X-Git-Url: https://git.exim.org/users/heiko/exim.git/blobdiff_plain/07eeb4df55e6c0843156aedaacf32bfebe0e9eaa..135e949699b889c8c9088bb05f810d44adc74246:/doc/doc-docbook/spec.xfpt?ds=inline

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index ca64f9f11..35f3eb80e 100644
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -45,14 +45,14 @@
 . Update the Copyright year (only) when changing content.
 . /////////////////////////////////////////////////////////////////////////////
 
-.set previousversion "4.87"
+.set previousversion "4.89"
 .include ./local_params
 
 .set ACL "access control lists (ACLs)"
 .set I   "    "
 
 .macro copyyear
-2016
+2017
 .endmacro
 
 . /////////////////////////////////////////////////////////////////////////////
@@ -436,6 +436,7 @@ directory are:
 .row &_filter.txt_&          "specification of the filter language"
 .row &_Exim3.upgrade_&       "upgrade notes from release 2 to release 3"
 .row &_Exim4.upgrade_&       "upgrade notes from release 3 to release 4"
+.row &_openssl.txt_&         "installing a current OpenSSL release"
 .endtable
 
 The main specification and the specification of the filtering language are also
@@ -463,7 +464,7 @@ which contains what used to be a separate FAQ, as well as various other
 examples, tips, and know-how that have been contributed by Exim users.
 
 .cindex Bugzilla
-An Exim Bugzilla exists at &url(http://bugs.exim.org). You can use
+An Exim Bugzilla exists at &url(https://bugs.exim.org). You can use
 this to report bugs, and also to add items to the wish list. Please search
 first to check that you are not duplicating a previous entry.
 
@@ -492,18 +493,11 @@ via this web page:
 Please ask Debian-specific questions on this list and not on the general Exim
 lists.
 
-.section "Exim training" "SECID4"
-.cindex "training courses"
-Training courses in Cambridge (UK) used to be run annually by the author of
-Exim, before he retired. At the time of writing, there are no plans to run
-further Exim courses in Cambridge. However, if that changes, relevant
-information will be posted at &url(http://www-tus.csx.cam.ac.uk/courses/exim/).
-
 .section "Bug reports" "SECID5"
 .cindex "bug reports"
 .cindex "reporting bugs"
 Reports of obvious bugs can be emailed to &'bugs@exim.org'& or reported
-via the Bugzilla (&url(http://bugs.exim.org)). However, if you are unsure
+via the Bugzilla (&url(https://bugs.exim.org)). However, if you are unsure
 whether some behaviour is a bug or not, the best thing to do is to post a
 message to the &'exim-dev'& mailing list and have it discussed.
 
@@ -514,10 +508,6 @@ message to the &'exim-dev'& mailing list and have it discussed.
 .cindex "distribution" "ftp site"
 The master ftp site for the Exim distribution is
 .display
-&*ftp://ftp.csx.cam.ac.uk/pub/software/email/exim*&
-.endd
-This is mirrored by
-.display
 &*ftp://ftp.exim.org/pub/exim*&
 .endd
 The file references that follow are relative to the &_exim_& directories at
@@ -2627,6 +2617,8 @@ users to set envelope senders.
 
 .cindex "&'From:'& header line"
 .cindex "&'Sender:'& header line"
+.cindex "header lines" "From:"
+.cindex "header lines" "Sender:"
 For a trusted user, there is never any check on the contents of the &'From:'&
 header line, and a &'Sender:'& line is never added. Furthermore, any existing
 &'Sender:'& line in incoming local (non-TCP/IP) messages is not removed.
@@ -3825,13 +3817,17 @@ This option is not intended for use by external callers. It is used internally
 by Exim in conjunction with the &%-MC%& option. It signifies that the
 remote host supports the ESMTP &_DSN_& extension.
 
-.new
-.vitem &%-MCG%&
+.vitem &%-MCG%&&~<&'queue&~name'&>
 .oindex "&%-MCG%&"
 This option is not intended for use by external callers. It is used internally
 by Exim in conjunction with the &%-MC%& option. It signifies that an
-alternate queue is used, named by the following option.
-.wen
+alternate queue is used, named by the following argument.
+
+.vitem &%-MCK%&
+.oindex "&%-MCK%&"
+This option is not intended for use by external callers. It is used internally
+by Exim in conjunction with the &%-MC%& option. It signifies that an
+remote host supports the ESMTP &_CHUNKING_& extension.
 
 .vitem &%-MCP%&
 .oindex "&%-MCP%&"
@@ -3861,6 +3857,15 @@ This option is not intended for use by external callers. It is used internally
 by Exim in conjunction with the &%-MC%& option, and passes on the fact that the
 host to which Exim is connected supports TLS encryption.
 
+.new
+.vitem &%-MCt%&&~<&'IP&~address'&>&~<&'port'&>&~<&'cipher'&>
+.oindex "&%-MCt%&"
+This option is not intended for use by external callers. It is used internally
+by Exim in conjunction with the &%-MC%& option, and passes on the fact that the
+connection is being proxied by a parent process for handling TLS encryption.
+The arguments give the local address and port being proxied, and the TLS cipher.
+.wen
+
 .vitem &%-Mc%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
 .oindex "&%-Mc%&"
 .cindex "hints database" "not overridden by &%-Mc%&"
@@ -4269,7 +4274,7 @@ or &%-bs%& is used. For &%-bh%&, the protocol is forced to one of the standard
 SMTP protocol names (see the description of &$received_protocol$& in section
 &<<SECTexpvar>>&). For &%-bs%&, the protocol is always &"local-"& followed by
 one of those same names. For &%-bS%& (batched SMTP) however, the protocol can
-be set by &%-oMr%&.
+be set by &%-oMr%&. Repeated use of this option is not supported.
 
 .vitem &%-oMs%&&~<&'host&~name'&>
 .oindex "&%-oMs%&"
@@ -4369,6 +4374,7 @@ host name and its colon can be omitted when only the protocol is to be set.
 Note the Exim already has two private options, &%-pd%& and &%-ps%&, that refer
 to embedded Perl. It is therefore impossible to set a protocol value of &`d`&
 or &`s`& using this option (but that does not seem a real limitation).
+Repeated use of this option is not supported.
 
 .vitem &%-q%&
 .oindex "&%-q%&"
@@ -4379,9 +4385,7 @@ relax this restriction (and also the same requirement for the &%-M%&, &%-R%&,
 and &%-S%& options).
 
 .cindex "queue runner" "description of operation"
-.new
 If other commandline options do not specify an action,
-.wen
 the &%-q%& option starts one queue runner process. This scans the queue of
 waiting messages, and runs a delivery process for each one in turn. It waits
 for each delivery process to finish before starting the next one. A delivery
@@ -4467,7 +4471,6 @@ The &'l'& (the letter &"ell"&) flag specifies that only local deliveries are to
 be done. If a message requires any remote deliveries, it remains on the queue
 for later delivery.
 
-.new
 .vitem &%-q[q][i][f[f]][l][G<name>[/<time>]]]%&
 .oindex "&%-qG%&"
 .cindex queue named
@@ -4479,15 +4482,14 @@ The name should not contain a &'/'& character.
 For a periodic queue run (see below)
 append to the name a slash and a time value.
 
-If other commandline options speicify an action, a &'-qG<name>'& option
+If other commandline options specify an action, a &'-qG<name>'& option
 will specify a queue to operate on.
 For example:
 .code
 exim -bp -qGquarantine
-mailq -qGquarantime
+mailq -qGquarantine
 exim -qGoffpeak -Rf @special.domain.example
 .endd
-.wen
 
 .vitem &%-q%&<&'qflags'&>&~<&'start&~id'&>&~<&'end&~id'&>
 When scanning the queue, Exim can be made to skip over messages whose ids are
@@ -4924,7 +4926,9 @@ using this syntax:
 .endd
 on a line by itself. Double quotes round the file name are optional. If you use
 the first form, a configuration error occurs if the file does not exist; the
-second form does nothing for non-existent files. In all cases, an absolute file
+second form does nothing for non-existent files.
+The first form allows a relative name. It is resolved relative to
+the directory of the including file. For the second form an absolute file
 name is required.
 
 Includes may be nested to any depth, but remember that Exim reads its
@@ -5031,6 +5035,31 @@ address lists. In Exim 4 these are handled better by named lists &-- see
 section &<<SECTnamedlists>>&.
 
 
+.section "Builtin macros" "SECTbuiltinmacros"
+Exim defines some macros depending on facilities available, which may
+differ due to build-time definitions and from one release to another.
+All of these macros start with an underscore.
+They can be used to conditionally include parts of a configuration
+(see below).
+
+The following classes of macros are defined:
+.display
+&` _HAVE_*                    `&  build-time defines
+&` _DRIVER_ROUTER_*           `&  router drivers
+&` _DRIVER_TRANSPORT_*        `&  transport drivers
+&` _DRIVER_AUTHENTICATOR_*    `&  authenticator drivers
+&` _OPT_MAIN_*                `&  main config options
+&` _OPT_ROUTERS_*             `&  generic router options
+&` _OPT_TRANSPORTS_*          `&  generic transport options
+&` _OPT_AUTHENTICATORS_*      `&  generic authenticator options
+&` _OPT_ROUTER_*_*            `&  private router options
+&` _OPT_TRANSPORT_*_*         `&  private transport options
+&` _OPT_AUTHENTICATOR_*_*     `&  private authenticator options
+.endd
+
+Use an &"exim -bP macros"& command to get the list of macros.
+
+
 .section "Conditional skips in the configuration file" "SECID46"
 .cindex "configuration file" "conditional skips"
 .cindex "&`.ifdef`&"
@@ -5134,7 +5163,9 @@ with the characters &"0x"&, in which case the remainder is interpreted as a
 hexadecimal number.
 
 If an integer value is followed by the letter K, it is multiplied by 1024; if
-it is followed by the letter M, it is multiplied by 1024x1024. When the values
+it is followed by the letter M, it is multiplied by 1024x1024;
+if by the letter G, 1024x1024x1024.
+When the values
 of integer option settings are output, values which are an exact multiple of
 1024 or 1024x1024 are sometimes, but not always, printed using the letters K
 and M. The printing style is independent of the actual input format that was
@@ -6262,7 +6293,9 @@ Chapter &<<CHAPplaintext>>& covers both.
 Exim supports the use of regular expressions in many of its options. It
 uses the PCRE regular expression library; this provides regular expression
 matching that is compatible with Perl 5. The syntax and semantics of
-regular expressions is discussed in many Perl reference books, and also in
+regular expressions is discussed in
+online Perl manpages, in
+many Perl reference books, and also in
 Jeffrey Friedl's &'Mastering Regular Expressions'&, which is published by
 O'Reilly (see &url(http://www.oreilly.com/catalog/regex2/)).
 
