xref: /freebsd/contrib/sendmail/cf/README (revision 065a643db393fd78e62e8b414b4789e13fbdb5ae)

		NEW SENDMAIL CONFIGURATION FILES

		Eric Allman <eric@Sendmail.ORG>

		@(#)README	8.184 (Berkeley) 12/29/1998


This document describes the sendmail configuration files being used
at Berkeley.  These use features in the new (R8) sendmail; they will
not work on other versions.

These configuration files are probably not as general as previous
versions, and don't handle as many of the weird cases automagically.
I was able to simplify them for two reasons.  First, the network
has become more consistent -- for example, at this point, everyone
on the internet is supposed to be running a name server, so hacks to
handle NIC-registered hosts can go away.  Second, I assumed that a
subdomain would be running SMTP internally -- UUCP is presumed to be
a long-haul protocol.  I realize that this is not universal, but it
does describe the vast majority of sites with which I am familiar,
including those outside the US.

Of course, the downside of this is that if you do live in a weird
world, things are going to get weirder for you.  I'm sorry about that,
but at the time we at Berkeley had a problem, and it seemed like the
right thing to do.

This package requires a post-V7 version of m4; if you are running the
4.2bsd, SysV.2, or 7th Edition version, I suggest finding a friend with
a newer version.  You can m4-expand on their system, then run locally.
SunOS's /usr/5bin/m4 or BSD-Net/2's m4 both work.  GNU m4 version 1.1
or later also works.  Unfortunately, I'm told that 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/m4-1.4.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.

IF YOU DON'T HAVE A BERKELEY MAKE, don't despair!  Just run
"m4 ../m4/cf.m4 foo.mc > foo.cf" -- that should be all you need.
There is also a fairly crude (but functional) Makefile.dist that works
on the old version of make.

To get started, you may want to look at tcpproto.mc (for TCP-only
sites), uucpproto.mc (for UUCP-only sites), and clientproto.mc (for
clusters of clients using a single mail host).  Others are versions
that we use at Berkeley, although not all are in current use.  For
example, ucbvax has gone away, but I've left ucbvax.mc in because
it demonstrates some interesting techniques.

I'm not pretending that this README describes everything that these
configuration files can do; clever people can probably tweak them
to great effect.  But it should get you started.

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


+--------------------------+
| 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

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 Sendmail, Inc.  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 I've included in my 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.  We use SCCS; you could use RCS, 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 site.  The
local mailer is always included automatically.  Beware: MAILER
declarations should always be at the end of the configuration file,
and MAILER(smtp) should always precede MAILER(uucp).  The general
rules are that the order should be:

	VERSIONID
	OSTYPE
	DOMAIN
	FEATURE
	local macro definitions
	MAILER
	LOCAL_RULESET_*


+----------------------------+
| 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'.

+----------------+
| 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.  8.9 will
serve as a transition release.  Beginning with 8.10, all of the files
will use this directory by default.

+--------+
| 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/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		[/usr/lib/sendmail.hf] 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.
STATUS_FILE		[/etc/sendmail.st] The file containing status
			information.
LOCAL_MAILER_PATH	[/bin/mail] The program used to deliver local mail.
LOCAL_MAILER_FLAGS	[rmn9] The flags used by the local mailer.  The
			flags lsDFM 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_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_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.
USENET_MAILER_PATH	[/usr/lib/news/inews] The name of the program
			used to submit news.
USENET_MAILER_FLAGS	[rlsDFMmn] The mailer flags for the usenet mailer.
USENET_MAILER_ARGS	[-m -h -n] The command line arguments for the
			usenet mailer.
USENET_MAILER_MAX	[100000] The maximum size of messages that will
			be accepted by 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' and "smtp8" adds `8'.
SMTP_MAILER_MAX		[undefined] The maximum size of messages that will
			be transported using the smtp, smtp8, or esmtp
			mailers.
SMTP_MAILER_ARGS	[IPC $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	[IPC $h] The arguments passed to the esmtp mailer.
SMTP8_MAILER_ARGS	[IPC $h] The arguments passed to the smtp8 mailer.
RELAY_MAILER_ARGS	[IPC $h] The arguments passed to the relay mailer.
SMTP_MAILER_CHARSET	[undefined] If defined, messages containing 8-bit data
			that ARRIVE from an address that resolves to one of
			the SMTP mailers and which are converted to MIME will
			be labeled with this character set.
UUCP_MAILER_PATH	[/usr/bin/uux] The program used to send UUCP mail.
UUCP_MAILER_FLAGS	[undefined] Flags added to UUCP mailer.  Default
			flags are `DFMhuU' (and `m' for uucp-new mailer,
			minus `U' for uucp-dom mailer).
UUCP_MAILER_ARGS	[uux - -r -z -a$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.
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 "lsDFM"
			are always added.
POP_MAILER_ARGS		[pop $u] The arguments passed to 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.
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.
PH_MAILER_PATH		[/usr/local/etc/phquery] The path to the phquery
			program.
PH_MAILER_FLAGS		[ehmu] Flags for the phquery mailer.
PH_MAILER_ARGS		[phquery -- $u] -- arguments to the phquery mailer.
CYRUS_MAILER_FLAGS	[A5@/:|] 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_BB_MAILER_FLAGS	[undefined] 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.
confEBINDIR		[/usr/libexec] The directory for executables.
			Currently used for FEATURE(local_lmtp) and
			FEATURE(smrsh).



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

You will probably want to collect domain-dependent defines into one
file, referenced by the DOMAIN macro.  For example, our 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	DEPRECATED.  The site that will handle unqualified
		names -- that is, names with out an @domain extension.
		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.

