chiark - git - mdw - exim-config/blob - base.m4

   1 ### -*-m4-*-
   2 ###
   3 ### Basic settings for distorted.org.uk Exim configuration
   4 ###
   5 ### (c) 2012 Mark Wooding
   6 ###
   7
   8 ###----- Licensing notice ---------------------------------------------------
   9 ###
  10 ### This program is free software; you can redistribute it and/or modify
  11 ### it under the terms of the GNU General Public License as published by
  12 ### the Free Software Foundation; either version 2 of the License, or
  13 ### (at your option) any later version.
  14 ###
  15 ### This program is distributed in the hope that it will be useful,
  16 ### but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ### GNU General Public License for more details.
  19 ###
  20 ### You should have received a copy of the GNU General Public License
  21 ### along with this program; if not, write to the Free Software Foundation,
  22 ### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  23
  24 ###--------------------------------------------------------------------------
  25 ### Global settings.
  26
  27 SECTION(global, priv)m4_dnl
  28 admin_groups = CONF_admin_groups
  29 trusted_groups = CONF_trusted_groups
  30 prod_requires_admin = false
  31
  32 SECTION(global, logging)m4_dnl
  33 log_file_path = : syslog
  34 log_selector = \
  35         +smtp_confirmation \
  36         +tls_peerdn
  37 log_timezone = true
  38 syslog_duplication = false
  39 syslog_timestamp = false
  40
  41 SECTION(global, daemon)m4_dnl
  42 local_interfaces = <; CONF_interfaces
  43 extra_local_interfaces = <; 0.0.0.0 ; ::0
  44
  45 SECTION(global, resource)m4_dnl
  46 deliver_queue_load_max = 8
  47 message_size_limit = 500M
  48 queue_only_load = 12
  49 smtp_accept_max = 16
  50 smtp_accept_queue = 32
  51 smtp_accept_reserve = 4
  52 smtp_load_reserve = 10
  53 smtp_reserve_hosts = +trusted
  54
  55 SECTION(global, policy)m4_dnl
  56 host_lookup = *
  57
  58 SECTION(global, users)m4_dnl
  59 gecos_name = $1
  60 gecos_pattern = ([^,:]*)
  61
  62 SECTION(global, incoming)m4_dnl
  63 rfc1413_hosts = *
  64 rfc1413_query_timeout = 10s
  65 received_header_text = Received: \
  66         ${if def:sender_rcvhost \
  67              {from $sender_rcvhost\n\t} \
  68              {${if def:sender_ident \
  69                    {from ${quote_local_part:$sender_ident} }}}}\
  70         by $primary_hostname \
  71         (Exim $version_number)\
  72         ${if def:tls_cipher {\n\t} { }}\
  73         ${if def:received_protocol \
  74              {with $received_protocol \
  75               ${if def:tls_cipher {(cipher=$tls_cipher)}}}}\n\t\
  76         ${if def:sender_address \
  77              {(envelope-from $sender_address\
  78               ${if def:authenticated_id \
  79                    {; auth=${quote_local_part:$authenticated_id}} \
  80                    {${if and {{def:authenticated_sender} \
  81                               {match_address{$authenticated_sender} \
  82                                             {*@CONF_master_domain}}} \
  83                          {; auth=${quote_local_part:\
  84                                     ${local_part:\
  85                                       $authenticated_sender}}}}}})\n\t}}\
  86         id $message_exim_id\
  87         ${if def:received_for {\n\tfor $received_for}}
  88
  89 SECTION(global, smtp)m4_dnl
  90 smtp_return_error_details = true
  91 accept_8bitmime = true
  92 chunking_advertise_hosts =
  93
  94 SECTION(global, env)m4_dnl
  95 keep_environment =
  96
  97 SECTION(global, process)m4_dnl
  98 extract_addresses_remove_arguments = false
  99 headers_charset = utf-8
 100 qualify_domain = CONF_master_domain
 101 untrusted_set_sender = *
 102 local_from_check = false
 103 local_sender_retain = true
 104
 105 SECTION(global, bounce)m4_dnl
 106 delay_warning = 1h : 24h : 2d
 107
 108 SECTION(global, tls)m4_dnl
 109 tls_certificate = CONF_certlist
 110 tls_privatekey = CONF_sysconf_dir/server.key
 111 tls_advertise_hosts = ${if exists {CONF_sysconf_dir/server.key} {*}{}}
 112 tls_dhparam = CONF_ca_dir/dh-param-2048.pem
 113 tls_require_ciphers = ${if or {{={$received_port}{CONF_submission_port}} \
 114                                {match_ip {$sender_host_address}{+trusted}}} \
 115                            {CONF_good_ciphers} \
 116                            {CONF_acceptable_ciphers}}
 117 tls_verify_certificates = CONF_ca_dir/ca.cert
 118 tls_verify_hosts = ${if eq{$acl_c_mode}{submission} {} {+allnets}}
 119
 120 DIVERT(null)
 121 ###--------------------------------------------------------------------------
 122 ### Access control lists.