@@ -6703,8 +6736,8 @@ PostgreSQL database. See section &<<SECTsql>>&.
 .next
 .cindex "Redis lookup type"
 .cindex lookup Redis
-&(redis)&: The format of the query is an SQL statement that is passed to a
-Redis database. See section &<<SECTsql>>&.
+&(redis)&: The format of the query is either a simple get or simple set,
+passed to a Redis database. See section &<<SECTsql>>&.
 
 .next
 .cindex "sqlite lookup type"
@@ -7082,7 +7115,7 @@ Retries for the dnsdb lookup can be controlled by a retry modifier.
 The form if &"retry_VAL"& where VAL is an integer.
 The default count is set by the main configuration option &%dns_retry%&.
 
-.cindex cacheing "of dns lookup"
+.cindex caching "of dns lookup"
 .cindex TTL "of dns lookup"
 .cindex DNS TTL
 Dnsdb lookup results are cached within a single process (and its children).
@@ -7777,6 +7810,17 @@ are rejected after a timeout period, during which the SQLite library
 waits for the lock to be released. In Exim, the default timeout is set
 to 5 seconds, but it can be changed by means of the &%sqlite_lock_timeout%&
 option.
+
+.section "More about Redis" "SECTredis"
+.cindex "lookup" "Redis"
+.cindex "redis lookup type"
+Redis is a non-SQL database. Commands are simple get and set.
+Examples:
+.code
+${lookup redis{set keyname ${quote_redis:objvalue plus}}}
+${lookup redis{get keyname}}
+.endd
+
 .ecindex IIDfidalo1
 .ecindex IIDfidalo2
 
@@ -7809,10 +7853,8 @@ domain, host, address and local part lists.
 .cindex "expansion" "of lists"
 Each list is expanded as a single string before it is used.
 
-.new
 &'Exception: the router headers_remove option, where list-item
 splitting is done before string-expansion.'&
-.wen
 
 The result of
 expansion must be a list, possibly containing empty items, which is split up
@@ -9079,7 +9121,7 @@ If the ACL returns defer the result is a forced-fail.  Otherwise the expansion f
 
 .vitem "&*${certextract{*&<&'field'&>&*}{*&<&'certificate'&>&*}&&&
        {*&<&'string2'&>&*}{*&<&'string3'&>&*}}*&"
-.cindex "expansion" "extracting cerificate fields"
+.cindex "expansion" "extracting certificate fields"
 .cindex "&%certextract%&" "certificate fields"
 .cindex "certificate" "extracting fields"
 The <&'certificate'&> must be a variable of type certificate.
@@ -9396,12 +9438,15 @@ message, and any that are added by an ACL statement or by a system
 filter. Header lines that are added to a particular copy of a message by a
 router or transport are not accessible.
 
-For incoming SMTP messages, no header lines are visible in ACLs that are obeyed
-before the DATA ACL, because the header structure is not set up until the
-message is received. Header lines that are added in a RCPT ACL (for example)
+For incoming SMTP messages, no header lines are visible in
+ACLs that are obeyed before the data phase completes,
+because the header structure is not set up until the message is received.
+They are visible in DKIM, PRDR and DATA ACLs.
+Header lines that are added in a RCPT ACL (for example)
 are saved until the message's incoming header lines are available, at which
-point they are added. When a DATA ACL is running, however, header lines added
-by earlier ACLs are visible.
+point they are added.
+When any of the above ACLs ar
+running, however, header lines added by earlier ACLs are visible.
 
 Upper case and lower case letters are synonymous in header names. If the
 following character is white space, the terminating colon may be omitted, but
@@ -9728,7 +9773,7 @@ locks out the use of this expansion item in filter files.
 
 
 .vitem "&*${readsocket{*&<&'name'&>&*}{*&<&'request'&>&*}&&&
-        {*&<&'timeout'&>&*}{*&<&'eol&~string'&>&*}{*&<&'fail&~string'&>&*}}*&"
+        {*&<&'options'&>&*}{*&<&'eol&~string'&>&*}{*&<&'fail&~string'&>&*}}*&"
 .cindex "expansion" "inserting from a socket"
 .cindex "socket, use of in expansion"
 .cindex "&%readsocket%& expansion item"
@@ -9758,6 +9803,15 @@ extend what can be done. Firstly, you can vary the timeout. For example:
 .code
 ${readsocket{/socket/name}{request string}{3s}}
 .endd
+The third argument is a list of options, of which the first element is the timeout
+and must be present if the argument is given.
+Further elements are options of form &'name=value'&.
+One option type is currently recognised, defining whether (the default)
+or not a shutdown is done on the connection after sending the request.
+Example, to not do so (preferred, eg. by some webservers):
+.code
+${readsocket{/socket/name}{request string}{3s:shutdown=no}}
+.endd
 A fourth argument allows you to change any newlines that are in the data
 that is read, in the same way as for &%readfile%& (see above). This example
 turns them into spaces:
@@ -10090,6 +10144,19 @@ Last:user@example.com
 user@example.com
 .endd
 
+.vitem &*${base32:*&<&'digits'&>&*}*&
+.cindex "&%base32%& expansion item"
+.cindex "expansion" "conversion to base 32"
+The string must consist entirely of decimal digits. The number is converted to
+base 32 and output as a (empty, for zero) string of characters.
+Only lowercase letters are used.
+
+.vitem &*${base32d:*&<&'base-32&~digits'&>&*}*&
+.cindex "&%base32d%& expansion item"
+.cindex "expansion" "conversion to base 32"
+The string must consist entirely of base-32 digits.
+The number is converted to decimal and output as a string.
+
 .vitem &*${base62:*&<&'digits'&>&*}*&
 .cindex "&%base62%& expansion item"
 .cindex "expansion" "conversion to base 62"
@@ -10141,6 +10208,13 @@ escape sequences starting with a backslash. Whether characters with the most
 significant bit set (so-called &"8-bit characters"&) count as printing or not
 is controlled by the &%print_topbitchars%& option.
 
+.vitem &*${escape8bit:*&<&'string'&>&*}*&
+.cindex "expansion" "escaping 8-bit characters"
+.cindex "&%escape8bit%& expansion item"
+If the string contains and characters with the most significant bit set,
+they are converted to escape sequences starting with a backslash.
+Backslashes and DEL characters are also converted.
+
 
 .vitem &*${eval:*&<&'string'&>&*}*&&~and&~&*${eval10:*&<&'string'&>&*}*&
 .cindex "expansion" "expression evaluation"
@@ -10527,17 +10601,14 @@ returns the SHA-1 hash fingerprint of the certificate.
 .cindex certificate fingerprint
 .cindex "expansion" "SHA-256 hashing"
 .cindex "&%sha256%& expansion item"
-.new
 The &%sha256%& operator computes the SHA-256 hash value of the string
 and returns
 it as a 64-digit hexadecimal number, in which any letters are in upper case.
-.wen
 
 If the string is a single variable of type certificate,
 returns the SHA-256 hash fingerprint of the certificate.
 
 
-.new
 .vitem &*${sha3:*&<&'string'&>&*}*& &&&
        &*${sha3_<n>:*&<&'string'&>&*}*&
 .cindex "SHA3 hash"
@@ -10553,7 +10624,6 @@ with 256 being the default.
 
 The &%sha3%& expansion item is only supported if Exim has been
 compiled with GnuTLS 3.5.0 or later.
-.wen
 
 
 .vitem &*${stat:*&<&'string'&>&*}*&
@@ -10962,9 +11032,14 @@ colon-separated components are permitted, each containing from one to four
 hexadecimal digits. There may be fewer than eight components if an empty
 component (adjacent colons) is present. Only one empty component is permitted.
 
-&*Note*&: The checks are just on the form of the address; actual numerical
-values are not considered. Thus, for example, 999.999.999.999 passes the IPv4
-check. The main use of these tests is to distinguish between IP addresses and
+.new
+&*Note*&: The checks used to be just on the form of the address; actual numerical
+values were not considered. Thus, for example, 999.999.999.999 passed the IPv4
+check.
+This is no longer the case.
+.wen
+
+The main use of these tests is to distinguish between IP addresses and
 host names, or between IPv4 and IPv6 addresses. For example, you could use
 .code
 ${if isip4{$sender_host_address}...
@@ -11121,8 +11196,8 @@ example is:
 ${if match_domain{a.b.c}{x.y.z:a.b.c:p.q.r}{yes}{no}}
 .endd
 In each case, the second argument may contain any of the allowable items for a
-list of the appropriate type. Also, because the second argument (after
-expansion) is a standard form of list, it is possible to refer to a named list.
+list of the appropriate type. Also, because the second argument
+is a standard form of list, it is possible to refer to a named list.
 Thus, you can use conditions like this:
 .code
 ${if match_domain{$domain}{+local_domains}{...
@@ -11993,6 +12068,9 @@ when the ACL &%malware%& condition is true (see section &<<SECTscanvirus>>&).
 This variable contains the number of bytes in the longest line that was
 received as part of the message, not counting the line termination
 character(s).
+.new
+It is not valid if the &%spool_files_wireformat%& option is used.
+.wen
 
 .vitem &$message_age$&
 .cindex "message" "age of"
@@ -12035,6 +12113,12 @@ in bytes. The count starts from the character after the blank line that
 separates the body from the header. Newlines are included in the count. See
 also &$message_size$&, &$body_linecount$&, and &$body_zerocount$&.
 
+.new
+If the spool file is wireformat
+(see the &%spool_files_wireformat%& main option)
+the CRLF line-terminators are included in the count.
+.wen
+
 .vitem &$message_exim_id$&
 .vindex "&$message_exim_id$&"
 When a message is being received or delivered, this variable contains the
@@ -12085,6 +12169,10 @@ deny message   = Too many lines in message header
 In the MAIL and RCPT ACLs, the value is zero because at that stage the
 message has not yet been received.
 
+.new
+This variable is not valid if the &%spool_files_wireformat%& option is used.
+.wen
+
 .vitem &$message_size$&
 .cindex "size" "of message"
 .cindex "message" "size"
@@ -12161,7 +12249,7 @@ normally the gid of the Exim user.
 .cindex "uid (user id)" "of originating user"
 .cindex "sender" "uid"
 .vindex "&$caller_uid$&"
-.vindex "&$originaltor_uid$&"
+.vindex "&$originator_uid$&"
 The value of &$caller_uid$& that was set when the message was received. For
 messages received via the command line, this is the uid of the sending user.
 For messages received by SMTP over TCP/IP, this is normally the uid of the Exim
@@ -12202,16 +12290,14 @@ a single-component name, Exim calls &[gethostbyname()]& (or
 qualified host name. See also &$smtp_active_hostname$&.
 
