Makefile: Improve commentary.

[exim-config] / base.m4

### -*-m4-*-
###
### Basic settings for distorted.org.uk Exim configuration
###
### (c) 2012 Mark Wooding
###

###----- Licensing notice ---------------------------------------------------
###
### This program is free software; you can redistribute it and/or modify
### it under the terms of the GNU General Public License as published by
### the Free Software Foundation; either version 2 of the License, or
### (at your option) any later version.
###
### This program is distributed in the hope that it will be useful,
### but WITHOUT ANY WARRANTY; without even the implied warranty of
### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
### GNU General Public License for more details.
###
### You should have received a copy of the GNU General Public License
### along with this program; if not, write to the Free Software Foundation,
### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

###--------------------------------------------------------------------------
### Global settings.

SECTION(global, priv)m4_dnl
prod_requires_admin = false

SECTION(global, logging)m4_dnl
log_file_path = : syslog
log_selector = \
	+smtp_confirmation \
	+tls_peerdn
log_timezone = true
syslog_duplication = false
syslog_timestamp = false

SECTION(global, daemon)m4_dnl
local_interfaces = <; CONF_interfaces
extra_local_interfaces = <; 0.0.0.0 ; ::

SECTION(global, resource)m4_dnl
deliver_queue_load_max = 8
queue_only_load = 12
smtp_accept_max = 16
smtp_accept_queue = 32
smtp_accept_reserve = 4
smtp_load_reserve = 10
smtp_reserve_hosts = +trusted

SECTION(global, policy)m4_dnl
host_lookup = *

SECTION(global, users)m4_dnl
gecos_name = $1
gecos_pattern = ([^,:]*)

SECTION(global, incoming)m4_dnl
received_header_text = Received: \
	${if def:sender_rcvhost {from $sender_rcvhost\n\t} \
	     {${if def:sender_ident \
		   {from ${quote_local_part:$sender_ident} }}\
	      ${if def:sender_helo_name \
		   {(helo=$sender_helo_name)\n\t}}}}\
	by $primary_hostname \
	${if def:received_protocol \
	     {with $received_protocol \
	      ${if def:tls_cipher {(cipher=$tls_cipher)\n\t}}}}\
	(Exim $version_number)\n\t\
	${if def:sender_address \
	     {(envelope-from <$sender_address>\
	      ${if def:authenticated_id \
		   {; auth=$authenticated_id}})\n\t}}\
	id $message_exim_id\
	${if def:received_for {\n\tfor $received_for}}

SECTION(global, smtp)m4_dnl
smtp_return_error_details = true
accept_8bitmime = true

SECTION(global, process)m4_dnl
extract_addresses_remove_arguments = false
headers_charset = utf-8
qualify_domain = CONF_master_domain

SECTION(global, bounce)m4_dnl
delay_warning = 1h : 24h : 2d

DIVERT(null)
###--------------------------------------------------------------------------
### Access control lists.

SECTION(global, acl-after)
SECTION(global, acl)m4_dnl
acl_smtp_helo = helo
SECTION(acl, misc)m4_dnl
helo:
	require	 message = The other one has bells on
		 verify = helo

	accept

SECTION(global, acl)m4_dnl
acl_smtp_mail = mail
SECTION(acl, mail)m4_dnl
mail:

	## Always allow the empty sender, so that we can receive bounces.
	accept	 senders = :

	## Ensure that the sender is routable.  This is important to prevent
	## undeliverable bounces.
	require	 message = Invalid sender; \
			($sender_verify_failure; $acl_verify_message)
		 verify = sender

	## If this is directly from a client then hack on it for a while.
	warn	 condition = ${if eq{$acl_c_mode}{submission}}
		 control = submission

SECTION(acl, mail-tail)m4_dnl
	## And we're done.
	accept

SECTION(global, acl)m4_dnl
acl_smtp_connect = connect
SECTION(acl, connect)m4_dnl
connect:
SECTION(acl, connect-tail)m4_dnl
	warn	 acl = check_submission
	accept

check_submission:
	## See whether this message needs hacking on.
	accept	!hosts = +localnet
		!condition = ${if ={$received_port}{CONF_submission_port}}
		 set acl_c_mode = relay

