIEND.  If
the argument is `hater', then the default behavior is to skip the rulesets
check_mail and check_relay and make a SPAM hater the exception.  The
other two rulesets will be applied only if the recipient address is
found and has RHS HATER.

This allows for simple exceptions from the tests, e.g., by activating
the friend option and having

	Spam:abuse@	FRIEND

in the access map, mail to abuse@localdomain will get through (where
"localdomain" is any domain in class {w}).  It is also possible to
specify a full address or an address with +detail:

	Spam:abuse@my.domain	FRIEND
	Spam:me+abuse@		FRIEND
	Spam:spam.domain	FRIEND

Note: The required tag has been changed in 8.12 from To: to Spam:.
This change is incompatible to previous versions.  However, you can
(for now) simply add the new entries to the access map, the old
ones will be ignored.  As soon as you removed the old entries from
the access map, specify a third parameter (`n') to this feature and
the backward compatibility rules will not be in the generated .cf
file.

Header Checks
-------------

You can also reject mail on the basis of the contents of headers.
This is done by adding a ruleset call to the 'H' header definition command
in sendmail.cf.  For example, this can be used to check the validity of
a Message-ID: header:

	LOCAL_CONFIG
	HMessage-Id: $>CheckMessageId

	LOCAL_RULESETS
	SCheckMessageId
	R< $+ @ $+ >		$@ OK
	R$*			$#error $: 553 Header Error

The alternative format:

	HSubject: $>+CheckSubject

that is, $>+ instead of $>, gives the full Subject: header including
comments to the ruleset (comments in parentheses () are stripped
by default).

A default ruleset for headers which don't have a specific ruleset
defined for them can be given by:

	H*: $>CheckHdr

Notice:
1. All rules act on tokens as explained in doc/op/op.{me,ps,txt}.
That may cause problems with simple header checks due to the
tokenization.  It might be simpler to use a regex map and apply it
to $&{currHeader}.
2. There are no default rulesets coming with this distribution of
sendmail.  You can write your own, can search the WWW for examples,
or take a look at cf/cf/knecht.mc.
3. When using a default ruleset for headers, the name of the header
currently being checked can be found in the $&{hdr_name} macro.

After all of the headers are read, the check_eoh ruleset will be called for
any final header-related checks.  The ruleset is called with the number of
headers and the size of all of the headers in bytes separated by $|.  One
example usage is to reject messages which do not have a Message-Id:
header.  However, the Message-Id: header is *NOT* a required header and is
not a guaranteed spam indicator.  This ruleset is an example and should
probably not be used in production.

	LOCAL_CONFIG
	Kstorage macro
	HMessage-Id: $>CheckMessageId

	LOCAL_RULESETS
	SCheckMessageId
	# Record the presence of the header
	R$*			$: $(storage {MessageIdCheck} $@ OK $) $1
	R< $+ @ $+ >		$@ OK
	R$*			$#error $: 553 Header Error

	Scheck_eoh
	# Check the macro
	R$*			$: < $&{MessageIdCheck} >
	# Clear the macro for the next message
	R$*			$: $(storage {MessageIdCheck} $) $1
	# Has a Message-Id: header
	R< $+ >			$@ OK
	# Allow missing Message-Id: from local mail
	R$*			$: < $&{client_name} >
	R< >			$@ OK
	R< $=w >		$@ OK
	# Otherwise, reject the mail
	R$*			$#error $: 553 Header Error


+--------------------+
| CONNECTION CONTROL |
+--------------------+

The features ratecontrol and conncontrol allow to establish connection
limits per client IP address or net.  These features can limit the
rate of connections (connections per time unit) or the number of
incoming SMTP connections, respectively.  If enabled, appropriate
rulesets are called at the end of check_relay, i.e., after DNS
blacklists and generic access_db operations.  The features require
FEATURE(`access_db') to be listed earlier in the mc file.

Note: FEATURE(`delay_checks') delays those connection control checks
after a recipient address has been received, hence making these
connection control features less useful.  To run the checks as early
as possible, specify the parameter `nodelay', e.g.,

	FEATURE(`ratecontrol', `nodelay')

In that case, FEATURE(`delay_checks') has no effect on connection
control (and it must be specified earlier in the mc file).

An optional second argument `terminate' specifies whether the
rulesets should return the error code 421 which will cause
sendmail to terminate the session with that error if it is
returned from check_relay, i.e., not delayed as explained in
the previous paragraph.  Example:

	FEATURE(`ratecontrol', `nodelay', `terminate')


+----------+
| STARTTLS |
+----------+

In this text, cert will be used as an abbreviation for X.509 certificate,
DN (CN) is the distinguished (common) name of a cert, and CA is a
certification authority, which signs (issues) certs.