 123
 124 SECTION(global, acl-after)
 125 SECTION(global, acl)m4_dnl
 126 acl_smtp_helo = helo
 127 SECTION(acl, misc)m4_dnl
 128 helo:
 129         ## Don't worry if this is local submission.  MUAs won't necessarily
 130         ## have a clear idea of their hostnames.  (For some reason.)
 131         accept   condition = ${if !eq{$acl_c_mode}{submission}}
 132
 133         ## Check that the caller's claimed identity is actually plausible.
 134         ## This seems like it's a fairly effective filter on spamminess, but
 135         ## it's too blunt a tool.  Rather than reject, add a warning header.
 136         ## Only we can't do this the easy way, so save it up for use in MAIL.
 137         ## Also, we're liable to get a subsequent HELO (e.g., after STARTTLS)
 138         ## and we should only care about the most recent one.
 139         warn     set acl_c_helo_warning = false
 140                 !condition = \
 141                         ${if and {{match_ip {$sender_host_address} \
 142                                             {<; 127.0.0.0/8 ; ::1}} \
 143                                   {match_domain {$sender_helo_name} \
 144                                                 {localhost : +thishost}}}}
 145                 !condition = \
 146                         ${if exists {CONF_sysconf_dir/helo.conf} \
 147                              {${lookup {$sender_helo_name} \
 148                                        partial0-lsearch \
 149                                        {CONF_sysconf_dir/helo.conf} \
 150                                        {${if match_ip \
 151                                              {$sender_host_address} \
 152                                              {<; $value}}}}}}
 153                 !verify = helo
 154                  set acl_c_helo_warning = true
 155
 156         accept
 157
 158 SECTION(global, acl)m4_dnl
 159 acl_not_smtp_start = not_smtp_start
 160 SECTION(acl, misc)m4_dnl
 161 not_smtp_start:
 162         ## Record the user's name.
 163         warn     set acl_c_user = $sender_ident
 164                  set acl_m_user = $sender_ident
 165
 166         ## Done.
 167         accept
 168
 169 SECTION(global, acl)m4_dnl
 170 acl_smtp_mail = mail
 171 SECTION(acl, mail)m4_dnl
 172 mail:
 173
 174         ## If we stashed a warning header about HELO from earlier, we should
 175         ## add it now.  Only don't bother if the client has authenticated
 176         ## successfully for submission (because we can't expect mobile
 177         ## clients to be properly set up knowing their names), or it's one of
 178         ## our own satellites (because they're either properly set up anyway,
 179         ## or satellites using us as a smarthost).
 180         warn     condition = $acl_c_helo_warning
 181                 !condition = ${if eq{$acl_c_mode}{submission}}
 182                 !hosts = +allnets
 183                  WARNING_HEADER(BADHELO,
 184                                 <:Client's HELO doesn't match its IP address.\n\t\
 185                                   helo-name=$sender_helo_name \
 186                                   address=$sender_host_address:>)
 187
 188         ## Always allow the empty sender, so that we can receive bounces.
 189         accept   senders = :
 190
 191         ## Ensure that the sender looks valid.
 192         require  acl = mail_check_sender
 193
 194         ## If this is directly from a client then hack on it for a while.
 195         warn     condition = ${if eq{$acl_c_mode}{submission}}
 196                  control = submission/sender_retain
 197
 198         ## Insist that a local client connect through TLS.
 199         deny     message = Hosts within CONF_master_domain must use TLS
 200                 !condition = ${if eq{$acl_c_mode}{submission}}
 201                  hosts = +allnets
 202                 !encrypted = *
 203
 204         ## Check that a submitted message's sender address is allowable.
 205         require  acl = mail_check_auth
 206
 207 SECTION(acl, mail-tail)m4_dnl
 208         ## And we're done.