	## Remember to apply submission controls.
	warn	 set acl_c_mode = submission

	## Done.
	accept

SECTION(global, acl)m4_dnl
acl_smtp_rcpt = rcpt
SECTION(acl, rcpt)m4_dnl
rcpt:

	## Reject if the client isn't allowed to relay and the recipient
	## isn't in one of our known domains.
	deny	 message = Relaying not permitted
		!hosts = CONF_relay_clients
		!authenticated = *
		!domains = +known

	## Ensure that the recipient is routable.
	require	 message = Invalid recipient \
			($recipient_verify_failure; $acl_verify_message)
		 verify = recipient

SECTION(acl, rcpt-tail)m4_dnl
	## Everything checks out OK: let this one go through.
	accept

SECTION(global, acl)m4_dnl
acl_smtp_data = data
SECTION(acl, data)m4_dnl
data:

SECTION(acl, data-tail)m4_dnl
	accept

SECTION(global, acl)m4_dnl
acl_smtp_expn = expn_vrfy
acl_smtp_vrfy = expn_vrfy
SECTION(acl)m4_dnl
expn_vrfy:
	accept	 hosts = +trusted
	deny	 message = Suck it and see

DIVERT(null)
###--------------------------------------------------------------------------
### Common options for forwarding routers.

## We're pretty permissive here.
m4_define(<:FILTER_BASE:>,
	<:driver = redirect
	modemask = 002
	check_owner = false
	check_group = false
	allow_filter = true
	allow_defer = true
	allow_fail = true
	forbid_blackhole = false
	check_ancestor = true:>)

## Common options for forwarding routers at verification time.
m4_define(<:FILTER_VERIFY:>,
	<:verify_only = true
	user = CONF_filter_user
	forbid_filter_dlfunc = true
	forbid_filter_logwrite = true
	forbid_filter_perl = true
	forbid_filter_readsocket = true
	forbid_filter_run = true
	file_transport = dummy
	directory_transport = dummy
	pipe_transport = dummy
	reply_transport = dummy:>)

## Transports for redirection filters.
m4_define(<:FILTER_TRANSPORTS:>,
	<:file_transport = mailbox
	directory_transport = maildir
	pipe_transport = pipe
	reply_transport = reply:>)

DIVERT(null)
###--------------------------------------------------------------------------
### Some standard transports.

m4_define(<:USER_DELIVERY:>,
	<:delivery_date_add = true
	envelope_to_add = true
	return_path_add = true:>)

SECTION(transports)m4_dnl
## A standard transport for remote delivery.  Try to do TLS, and don't worry
## too much if it's not very secure: the alternative is sending in plaintext
## anyway.
smtp:
	driver = smtp
	tls_require_ciphers = CONF_acceptable_ciphers
	tls_dh_min_bits = 1020
	tls_tempfail_tryclear = true

## Transport to a local SMTP server; use TLS and perform client
## authentication.
smtp_local:
	driver = smtp
	hosts_require_tls = *
	tls_certificate = CONF_sysconf_dir/client.cert
	tls_privatekey = CONF_sysconf_dir/client.key
	tls_verify_certificates = CONF_ca_dir/ca.cert
	tls_require_ciphers = CONF_good_ciphers
	tls_dh_min_bits = 3070
	tls_tempfail_tryclear = false
	authenticated_sender = ${if def:authenticated_id \
				    ${authenticated_id@CONF_master_domain} \
				    fail}

## A standard transport for local delivery.
deliver:
	driver = appendfile
	file = /var/mail/$local_part
	USER_DELIVERY

## Transports for user filters.
mailbox:
	driver = appendfile
	USER_DELIVERY

maildir:
	driver = appendfile
	maildir_format = true
	USER_DELIVERY

pipe:
	driver = pipe
	return_output = true

## A special dummy transport for use during address verification.
dummy:
	driver = appendfile
	file = /dev/null

DIVERT(null)
###--------------------------------------------------------------------------
### Retry configuration.

SECTION(retry, default)m4_dnl
## Default.
*					* \
	F,2h,15m; G,16h,2h,1.5; F,4d,6h

DIVERT(null)
###----- That's all, folks --------------------------------------------------