 
-.new
 .vitem &$proxy_external_address$& &&&
        &$proxy_external_port$& &&&
        &$proxy_local_address$& &&&
        &$proxy_local_port$& &&&
        &$proxy_session$&
 These variables are only available when built with Proxy Protocol
-or Socks5 support
+or SOCKS5 support.
 For details see chapter &<<SECTproxyInbound>>&.
-.wen
 
 .vitem &$prdr_requested$&
 .cindex "PRDR" "variable for"
@@ -12242,13 +12328,11 @@ The value set for the &%qualify_domain%& option in the configuration file.
 The value set for the &%qualify_recipient%& option in the configuration file,
 or if not set, the value of &$qualify_domain$&.
 
-.new
 .vitem &$queue_name$&
 .vindex &$queue_name$&
 .cindex "named queues"
 .cindex queues named
 The name of the spool queue in use; empty for the default queue.
-.wen
 
 .vitem &$rcpt_count$&
 .vindex "&$rcpt_count$&"
@@ -12562,6 +12646,11 @@ validating resolver (e.g. unbound, or bind with suitable configuration).
 If you have changed &%host_lookup_order%& so that &`bydns`& is not the first
 mechanism in the list, then this variable will be false.
 
+This requires that your system resolver library support EDNS0 (and that
+DNSSEC flags exist in the system headers).  If the resolver silently drops
+all EDNS0 options, then this will have no effect.  OpenBSD's asr resolver
+is known to currently ignore EDNS0, documented in CAVEATS of asr_run(3).
+
 
 .vitem &$sender_host_name$&
 .vindex "&$sender_host_name$&"
@@ -12704,6 +12793,15 @@ argument, that is, the text that follows the command name, with leading white
 space removed. Following the introduction of &$smtp_command$&, this variable is
 somewhat redundant, but is retained for backwards compatibility.
 
+.new
+.vitem &$smtp_command_history$&
+.cindex SMTP "command history"
+.vindex "&$smtp_command_history$&"
+A comma-separated list (with no whitespace) of the most-recent SMTP commands
+received, in time-order left to right.  Only a limited number of commands
+are remembered.
+.wen
+
 .vitem &$smtp_count_at_connection_start$&
 .vindex "&$smtp_count_at_connection_start$&"
 This variable is set greater than zero only in processes spawned by the Exim
@@ -12783,7 +12881,7 @@ If TLS has not been negotiated, the value will be 0.
 
 .vitem &$tls_in_ourcert$&
 .vindex "&$tls_in_ourcert$&"
-.cindex certificate veriables
+.cindex certificate variables
 This variable refers to the certificate presented to the peer of an
 inbound connection when the message was received.
 It is only useful as the argument of a
@@ -12973,8 +13071,7 @@ or external command, as described above. It is also used during a
 
 .vitem &$verify_mode$&
 .vindex "&$verify_mode$&"
-While a router or transport is being run in verify mode
-or for cutthrough delivery,
+While a router or transport is being run in verify mode or for cutthrough delivery,
 contains "S" for sender-verification or "R" for recipient-verification.
 Otherwise, empty.
 
@@ -13050,16 +13147,14 @@ overriding the setting of &%perl_at_start%&.
 There is also a command line option &%-pd%& (for delay) which suppresses the
 initial startup, even if &%perl_at_start%& is set.
 
-.new
 .ilist
 .oindex "&%perl_taintmode%&"
 .cindex "Perl" "taintmode"
 To provide more security executing Perl code via the embedded Perl
-interpeter, the &%perl_taintmode%& option can be set. This enables the
+interpreter, the &%perl_taintmode%& option can be set. This enables the
 taint mode of the Perl interpreter. You are encouraged to set this
 option to a true value. To avoid breaking existing installations, it
 defaults to false.
-.wen
 
 
 .section "Calling Perl subroutines" "SECID86"
@@ -13486,6 +13581,7 @@ listed in more than one group.
 .section "Miscellaneous" "SECID96"
 .table2
 .row &%bi_command%&                  "to run for &%-bi%& command line option"
+.row &%debug_store%&                 "do extra internal checks"
 .row &%disable_ipv6%&                "do no IPv6 processing"
 .row &%keep_malformed%&              "for broken files &-- should not happen"
 .row &%localhost_number%&            "for unique message ids in clusters"
@@ -13493,6 +13589,7 @@ listed in more than one group.
 .row &%message_body_visible%&        "how much to show in &$message_body$&"
 .row &%mua_wrapper%&                 "run in &""MUA wrapper""& mode"
 .row &%print_topbitchars%&           "top-bit characters are printing"
+.row &%spool_wireformat%&            "use wire-format spool data files when possible"
 .row &%timezone%&                    "force time zone"
 .endtable
 
@@ -13512,6 +13609,7 @@ listed in more than one group.
 .section "Privilege controls" "SECID98"
 .table2
 .row &%admin_groups%&                "groups that are Exim admin users"
+.row &%commandline_checks_require_admin%& "require admin for various checks"
 .row &%deliver_drop_privilege%&      "drop root for delivery processes"
 .row &%local_from_check%&            "insert &'Sender:'& if necessary"
 .row &%local_from_prefix%&           "for testing &'From:'& for local sender"
@@ -13539,6 +13637,7 @@ listed in more than one group.
 .row &%slow_lookup_log%&             "control logging of slow DNS lookups"
 .row &%syslog_duplication%&          "controls duplicate log lines on syslog"
 .row &%syslog_facility%&             "set syslog &""facility""& field"
+.row &%syslog_pid%&                  "pid in syslog lines"
 .row &%syslog_processname%&          "set syslog &""ident""& field"
 .row &%syslog_timestamp%&            "timestamp syslog lines"
 .row &%write_rejectlog%&             "control use of message log"
@@ -13801,6 +13900,7 @@ See also the &'Policy controls'& section above.
 .table2
 .row &%accept_8bitmime%&             "advertise 8BITMIME"
 .row &%auth_advertise_hosts%&        "advertise AUTH to these hosts"
+.row &%chunking_advertise_hosts%&    "advertise CHUNKING to these hosts"
 .row &%dsn_advertise_hosts%&         "advertise DSN extensions to these hosts"
 .row &%ignore_fromline_hosts%&       "allow &""From ""& from these hosts"
 .row &%ignore_fromline_local%&       "allow &""From ""& from local SMTP"
@@ -13974,6 +14074,7 @@ acknowledgment is sent. See chapter &<<CHAPACL>>& for further details.
 .option acl_smtp_dkim main string&!! unset
 .cindex DKIM "ACL for"
 This option defines the ACL that is run for each DKIM signature
+(by default, or as specified in the dkim_verify_signers option)
 of a received message.
 See chapter &<<CHAPdkim>>& for further details.
 
@@ -14290,11 +14391,11 @@ $primary_hostname-$tod_epoch-testing
 See section &<<CALLaddparcall>>& for details of how this value is used.
 
 
-.option check_log_inodes main integer 0
+.option check_log_inodes main integer 100
 See &%check_spool_space%& below.
 
 
-.option check_log_space main integer 0
+.option check_log_space main integer 10M
 See &%check_spool_space%& below.
 
 .oindex "&%check_rfc2047_length%&"
@@ -14309,11 +14410,11 @@ of the RFC, generates overlong encoded words. If &%check_rfc2047_length%& is
 set false, Exim recognizes encoded words of any length.
 
 
-.option check_spool_inodes main integer 0
+.option check_spool_inodes main integer 100
 See &%check_spool_space%& below.
 
 
-.option check_spool_space main integer 0
+.option check_spool_space main integer 10M
 .cindex "checking disk space"
 .cindex "disk space, checking"
 .cindex "spool directory" "checking space"
@@ -14324,7 +14425,7 @@ message is accepted.
 .vindex "&$log_space$&"
 .vindex "&$spool_inodes$&"
 .vindex "&$spool_space$&"
-When any of these options are set, they apply to all incoming messages. If you
+When any of these options are nonzero, they apply to all incoming messages. If you
 want to apply different checks to different kinds of message, you can do so by
 testing the variables &$log_inodes$&, &$log_space$&, &$spool_inodes$&, and
 &$spool_space$& in an ACL with appropriate additional conditions.
@@ -14333,7 +14434,7 @@ testing the variables &$log_inodes$&, &$log_space$&, &$spool_inodes$&, and
 &%check_spool_space%& and &%check_spool_inodes%& check the spool partition if
 either value is greater than zero, for example:
 .code
-check_spool_space = 10M
+check_spool_space = 100M
 check_spool_inodes = 100
 .endd
 The spool partition is the one that contains the directory defined by
@@ -14352,12 +14453,40 @@ SIZE parameter on the MAIL command, its value is added to the
 &%check_spool_space%& is zero, unless &%no_smtp_check_spool_space%& is set.
 
 The values for &%check_spool_space%& and &%check_log_space%& are held as a
-number of kilobytes. If a non-multiple of 1024 is specified, it is rounded up.
+number of kilobytes (though specified in bytes).
+If a non-multiple of 1024 is specified, it is rounded up.
 
 For non-SMTP input and for batched SMTP input, the test is done at start-up; on
 failure a message is written to stderr and Exim exits with a non-zero code, as
 it obviously cannot send an error message of any kind.
 
+There is a slight performance penalty for these checks.
+Versions of Exim preceding 4.88 had these disabled by default;
+high-rate installations confident they will never run out of resources
+may wish to deliberately disable them.
+
+.option chunking_advertise_hosts main "host list&!!" *
+.cindex CHUNKING advertisement
+.cindex "RFC 3030" "CHUNKING"
+The CHUNKING extension (RFC3030) will be advertised in the EHLO message to
+these hosts.
+Hosts may use the BDAT command as an alternate to DATA.
+
+.new
+.option commandline_checks_require_admin main boolean &`false`&
+.cindex "restricting access to features"
+This option restricts various basic checking features to require an
+administrative user.
+This affects most of the &%-b*%& options, such as &%-be%&.
+.wen
+
+.option debug_store main boolean &`false`&
+.cindex debugging "memory corruption"
+.cindex memory debugging
+This option, when true, enables extra checking in Exim's internal memory
+management.  For use when a memory corruption issue is being investigated,
+it should normally be left as default.
+
 .option daemon_smtp_ports main string &`smtp`&
 .cindex "port" "for daemon"
 .cindex "TCP/IP" "setting listening ports"
@@ -14379,6 +14508,7 @@ See &%daemon_startup_retries%&.
 .option delay_warning main "time list" 24h
 .cindex "warning of delay"
 .cindex "delay warning, specifying"
+.cindex "queue" "delay warning"
 When a message is delayed, Exim sends a warning message to the sender at
 intervals specified by this option. The data is a colon-separated list of times
 after which to send warning messages. If the value of the option is an empty
@@ -14606,6 +14736,7 @@ record in the authoritative section is used instead.
 .option dns_use_edns0 main integer -1
 .cindex "DNS" "resolver options"
 .cindex "DNS" "EDNS0"
+.cindex "DNS" "OpenBSD
 If this option is set to a non-negative number then Exim will initialise the
 DNS resolver library to either use or not use EDNS0 extensions, overriding
 the system default. A value of 0 coerces EDNS0 off, a value of 1 coerces EDNS0
@@ -14613,6 +14744,10 @@ on.
 