 209         accept
 210
 211 SECTION(acl, misc)m4_dnl
 212 mail_check_sender:
 213
 214         ## See whether there's a special exception for this sender domain.
 215         accept   senders = ${LOOKUP_DOMAIN($sender_address_domain,
 216                              {KV(senders, {$value}{})},
 217                              {})}
 218
 219         ## Ensure that the sender is routable.  This is important to prevent
 220         ## undeliverable bounces.
 221         require  message = Invalid sender; \
 222                         ($sender_verify_failure; $acl_verify_message)
 223                  verify = sender
 224
 225         ## We're good, then.
 226         accept
 227
 228 SECTION(global, acl)m4_dnl
 229 acl_smtp_connect = connect
 230 SECTION(acl, connect)m4_dnl
 231 connect:
 232 SECTION(acl, connect-tail)m4_dnl
 233         ## Configure variables according to the submission mode.
 234         warn     acl = check_submission
 235
 236         ## Done.
 237         accept
 238
 239 check_submission:
 240         ## See whether this message needs hacking on.
 241         accept  !hosts = +thishost
 242                 !condition = ${if ={$received_port}{CONF_submission_port}}
 243                  set acl_c_mode = relay
 244
 245         ## Remember to apply submission controls.
 246         warn     set acl_c_mode = submission
 247                  control = no_enforce_sync
 248
 249         ## Done.
 250         accept
 251
 252 SECTION(global, acl)m4_dnl
 253 acl_smtp_rcpt = rcpt
 254 SECTION(acl, rcpt)m4_dnl
 255 rcpt:
 256
 257         ## Reject if the client isn't allowed to relay and the recipient
 258         ## isn't in one of our known domains.
 259         require  message = Relaying not permitted
 260                  acl = check_relay
 261
 262         ## Ensure that the recipient is routable.
 263         require  message = Invalid recipient \
 264                         ($recipient_verify_failure; $acl_verify_message)
 265                  verify = recipient
 266
 267 SECTION(acl, misc)m4_dnl
 268 check_relay:
 269         ## Accept either if the client is allowed to relay through us, or if
 270         ## we're the correct place to send this mail.
 271
 272         ## Known clients and authenticated users are OK.
 273         accept   hosts = CONF_relay_clients
 274         accept   authenticated = *
 275
 276         ## Known domains are OK.
 277         accept   domains = +public
 278
 279         ## Finally, domains in our table are OK, unless they say they aren't.
 280         accept   domains = \
 281                  ${if exists{CONF_sysconf_dir/domains.conf} \
 282                      {partial0-lsearch; CONF_sysconf_dir/domains.conf}}
 283                  condition = DOMKV(service, {$value}{true})
 284
 285         ## Nope, that's not allowed.
 286         deny
 287
 288 SECTION(acl, rcpt-tail)m4_dnl
 289         ## Everything checks out OK: let this one go through.
 290         accept
 291
 292 SECTION(global, acl)m4_dnl
 293 acl_smtp_data = data
 294 SECTION(acl, data)m4_dnl
 295 data:
 296         ## Don't accept messages with overly-long lines.
 297         deny     message = line length exceeds SMTP permitted maximum: \
 298                         $max_received_linelength > 998
 299                  condition = ${if >{$max_received_linelength}{998}}
 300
 301 SECTION(acl, data-tail)m4_dnl
 302         accept
 303
 304 SECTION(global, acl)m4_dnl
 305 acl_smtp_expn = expn_vrfy
 306 acl_smtp_vrfy = expn_vrfy
 307 SECTION(acl, misc)m4_dnl
 308 expn_vrfy:
 309         accept   hosts = +trusted
 310         deny     message = Suck it and see
 311
 312 DIVERT(null)
 313 ###--------------------------------------------------------------------------
 314 ### Verification of sender address.
 315
 316 SECTION(acl, misc)m4_dnl
 317 mail_check_auth:
 318
 319         ## If this isn't a submission then it doesn't need checking.
 320         accept   condition = ${if !eq{$acl_c_mode}{submission}}
 321
 322         ## If the caller hasn't formally authenticated, but this is a
 323         ## loopback connection, then we can trust identd to tell us the right
 324         ## answer.  So we should stash the right name somewhere consistent.
 325         warn     set acl_c_user = $authenticated_id
 326                  hosts = +thishost
 327                 !authenticated = *
 328                  condition = ${if def:sender_ident}
 329                  set acl_c_user = $sender_ident
 330
 331         ## User must be authenticated by now.
