&<<CHAPlocalscan>>&)
&`lookup `& general lookup code and all lookups
&`memory `& memory handling
-&`pid `& add pid to debug output lines
+&`noutf8 `& modifier: avoid UTF-8 line-drawing
+&`pid `& modifier: add pid to debug output lines
&`process_info `& setting info for the process log
&`queue_run `& queue runs
&`receive `& general message reception logic
&`retry `& retry handling
&`rewrite `& address rewriting
&`route `& address routing
-&`timestamp `& add timestamp to debug output lines
+&`timestamp `& modifier: add timestamp to debug output lines
&`tls `& TLS logic
&`transport `& transports
&`uid `& changes of uid/gid and looking up uid/gid
of all debug output lines. This can be useful when trying to track down delays
in processing.
+.new
+.cindex debugging "UTF-8 in"
+.cindex UTF-8 "in debug output"
+The &`noutf8`& selector disables the use of
+UTF-8 line-drawing characters to group related information.
+When disabled. ascii-art is used instead.
+Using the &`+all`& option does not set this modifier,
+.wen
+
If the &%debug_print%& option is set in any driver, it produces output whenever
any debugging is selected, or if &%-v%& is used.
+.section "Macros" "SECTdefconfmacros"
+All macros should be defined before any options.
+
+One macro is specified, but commented out, in the default configuration:
+.code
+# ROUTER_SMARTHOST=MAIL.HOSTNAME.FOR.CENTRAL.SERVER.EXAMPLE
+.endd
+If all off-site mail is expected to be delivered to a "smarthost", then set the
+hostname here and uncomment the macro. This will affect which router is used
+later on. If this is left commented out, then Exim will perform direct-to-MX
+deliveries using a &(dnslookup)& router.
+
+In addition to macros defined here, Exim includes a number of built-in macros
+to enable configuration to be guarded by a binary built with support for a
+given feature. See section &<<SECTbuiltinmacros>>& for more details.
+
+
.section "Main configuration settings" "SECTdefconfmain"
-The main (global) configuration option settings must always come first in the
-file. The first thing you'll see in the file, after some initial comments, is
-the line
+The main (global) configuration option settings section must always come first
+in the file, after the macros.
+The first thing you'll see in the file, after some initial comments, is the line
.code
# primary_hostname =
.endd
support domain literal addresses (those of the form &'user@[10.9.8.7]'&). If
you uncomment this router, you also need to uncomment the setting of
&%allow_domain_literals%& in the main part of the configuration.
+
+Which router is used next depends upon whether or not the ROUTER_SMARTHOST
+macro has been defined, per
.code
+.ifdef ROUTER_SMARTHOST
+smarthost:
+#...
+.else
dnslookup:
- driver = dnslookup
+#...
+.endif
+.endd
+
+If ROUTER_SMARTHOST has been defined, either at the top of the file or on the
+command-line, then we route all non-local mail to that smarthost; otherwise, we'll
+perform DNS lookups for direct-to-MX lookup. Any mail which is to a local domain will
+skip these routers because of the &%domains%& option.
+
+.code
+smarthost:
+ driver = manualroute
domains = ! +local_domains
- transport = remote_smtp
- ignore_target_hosts = 0.0.0.0 : 127.0.0.0/8
+ transport = smarthost_smtp
+ route_data = ROUTER_SMARTHOST
+ ignore_target_hosts = <; 0.0.0.0 ; 127.0.0.0/8 ; ::1
no_more
.endd
-The first uncommented router handles addresses that do not involve any local
-domains. This is specified by the line
+This router only handles mail which is not to any local domains; this is
+specified by the line
.code
domains = ! +local_domains
.endd
indicates that it is referring to a named list. Addresses in other domains are
passed on to the following routers.
+The name of the router driver is &(manualroute)& because we are manually
+specifying how mail should be routed onwards, instead of using DNS MX.
+While the name of this router instance is arbitrary, the &%driver%& option must
+be one of the driver modules that is in the Exim binary.