 If the resolver library does not support EDNS0 then this option has no effect.
 
+OpenBSD's asr resolver routines are known to ignore the EDNS0 option; this
+means that DNSSEC will not work with Exim on that platform either, unless Exim
+is linked against an alternative DNS client library.
+
 
 .option drop_cr main boolean false
 This is an obsolete option that is now a no-op. It used to affect the way Exim
@@ -14711,7 +14846,7 @@ not used.
 .option event_action main string&!! unset
 .cindex events
 This option declares a string to be expanded for Exim's events mechanism.
-For details see &<<CHAPevents>>&.
+For details see chapter &<<CHAPevents>>&.
 
 
 .option exim_group main string "compile-time configured"
@@ -15062,7 +15197,7 @@ If the &%smtp_connection%& log selector is not set, this option has no effect.
 .option hosts_proxy main "host list&!!" unset
 .cindex proxy "proxy protocol"
 This option enables use of Proxy Protocol proxies for incoming
-connections.  For details see &<<SECTproxyInbound>>&.
+connections.  For details see section &<<SECTproxyInbound>>&.
 
 
 .option hosts_treat_as_local main "domain list&!!" unset
@@ -15236,6 +15371,7 @@ connecting on a regular LDAP port.  This is the LDAP equivalent of SMTP's
 of SSL-on-connect.
 In the event of failure to negotiate TLS, the action taken is controlled
 by &%ldap_require_cert%&.
+This option is ignored for &`ldapi`& connections.
 
 
 .option ldap_version main integer unset
@@ -15576,7 +15712,7 @@ harm. This option overrides the &%pipe_as_creator%& option of the &(pipe)&
 transport driver.
 
 
-.option openssl_options main "string list" "+no_sslv2 +single_dh_use"
+.option openssl_options main "string list" "+no_sslv2 +single_dh_use +no_ticket"
 .cindex "OpenSSL "compatibility options"
 This option allows an administrator to adjust the SSL options applied
 by OpenSSL to connections.  It is given as a space-separated list of items,
@@ -15825,12 +15961,13 @@ different spool directories.
 
 
 .option prod_requires_admin main boolean true
+.cindex "restricting access to features"
 .oindex "&%-M%&"
 .oindex "&%-R%&"
 .oindex "&%-q%&"
 The &%-M%&, &%-R%&, and &%-q%& command-line options require the caller to be an
 admin user unless &%prod_requires_admin%& is set false. See also
-&%queue_list_requires_admin%&.
+&%queue_list_requires_admin%& and &%commandline_checks_require_admin%&.
 
 
 .option qualify_domain main string "see below"
@@ -15869,10 +16006,12 @@ next queue run. See also &%hold_domains%& and &%queue_smtp_domains%&.
 
 
 .option queue_list_requires_admin main boolean true
+.cindex "restricting access to features"
 .oindex "&%-bp%&"
 The &%-bp%& command-line option, which lists the messages that are on the
 queue, requires the caller to be an admin user unless
-&%queue_list_requires_admin%& is set false. See also &%prod_requires_admin%&.
+&%queue_list_requires_admin%& is set false.
+See also &%prod_requires_admin%& and &%commandline_checks_require_admin%&.
 
 
 .option queue_only main boolean false
@@ -15975,12 +16114,10 @@ the limit, allowing any number of simultaneous queue runner processes to be
 run. If you do not want queue runs to occur, omit the &%-q%&&'xx'& setting on
 the daemon's command line.
 
-.new
 .cindex queues named
 .cindex "named queues"
 To set limits for different named queues use
 an expansion depending on the &$queue_name$& variable.
-.wen
 
 .option queue_smtp_domains main "domain list&!!" unset
 .cindex "queueing incoming messages"
@@ -16654,7 +16791,7 @@ example, instead of &"Administrative prohibition"&, it might give:
 .option smtputf8_advertise_hosts main "host list&!!" *
 .cindex "SMTPUTF8" "advertising"
 When Exim is built with support for internationalised mail names,
-the availability therof is advertised in
+the availability thereof is advertised in
 response to EHLO only to those client hosts that match this option. See
 chapter &<<CHAPi18n>>& for details of Exim's support for internationalisation.
 
@@ -16720,6 +16857,32 @@ as failures in the configuration file.
 By using this option to override the compiled-in path, it is possible to run
 tests of Exim without using the standard spool.
 
+.new
+.option spool_wireformat main boolean false
+.cindex "spool directory" "file formats"
+If this option is set, Exim may for some messages use an alternate format
+for data-files in the spool which matches the wire format.
+Doing this permits more efficient message reception and transmission.
+Currently it is only done for messages received using the EMSTP CHUNKING
+option.
+
+The following variables will not have useful values:
+.code
+$max_received_linelength
+$body_linecount
+$body_zerocount
+.endd
+
+Users of the local_scan() API (see &<<CHAPlocalscan>>&),
+and any external programs which are passed a reference to a message data file
+(except via the &"regex"&, &"malware"& or &"spam"&) ACL conditions)
+will need to be aware of the potential different format.
+
+Using any of the ACL conditions noted will negate the reception benefit
+(as a Unix-mbox-format file is contructed for them).
+The transimssion benefit is maintained.
+.wen
+
 .option sqlite_lock_timeout main time 5s
 .cindex "sqlite lookup type" "lock timeout"
 This option controls the timeout that the &(sqlite)& lookup uses when trying to
@@ -16775,6 +16938,15 @@ If this option is unset, &"mail"& is used. See chapter &<<CHAPlog>>& for
 details of Exim's logging.
 
 
+.option syslog_pid main boolean true
+.cindex "syslog" "pid"
+If &%syslog_pid%& is set false, the PID on Exim's log lines are
+omitted when these lines are sent to syslog. (Syslog normally prefixes
+the log lines with the PID of the logging process automatically.) You need
+to enable the &`+pid`& log selector item, if you want Exim to write it's PID
+into the logs.) See chapter &<<CHAPlog>>& for details of Exim's logging.
+
+
 
 .option syslog_processname main string &`exim`&
 .cindex "syslog" "process name; setting"
@@ -16802,6 +16974,7 @@ generates any deliveries to files or pipes, or any new mail messages, the
 appropriate &%system_filter_..._transport%& option(s) must be set, to define
 which transports are to be used. Details of this facility are given in chapter
 &<<CHAPsystemfilter>>&.
+A forced expansion failure results in no filter operation.
 
 
 .option system_filter_directory_transport main string&!! unset
@@ -16934,10 +17107,8 @@ if the OpenSSL build supports TLS extensions and the TLS client sends the
 Server Name Indication extension, then this option and others documented in
 &<<SECTtlssni>>& will be re-expanded.
 
-.new
 If this option is unset or empty a fresh self-signed certificate will be
 generated for every connection.
-.wen
 
 .option tls_crl main string&!! unset
 .cindex "TLS" "server certificate revocation list"
@@ -16974,7 +17145,13 @@ larger prime than requested.
 The value of this option is expanded and indicates the source of DH parameters
 to be used by Exim.
 
-If it is a filename starting with a &`/`&, then it names a file from which DH
+&*Note: The Exim Maintainers strongly recommend using a filename with site-generated
+local DH parameters*&, which has been supported across all versions of Exim.  The
+other specific constants available are a fallback so that even when
+"unconfigured", Exim can offer Perfect Forward Secrecy in older ciphersuites in TLS.
+
+If &%tls_dhparam%& is a filename starting with a &`/`&,
+then it names a file from which DH
 parameters should be loaded.  If the file exists, it should hold a PEM-encoded
 PKCS#3 representation of the DH prime.  If the file does not exist, for
 OpenSSL it is an error.  For GnuTLS, Exim will attempt to create the file and
@@ -16991,22 +17168,36 @@ does not exist, Exim will attempt to create it.
 See section &<<SECTgnutlsparam>>& for further details.
 
 If Exim is using OpenSSL and this option is empty or unset, then Exim will load
-a default DH prime; the default is the 2048 bit prime described in section
+a default DH prime; the default is Exim-specific but lacks verifiable provenance.
+
+In older versions of Exim the default was the 2048 bit prime described in section
 2.2 of RFC 5114, "2048-bit MODP Group with 224-bit Prime Order Subgroup", which
 in IKE is assigned number 23.
 
 Otherwise, the option must expand to the name used by Exim for any of a number
-of DH primes specified in RFC 2409, RFC 3526 and RFC 5114.  As names, Exim uses
-"ike" followed by the number used by IKE, or "default" which corresponds to
-"ike23".
+of DH primes specified in RFC 2409, RFC 3526, RFC 5114, RFC 7919, or from other
+sources.  As names, Exim uses a standard specified name, else "ike" followed by
+the number used by IKE, or "default" which corresponds to
+&`exim.dev.20160529.3`&.
 
-The available primes are:
+The available standard primes are:
+&`ffdhe2048`&, &`ffdhe3072`&, &`ffdhe4096`&, &`ffdhe6144`&, &`ffdhe8192`&,
 &`ike1`&, &`ike2`&, &`ike5`&,
 &`ike14`&, &`ike15`&, &`ike16`&, &`ike17`&, &`ike18`&,
-&`ike22`&, &`ike23`& (aka &`default`&) and &`ike24`&.
+&`ike22`&, &`ike23`& and &`ike24`&.
+
+The available additional primes are:
+&`exim.dev.20160529.1`&, &`exim.dev.20160529.2`& and &`exim.dev.20160529.3`&.
 
 Some of these will be too small to be accepted by clients.
 Some may be too large to be accepted by clients.
+The open cryptographic community has suspicions about the integrity of some
+of the later IKE values, which led into RFC7919 providing new fixed constants
+(the "ffdhe" identifiers).
+
+At this point, all of the "ike" values should be considered obsolete;
+they're still in Exim to avoid breaking unusual configurations, but are
+candidates for removal the next time we have backwards-incompatible changes.
 
 The TLS protocol does not negotiate an acceptable size for this; clients tend
 to hard-drop connections if what is offered by the server is unacceptable,
@@ -17024,17 +17215,20 @@ prior to the 4.80 release, as Debian used to patch Exim to raise the minimum
 acceptable bound from 1024 to 2048.
 
 
-.option tls_eccurve main string&!! prime256v1
+.option tls_eccurve main string&!! &`auto`&
 .cindex TLS "EC cryptography"
-If built with a recent-enough version of OpenSSL,
-this option selects a EC curve for use by Exim.
+This option selects a EC curve for use by Exim when used with OpenSSL.
+It has no effect when Exim is used with GnuTLS.
+
+After expansion it must contain a valid EC curve parameter, such as
+&`prime256v1`&, &`secp384r1`&, or &`P-512`&. Consult your OpenSSL manual
+for valid selections.
 