 332         deny     message = Sender not authenticated
 333                  condition = ${if !def:acl_c_user}
 334
 335         ## Set the per-message authentication flag, since we now know that
 336         ## there's a sensible value.
 337         warn     set acl_m_user = $acl_c_user
 338
 339         ## All done.
 340         accept
 341
 342 DIVERT(null)
 343 ###--------------------------------------------------------------------------
 344 ### Common options for forwarding routers.
 345
 346 ## We're pretty permissive here.
 347 m4_define(<:FILTER_BASE:>,
 348         <:driver = redirect
 349         modemask = 002
 350         check_owner = false
 351         check_group = false
 352         allow_filter = true
 353         allow_defer = true
 354         allow_fail = true
 355         forbid_blackhole = false
 356         check_ancestor = true:>)
 357
 358 ## Common options for forwarding routers at verification time.
 359 m4_define(<:FILTER_VERIFY:>,
 360         <:verify_only = true
 361         user = CONF_filter_user
 362         forbid_filter_dlfunc = true
 363         forbid_filter_logwrite = true
 364         forbid_filter_perl = true
 365         forbid_filter_readsocket = true
 366         forbid_filter_run = true
 367         file_transport = dummy
 368         directory_transport = dummy
 369         pipe_transport = dummy
 370         reply_transport = dummy:>)
 371
 372 ## Transports for redirection filters.
 373 m4_define(<:FILTER_TRANSPORTS:>,
 374         <:file_transport = mailbox
 375         directory_transport = maildir
 376         pipe_transport = pipe
 377         reply_transport = reply:>)
 378
 379 m4_define(<:FILTER_ROUTER:>,
 380 <:$1_vrf:
 381         $2
 382         FILTER_VERIFY<::>$3
 383 $1:
 384         $2
 385         verify = no
 386         FILTER_TRANSPORTS<::>$4:>)
 387
 388 DIVERT(null)
 389 ###--------------------------------------------------------------------------
 390 ### Common routers.
 391
 392 SECTION(routers, alias)m4_dnl
 393 ## Look up the local part in the address map.
 394 alias:
 395         driver = redirect
 396         allow_fail = true
 397         allow_defer = true
 398         user = CONF_filter_user
 399         FILTER_TRANSPORTS
 400         local_parts = nwildlsearch; CONF_alias_file
 401         data = ${expand:$local_part_data}
 402 SECTION(routers, alias-opts)m4_dnl
 403
 404 DIVERT(null)
 405 ###--------------------------------------------------------------------------
 406 ### Some standard transports.
 407
 408 m4_define(<:USER_DELIVERY:>,
 409         <:delivery_date_add = true
 410         envelope_to_add = true
 411         return_path_add = true:>)
 412
 413 m4_define(<:APPLY_HEADER_CHANGES:>,
 414         <:headers_add = m4_ifelse(<:$1:>, <::>,
 415                 <:$acl_m_hdradd:>,
 416                 <:${if def:acl_m_hdradd{$acl_m_hdradd\n}}\
 417                 $1:>)
 418         headers_remove = m4_ifelse(<:$2:>, <::>,
 419                 <:$acl_m_hdrrm:>,
 420                 <:${if def:acl_m_hdrrm{$acl_m_hdrrm:}}\
 421                 $2:>):>)
 422
 423 m4_define(<:SMTP_DELIVERY:>,
 424         <:## Prevent sending messages with overly long lines.  The use of
 425         ## `message_size_limit' here is somewhat misleading.
 426         message_size_limit = ${if >{$max_received_linelength}{998}{1}{0}}:>)
 427
 428 SECTION(transports)m4_dnl
 429 ## A standard transport for remote delivery.  By default, try to do TLS, and
 430 ## don't worry too much if it's not very secure: the alternative is sending
 431 ## in plaintext anyway.  But all of this can be overridden from the
 432 ## `domains.conf' file.  Annoyingly, the `tls_dh_min_bits' setting isn't
 433 ## expanded before use, so we can't set it the obvious way.  Instead, encode
 434 ## it into the transport name.  This is very unpleasant, of course.
