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, tls)m4_dnl
  28 tls_certificate = CONF_sysconf_dir/server.cert
  29 tls_privatekey = CONF_sysconf_dir/server.key
  30 tls_advertise_hosts = *
  31 tls_dhparam = CONF_ca_dir/dh-param.pem
  32 tls_require_ciphers = ${if or {{={$received_port}{CONF_submission_port}} \
  33                                {match_ip {$sender_host_address}{+trusted}}} \
  34                            {CONF_good_ciphers} \
  35                            {CONF_acceptable_ciphers}}
  36 tls_verify_certificates = CONF_ca_dir/ca.cert
  37 tls_verify_hosts = ${if eq{$acl_c_mode}{submission} {} {+allnets}}
  38
  39 DIVERT(null)
  40 ###--------------------------------------------------------------------------
  41 ### Check source addresses for apparently local senders.
  42
  43 SECTION(acl, mail-hooks)m4_dnl
  44         ## Check that a submitted message's sender address is allowable.
  45         require  acl = mail_client_addr
  46
  47         ## Insist that a local client connect through TLS.
  48         deny     message = Hosts within CONF_master_domain must use TLS
  49                 !condition = ${if eq{$acl_c_mode}{submission}}
  50                  hosts = +allnets
  51                 !encrypted = *
  52
  53 SECTION(acl, misc)m4_dnl
  54 mail_client_addr:
  55
  56         ## If this is a message submission then that's handled elsewhere.
  57         accept   condition = ${if eq{$acl_c_mode}{submission}}
  58
  59         ## Make sure that the sender matches the client address.  I feel like
  60         ## I want to reject these, but that will break stuff.  For example,
  61         ## if I send mail to an externally hosted address which is really a
  62         ## distribution list containing some local address, then we'll
  63         ## (approximately legitimately) receive mail with an apparently-local
  64         ## sender from a remote host.
  65         warn    !hosts = ${LOOKUP_DOMAIN($sender_address_domain,
  66                            {KV(hosts, {$value}{+allnets})},
  67                            {${if match_domain {$sender_address_domain} \
  68                                               {+public} \
  69                                  {+allnets}{! +allnets}}})}
  70                  add_header = :after_received:X-Distorted-Warning: \
  71                         RCLNTLSNDR \
  72                         Apparently local sender, but received from remote \
  73                         server.
  74
  75         ## OK.
  76         accept
  77
  78 DIVERT(null)
  79 ###--------------------------------------------------------------------------
  80 ### The obvious trivial router.
  81
  82 SECTION(routers, remote)m4_dnl
  83 ## Send mail on to a host in our own network.  We must apply extra security.
  84 local:
  85         driver = dnslookup
  86         domains = ! +known : *.CONF_master_domain
  87         self = fail
  88         transport = smtp_local
  89         no_more
  90
  91 ## Send mail on to unknown hosts.
  92 remote:
  93         driver = dnslookup
  94         domains = ! +known
  95         self = fail
  96         transport = smtp
  97         no_more
  98
  99 DIVERT(null)
 100 ###----- That's all, folks --------------------------------------------------