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

   1 ### -*-m4-*-
   2 ###
   3 ### Transmission to remote hosts 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 ### Listen for incoming connections.
  26
  27 SECTION(global, daemon)m4_dnl
  28 daemon_smtp_ports = CONF_smtp_port : CONF_submission_port
  29
  30 DIVERT(null)
  31 ###--------------------------------------------------------------------------
  32 ### Check source addresses for apparently local senders.
  33
  34 SECTION(acl, mail-hooks)m4_dnl
  35         ## Check that a submitted message's sender address is allowable.
  36         require  acl = mail_client_addr
  37
  38 SECTION(acl, misc)m4_dnl
  39 mail_client_addr:
  40
  41         ## If this is a message submission then that's handled elsewhere.
  42         accept   condition = ${if eq{$acl_c_mode}{submission}}
  43
  44         ## Make sure that the sender matches the client address.  I feel like
  45         ## I want to reject these, but that will break stuff.  For example,
  46         ## if I send mail to an externally hosted address which is really a
  47         ## distribution list containing some local address, then we'll
  48         ## (approximately legitimately) receive mail with an apparently-local
  49         ## sender from a remote host.
  50         warn    !hosts = ${LOOKUP_DOMAIN($sender_address_domain,
  51                            {KV(hosts, {$value}{+allnets})},
  52                            {${if match_domain {$sender_address_domain} \
  53                                               {+public} \
  54                                  {+allnets}{! +allnets}}})}
  55                   WARNING_HEADER(RCLNTLSNDR,
  56                                  <:Apparently local sender, but received from remote \
  57                                    server.\n\t\
  58                                    sender=$sender_address \
  59                                    host=$sender_host_address:>)
  60
  61         ## OK.
  62         accept
  63
  64 DIVERT(null)
  65 ###--------------------------------------------------------------------------
  66 ### Rename locally-meaningful headers in mail from outside.
  67
  68 m4_define(<:DISTORTED_HEADERS:>,
  69 <:X-CONF_header_token-SpamAssassin-Score,
  70 X-CONF_header_token-SpamAssassin-Status:>)
  71
  72 SECTION(acl, data)m4_dnl
  73         ## If this message is coming from outside then rename headers which
  74         ## look like the ones we're likely to add.  This is most relevant for
  75         ## our spam-report headers, because I'm not sure I understand why
  76         ## someone would want to fake an X-Distorted-Warning header.
  77         warn    !condition = ${if eq{$acl_c_mode}{submission}}
  78                 !hosts = +allnets
  79                  set acl_m_hdradd = ${if def:acl_m_hdradd{$acl_m_hdradd}}\
  80                         RENAME_HEADERS_ADD(<:DISTORTED_HEADERS:>)
  81                  set acl_m_hdrrm = ${if def:acl_m_hdrrm{$acl_m_hdrrm:}}\
  82                         RENAME_HEADERS_REMOVE(<:DISTORTED_HEADERS:>)
  83
  84 DIVERT(null)
  85 ###--------------------------------------------------------------------------
  86 ### The obvious trivial router.
  87
  88 SECTION(routers, remote)m4_dnl
  89 ## Send mail on to a host in our own network.  We must apply extra security.
  90 local:
  91         driver = dnslookup
  92         domains = ${if bool {${LOOKUP_DOMAIN($domain,
  93                                {KV(service, {$value}{true})},
  94                                {false})}} \
  95                        {}{ ! +public : \
  96                            CONF_master_domain : \
  97                            *.CONF_master_domain }}
  98         self = fail
  99         transport = smtp_local
 100         no_more
 101
 102 ## Send mail on to unknown hosts.
 103 remote:
 104         driver = dnslookup
 105         domains = ${if bool {${LOOKUP_DOMAIN($domain,
 106                                {KV(service, {$value}{true})},
 107                                {false})}} \
 108                        {}{ ! +public }}
 109         self = fail
 110         transport = smtp
 111         no_more
 112
 113 DIVERT(null)
 114 ###----- That's all, folks --------------------------------------------------