 435 smtp:
 436         driver = smtp
 437         APPLY_HEADER_CHANGES
 438         tls_require_ciphers = CONF_acceptable_ciphers
 439         tls_dh_min_bits = 508
 440         tls_tempfail_tryclear = true
 441
 442 m4_define(<:SMTP_TRANS_DHBITS:>,
 443         <:driver = smtp
 444         SMTP_DELIVERY
 445         APPLY_HEADER_CHANGES
 446         hosts_try_auth = *
 447         hosts_require_tls = DOMKV(tls-peer-ca, {*}{})
 448         hosts_require_auth = \
 449                 ${if bool {DOMKV(require-auth, {$value}{false})} {*}{}}
 450         tls_certificate = DOMKV(tls-certificate, {${expand:$value}}fail)
 451         tls_privatekey = DOMKV(tls-private-key, {${expand:$value}}fail)
 452         tls_verify_certificates = DOMKV(tls-peer-ca, {${expand:$value}}fail)
 453         tls_require_ciphers = \
 454                 DOMKV(tls-ciphers,
 455                       {${extract {${expand:$value}} \
 456                                  { good = CONF_good_ciphers \
 457                                    any = CONF_acceptable_ciphers } \
 458                                  {$value} \
 459                                  {${expand:$value}}}} \
 460                       {CONF_acceptable_ciphers})
 461         tls_dh_min_bits = $1
 462         tls_tempfail_tryclear = true:>)m4_dnl
 463 smtp_dhbits_512:
 464         SMTP_TRANS_DHBITS(508)
 465 smtp_dhbits_768:
 466         SMTP_TRANS_DHBITS(764)
 467 smtp_dhbits_1024:
 468         SMTP_TRANS_DHBITS(1020)
 469 smtp_dhbits_2048:
 470         SMTP_TRANS_DHBITS(2044)
 471
 472 ## Transport to a local SMTP server; use TLS and perform client
 473 ## authentication.
 474 smtp_local:
 475         driver = smtp
 476         SMTP_DELIVERY
 477         APPLY_HEADER_CHANGES
 478         hosts_require_tls = *
 479         tls_certificate = CONF_sysconf_dir/client.certlist
 480         tls_privatekey = CONF_sysconf_dir/client.key
 481         tls_verify_certificates = CONF_ca_dir/ca.cert
 482         tls_require_ciphers = CONF_good_ciphers
 483         tls_dh_min_bits = 2046
 484         tls_tempfail_tryclear = false
 485         authenticated_sender_force = true
 486         authenticated_sender = \
 487                 ${if def:acl_m_user {$acl_m_user@CONF_master_domain} \
 488                      {${if def:authenticated_sender {$authenticated_sender} \
 489                            fail}}}
 490
 491 ## A standard transport for local delivery.
 492 deliver:
 493         driver = appendfile
 494         APPLY_HEADER_CHANGES
 495         file = /var/mail/$local_part
 496         group = mail
 497         mode = 0600
 498         mode_fail_narrower = false
 499         USER_DELIVERY
 500
 501 ## Transports for user filters.
 502 mailbox:
 503         driver = appendfile
 504         APPLY_HEADER_CHANGES
 505         initgroups = true
 506         USER_DELIVERY
 507
 508 maildir:
 509         driver = appendfile
 510         APPLY_HEADER_CHANGES
 511         maildir_format = true
 512         initgroups = true
 513         USER_DELIVERY
 514
 515 pipe:
 516         driver = pipe
 517         APPLY_HEADER_CHANGES
 518         path = ${if and {{def:home} {exists{$home/bin}}} {$home/bin:} {}}\
 519                 /usr/local/bin:/usr/local/sbin:\
 520                 /usr/bin:/usr/sbin:/bin:/sbin
 521         initgroups = true
 522         umask = 002
 523         return_fail_output = true
 524         log_output = true
 525
 526 ## A special dummy transport for use during address verification.
 527 dummy:
 528         driver = appendfile
 529         file = /dev/null
 530
 531 DIVERT(null)
 532 ###--------------------------------------------------------------------------
 533 ### Retry configuration.
 534
 535 SECTION(retry, default)m4_dnl
 536 ## Be persistent when sending to the site relay.  It ought to work, but
 537 ## particularly satellites such as laptops often encounter annoying temporary
 538 ## failures due to network unavailability, and the usual gradual policy can
 539 ## leave mail building up for no good reason.
 540 CONF_smarthost                          * \
 541         F,4d,15m
 542
 543 ## Default.
 544 *                                       * \
 545         F,2h,15m; G,16h,2h,1.5; F,4d,6h
 546
 547 DIVERT(null)
 548 ###----- That's all, folks --------------------------------------------------