-Curve names of the form &'prime256v1'& are accepted.
-For even more-recent library versions, names of the form &'P-512'&
-are also accepted, plus the special value &'auto'&
-which tells the library to choose.
+For OpenSSL versions before (and not including) 1.0.2, the string
+&`auto`& selects &`prime256v1`&. For more recent OpenSSL versions
+&`auto`& tells the library to choose.
 
-If the option is set to an empty string, no EC curves will be enabled.
+If the option expands to an empty string, no EC curves will be enabled.
 
 
 .option tls_ocsp_file main string&!! unset
@@ -19284,6 +19478,10 @@ instead of TRY_AGAIN. That is why the default action is to try a DNS
 lookup first. Only if that gives a definite &"no such host"& is the local
 function called.
 
+&*Compatibility*&: From Exim 4.85 until fixed for 4.90, there was an
+inadvertent constraint that a transport name as an option had to be the last
+option specified.
+
 
 
 If no IP address for a host can be found, what happens is controlled by the
@@ -19873,12 +20071,17 @@ list1:   :include:/opt/lists/list1
 .endd
 .next
 .cindex "address redirection" "to black hole"
-Sometimes you want to throw away mail to a particular local part. Making the
-&%data%& option expand to an empty string does not work, because that causes
-the router to decline. Instead, the alias item
+.cindex "delivery" "discard"
+.cindex "delivery" "blackhole"
 .cindex "black hole"
 .cindex "abandoning mail"
-&':blackhole:'& can be used. It does what its name implies. No delivery is
+Sometimes you want to throw away mail to a particular local part.  Making the
+&%data%& option expand to an empty string does not work, because that causes
+the router to decline. Instead, the alias item
+.code
+:blackhole:
+.endd
+can be used. It does what its name implies. No delivery is
 done, and no error message is generated. This has the same effect as specifying
 &_/dev/null_& as a destination, but it can be independently disabled.
 
@@ -20156,11 +20359,15 @@ relative path is then passed to the transport unmodified.
 
 
 .option forbid_blackhole redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 If this option is true, the &':blackhole:'& item may not appear in a
 redirection list.
 
 
 .option forbid_exim_filter redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 If this option is set true, only Sieve filters are permitted when
 &%allow_filter%& is true.
 
@@ -20168,7 +20375,9 @@ If this option is set true, only Sieve filters are permitted when
 
 
 .option forbid_file redirect boolean false
+.cindex "restricting access to features"
 .cindex "delivery" "to file; forbidding"
+.cindex "filter" "locking out certain features"
 .cindex "Sieve filter" "forbidding delivery to a file"
 .cindex "Sieve filter" "&""keep""& facility; disabling"
 If this option is true, this router may not generate a new address that
@@ -20179,17 +20388,22 @@ locks out the Sieve's &"keep"& facility.
 
 
 .option forbid_filter_dlfunc redirect boolean false
+.cindex "restricting access to features"
 .cindex "filter" "locking out certain features"
 If this option is true, string expansions in Exim filters are not allowed to
 make use of the &%dlfunc%& expansion facility to run dynamically loaded
 functions.
 
 .option forbid_filter_existstest redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 .cindex "expansion" "statting a file"
 If this option is true, string expansions in Exim filters are not allowed to
 make use of the &%exists%& condition or the &%stat%& expansion item.
 
 .option forbid_filter_logwrite redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 If this option is true, use of the logging facility in Exim filters is not
 permitted. Logging is in any case available only if the filter is being run
 under some unprivileged uid (which is normally the case for ordinary users'
@@ -20197,27 +20411,37 @@ under some unprivileged uid (which is normally the case for ordinary users'
 
 
 .option forbid_filter_lookup redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 If this option is true, string expansions in Exim filter files are not allowed
 to make use of &%lookup%& items.
 
 
 .option forbid_filter_perl redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 This option has an effect only if Exim is built with embedded Perl support. If
 it is true, string expansions in Exim filter files are not allowed to make use
 of the embedded Perl support.
 
 
 .option forbid_filter_readfile redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 If this option is true, string expansions in Exim filter files are not allowed
 to make use of &%readfile%& items.
 
 
 .option forbid_filter_readsocket redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 If this option is true, string expansions in Exim filter files are not allowed
 to make use of &%readsocket%& items.
 
 
 .option forbid_filter_reply redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 If this option is true, this router may not generate an automatic reply
 message. Automatic replies can be generated only from Exim or Sieve filter
 files, not from traditional forward files. This option is forced to be true if
@@ -20225,11 +20449,15 @@ files, not from traditional forward files. This option is forced to be true if
 
 
 .option forbid_filter_run redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 If this option is true, string expansions in Exim filter files are not allowed
 to make use of &%run%& items.
 
 
 .option forbid_include redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 If this option is true, items of the form
 .code
 :include:<path name>
@@ -20238,6 +20466,8 @@ are not permitted in non-filter redirection lists.
 
 
 .option forbid_pipe redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 .cindex "delivery" "to pipe; forbidding"
 If this option is true, this router may not generate a new address which
 specifies delivery to a pipe, either from an Exim filter or from a conventional
@@ -20245,6 +20475,8 @@ forward file. This option is forced to be true if &%one_time%& is set.
 
 
 .option forbid_sieve_filter redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 If this option is set true, only Exim filters are permitted when
 &%allow_filter%& is true.
 
@@ -20798,7 +21030,7 @@ resent to other recipients.
 .option event_action transports string&!! unset
 .cindex events
 This option declares a string to be expanded for Exim's events mechanism.
-For details see &<<CHAPevents>>&.
+For details see chapter &<<CHAPevents>>&.
 
 
 .option group transports string&!! "Exim group"
@@ -20913,7 +21145,7 @@ The control does not apply to shadow transports.
 
 .cindex "hints database" "transport concurrency control"
 Exim implements this control by means of a hints database in which a record is
-incremented whenever a transport process is beaing created. The record
+incremented whenever a transport process is being created. The record
 is decremented and possibly removed when the process terminates.
 Obviously there is scope for
 records to get left lying around if there is a system or program crash. To
@@ -21909,10 +22141,14 @@ the obvious value which users understand most easily.
 
 The value of the option is expanded, and must then be a numerical value
 (decimal point allowed), optionally followed by one of the letters K, M, or G,
-for kilobytes, megabytes, or gigabytes. If Exim is running on a system with
+for kilobytes, megabytes, or gigabytes, optionally followed by a slash
+and further option modifiers. If Exim is running on a system with
 large file support (Linux and FreeBSD have this), mailboxes larger than 2G can
 be handled.
 
+The option modifier &%no_check%& can be used to force delivery even if the over
+quota condition is met. The quota gets updated as usual.
+
 &*Note*&: A value of zero is interpreted as &"no quota"&.
 
 The expansion happens while Exim is running as root, before it changes uid for
@@ -21947,6 +22183,8 @@ can only be used if &%quota%& is also set. The value is expanded; an expansion
 failure causes delivery to be deferred. A value of zero is interpreted as
 &"no quota"&.
 
+The option modifier &%no_check%& can be used to force delivery even if the over
+quota condition is met. The quota gets updated as usual.
 
 .option quota_is_inclusive appendfile boolean true
 See &%quota%& above.
@@ -23170,12 +23408,10 @@ message_suffix =
 &`\n`& to &`\r\n`& in &%message_suffix%&.
 
 
-.option path pipe string "see below"
-This option specifies the string that is set up in the PATH environment
-variable of the subprocess. The default is:
-.code
-/bin:/usr/bin
-.endd
+.option path pipe string&!! "/bin:/usr/bin"
+This option is expanded and
+specifies the string that is set up in the PATH environment
+variable of the subprocess.
 If the &%command%& option does not yield an absolute path name, the command is
 sought in the PATH directories, in the usual way. &*Warning*&: This does not
 apply to a command specified as a transport filter.
@@ -23554,13 +23790,13 @@ the message. As a result, the overall timeout for a message depends on the size
 of the message. Its value must not be zero. See also &%final_timeout%&.
 
 
-.option dkim_domain smtp string&!! unset
+.option dkim_domain smtp string list&!! unset
 .option dkim_selector smtp string&!! unset
 .option dkim_private_key smtp string&!! unset
 .option dkim_canon smtp string&!! unset
 .option dkim_strict smtp string&!! unset
 .option dkim_sign_headers smtp string&!! unset
-DKIM signing options.  For details see &<<SECDKIMSIGN>>&.
+DKIM signing options.  For details see section &<<SECDKIMSIGN>>&.
 
 
 .option delay_after_cutoff smtp boolean true
@@ -23803,6 +24039,25 @@ been started will not be passed to a new delivery process for sending another
 message on the same connection. See section &<<SECTmulmessam>>& for an
 explanation of when this might be needed.
 
+.new
+.option hosts_noproxy_tls smtp "host list&!!" *
+.cindex "TLS" "passing connection"
+.cindex "multiple SMTP deliveries"
+.cindex "TLS" "multiple message deliveries"
+For any host that matches this list, a TLS session which has
+been started will not be passed to a new delivery process for sending another
+message on the same session.
+
+The traditional implementation closes down TLS and re-starts it in the new
+process, on the same open TCP connection, for each successive message
+sent.  If permitted by this option a pipe to to the new process is set up
+instead, and the original process maintains the TLS connection and proxies
+the SMTP connection from and to the new process and any subsequents.
+The new process has no access to TLS information, so cannot include it in
+logging.
+.wen
+
+
 
 .option hosts_override smtp boolean false
 If this option is set and the &%hosts%& option is also set, any hosts that are
@@ -23871,6 +24126,31 @@ connects. If authentication fails, Exim will try to transfer the message
 unauthenticated. See also &%hosts_require_auth%&, and chapter
 &<<CHAPSMTPAUTH>>& for details of authentication.
 
+.option hosts_try_chunking smtp "host list&!!" *
+.cindex CHUNKING "enabling, in client"
+.cindex BDAT "SMTP command"
+.cindex "RFC 3030" "CHUNKING"
+This option provides a list of servers to which, provided they announce
+CHUNKING support, Exim will attempt to use BDAT commands rather than DATA.
+BDAT will not be used in conjunction with a transport filter.
+
+.option hosts_try_fastopen smtp "host list!!" unset
+.cindex "fast open, TCP" "enabling, in client"
+.cindex "TCP Fast Open" "enabling, in client"
+.cindex "RFC 7413" "TCP Fast Open"
+This option provides a list of servers to which, provided
+the facility is supported by this system, Exim will attempt to
+perform a TCP Fast Open.
+No data is sent on the SYN segment but, if the remote server also
+supports the facility, it can send its SMTP banner immediately after
+the SYN,ACK segment.  This can save up to one round-trip time.
+
+The facility is only active for previously-contacted servers,
+as the initiator must present a cookie in the SYN segment.
+
+On (at least some) current Linux distributions the facility must be enabled
+in the kernel by the sysadmin before the support is usable.
+
 .option hosts_try_prdr smtp "host list&!!" *
 .cindex "PRDR" "enabling, optional in client"
 This option provides a list of servers to which, provided they announce
@@ -24041,7 +24321,7 @@ the use of the SIZE option altogether.
 .option socks_proxy smtp string&!! unset
 .cindex proxy SOCKS
 This option enables use of SOCKS proxies for connections made by the
-transport.  For details see &<<SECTproxySOCKS>>&.
+transport.  For details see section &<<SECTproxySOCKS>>&.
 