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, and always put MAILER(smtp)
before MAILER(uucp) -- several features and definitions will modify
the definition of mailers, and the smtp mailer modifies the UUCP
mailer.

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
		four 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), and "relay" for
		transmission to our RELAY_HOST, LUSER_RELAY, or
		MAILER_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 also 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
		the $=U class and sends them to the uucp-old mailer; all
		names in the $=Y class are sent to uucp-new; and all
		names in the $=Z class 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.vix.com/hylafax/.

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.  Within the 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.

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; 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 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/sendmail.cw
file to get values for class $=w.  The FEATURE may contain a single
optional parameter -- 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.

Available features are:

use_cw_file	Read the file /etc/sendmail.cw 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/sendmail.ct 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 not local; 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 do anything special with UUCP addresses at all.

nocanonify	Don't pass addresses to $[ ... $] for canonification.
		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.

stickyhost	If set, email sent to "user@local.host" are marked
		as "sticky" -- that is, the local addresses aren't
		matched against UDB and don't go through ruleset 5.
		This is used if you want a set up where "user" is
		not necessarily the same as "user@local.host", e.g.,
		to make a distinct domain-wide namespace.  Prior to
		8.7 this was the default, and notsticky was used to
		turn this off.

mailertable	Include a "mailer table" which can be used to override
		routing for particular domains.  The argument of the
		FEATURE may be the key definition.  If none is specified,
		the definition used is:
			hash -o /etc/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".
		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
		will give an error message with the indicated code and
		message.

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 -o /etc/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 -o /etc/bitdomain.db
		Keys are the bitnet hostname; values are the corresponding
		internet hostname.

uucpdomain	Similar feature for UUCP hosts.  The default map definition
		is:
			hash -o /etc/uudomain.db
		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.

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 $=w are masqueraded.  If this
		feature is given, only the hosts listed in $=M 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.

genericstable	This feature will cause certain addresses originating locally
		(i.e. that are unqualified) or a domain listed in $=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.  This
		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 the list of names given by the
		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 -o /etc/genericstable

		The key for this table is either the full address or the
		unqualified username (the former is tried first); 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.

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

			info@foo.com	foo-info
			info@bar.com	bar-info
			@baz.org	jane@elsewhere.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@elsewhere.net.  The username
		from the original address is passed as %1 allowing:

			@foo.org	%1@elsewhere.com

		meaning someone@foo.org will be sent to someone@elsewhere.com.

		All the host names on the left hand side (foo.com, bar.com,
		and baz.org) must be in $=w.  The default map definition is:

			hash -o /etc/virtusertable

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

			FEATURE(virtusertable, dbm -o /etc/mail/virtusers)

nodns		We aren't running DNS at our site (for example,
		we 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 stripped down
		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 "nocanonify" (this causes addresses to
		be sent unqualified via the SMTP connection; normally
		they are qualified with the masquerade name, which
		defaults to the name of the hub machine).  No mailers
		should be defined.  No aliasing or forwarding is done.
		Also, note that absolutely no anti-spam or anti-relaying
		is done in a null client configuration.  More information
		can be found in the ANTI-SPAM CONFIGURATION CONTROL section.

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.

local_procmail	Use procmail as the local mailer.  This 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.  The
		argument to this feature is the pathname of procmail,
		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.

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
		domain and sending it to another host outside your domain).
		This option sets your site to allow mail relaying from any
		site to any site.  In general, it is better to control the
		relaying more carefully with the access db and the 'R'
		class ($=R).  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
		By default, only hosts listed as RELAY in the access db
		will be allowed to relay.  This option also allows any
		host in your domain as defined by the 'm' class ($=m).

relay_hosts_only
		By default, names that are listed as RELAY in the access
		db and class 'R' ($=R) are 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_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.

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., 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.  By default,
		the access database specification is
		``hash -o /etc/mail/access''.  The format of the
		database is described below.

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 below.

rbl		Turns on rejection of hosts found in the Realtime Blackhole
		List.  If an argument is provided it is used as the
                name sever to contact; otherwise, the main RBL server at
		rbl.maps.vix.com is used.  For details, see
		http://maps.vix.com/rbl/.

loose_relay_check
		Normally, if a recipient using % addressing is used, 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.


+-------+
| 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 we move 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.

If your host is known by several different names, you need to augment
the $=w class.  This is a list of names by which you are known, and
anything sent to an address using a host name in this list will be
treated as local mail.  You can do this in two ways: either create
the file /etc/sendmail.cw containing a list of your aliases (one per
line), and use ``FEATURE(use_cw_file)'' in the .mc file, or add the
line:

	Cw alias.host.name

at the end of that file.  See the ``vangogh.mc'' file for an example.
Be sure you use the fully-qualified name of the host, rather than a
short name.

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.  The $=W class 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 I've left
this out-of-date configuration file 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 $=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).


+--------------------+
| 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 accros 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 also specified.

	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.

Examples:

We are 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, and can be used to
declare local database maps or whatever.  For example:

	LOCAL_CONFIG
	Khostmap hash /etc/hostmap.db
	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 I 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 $=w, the list
of local domain names).  You can augment this list 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.

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.  You can add users to this list using

	EXPOSED_USER(usernames)

This adds users to class E; you could also use something like

	FE/etc/sendmail.cE

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 something like

	FL/etc/sendmail.cL

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.
Names in $=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.

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 ---^


+---------------------------------+
| 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 domain to
another site outside your domain) is denied by default.  Note that
this changed in sendmail 8.9; previous versions allowed relaying by
default.  If you 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' ($=R) using RELAY_DOMAIN() and RELAY_DOMAIN_FILE() or via the
access database (described below).