+
+With no pre-conditions other than &%domains%&, all mail for non-local domains
+will be handled by this router, and the &%no_more%& setting will ensure that no
+other routers will be used for messages matching the pre-conditions. See
+&<<SECTrouprecon>>& for more on how the pre-conditions apply. For messages which
+are handled by this router, we provide a hostname to deliver to in &%route_data%&
+and the macro supplies the value; the address is then queued for the
+&(smarthost_smtp)& transport.
+
+.code
+dnslookup:
+ driver = dnslookup
+ domains = ! +local_domains
+ transport = remote_smtp
+ ignore_target_hosts = 0.0.0.0 : 127.0.0.0/8
+ no_more
+.endd
+The &%domains%& option behaves as per smarthost, above.
+
The name of the router driver is &(dnslookup)&,
and is specified by the &%driver%& option. Do not be confused by the fact that
the name of this router instance is the same as the name of the driver. The
.code
begin transports
.endd
-One remote transport and four local transports are defined.
+Two remote transports and four local transports are defined.
.code
remote_smtp:
driver = smtp
- hosts_try_prdr = *
+ message_size_limit = ${if > {$max_received_linelength}{998} {1}{0}}
+.ifdef _HAVE_DANE
+ dnssec_request_domains = *
+ hosts_try_dane = *
+.endif
.endd
This transport is used for delivering messages over SMTP connections.
The list of remote hosts comes from the router.
-The &%hosts_try_prdr%& option enables an efficiency SMTP option.
-It is negotiated between client and server
-and not expected to cause problems but can be disabled if needed.
-All other options are defaulted.
+The &%message_size_limit%& usage is a hack to avoid sending on messages
+with over-long lines. The built-in macro _HAVE_DANE guards configuration
+to try to use DNSSEC for all queries and to use DANE for delivery;
+see section &<<SECDANE>>& for more details.
+
+The other remote transport is used when delivering to a specific smarthost
+with whom there must be some kind of existing relationship, instead of the
+usual federated system.
+
+.code
+smarthost_smtp:
+ driver = smtp
+ message_size_limit = ${if > {$max_received_linelength}{998} {1}{0}}
+ multi_domain
+ #
+.ifdef _HAVE_TLS
+ # Comment out any of these which you have to, then file a Support
+ # request with your smarthost provider to get things fixed:
+ hosts_require_tls = *
+ tls_verify_hosts = *
+ # As long as tls_verify_hosts is enabled, this won't matter, but if you
+ # have to comment it out then this will at least log whether you succeed
+ # or not:
+ tls_try_verify_hosts = *
+ #
+ # The SNI name should match the name which we'll expect to verify;
+ # many mail systems don't use SNI and this doesn't matter, but if it does,
+ # we need to send a name which the remote site will recognize.
+ # This _should_ be the name which the smarthost operators specified as
+ # the hostname for sending your mail to.
+ tls_sni = ROUTER_SMARTHOST
+ #
+.ifdef _HAVE_OPENSSL
+ tls_require_ciphers = HIGH:!aNULL:@STRENGTH
+.endif
+.ifdef _HAVE_GNUTLS
+ tls_require_ciphers = SECURE192:-VERS-SSL3.0:-VERS-TLS1.0:-VERS-TLS1.1
+.endif
+.endif
+.endd
+After the same &%message_size_limit%& hack, we then specify that this Transport
+can handle messages to multiple domains in one run. The assumption here is
+that you're routing all non-local mail to the same place and that place is
+happy to take all messages from you as quickly as possible.
+All other options depend upon built-in macros; if Exim was built without TLS support
+then no other options are defined.
+If TLS is available, then we configure "stronger than default" TLS ciphersuites
+and versions using the &%tls_require_ciphers%& option, where the value to be
+used depends upon the library providing TLS.