For STARTTLS to be offered by sendmail you need to set at least
these variables (the file names and paths are just examples):

	define(`confCACERT_PATH', `/etc/mail/certs/')
	define(`confCACERT', `/etc/mail/certs/CA.cert.pem')
	define(`confSERVER_CERT', `/etc/mail/certs/my.cert.pem')
	define(`confSERVER_KEY', `/etc/mail/certs/my.key.pem')

On systems which do not have the compile flag HASURANDOM set (see
sendmail/README) you also must set confRAND_FILE.

See doc/op/op.{me,ps,txt} for more information about these options,
especially the sections ``Certificates for STARTTLS'' and ``PRNG for
STARTTLS''.

Macros related to STARTTLS are:

${cert_issuer} holds the DN of the CA (the cert issuer).
${cert_subject} holds the DN of the cert (called the cert subject).
${cn_issuer} holds the CN of the CA (the cert issuer).
${cn_subject} holds the CN of the cert (called the cert subject).
${tls_version} the TLS/SSL version used for the connection, e.g., TLSv1,
	TLSv1/SSLv3, SSLv3, SSLv2.
${cipher} the cipher used for the connection, e.g., EDH-DSS-DES-CBC3-SHA,
	EDH-RSA-DES-CBC-SHA, DES-CBC-MD5, DES-CBC3-SHA.
${cipher_bits} the keylength (in bits) of the symmetric encryption algorithm
	used for the connection.
${verify} holds the result of the verification of the presented cert.
	Possible values are:
	OK	 verification succeeded.
	NO	 no cert presented.
	NOT	 no cert requested.
	FAIL	 cert presented but could not be verified,
		 e.g., the cert of the signing CA is missing.
	NONE	 STARTTLS has not been performed.
	TEMP	 temporary error occurred.
	PROTOCOL protocol error occurred (SMTP level).
	SOFTWARE STARTTLS handshake failed.
${server_name} the name of the server of the current outgoing SMTP
	connection.
${server_addr} the address of the server of the current outgoing SMTP
	connection.

Relaying
--------

SMTP STARTTLS can allow relaying for remote SMTP clients which have
successfully authenticated themselves.  If the verification of the cert
failed (${verify} != OK), relaying is subject to the usual rules.
Otherwise the DN of the issuer is looked up in the access map using the
tag CERTISSUER.  If the resulting value is RELAY, relaying is allowed.
If it is SUBJECT, the DN of the cert subject is looked up next in the
access map using the tag CERTSUBJECT.  If the value is RELAY, relaying
is allowed.

To make things a bit more flexible (or complicated), the values for
${cert_issuer} and ${cert_subject} can be optionally modified by regular
expressions defined in the m4 variables _CERT_REGEX_ISSUER_ and
_CERT_REGEX_SUBJECT_, respectively.  To avoid problems with those macros in
rulesets and map lookups, they are modified as follows: each non-printable
character and the characters '<', '>', '(', ')', '"', '+', ' ' are replaced
by their HEX value with a leading '+'.  For example:

/C=US/ST=California/O=endmail.org/OU=private/CN=Darth Mail (Cert)/Email=
darth+cert@endmail.org

is encoded as:

/C=US/ST=California/O=endmail.org/OU=private/CN=
Darth+20Mail+20+28Cert+29/Email=darth+2Bcert@endmail.org

(line breaks have been inserted for readability).

The  macros  which are subject to this encoding are ${cert_subject},
${cert_issuer},  ${cn_subject},  and ${cn_issuer}.

Examples:

To allow relaying for everyone who can present a cert signed by

/C=US/ST=California/O=endmail.org/OU=private/CN=
Darth+20Mail+20+28Cert+29/Email=darth+2Bcert@endmail.org

simply use:

CertIssuer:/C=US/ST=California/O=endmail.org/OU=private/CN=
Darth+20Mail+20+28Cert+29/Email=darth+2Bcert@endmail.org	RELAY

To allow relaying only for a subset of machines that have a cert signed by

/C=US/ST=California/O=endmail.org/OU=private/CN=
Darth+20Mail+20+28Cert+29/Email=darth+2Bcert@endmail.org

use:

CertIssuer:/C=US/ST=California/O=endmail.org/OU=private/CN=
Darth+20Mail+20+28Cert+29/Email=darth+2Bcert@endmail.org	SUBJECT
CertSubject:/C=US/ST=California/O=endmail.org/OU=private/CN=
DeathStar/Email=deathstar@endmail.org		RELAY

Notes:
- line breaks have been inserted after "CN=" for readability,
  each tagged entry must be one (long) line in the access map.
- if OpenSSL 0.9.7 or newer is used then the "Email=" part of a DN
  is replaced by "emailAddress=".