If you use

	FEATURE(relay_entire_domain)

then any host in any of your local domains (that is, the $=m class)
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.  Note that this 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 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.

If source routing is used in the recipient address (i.e.
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.

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).  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)

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)

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)

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

	FEATURE(access_db, hash -o /etc/mail/access)

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.  For example,

	spammer@aol.com		REJECT
	cyberspammer.com	REJECT
	192.168.212		REJECT

would refuse mail from spammer@aol.com, any user from cyberspammer.com
(or any host within the cyberspammer.com domain), and any host on the
192.168.212.* network.

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.
	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.  This only works for sender
			addresses (i.e., it indicates that you should
			discard anything received from the indicated
			domain).
	### any text	where ### is an RFC 821 compliant error code
			and "any text" is a message to return for
			the command.

For example:

	cyberspammer.com	550 We don't accept mail from spammers
	okay.cyberspammer.com	OK
	sendmail.org		OK
	128.32			RELAY

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 accept mail from any hosts in the sendmail.org domain,
and allow relaying for the 128.32.*.* network.  Note, UUCP users may
need to add hostname.UUCP to the access database or class 'R' ($=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' ($=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:

	FREE.STEALTH.MAILER@	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:

	badlocaluser		550 Mailbox disabled for this username
	host.mydomain.com	550 That host does not accept mail
	user@otherhost.mydomain.com	550 Mailbox disabled for this recipient

This would prevent a recipient of badlocaluser@mydomain.com, any
user at host.mydomain.com, and the single address
user@otherhost.mydomain.com from receiving mail.  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.

There is also a ``Realtime Blackhole List'' run by the MAPS project
at http://maps.vix.com/.  This is a database maintained in DNS of
spammers.  To use this database, use

	FEATURE(rbl)

This will cause sendmail to reject mail from any site in the
Realtime Blackhole List database.  You can specify an alternative
RBL name server to contact by specifying an argument to the FEATURE.

The features described above make use of the check_relay, check_mail,
and check_rcpt rulesets.  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 new 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.  Otherwise, the results of the local
rewriting are ignored.


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_RULESETS
	HMessage-Id: $>CheckMessageId

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

Users of FEATURE(nullclient) who desire to use the anti-spam and
anti-relaying capabilities should replace FEATURE(nullclient, mailhub)
with:

	undefine(`ALIAS_FILE')
	define(`MAIL_HUB', `mailhub')
	define(`SMART_HOST', `mailhub')
	define(`confFORWARD_PATH', `')

where mailhub is the fully qualified hostname for their mail server.


+--------------------------------+
| ADDING NEW MAILERS OR RULESETS |
+--------------------------------+

Sometimes you may need to add entirely new mailers or rulesets.  They
should be introduced with the constructs MAILER_DEFINITIONS and
LOCAL_RULESETS respectively.  For example:

	MAILER_DEFINITIONS
	Mmymailer, ...
	...

	LOCAL_RULESETS
	Smyruleset
	...


+-------------------------------+
| NON-SMTP BASED CONFIGURATIONS |
+-------------------------------+

These configuration files are designed primarily for use by SMTP-based
sites.  I don't pretend that they are well tuned for UUCP-only or
UUCP-primarily nodes (the latter is defined as a small local net
connected to the rest of the world via UUCP).  However, there is one
hook to handle some special cases.

You can define a ``smart host'' that understands a richer address syntax
using:

	define(`SMART_HOST', mailer:hostname)

In this case, the ``mailer:'' defaults to "relay".  Any messages that
can't be handled using the usual UUCP rules are passed to this host.

If you are on a local SMTP-based net that connects to the outside
world via UUCP, you can use LOCAL_NET_CONFIG to add appropriate rules.
For example:

	define(`SMART_HOST', suucp:uunet)
	LOCAL_NET_CONFIG
	R$* < @ $* .$m. > $*	$#smtp $@ $2.$m. $: $1 < @ $2.$m. > $3

This will cause all names that end in your domain name ($m) via
SMTP; anything else will be sent via suucp (smart UUCP) to uunet.
If you have FEATURE(nocanonify), you may need to omit the dots after
the $m.  If you are running a local DNS inside your domain which is
not otherwise connected to the outside world, you probably want to
use:

	define(`SMART_HOST', smtp:fire.wall.com)
	LOCAL_NET_CONFIG
	R$* < @ $* . > $*	$#smtp $@ $2. $: $1 < @ $2. > $3

That is, send directly only to things you found in your DNS lookup;
anything else goes through SMART_HOST.

You may need to turn off the anti-spam rules in order to accept
UUCP mail with FEATURE(promiscuous_relay) and
FEATURE(accept_unresolvable_domains).


+-----------+
| WHO AM I? |
+-----------+

Normally, the $j macro is automatically defined to be your fully
qualified domain name (FQDN).  Sendmail does this by getting your
host name using gethostname and then calling gethostbyname on the
result.  For example, in some environments gethostname returns
only the root of the host name (such as "foo"); gethostbyname is
supposed to return the FQDN ("foo.bar.com").  In some (fairly rare)
cases, gethostbyname may fail to return the FQDN.  In this case
you MUST define confDOMAIN_NAME to be your fully qualified domain
name.  This is usually done using:

	Dmbar.com
	define(`confDOMAIN_NAME', `$w.$m')dnl


+--------------------+
| USING MAILERTABLES |
+--------------------+

To use FEATURE(mailertable), you will have to create an external
database containing the routing information for various domains.
For example, a mailertable file in text format might be:

	.my.domain		xnet:%1.my.domain
	uuhost1.my.domain	suucp:uuhost1
	.bitnet			smtp:relay.bit.net

This should normally be stored in /etc/mailertable.  The actual
database version of the mailertable is built using:

	makemap hash /etc/mailertable.db < /etc/mailertable

The semantics are simple.  Any LHS entry that does not begin with
a dot matches the full host name indicated.  LHS entries beginning
with a dot match anything ending with that domain name -- that is,
they can be thought of as having a leading "*" wildcard.  Matching
is done in order of most-to-least qualified -- for example, even
though ".my.domain" is listed first in the above example, an entry
of "uuhost1.my.domain" will match the second entry since it is
more explicit.