 
 .option tls_certificate smtp string&!! unset
@@ -25746,6 +26026,17 @@ turned into a permanent error if you wish. In the second case, Exim tries to
 deliver the message unauthenticated.
 .endlist
 
+Note that the hostlist test for whether to do authentication can be
+confused if name-IP lookups change between the time the peer is decided
+on and the transport running.  For example, with a manualroute
+router given a host name, and DNS "round-robin" use by that name: if
+the local resolver cache times out between the router and the transport
+running, the transport may get an IP for the name for its authentication
+check which does not match the connection peer IP.
+No authentication will then be done, despite the names being identical.
+
+For such cases use a separate transport which always authenticates.
+
 .cindex "AUTH" "on MAIL command"
 When Exim has authenticated itself to a remote server, it adds the AUTH
 parameter to the MAIL commands it sends, if it has an authenticated sender for
@@ -26655,7 +26946,7 @@ tls:
 .endd
 This accepts a client certificate that is verifiable against any
 of your configured trust-anchors
-which usually means the full set of public CAs)
+(which usually means the full set of public CAs)
 and which has a SAN with a good account name.
 Note that the client cert is on the wire in-clear, including the SAN,
 whereas a plaintext SMTP AUTH done inside TLS is not.
@@ -27017,10 +27308,12 @@ tls_require_ciphers = ${if =={$received_port}{25}\
 .cindex "TLS" "configuring an Exim server"
 When Exim has been built with TLS support, it advertises the availability of
 the STARTTLS command to client hosts that match &%tls_advertise_hosts%&,
-but not to any others. The default value of this option is unset, which means
-that STARTTLS is not advertised at all. This default is chosen because you
-need to set some other options in order to make TLS available, and also it is
-sensible for systems that want to use TLS only as a client.
+but not to any others. The default value of this option is *, which means
+that STARTTLS is alway advertised.  Set it to blank to never advertise;
+this is reasonble for systems that want to use TLS only as a client.
+
+If STARTTLS is to be used you
+need to set some other options in order to make TLS available.
 
 If a client issues a STARTTLS command and there is some configuration
 problem in the server, the command is rejected with a 454 error. If the client
@@ -27035,12 +27328,10 @@ rejected with a 554 error code.
 To enable TLS operations on a server, the &%tls_advertise_hosts%& option
 must be set to match some hosts. The default is * which matches all hosts.
 
-.new
 If this is all you do, TLS encryption will be enabled but not authentication -
 meaning that the peer has no assurance it is actually you he is talking to.
 You gain protection from a passive sniffer listening on the wire but not
 from someone able to intercept the communication.
-.wen
 
 Further protection requires some further configuration at the server end.
 
@@ -27417,8 +27708,11 @@ during TLS session handshake, to permit alternative values to be chosen:
 
 Great care should be taken to deal with matters of case, various injection
 attacks in the string (&`../`& or SQL), and ensuring that a valid filename
-can always be referenced; it is important to remember that &$tls_sni$& is
+can always be referenced; it is important to remember that &$tls_in_sni$& is
 arbitrary unverified data provided prior to authentication.
+Further, the initial certificate is loaded before SNI is arrived, so
+an expansion for &%tls_certificate%& must have a default which is used
+when &$tls_in_sni$& is empty.
 
 The Exim developers are proceeding cautiously and so far no other TLS options
 are re-expanded.
@@ -27438,13 +27732,22 @@ built, then you have SNI support).
          "SECTmulmessam"
 .cindex "multiple SMTP deliveries with TLS"
 .cindex "TLS" "multiple message deliveries"
+.new
 Exim sends multiple messages down the same TCP/IP connection by starting up
 an entirely new delivery process for each message, passing the socket from
 one process to the next. This implementation does not fit well with the use
 of TLS, because there is quite a lot of state information associated with a TLS
 connection, not just a socket identification. Passing all the state information
-to a new process is not feasible. Consequently, Exim shuts down an existing TLS
-session before passing the socket to a new process. The new process may then
+to a new process is not feasible. Consequently, for sending using TLS Exim
+starts an additional proxy process for handling the encryption, piping the
+unencrypted data stream from and to the delivery processes.
+
+An older mode of operation can be enabled on a per-host basis by the
+&%hosts_noproxy_tls%& option on the &(smtp)& transport.  If the host matches
+this list the proxy process descibed above is not used; instead Exim
+.wen
+shuts down an existing TLS session being run by the delivery process
+before passing the socket to a new process. The new process may then
 try to start a new TLS session, and if successful, may try to re-authenticate
 if AUTH is in use, before sending the next message.
 
@@ -27741,6 +28044,15 @@ received, before the final response to the DATA command is sent. This is
 the ACL specified by &%acl_smtp_data%&, which is the second ACL that is
 associated with the DATA command.
 
+.cindex CHUNKING "BDAT command"
+.cindex BDAT "SMTP command"
+.cindex "RFC 3030" CHUNKING
+If CHUNKING was advertised and a BDAT command sequence is received,
+the &%acl_smtp_predata%& ACL is not run.
+. XXX why not?  It should be possible, for the first BDAT.
+The &%acl_smtp_data%& is run after the last BDAT command and all of
+the data specified is received.
+
 For both of these ACLs, it is not possible to reject individual recipients. An
 error response rejects the entire message. Unfortunately, it is known that some
 MTAs do not treat hard (5&'xx'&) responses to the DATA command (either
@@ -27951,6 +28263,9 @@ run. A &"discard"& return from the DATA or the non-SMTP ACL discards all the
 remaining recipients. The &"discard"& return is not permitted for the
 &%acl_smtp_predata%& ACL.
 
+If the ACL for VRFY returns &"accept"&, a recipient verify (without callout)
+is done on the address and the result determines the SMTP response.
+
 
 .cindex "&[local_scan()]& function" "when all recipients discarded"
 The &[local_scan()]& function is always run, even if there are no remaining
@@ -28062,7 +28377,7 @@ provides a means of specifying an &"and"& conjunction between conditions. For
 example:
 .code
 deny  dnslists = list1.example
-dnslists = list2.example
+      dnslists = list2.example
 .endd
 If there are no conditions, the verb is always obeyed. Exim stops evaluating
 the conditions and modifiers when it reaches a condition that fails. What
@@ -28084,8 +28399,8 @@ after &%endpass%&, the ACL returns &"deny"&. Consider this statement, used to
 check a RCPT command:
 .code
 accept domains = +local_domains
-endpass
-verify = recipient
+       endpass
+       verify = recipient
 .endd
 If the recipient domain does not match the &%domains%& condition, control
 passes to the next statement. If it does match, the recipient is verified, and
@@ -28637,7 +28952,6 @@ all the conditions are true, wherever it appears in an ACL command, whereas
 effect.
 
 
-.new
 .vitem &*queue*&&~=&~<&'text'&>
 This modifier specifies the use of a named queue for spool files
 for the message.
@@ -28647,7 +28961,6 @@ This could be used, for example, for known high-volume burst sources
 of traffic, or for quarantine of messages.
 Separate queue-runner processes will be needed for named queues.
 If the text after expansion is empty, the default queue is used.
-.wen
 
 
 .vitem &*remove_header*&&~=&~<&'text'&>
@@ -28736,7 +29049,7 @@ Notice that we put back the lower cased version afterwards, assuming that
 is what is wanted for subsequent tests.
 
 
-.vitem &*control&~=&~cutthrough_delivery*&
+.vitem &*control&~=&~cutthrough_delivery/*&<&'options'&>
 .cindex "&ACL;" "cutthrough routing"
 .cindex "cutthrough" "requesting"
 This option requests delivery be attempted while the item is being received.
@@ -28762,6 +29075,11 @@ and cannot depend on content of received headers.
 Note also that headers cannot be
 modified by any of the post-data ACLs (DATA, MIME and DKIM).
 Headers may be modified by routers (subject to the above) and transports.
+.new
+The Received-By: header is generated as soon as the body reception starts,
+rather than the traditional time after the full message is received;
+this will affect the timestamp.
+.wen
 
 All the usual ACLs are called; if one results in the message being
 rejected, all effort spent in delivery (including the costs on
@@ -28772,15 +29090,24 @@ message body.
 Cutthrough delivery is not supported via transport-filters or when DKIM signing
 of outgoing messages is done, because it sends data to the ultimate destination
 before the entire message has been received from the source.
-It is not supported for messages received with the SMTP PRDR option in use.
+It is not supported for messages received with the SMTP PRDR
+or CHUNKING
+options in use.
 
 Should the ultimate destination system positively accept or reject the mail,
 a corresponding indication is given to the source system and nothing is queued.
-If there is a temporary error the item is queued for later delivery in the
-usual fashion. If the item is successfully delivered in cutthrough mode
+If the item is successfully delivered in cutthrough mode
 the delivery log lines are tagged with ">>" rather than "=>" and appear
 before the acceptance "<=" line.
 