Of course it is also possible to write a simple ruleset that allows
relaying for everyone who can present a cert that can be verified, e.g.,

LOCAL_RULESETS
SLocal_check_rcpt
R$*	$: $&{verify}
ROK	$# OK

Allowing Connections
--------------------

The rulesets tls_server, tls_client, and tls_rcpt are used to decide whether
an SMTP connection is accepted (or should continue).

tls_server is called when sendmail acts as client after a STARTTLS command
(should) have been issued.  The parameter is the value of ${verify}.

tls_client is called when sendmail acts as server, after a STARTTLS command
has been issued, and from check_mail.  The parameter is the value of
${verify} and STARTTLS or MAIL, respectively.

Both rulesets behave the same.  If no access map is in use, the connection
will be accepted unless ${verify} is SOFTWARE, in which case the connection
is always aborted.  For tls_server/tls_client, ${client_name}/${server_name}
is looked up in the access map using the tag TLS_Srv/TLS_Clt, which is done
with the ruleset LookUpDomain.  If no entry is found, ${client_addr}
(${server_addr}) is looked up in the access map (same tag, ruleset
LookUpAddr).  If this doesn't result in an entry either, just the tag is
looked up in the access map (included the trailing colon).  Notice:
requiring that e-mail is sent to a server only encrypted, e.g., via

TLS_Srv:secure.domain	ENCR:112

doesn't necessarily mean that e-mail sent to that domain is encrypted.
If the domain has multiple MX servers, e.g.,

secure.domain.	IN MX 10	mail.secure.domain.
secure.domain.	IN MX 50	mail.other.domain.

then mail to user@secure.domain may go unencrypted to mail.other.domain.
tls_rcpt can be used to address this problem.

tls_rcpt is called before a RCPT TO: command is sent.  The parameter is the
current recipient.  This ruleset is only defined if FEATURE(`access_db')
is selected.  A recipient address user@domain is looked up in the access
map in four formats: TLS_Rcpt:user@domain, TLS_Rcpt:user@, TLS_Rcpt:domain,
and TLS_Rcpt:; the first match is taken.

The result of the lookups is then used to call the ruleset TLS_connection,
which checks the requirement specified by the RHS in the access map against
the actual parameters of the current TLS connection, esp. ${verify} and
${cipher_bits}.  Legal RHSs in the access map are:

VERIFY		verification must have succeeded
VERIFY:bits	verification must have succeeded and ${cipher_bits} must
		be greater than or equal bits.
ENCR:bits	${cipher_bits} must be greater than or equal bits.

The RHS can optionally be prefixed by TEMP+ or PERM+ to select a temporary
or permanent error.  The default is a temporary error code (403 4.7.0)
unless the macro TLS_PERM_ERR is set during generation of the .cf file.

If a certain level of encryption is required, then it might also be
possible that this level is provided by the security layer from a SASL
algorithm, e.g., DIGEST-MD5.

Furthermore, there can be a list of extensions added.  Such a list
starts with '+' and the items are separated by '++'.  Allowed
extensions are:

CN:name		name must match ${cn_subject}
CN		${server_name} must match ${cn_subject}
CS:name		name must match ${cert_subject}
CI:name		name must match ${cert_issuer}

Example: e-mail sent to secure.example.com should only use an encrypted
connection.  E-mail received from hosts within the laptop.example.com domain
should only be accepted if they have been authenticated.  The host which
receives e-mail for darth@endmail.org must present a cert that uses the
CN smtp.endmail.org.

TLS_Srv:secure.example.com      ENCR:112
TLS_Clt:laptop.example.com      PERM+VERIFY:112
TLS_Rcpt:darth@endmail.org	ENCR:112+CN:smtp.endmail.org


Disabling STARTTLS And Setting SMTP Server Features
---------------------------------------------------

By default STARTTLS is used whenever possible.  However, there are
some broken MTAs that don't properly implement STARTTLS.  To be able
to send to (or receive from) those MTAs, the ruleset try_tls
(srv_features) can be u