The RHS should always be a "mailer:host" pair.  The mailer is the
configuration name of a mailer (that is, an `M' line in the
sendmail.cf file).  The "host" will be the hostname passed to
that mailer.  In domain-based matches (that is, those with leading
dots) the "%1" may be used to interpolate the wildcarded part of
the host name.  For example, the first line above sends everything
addressed to "anything.my.domain" to that same host name, but using
the (presumably experimental) xnet mailer.

In some cases you may want to temporarily turn off MX records,
particularly on gateways.  For example, you may want to MX
everything in a domain to one machine that then forwards it
directly.  To do this, you might use the DNS configuration:

	*.domain.	IN	MX	0	relay.machine

and on relay.machine use the mailertable:

	.domain		smtp:[gateway.domain]

The [square brackets] turn off MX records for this host only.
If you didn't do this, the mailertable would use the MX record
again, which would give you an MX loop.


+--------------------------------+
| USING USERDB TO MAP FULL NAMES |
+--------------------------------+

The user database was not originally intended for mapping full names
to login names (e.g., Eric.Allman => eric), but some people are using
it that way.  (I would recommend that you set up aliases for this
purpose instead -- since you can specify multiple alias files, this
is fairly easy.)  The intent was to locate the default maildrop at
a site, but allow you to override this by sending to a specific host.

If you decide to set up the user database in this fashion, it is
imperative that you not use FEATURE(stickyhost) -- otherwise,
e-mail sent to Full.Name@local.host.name will be rejected.

To build the internal form of the user database, use:

	makemap btree /usr/data/base.db < /usr/data/base.txt

As a general rule, I am adamantly opposed to using full names as
e-mail addresses, since they are not in any sense unique.  For example,
the Unix software-development community has two Andy Tannenbaums,
at least two well-known Peter Deutsches, and at one time Bell Labs
had two Stephen R. Bournes with offices along the same hallway.
Which one will be forced to suffer the indignity of being
Stephen_R_Bourne_2?  The less famous of the two, or the one that
was hired later?

Finger should handle full names (and be fuzzy).  Mail should use
handles, and not be fuzzy.  [Not that I expect anyone to pay any
attention to my opinions.]


+--------------------------------+
| MISCELLANEOUS SPECIAL FEATURES |
+--------------------------------+

Plussed users
	Sometimes it is convenient to merge configuration on a
	centralized mail machine, for example, to forward all
	root mail to a mail server.  In this case it might be
	useful to be able to treat the root addresses as a class
	of addresses with subtle differences.  You can do this
	using plussed users.  For example, a client might include
	the alias:

		root:  root+client1@server

	On the server, this will match an alias for "root+client1".
	If that is not found, the alias "root+*" will be tried,
	then "root".

LDAP
	For notes on use LDAP in sendmail, see
	http://www.stanford.edu/~bbense/Inst.html



+----------------+
| SECURITY NOTES |
+----------------+

A lot of sendmail security comes down to you.  Sendmail 8 is much
more careful about checking for security problems than previous
versions, but there are some things that you still need to watch
for.  In particular:

* Make sure the aliases file isn't writable except by trusted
  system personnel.  This includes both the text and database
  version.

* Make sure that other files that sendmail reads, such as the
  mailertable, are only writable by trusted system personnel.

* The queue directory should not be world writable PARTICULARLY
  if your system allows "file giveaways" (that is, if a non-root
  user can chown any file they own to any other user).

* If your system allows file giveaways, DO NOT create a publically
  writable directory for forward files.  This will allow anyone
  to steal anyone else's e-mail.  Instead, create a script that
  copies the .forward file from users' home directories once a
  night (if you want the non-NFS-mounted forward directory).

* If your system allows file giveaways, you'll find that
  sendmail is much less trusting of :include: files -- in
  particular, you'll have to have /SENDMAIL/ANY/SHELL/ in
  /etc/shells before they will be trusted (that is, before
  files and programs listed in them will be honored).

In general, file giveaways are a mistake -- if you can turn them
off I recommend you do so.


+--------------------------------+
| TWEAKING CONFIGURATION OPTIONS |
+--------------------------------+

There are a large number of configuration options that don't normally
need to be changed.  However, if you feel you need to tweak them, you
can define the following M4 variables.  This list is shown in four
columns:  the name you define, the default value for that definition,
the option or macro that is affected (either Ox for an option or Dx
for a macro), and a brief description.  Greater detail of the semantics
can be found in the Installation and Operations Guide.

Some options are likely to be deprecated in future versions -- that is,
the option is only included to provide back-compatibility.  These are
marked with "*".

Remember that these options are M4 variables, and hence may need to
be quoted.  In particular, arguments with commas will usually have to
be ``double quoted, like this phrase'' to avoid having the comma
confuse things.  This is common for alias file definitions and for
the read timeout.