+Beyond that, the options adopt the stance that you should have TLS support available
+from your smarthost on today's Internet, so we turn on requiring TLS for the
+mail to be delivered, and requiring that the certificate be valid, and match
+the expected hostname. The &%tls_sni%& option can be used by service providers
+to select an appropriate certificate to present to you and here we re-use the
+ROUTER_SMARTHOST macro, because that is unaffected by CNAMEs present in DNS.
+You want to specify the hostname which you'll expect to validate for, and that
+should not be subject to insecure tampering via DNS results.
+
.code
local_delivery:
driver = appendfile
&*Warning*&: Unlike most other single-key lookup types, a file of data for
&((n)wildlsearch)& can &'not'& be turned into a DBM or cdb file, because those
lookup types support only literal keys.
+
+.next
+.cindex "lookup" "spf"
+If Exim is built with SPF support, manual lookups can be done
+(as opposed to the standard ACL condition method.
+For details see section &<<SECSPF>>&.
.endlist ilist
This forces an expansion failure (see section &<<SECTforexpfai>>&);
{<&'string2'&>} must be present for &"fail"& to be recognized.
+.new
+.vitem "&*${extract json{*&<&'key'&>&*}{*&<&'string1'&>&*}{*&<&'string2'&>&*}&&&
+ {*&<&'string3'&>&*}}*&"
+.cindex "expansion" "extracting from JSON object"
+.cindex JSON expansions
+The key and <&'string1'&> are first expanded separately. Leading and trailing
+white space is removed from the key (but not from any of the strings). The key
+must not be empty and must not consist entirely of digits.
+The expanded <&'string1'&> must be of the form:
+.display
+{ <&'"key1"'&> : <&'value1'&> , <&'"key2"'&> , <&'value2'&> ... }
+.endd
+.vindex "&$value$&"
+The braces, commas and colons, and the quoting of the member name are required;
+the spaces are optional.
+Matching of the key against the member names is done case-sensitively.
+. XXX should be a UTF-8 compare
+
+The results of matching are handled as above.
+.wen
+
.vitem "&*${extract{*&<&'number'&>&*}{*&<&'separators'&>&*}&&&
{*&<&'string1'&>&*}{*&<&'string2'&>&*}{*&<&'string3'&>&*}}*&"
empty (for example, the fifth field above).
+.new
+.vitem "&*${extract json{*&<&'number'&>&*}}&&&
+ {*&<&'string1'&>&*}{*&<&'string2'&>&*}{*&<&'string3'&>&*}}*&"
+.cindex "expansion" "extracting from JSON array"
+.cindex JSON expansions
+The <&'number'&> argument must consist entirely of decimal digits,
+apart from leading and trailing white space, which is ignored.
+
+Field selection and result handling is as above;
+there is no choice of field separator.
+.wen
+
+
.vitem &*${filter{*&<&'string'&>&*}{*&<&'condition'&>&*}}*&
.cindex "list" "selecting by condition"
.cindex "expansion" "selecting from list by condition"
.vitem &*$rheader_*&<&'header&~name'&>&*:*&&~or&~&*$rh_*&<&'header&~name'&>&*:*&
This item inserts &"raw"& header lines. It is described with the &%header%&
-expansion item above.
+expansion item in section &<<SECTexpansionitems>>& above.
.vitem "&*${run{*&<&'command'&>&*&~*&<&'args'&>&*}{*&<&'string1'&>&*}&&&
{*&<&'string2'&>&*}}*&"
the value of &$authenticated_id$& is normally the login name of the calling
process. However, a trusted user can override this by means of the &%-oMai%&
command line option.
-This second case also sets up inforamtion used by the
+This second case also sets up information used by the
&$authresults$& expansion item.
.vitem &$authenticated_fail_id$&
inserting the message header line with the given name. Note that the name must
be terminated by colon or white space, because it may contain a wide variety of
characters. Note also that braces must &'not'& be used.
+See the full description in section &<<SECTexpansionitems>>& above.