+If there is a temporary error the item is queued for later delivery in the
+usual fashion.
+This behaviour can be adjusted by appending the option &*defer=*&<&'value'&>
+to the control; the default value is &"spool"& and the alternate value
+&"pass"& copies an SMTP defer response from the target back to the initiator
+and does not queue the message.
+Note that this is independent of any recipient verify conditions in the ACL.
+
 Delivery in this mode avoids the generation of a bounce mail to a
 (possibly faked)
 sender when the destination system is doing content-scan based rejection.
@@ -28790,14 +29117,14 @@ sender when the destination system is doing content-scan based rejection.
 .cindex "&ACL;" "enabling debug logging"
 .cindex "debugging" "enabling from an ACL"
 This control turns on debug logging, almost as though Exim had been invoked
-with &`-d`&, with the output going to a new logfile, by default called
-&'debuglog'&.  The filename can be adjusted with the &'tag'& option, which
+with &`-d`&, with the output going to a new logfile in the usual logs directory,
+by default called &'debuglog'&.
+The filename can be adjusted with the &'tag'& option, which
 may access any variables already defined.  The logging may be adjusted with
 the &'opts'& option, which takes the same values as the &`-d`& command-line
 option.
-.new
-Logging may be stopped, and the file removed, with the &'kill'& option.
-.wen
+Logging started this way may be stopped, and the file removed,
+with the &'kill'& option.
 Some examples (which depend on variables that don't exist in all
 contexts):
 .code
@@ -29005,7 +29332,7 @@ that are being submitted at the same time using &%-bs%& or &%-bS%&.
 .vitem &*control&~=&~utf8_downconvert*&
 This control enables conversion of UTF-8 in message addresses
 to a-label form.
-For details see &<<SECTi18nMTA>>&.
+For details see section &<<SECTi18nMTA>>&.
 .endlist vlist
 
 
@@ -29618,6 +29945,13 @@ to avoid doing it more than once per message.
 .cindex "&%verify%& ACL condition"
 This is a variation of the previous option, in which a modified address is
 verified as a sender.
+
+Note that '/' is legal in local-parts; if the address may have such
+(eg. is generated from the received message)
+they must be protected from the options parsing by doubling:
+.code
+verify = sender=${sg{${address:$h_sender:}}{/}{//}}
+.endd
 .endlist
 
 
@@ -29677,7 +30011,7 @@ deny  dnslists = blackholes.mail-abuse.org
 warn  message  = X-Warn: sending host is on dialups list
       dnslists = dialups.mail-abuse.org
 .endd
-.cindex cacheing "of dns lookup"
+.cindex caching "of dns lookup"
 .cindex DNS TTL
 DNS list lookups are cached by Exim for the duration of the SMTP session
 (but limited by the DNS return TTL value),
@@ -29790,7 +30124,7 @@ multiple DNS records. The inner dnsdb lookup produces a list of MX hosts
 and the outer dnsdb lookup finds the IP addresses for these hosts. The result
 of expanding the condition might be something like this:
 .code
-dnslists = sbl.spahmaus.org/<|192.168.2.3|192.168.5.6|...
+dnslists = sbl.spamhaus.org/<|192.168.2.3|192.168.5.6|...
 .endd
 Thus, this example checks whether or not the IP addresses of the sender
 domain's mail servers are on the Spamhaus black list.
@@ -30680,6 +31014,23 @@ command when performing the callout, instead of an empty address. There is no
 need to use this option unless you know that the called hosts make use of the
 sender when checking recipients. If used indiscriminately, it reduces the
 usefulness of callout caching.
+
+.new
+.vitem &*hold*&
+This option applies to recipient callouts only. For example:
+.code
+require  verify = recipient/callout=use_sender,hold
+.endd
+It causes the connection to be helod open and used for any further recipients
+and for eventual delivery (should that be done quickly).
+Doing this saves on TCP and SMTP startup costs, and TLS costs also
+when that is used for the connections.
+The advantage is only gained if there are no callout cache hits
+(which could be enforced by the no_cache option),
+if the use_sender option is used,
+if neither the random nor the use_postmaster option is used,
+and if no other callouts intervene.
+.wen
 .endlist
 
 If you use any of the parameters that set a non-empty sender for the MAIL
@@ -31316,6 +31667,18 @@ av_scanner = f-protd:localhost 10200-10204
 .endd
 If you omit the argument, the default values show above are used.
 
+.new
+.vitem &%f-prot6d%&
+.cindex "virus scanners" "f-prot6d"
+The f-prot6d scanner is accessed using the FPSCAND protocol over TCP.
+One argument is taken, being a space-separated hostname and port number.
+For example:
+.code
+av_scanner = f-prot6d:localhost 10200
+.endd
+If you omit the argument, the default values show above are used.
+.wen
+
 .vitem &%fsecure%&
 .cindex "virus scanners" "F-Secure"
 The F-Secure daemon scanner (&url(http://www.f-secure.com)) takes one
@@ -31359,14 +31722,18 @@ an address (which may be an IP address and port, or the path of a Unix socket),
 a commandline to send (may include a single %s which will be replaced with
 the path to the mail file to be scanned),
 an RE to trigger on from the returned data,
-an RE to extract malware_name from the returned data.
+and an RE to extract malware_name from the returned data.
 For example:
 .code
-av_scanner = sock:127.0.0.1 6001:%s:(SPAM|VIRUS):(.*)\$
+av_scanner = sock:127.0.0.1 6001:%s:(SPAM|VIRUS):(.*)$
 .endd
-Default for the socket specifier is &_/tmp/malware.sock_&.
-Default for the commandline is &_%s\n_&.
-Both regular-expressions are required.
+.new
+Note that surrounding whitespace is stripped from each option, meaning
+there is no way to specify a trailing newline.
+The socket specifier and both regular-expressions are required.
+Default for the commandline is &_%s\n_& (note this does have a trailing newline);
+specify an empty element to get this.
+.wen
 
 .vitem &%sophie%&
 .cindex "virus scanners" "Sophos and Sophie"
@@ -31494,6 +31861,15 @@ configuration as follows (example):
 .code
 spamd_address = 192.168.99.45 387
 .endd
+The SpamAssassin protocol relies on a TCP half-close from the client.
+If your SpamAssassin client side is running a Linux system with an
+iptables firewall, consider setting
+&%net.netfilter.nf_conntrack_tcp_timeout_close_wait%& to at least the
+timeout, Exim uses when waiting for a response from the SpamAssassin
+server (currently defaulting to 120s).  With a lower value the Linux
+connection tracking may consider your half-closed connection as dead too
+soon.
+
 
 To use Rspamd (which by default listens on all local addresses
 on TCP port 11333)
@@ -31524,7 +31900,7 @@ condition defers.
 
 Unix and TCP socket specifications may be mixed in any order.
 Each element of the list is a list itself, space-separated by default
-and changeable in the usual way.
+and changeable in the usual way; take care to not double the separator.
 
 For TCP socket specifications a host name or IP (v4 or v6, but
 subject to list-separator quoting rules) address can be used,
@@ -31651,6 +32027,9 @@ spam bar is 50 characters.
 A multiline text table, containing the full SpamAssassin report for the
 message. Useful for inclusion in headers or reject messages.
 This variable is only usable in a DATA-time ACL.
+Beware that SpamAssassin may return non-ASCII characters, especially
+when running in country-specific locales, which are not legal
+unencoded in headers.
 
 .vitem &$spam_action$&
 For SpamAssassin either 'reject' or 'no action' depending on the
@@ -32194,9 +32573,15 @@ C variables are as follows:
 .vlist
 .vitem &*int&~body_linecount*&
 This variable contains the number of lines in the message's body.
+.new
+It is not valid if the &%spool_files_wireformat%& option is used.
+.wen
 
 .vitem &*int&~body_zerocount*&
 This variable contains the number of binary zero bytes in the message's body.
+.new
+It is not valid if the &%spool_files_wireformat%& option is used.
+.wen
 
 .vitem &*unsigned&~int&~debug_selector*&
 This variable is set to zero when no debugging is taking place. Otherwise, it
@@ -33236,6 +33621,7 @@ incoming SMTP message from a source that is not permitted to send them.
 
 .section "Resent- header lines" "SECID220"
 .cindex "&%Resent-%& header lines"
+.cindex "header lines" "Resent-"
 RFC 2822 makes provision for sets of header lines starting with the string
 &`Resent-`& to be added to a message when it is resent by the original
 recipient to somebody else. These headers are &'Resent-Date:'&,
@@ -33292,6 +33678,7 @@ existing &'Bcc:'& is not removed.
 
 .section "The Date: header line" "SECID223"
 .cindex "&'Date:'& header line"
+.cindex "header lines" "Date:"
 If a locally-generated or submission-mode message has no &'Date:'& header line,
 Exim adds one, using the current date and time, unless the
 &%suppress_local_fixups%& control has been specified.
@@ -33309,6 +33696,7 @@ messages.
 
 .section "The Envelope-to: header line" "SECID225"
 .cindex "&'Envelope-to:'& header line"
+.cindex "header lines" "Envelope-to:"
 .oindex "&%envelope_to_remove%&"
 &'Envelope-to:'& header lines are not part of the standard RFC 2822 header set.
 Exim can be configured to add them to the final delivery of messages. (See the
@@ -33320,6 +33708,7 @@ messages.
 
 .section "The From: header line" "SECTthefrohea"
 .cindex "&'From:'& header line"
+.cindex "header lines" "From:"
 .cindex "Sendmail compatibility" "&""From""& line"
 .cindex "message" "submission"
 .cindex "submission mode"
@@ -33363,6 +33752,7 @@ name as described in section &<<SECTconstr>>&.
 
 .section "The Message-ID: header line" "SECID226"
 .cindex "&'Message-ID:'& header line"
+.cindex "header lines" "Message-ID:"
 .cindex "message" "submission"
 .oindex "&%message_id_header_text%&"
 If a locally-generated or submission-mode incoming message does not contain a
@@ -33378,6 +33768,7 @@ in this header line by setting the &%message_id_header_text%& and/or
 
 .section "The Received: header line" "SECID227"
 .cindex "&'Received:'& header line"
+.cindex "header lines" "Received:"
 A &'Received:'& header line is added at the start of every message. The
 contents are defined by the &%received_header_text%& configuration option, and
 Exim automatically adds a semicolon and a timestamp to the configured string.
@@ -33394,6 +33785,7 @@ changed to the time of acceptance, which is (apart from a small delay while the
 
 .section "The References: header line" "SECID228"
 .cindex "&'References:'& header line"
+.cindex "header lines" "References:"
 Messages created by the &(autoreply)& transport include a &'References:'&
 header line. This is constructed according to the rules that are described in
 section 3.64 of RFC 2822 (which states that replies should contain such a
@@ -33408,6 +33800,7 @@ incoming message. If there are more than 12, the first one and then the final
 
 .section "The Return-path: header line" "SECID229"
 .cindex "&'Return-path:'& header line"
+.cindex "header lines" "Return-path:"
 .oindex "&%return_path_remove%&"
 &'Return-path:'& header lines are defined as something an MTA may insert when
 it does the final delivery of messages. (See the generic &%return_path_add%&
@@ -33420,6 +33813,7 @@ default), Exim removes &'Return-path:'& header lines from incoming messages.
 .section "The Sender: header line" "SECTthesenhea"
 .cindex "&'Sender:'& header line"
 .cindex "message" "submission"
+.cindex "header lines" "Sender:"
 For a locally-originated message from an untrusted user, Exim may remove an
 existing &'Sender:'& header line, and it may add a new one. You can modify
 these actions by setting the &%local_sender_retain%& option true, the
@@ -35388,6 +35782,7 @@ picked out by the distinctive two-character flags that immediately follow the
 timestamp. The flags are:
 .display
 &`<=`&     message arrival
+&`(=`&     message fakereject
 &`=>`&     normal message delivery
 &`->`&     additional address in same delivery
 &`>>`&     cutthrough message delivery
@@ -35510,6 +35905,12 @@ SMTP RCPT commands in one transaction) the second and subsequent addresses are
 flagged with &`->`& instead of &`=>`&. When two or more messages are delivered
 down a single SMTP connection, an asterisk follows the IP address in the log
 lines for the second and subsequent messages.
+.new
+When two or more messages are delivered down a single TLS connection, the
+DNS and some TLS-related information logged for the first message delivered
+will not be present in the log lines for the second and subsequent messages.
+TLS cipher information is still available.
+.wen
 