M4 Variable Name	Configuration	Description & [Default]
================	=============	=======================
confMAILER_NAME		$n macro	[MAILER-DAEMON] The sender name used
					for internally generated outgoing
					messages.
confDOMAIN_NAME		$j macro	If defined, sets $j.  This should
					only be done if your system cannot
					determine your local domain name,
					and then it should be set to
					$w.Foo.COM, where Foo.COM is your
					domain name.
confCF_VERSION		$Z macro	If defined, this is appended to the
					configuration version name.
confFROM_HEADER		From:		[$?x$x <$g>$|$g$.] The format of an
					internally generated From: address.
confRECEIVED_HEADER	Received:
		[$?sfrom $s $.$?_($?s$|from $.$_)
			$.by $j ($v/$Z)$?r with $r$. id $i$?u
			for $u; $|;
			$.$b]
					The format of the Received: header
					in messages passed through this host.
					It is unwise to try to change this.
confCW_FILE		Fw class	[/etc/sendmail.cw] Name of file used
					to get the local additions to the $=w
					(local host names) class.
confCT_FILE		Ft class	[/etc/sendmail.ct] Name of file used
					to get the local additions to the $=t
					(trusted users) class.
confCR_FILE		FR class	[/etc/mail/relay-domains] Name of
					file used to get the local additions
					to the $=R (hosts allowed to relay)
					class.
confTRUSTED_USERS	Ct class	[no default] Names of users to add to
					the list of trusted users.  This list
					always includes root, uucp, and daemon.
					See also FEATURE(use_ct_file).
confSMTP_MAILER		-		[esmtp] The mailer name used when
					SMTP connectivity is required.
					One of "smtp", "smtp8", or "esmtp".
confUUCP_MAILER		-		[uucp-old] The mailer to be used by
					default for bang-format recipient
					addresses.  See also discussion of
					$=U, $=Y, and $=Z in the MAILER(uucp)
					section.
confLOCAL_MAILER	-		[local] The mailer name used when
					local connectivity is required.
					Almost always "local".
confRELAY_MAILER	-		[relay] The default mailer name used
					for relaying any mail (e.g., to a
					BITNET_RELAY, a SMART_HOST, or
					whatever).  This can reasonably be
					"uucp-new" if you are on a
					UUCP-connected site.
confSEVEN_BIT_INPUT	SevenBitInput	[False] Force input to seven bits?
confEIGHT_BIT_HANDLING	EightBitMode	[pass8] 8-bit data handling
confALIAS_WAIT		AliasWait	[10m] Time to wait for alias file
					rebuild until you get bored and
					decide that the apparently pending
					rebuild failed.
confMIN_FREE_BLOCKS	MinFreeBlocks	[100] Minimum number of free blocks on
					queue filesystem to accept SMTP mail.
					(Prior to 8.7 this was minfree/maxsize,
					where minfree was the number of free
					blocks and maxsize was the maximum
					message size.  Use confMAX_MESSAGE_SIZE
					for the second value now.)
confMAX_MESSAGE_SIZE	MaxMessageSize	[infinite] The maximum size of messages
					that will be accepted (in bytes).
confBLANK_SUB		BlankSub	[.] Blank (space) substitution
					character.
confCON_EXPENSIVE	HoldExpensive	[False] Avoid connecting immediately
					to mailers marked expensive?
confCHECKPOINT_INTERVAL	CheckpointInterval
					[10] Checkpoint queue files every N
					recipients.
confDELIVERY_MODE	DeliveryMode	[background] Default delivery mode.
confAUTO_REBUILD	AutoRebuildAliases
					[False] Automatically rebuild alias
					file if needed.
confERROR_MODE		ErrorMode	[print] Error message mode.
confERROR_MESSAGE	ErrorHeader	[undefined] Error message header/file.
confSAVE_FROM_LINES	SaveFromLine	Save extra leading From_ lines.
confTEMP_FILE_MODE	TempFileMode	[0600] Temporary file mode.
confMATCH_GECOS		MatchGECOS	[False] Match GECOS field.
confMAX_HOP		MaxHopCount	[25] Maximum hop count.
confIGNORE_DOTS*	IgnoreDots	[False; always False in -bs or -bd mode]
					Ignore dot as terminator for incoming
					messages?
confBIND_OPTS		ResolverOptions	[undefined] Default options for DNS
					resolver.
confMIME_FORMAT_ERRORS*	SendMimeErrors	[True] Send error messages as MIME-
					encapsulated messages per RFC 1344.
confFORWARD_PATH	ForwardPath	[$z/.forward.$w:$z/.forward]
					The colon-separated list of places to
					search for .forward files.  N.B.: see
					the Security Notes section.
confMCI_CACHE_SIZE	ConnectionCacheSize
					[2] Size of open connection cache.
confMCI_CACHE_TIMEOUT	ConnectionCacheTimeout
					[5m] Open connection cache timeout.
confHOST_STATUS_DIRECTORY HostStatusDirectory
					[undefined] If set, host status is kept
					on disk between sendmail runs in the
					named directory tree.  This need not be
					a full pathname, in which case it is
					interpreted relative to the queue
					directory.
confSINGLE_THREAD_DELIVERY  SingleThreadDelivery
					[False] If this option and the
					HostStatusDirectory option are both
					set, single thread deliveries to other
					hosts.  That is, don't allow any two
					sendmails on this host to connect
					simultaneously to any other single
					host.  This can slow down delivery in
					some cases, in particular since a
					cached but otherwise idle connection
					to a host will prevent other sendmails
					from connecting to the other host.
confUSE_ERRORS_TO*	UserErrorsTo	[False] Use the Errors-To: header to
					deliver error messages.  This should
					not be necessary because of general
					acceptance of the envelope/header
					distinction.
confLOG_LEVEL		LogLevel	[9] Log level.
confME_TOO		MeToo		[False] Include sender in group
					expansions.
confCHECK_ALIASES	CheckAliases	[False] Check RHS of aliases when
					running newaliases.  Since this does
					DNS lookups on every address, it can
					slow down the alias rebuild process
					considerably on large alias files.
confOLD_STYLE_HEADERS*	OldStyleHeaders	[True] Assume that headers without