.vitem &$headers_added$&
.vindex "&$headers_added$&"
A list of hosts, whether obtained via &%route_data%& or &%route_list%&, is
always separately expanded before use. If the expansion fails, the router
declines. The result of the expansion must be a colon-separated list of names
-and/or IP addresses, optionally also including ports. The format of each item
+and/or IP addresses, optionally also including ports.
+If the list is written with spaces, it must be protected with quotes.
+The format of each item
in the list is described in the next section. The list separator can be changed
as described in section &<<SECTlistconstruct>>&.
.option delay_after_cutoff smtp boolean true
+.cindex "final cutoff" "retries, controlling"
+.cindex retry "final cutoff"
This option controls what happens when all remote IP addresses for a given
domain have been inaccessible for so long that they have passed their retry
cutoff times.
If the value of this option begins with a digit it is taken as a port number;
otherwise it is looked up using &[getservbyname()]&. The default value is
-normally &"smtp"&, but if &%protocol%& is set to &"lmtp"&, the default is
-&"lmtp"&. If the expansion fails, or if a port number cannot be found, delivery
+normally &"smtp"&,
+but if &%protocol%& is set to &"lmtp"& the default is &"lmtp"&
+and if &%protocol%& is set to &"smtps"& the default is &"smtps"&.
+If the expansion fails, or if a port number cannot be found, delivery
is deferred.
+.new
+Note that at least one Linux distribution has been seen failing
+to put &"smtps"& in its &"/etc/services"& file, resulting is such deferrals.
+.wen
+
.option protocol smtp string smtp
If this option is set to &"smtps"&, the default value for the &%port%& option
changes to &"smtps"&, and the transport initiates TLS immediately after
connecting, as an outbound SSL-on-connect, instead of using STARTTLS to upgrade.
-The Internet standards bodies strongly discourage use of this mode.
+.new
+The Internet standards bodies used to strongly discourage use of this mode,
+but as of RFC 8314 it is perferred over STARTTLS for message submission
+(as distinct from MTA-MTA communication).
+.wen
.option retry_include_ip_address smtp boolean&!! true
messages. If this delivery fails, the address fails immediately. The
post-cutoff retry time is not used.
+.cindex "final cutoff" "retries, controlling"
+.cindex retry "final cutoff"
If the delivery is remote, there are two possibilities, controlled by the
.oindex "&%delay_after_cutoff%&"
&%delay_after_cutoff%& option of the &(smtp)& transport. The option is true by
-default. Until the post-cutoff retry time for one of the IP addresses is
+default. Until the post-cutoff retry time for one of the IP addresses,
+as set by the &%retry_data_expire%& option, is
reached, the failing email address is bounced immediately, without a delivery
attempt taking place. After that time, one new delivery attempt is made to
those IP addresses that are past their retry times, and if that still fails,
.option server_set_id authenticators string&!! unset
.vindex "&$authenticated_id$&"
+.vindex "&$authenticated_fail_id$&"
When an Exim server successfully authenticates a client, this string is
expanded using data from the authentication, and preserved for any incoming
messages in the variable &$authenticated_id$&. It is also included in the log
lines for incoming messages. For example, a user/password authenticator
configuration might preserve the user name that was used to authenticate, and
refer to it subsequently during delivery of the message.
+On a failing authentication the expansion result is instead saved in
+the &$authenticated_fail_id$& variable.
If expansion fails, the option is ignored.
made that any particular new authentication mechanism will be supported
without code changes in Exim.
+Exim's &(gsasl)& authenticator does not have client-side support at this
+time; only the server-side support is implemented. Patches welcome.
+
.option server_channelbinding gsasl boolean false
Do not set this true without consulting a cryptographic engineer.
&%pipelining%&: A field is added to delivery and accept
log lines when the ESMTP PIPELINING extension was used.
The field is a single "L".
+
On accept lines, where PIPELINING was offered but not used by the client,
the field has a minus appended.
.next
projects / exim.git / blobdiff