					special chars are old style.
confDAEMON_OPTIONS	DaemonPortOptions
					[none] SMTP daemon options.
confPRIVACY_FLAGS	PrivacyOptions	[authwarnings] Privacy flags.
confCOPY_ERRORS_TO	PostmasterCopy	[undefined] Address for additional
					copies of all error messages.
confQUEUE_FACTOR	QueueFactor	[600000] Slope of queue-only function.
confDONT_PRUNE_ROUTES	DontPruneRoutes	[False] Don't prune down route-addr
					syntax addresses to the minimum
					possible.
confSAFE_QUEUE*		SuperSafe	[True] Commit all messages to disk
					before forking.
confTO_INITIAL		Timeout.initial	[5m] The timeout waiting for a response
					on the initial connect.
confTO_CONNECT		Timeout.connect	[0] The timeout waiting for an initial
					connect() to complete.  This can only
					shorten connection timeouts; the kernel
					silently enforces an absolute maximum
					(which varies depending on the system).
confTO_ICONNECT		Timeout.iconnect
					[undefined] Like Timeout.connect, but
					applies only to the very first attempt
					to connect to a host in a message.
					This allows a single very fast pass
					followed by more careful delivery
					attempts in the future.
confTO_HELO		Timeout.helo	[5m] The timeout waiting for a response
					to a HELO or EHLO command.
confTO_MAIL		Timeout.mail	[10m] The timeout waiting for a
					response to the MAIL command.
confTO_RCPT		Timeout.rcpt	[1h] The timeout waiting for a response
					to the RCPT command.
confTO_DATAINIT		Timeout.datainit
					[5m] The timeout waiting for a 354
					response from the DATA command.
confTO_DATABLOCK	Timeout.datablock
					[1h] The timeout waiting for a block
					during DATA phase.
confTO_DATAFINAL	Timeout.datafinal
					[1h] The timeout waiting for a response
					to the final "." that terminates a
					message.
confTO_RSET		Timeout.rset	[5m] The timeout waiting for a response
					to the RSET command.
confTO_QUIT		Timeout.quit	[2m] The timeout waiting for a response
					to the QUIT command.
confTO_MISC		Timeout.misc	[2m] The timeout waiting for a response
					to other SMTP commands.
confTO_COMMAND		Timeout.command	[1h] In server SMTP, the timeout waiting
					for a command to be issued.
confTO_IDENT		Timeout.ident	[30s] The timeout waiting for a response
					to an IDENT query.
confTO_FILEOPEN		Timeout.fileopen
					[60s] The timeout waiting for a file
					(e.g., :include: file) to be opened.
confTO_QUEUERETURN	Timeout.queuereturn
					[5d] The timeout before a message is
					returned as undeliverable.
confTO_QUEUERETURN_NORMAL
			Timeout.queuereturn.normal
					[undefined] As above, for normal
					priority messages.
confTO_QUEUERETURN_URGENT
			Timeout.queuereturn.urgent
					[undefined] As above, for urgent
					priority messages.
confTO_QUEUERETURN_NONURGENT
			Timeout.queuereturn.non-urgent
					[undefined] As above, for non-urgent
					(low) priority messages.
confTO_QUEUEWARN	Timeout.queuewarn
					[4h] The timeout before a warning
					message is sent to the sender telling
					them that the message has been deferred.
confTO_QUEUEWARN_NORMAL	Timeout.queuewarn.normal
					[undefined] As above, for normal
					priority messages.
confTO_QUEUEWARN_URGENT	Timeout.queuewarn.urgent
					[undefined] As above, for urgent
					priority messages.
confTO_QUEUEWARN_NONURGENT
			Timeout.queuewarn.non-urgent
					[undefined] As above, for non-urgent
					(low) priority messages.
confTO_HOSTSTATUS	Timeout.hoststatus
					[30m] How long information about host
					statuses will be maintained before it
					is considered stale and the host should
					be retried.  This applies both within
					a single queue run and to persistent
					information (see below).
confTIME_ZONE		TimeZoneSpec	[USE_SYSTEM] Time zone info -- can be
					USE_SYSTEM to use the system's idea,
					USE_TZ to use the user's TZ envariable,
					or something else to force that value.
confDEF_USER_ID		DefaultUser	[1:1] Default user id.
confUSERDB_SPEC		UserDatabaseSpec
					[undefined] User database specification.
confFALLBACK_MX		FallbackMXhost	[undefined] Fallback MX host.
confTRY_NULL_MX_LIST	TryNullMXList	[False] If we are the best MX for a
					host and haven't made other
					arrangements, try connecting to the
					host directly; normally this would be
					a config error.
confQUEUE_LA		QueueLA		[8] Load average at which queue-only
					function kicks in.
confREFUSE_LA		RefuseLA	[12] Load average at which incoming
					SMTP connections are refused.
confMAX_DAEMON_CHILDREN	MaxDaemonChildren
					[undefined] The maximum number of
					children the daemon will permit.  After
					this number, connections will be
					rejected.  If not set or <= 0, there is
					no limit.
confCONNECTION_RATE_THROTTLE ConnectionRateThrottle
					[undefined] The maximum number of
					connections permitted per second.
					After this many connections are
					accepted, further connections will be
					delayed.  If not set or <= 0, there is
					no limit.
confWORK_RECIPIENT_FACTOR
			RecipientFactor	[30000] Cost of each recipient.
confSEPARATE_PROC	ForkEachJob	[False] Run all deliveries in a separate
					process.
confWORK_CLASS_FACTOR	ClassFactor	[1800] Priority multiplier for class.
confWORK_TIME_FACTOR	RetryFactor	[90000] Cost of each delivery attempt.
confQUEUE_SORT_ORDER	QueueSortOrder	[Priority] Queue sort algorithm:
					Priority, Host, or Time.
confMIN_QUEUE_AGE	MinQueueAge	[0] The minimum amount of time a job
					must sit in the queue between queue
					runs.  This allows you to set the
					queue run interval low for better
					responsiveness without trying all
					jobs in each run.
confDEF_CHAR_SET	DefaultCharSet	[unknown-8bit] When converting
					unlabeled 8 bit input to MIME, the
					character set to use by default.
confSERVICE_SWITCH_FILE	ServiceSwitchFile
					[/etc/service.switch] The file to use
					for the service switch on systems that
					do not have a system-defined switch.
confHOSTS_FILE		HostsFile	[/etc/hosts] The file to use when doing
					"file" type access of hosts names.
confDIAL_DELAY		DialDelay	[0s] If a connection fails, wait this
					long and try again.  Zero means "don't
					retry".  This is to allow "dial on
					demand" connections to have enough time
					to complete a connection.
confNO_RCPT_ACTION	NoRecipientAction
					[none] What to do if there are no legal
					recipient fields (To:, Cc: or Bcc:)
					in the message.  Legal values can
					be "none" to just leave the
					nonconforming message as is, "add-to"
					to add a To: header with all the
					known recipients (which may expose
					blind recipients), "add-apparently-to"
					to do the same but use Apparently-To:
					instead of To:, "add-bcc" to add an
					empty Bcc: header, or
					"add-to-undisclosed" to add the header
					``To: undisclosed-recipients:;''.
confSAFE_FILE_ENV	SafeFileEnvironment
					[undefined] If set, sendmail will do a
					chroot() into this directory before
					writing files.
confCOLON_OK_IN_ADDR	ColonOkInAddr	[True unless Configuration Level > 6]
					If set, colons are treated as a regular
					character in addresses.  If not set,
					they are treated as the introducer to
					the RFC 822 "group" syntax.  Colons are
					handled properly in route-addrs.  This
					option defaults on for V5 and lower
					configuration files.
confMAX_QUEUE_RUN_SIZE	MaxQueueRunSize	[0] If set, limit the maximum size of
					any given queue run to this number of
					entries.  Essentially, this will stop
					reading the queue directory after this
					number of entries are reached; it does
					_not_ pick the highest priority jobs,
					so this should be as large as your
					system can tolerate.  If not set, there
					is no limit.
confDONT_EXPAND_CNAMES	DontExpandCnames
					[False] If set, $[ ... $] lookups that
					do DNS based lookups do not expand
					CNAME records.  This currently violates
					the published standards, but the IETF
					seems to be moving toward legalizing
					this.  For example, if "FTP.Foo.ORG"
					is a CNAME for "Cruft.Foo.ORG", then
					with this option set a lookup of
					"FTP" will return "FTP.Foo.ORG"; if
					clear it returns "Cruft.FOO.ORG".  N.B.
					you may not see any effect until your
					downstream neighbors stop doing CNAME
					lookups as well.
confFROM_LINE		UnixFromLine	[From $g  $d] The From_ line used
					when sending to files or programs.
confSINGLE_LINE_FROM_HEADER  SingleLineFromHeader
					[False] From: lines that have
					embedded newlines are unwrapped
					onto one line.
confALLOW_BOGUS_HELO	AllowBogusHELO	[False] Allow HELO SMTP command that
					does not include a host name.
confMUST_QUOTE_CHARS	MustQuoteChars	[.'] Characters to be quoted in a full
					name phrase (@,;:\()[] are automatic).
confOPERATORS		OperatorChars	[.:%@!^/[]+] Address operator
					characters.
confSMTP_LOGIN_MSG	SmtpGreetingMessage
					[$j Sendmail $v/$Z; $b]
					The initial (spontaneous) SMTP
					greeting message.  The word "ESMTP"
					will be inserted between the first and
					second words to convince other
					sendmails to try to speak ESMTP.
confDONT_INIT_GROUPS	DontInitGroups	[False] If set, the initgroups(3)
					routine will never be invoked.  You
					might want to do this if you are
					running NIS and you have a large group
					map, since this call does a sequential
					scan of the map; in a large site this
					can cause your ypserv to run
					essentially full time.  If you set
					this, agents run on behalf of users
					will only have their primary
					(/etc/passwd) group permissions.
confUNSAFE_GROUP_WRITES	UnsafeGroupWrites
					[False] If set, group-writable
					:include: and .forward files are
					considered "unsafe", that is, programs
					and files cannot be directly referenced
					from such files.  World-writable files
					are always considered unsafe.
confDOUBLE_BOUNCE_ADDRESS  DoubleBounceAddress
					[postmaster] If an error occurs when
					sending an error message, send that
					"double bounce" error message to this
					address.
confRUN_AS_USER		RunAsUser	[undefined] If set, become this user
					when reading and delivering mail.
					Causes all file reads (e.g., .forward
					and :include: files) to be done as
					this user.  Also, all programs will
					be run as this user, and all output
					files will be written as this user.
					Intended for use only on firewalls
					where users do not have accounts.
confMAX_RCPTS_PER_MESSAGE  MaxRecipientsPerMessage
					[infinite] If set, allow no more than
					the specified number of recipients in
					an SMTP envelope.  Further recipients
					receive a 452 error code (i.e., they
					are deferred for the next delivery
					attempt).
confDONT_PROBE_INTERFACES  DontProbeInterfaces
					[False] If set, sendmail will _not_
					insert the names and addresses of any
					local interfaces into the $=w class
					(list of known "equivalent" addresses).
					If you set this, you must also include
					some support for these addresses (e.g.,
					in a mailertable entry) -- otherwise,
					mail to addresses in this list will
					bounce with a configuration error.
confDONT_BLAME_SENDMAIL	DontBlameSendmail
					[safe] Override sendmail's file
					safety checks.  This will definitely
					compromise system security and should
					not be used unless absolutely
					necessary.
confREJECT_MSG		-		[550 Access denied] The message
					given if the access database contains
					REJECT in the value portion.

See also the description of OSTYPE for some parameters that can be
tweaked (generally pathnames to mailers).


+-----------+
| HIERARCHY |
+-----------+

Within this directory are several subdirectories, to wit:

m4		General support routines.  These are typically
		very important and should not be changed without
		very careful consideration.

cf		The configuration files themselves.  They have
		".mc" suffixes, and must be run through m4 to
		become complete.  The resulting output should
		have a ".cf" suffix.

ostype		Definitions describing a particular operating
		system type.  These should always be referenced
		using the OSTYPE macro in the .mc file.  Examples
		include "bsd4.3", "bsd4.4", "sunos3.5", and
		"sunos4.1".

domain		Definitions describing a particular domain, referenced
		using the DOMAIN macro in the .mc file.  These are
		site dependent; for example, "CS.Berkeley.EDU.m4"
		describes hosts in the CS.Berkeley.EDU subdomain.

mailer		Descriptions of mailers.   These are referenced using
		the MAILER macro in the .mc file.

sh		Shell files used when building the .cf file from the
		.mc file in the cf subdirectory.

feature		These hold special orthogonal features that you might
		want to include.  They should be referenced using
		the FEATURE macro.

hack		Local hacks.  These can be referenced using the HACK
		macro.  They shouldn't be of more than voyeuristic
		interest outside the .Berkeley.EDU domain, but who knows?
		We've all got our own peccadillos.

siteconfig	Site configuration -- e.g., tables of locally connected
		UUCP sites.


+------------------------+
| ADMINISTRATIVE DETAILS |
+------------------------+

The following sections detail usage of certain internal parts of the
sendmail.cf file.  Read them carefully if you are trying to modify
the current model.  If you find the above descriptions adequate, these
should be {boring, confusing, tedious, ridiculous} (pick one or more).

RULESETS (* means built in to sendmail)

   0 *	Parsing
   1 *	Sender rewriting
   2 *	Recipient rewriting
   3 *	Canonicalization
   4 *	Post cleanup
   5 *	Local address rewrite (after aliasing)
  1x	mailer rules (sender qualification)
  2x	mailer rules (recipient qualification)
  3x	mailer rules (sender header qualification)
  4x	mailer rules (recipient header qualification)
  5x	mailer subroutines (general)
  6x	mailer subroutines (general)
  7x	mailer subroutines (general)
  8x	reserved
  90	Mailertable host stripping
  96	Bottom half of Ruleset 3 (ruleset 6 in old sendmail)
  97	Hook for recursive ruleset 0 call (ruleset 7 in old sendmail)
  98	Local part of ruleset 0 (ruleset 8 in old sendmail)
  99	Guaranteed null (for debugging)


MAILERS

   0	local, prog	local and program mailers
   1	[e]smtp, relay	SMTP channel
   2	uucp-*		UNIX-to-UNIX Copy Program
   3	netnews		Network News delivery
   4	fax		Sam Leffler's HylaFAX software
   5	mail11		DECnet mailer


MACROS

   A
   B	Bitnet Relay
   C	DECnet Relay
   D	The local domain -- usually not needed
   E	reserved for X.400 Relay
   F	FAX Relay
   G
   H	mail Hub (for mail clusters)
   I
   J
   K
   L	Luser Relay
   M	Masquerade (who I claim to be)
   N
   O
   P
   Q
   R	Relay (for unqualified names)
   S	Smart Host
   T
   U	my UUCP name (if I have a UUCP connection)
   V	UUCP Relay (class V hosts)
   W	UUCP Relay (class W hosts)
   X	UUCP Relay (class X hosts)
   Y	UUCP Relay (all other hosts)
   Z	Version number


CLASSES

   A
   B	domains that are candidates for bestmx lookup
   C
   D
   E	addresses that should not seem to come from $M
   F	hosts we forward for
   G	domains that should be looked up in genericstable
   H
   I
   J
   K
   L	addresses that should not be forwarded to $R
   M	domains that should be mapped to $M
   N
   O	operators that indicate network operations (cannot be in local names)
   P	top level pseudo-domains: BITNET, DECNET, FAX, UUCP, etc.
   Q
   R	domains we are willing to relay (pass anti-spam filters)
   S
   T
   U	locally connected UUCP hosts
   V	UUCP hosts connected to relay $V
   W	UUCP hosts connected to relay $W
   X	UUCP hosts connected to relay $X
   Y	locally connected smart UUCP hosts
   Z	locally connected domain-ized UUCP hosts
   .	the class containing only a dot
   [	the class containing only a left bracket


M4 DIVERSIONS

   1	Local host detection and resolution
   2	Local Ruleset 3 additions
   3	Local Ruleset 0 additions
   4	UUCP Ruleset 0 additions
   5	locally interpreted names (overrides $R)
   6	local configuration (at top of file)
   7	mailer definitions
   8
   9	special local rulesets (1 and 2)