 .cindex "delivery" "cutthrough; logging"
 .cindex "cutthrough" "logging"
@@ -35620,10 +36021,13 @@ the following table:
 &`F   `&        sender address (on delivery lines)
 &`H   `&        host name and IP address
 &`I   `&        local interface used
+&`K   `&        CHUNKING extension used
 &`id  `&        message id for incoming message
+&`M8S `&        8BITMIME status for incoming message
 &`P   `&        on &`<=`& lines: protocol used
 &`    `&        on &`=>`& and &`**`& lines: return path
-&`PRX `&        on &'<='& and&`=>`& lines: proxy address
+&`PRDR`&        PRDR extension used
+&`PRX `&        on &`<=`& and &`=>`& lines: proxy address
 &`Q   `&        alternate queue name
 &`QT  `&        on &`=>`& lines: time spent on queue so far
 &`    `&        on &"Completed"& lines: time spent on queue
@@ -35714,6 +36118,7 @@ selection marked by asterisks:
 &` incoming_interface         `&  local interface on <= and => lines
 &` incoming_port              `&  remote port on <= lines
 &`*lost_incoming_connection   `&  as it says (includes timeouts)
+&` millisec                   `&  millisecond timestamps and QT,DT,D times
 &` outgoing_interface         `&  local interface on => lines
 &` outgoing_port              `&  add remote port to => lines
 &`*queue_run                  `&  start and end queue runs
@@ -35803,6 +36208,8 @@ process is started because &%queue_only%& is set or &%-odq%& was used.
 .cindex "log" "delivery duration"
 &%deliver_time%&: For each delivery, the amount of real time it has taken to
 perform the actual delivery is logged as DT=<&'time'&>, for example, &`DT=1s`&.
+If millisecond logging is enabled, short times will be shown with greater
+precision, eg. &`DT=0.304`&.
 .next
 .cindex "log" "message size on delivery"
 .cindex "size" "of message"
@@ -35859,7 +36266,7 @@ The latter can be disabled by turning off the &%outgoing_interface%& option.
 &%proxy%&: The internal (closest to the system running Exim) IP address
 of the proxy, tagged by PRX=, on the &"<="& line for a message accepted
 on a proxied connection
-or the &"=>"& line for a message delivered on a proxied connection..
+or the &"=>"& line for a message delivered on a proxied connection.
 See &<<SECTproxyInbound>>& for more information.
 .next
 .cindex "log" "incoming remote port"
@@ -35878,6 +36285,14 @@ important with the widening use of NAT (see RFC 2505).
 &%lost_incoming_connection%&: A log line is written when an incoming SMTP
 connection is unexpectedly dropped.
 .next
+.new
+.cindex "log" "millisecond timestamps"
+.cindex millisecond logging
+.cindex timstamps "millisecond, in logs"
+&%millisec%&: Timestamps have a period and three decimal places of finer granularity
+appended to the seconds value.
+.wen
+.next
 .cindex "log" "outgoing interface"
 .cindex "log" "local interface"
 .cindex "log" "local address and port"
@@ -35890,7 +36305,7 @@ off the &%outgoing_interface%& option.
 .next
 .cindex "log" "outgoing remote port"
 .cindex "port" "logging outgoint remote"
-.cindex "TCP/IP" "logging ougtoing remote port"
+.cindex "TCP/IP" "logging outgoing remote port"
 &%outgoing_port%&: The remote port number is added to delivery log lines (those
 containing => tags) following the IP address.
 The local port is also added if &%incoming_interface%& and
@@ -35916,6 +36331,8 @@ includes reception time as well as the delivery time for the current address.
 This means that it may be longer than the difference between the arrival and
 delivery log line times, because the arrival log line is not written until the
 message has been successfully received.
+If millisecond logging is enabled, short times will be shown with greater
+precision, eg. &`QT=1.578s`&.
 .next
 &%queue_time_overall%&: The amount of time the message has been in the queue on
 the local host is logged as QT=<&'time'&> on &"Completed"& lines, for
@@ -36368,8 +36785,7 @@ autodetection of some well known compression extensions.
 .cindex "&'exipick'&"
 John Jetmore's &'exipick'& utility is included in the Exim distribution. It
 lists messages from the queue according to a variety of criteria. For details
-of &'exipick'&'s facilities, visit the web page at
-&url(http://www.exim.org/eximwiki/ToolExipickManPage) or run &'exipick'& with
+of &'exipick'&'s facilities, run &'exipick'& with
 the &%--help%& option.
 
 
@@ -37619,6 +38035,13 @@ the contents of files on the spool via the Exim monitor (which runs
 unprivileged), Exim must be built to allow group read access to its spool
 files.
 
+.new
+By default, regular users are trusted to perform basic testing and
+introspection commands, as themselves.  This setting can be tightened by
+setting the &%commandline_checks_require_admin%& option.
+This affects most of the checking options,
+such as &%-be%& and anything else &%-b*%&.
+.wen
 
 
 .section "Spool files" "SECID275"
@@ -37719,9 +38142,8 @@ lock will be lost at the instant of rename.
 .next
 .vindex "&$body_linecount$&"
 If you change the number of lines in the file, the value of
-&$body_linecount$&, which is stored in the -H file, will be incorrect. At
-present, this value is not used by Exim, but there is no guarantee that this
-will always be the case.
+&$body_linecount$&, which is stored in the -H file, will be incorrect and can
+cause incomplete transmission of messages or undeliverable messages.
 .next
 If the message is in MIME format, you must take care not to break it.
 .next
@@ -37740,6 +38162,13 @@ file remains in existence. When Exim next processes the message, it notices the
 -J file and uses it to update the -H file before starting the next delivery
 attempt.
 
+.new
+Files whose names end with -K or .eml may also be seen in the spool.
+These are temporaries used for DKIM or malware processing, when that is used.
+They should be tidied up by normal operations; any old ones are probably
+relics of crashes and can be removed.
+.wen
+
 .section "Format of the -H file" "SECID282"
 .cindex "uid (user id)" "in spool file"
 .cindex "gid (group id)" "in spool file"
@@ -37817,8 +38246,8 @@ The address of an authenticated sender &-- the value of the
 &$authenticated_sender$& variable.
 
 .vitem "&%-body_linecount%&&~<&'number'&>"
-This records the number of lines in the body of the message, and is always
-present.
+This records the number of lines in the body of the message, and is
+present unless &%-spool_file_wireformat%& is.
 
 .vitem "&%-body_zerocount%&&~<&'number'&>"
 This records the number of binary zero bytes in the body of the message, and is
@@ -37900,6 +38329,14 @@ to ensure that the caller is displayed in queue listings).
 If a message was scanned by SpamAssassin, this is present. It records the value
 of &$spam_score_int$&.
 
+.new
+.vitem &%-spool_file_wireformat%&
+The -D file for this message is in wire-format (for ESMTP CHUNKING)
+rather than Unix-format.
+The line-ending is CRLF rather than newline.
+There is still, however, no leading-dot-stuffing.
+.wen
+
 .vitem &%-tls_certificate_verified%&
 A TLS certificate was received from the client that sent this message, and the
 certificate was verified by the server.
@@ -38007,6 +38444,20 @@ unqualified domain &'foundation'&.
 .ecindex IIDforspo2
 .ecindex IIDforspo3
 
+.new
+.section "Format of the -D file" "SECID282a"
+The data file is traditionally in Unix-standard format: lines are ended with
+an ASCII newline character.
+However, when the &%spool_wireformat%& main option is used some -D files
+can have an alternate format.
+This is flagged by a &%-spool_file_wireformat%& line in the corresponding -H file.
+The -D file lines (not including the first name-component line) are
+suitable for direct copying to the wire when transmitting using the
+ESMTP CHUNKING option, meaning lower processing overhead.
+Lines are terminated with an ASCII CRLF pair.
+There is no dot-stuffing (and no dot-termination).
+.wen
+
 . ////////////////////////////////////////////////////////////////////////////
 . ////////////////////////////////////////////////////////////////////////////
 
@@ -38022,14 +38473,14 @@ DKIM is documented in RFC 4871.
 DKIM support is compiled into Exim by default if TLS support is present.
 It can be disabled by setting DISABLE_DKIM=yes in &_Local/Makefile_&.
 
-Exim's DKIM implementation allows to
+Exim's DKIM implementation allows for
 .olist
-Sign outgoing messages: This function is implemented in the SMTP transport.
+Signing outgoing messages: This function is implemented in the SMTP transport.
 It can co-exist with all other Exim features
 (including transport filters)
 except cutthrough delivery.
 .next
-Verify signatures in incoming messages: This is implemented by an additional
+Verifying signatures in incoming messages: This is implemented by an additional
 ACL (acl_smtp_dkim), which can be called several times per message, with
 different signature contexts.
 .endlist
@@ -38058,24 +38509,29 @@ senders).
 .section "Signing outgoing messages" "SECDKIMSIGN"
 .cindex "DKIM" "signing"
 
-Signing is implemented by setting private options on the SMTP transport.
+Signing is enabled by setting private options on the SMTP transport.
 These options take (expandable) strings as arguments.
 
-.option dkim_domain smtp string&!! unset
-MANDATORY:
-The domain you want to sign with. The result of this expanded
-option is put into the &%$dkim_domain%& expansion variable.
+.option dkim_domain smtp string list&!! unset
+The domain(s) you want to sign with.
+.new
+After expansion, this can be a list.
+Each element in turn is put into the &%$dkim_domain%& expansion variable
+while expanding the remaining signing options.
+.wen
+If it is empty after expansion, DKIM signing is not done.
 
 .option dkim_selector smtp string&!! unset
-MANDATORY:
-This sets the key selector string. You can use the &%$dkim_domain%& expansion
-variable to look up a matching selector. The result is put in the expansion
+This sets the key selector string.
+You can use the &%$dkim_domain%& expansion variable to look up a matching selector.
+The result is put in the expansion
 variable &%$dkim_selector%& which may be used in the &%dkim_private_key%&
 option along with &%$dkim_domain%&.
+If the option is empty after expansion, DKIM signing is not done.
 
 .option dkim_private_key smtp string&!! unset
-MANDATORY:
-This sets the private key to use. You can use the &%$dkim_domain%& and
+This sets the private key to use.
+You can use the &%$dkim_domain%& and
 &%$dkim_selector%& expansion variables to determine the private key to use.
 The result can either
 .ilist
@@ -38088,16 +38544,15 @@ be "0", "false" or the empty string, in which case the message will not
 be signed. This case will not result in an error, even if &%dkim_strict%&
 is set.
 .endlist
+If the option is empty after expansion, DKIM signing is not done.
 
 .option dkim_canon smtp string&!! unset
-OPTIONAL:
 This option sets the canonicalization method used when signing a message.
 The DKIM RFC currently supports two methods: "simple" and "relaxed".
 The option defaults to "relaxed" when unset. Note: the current implementation
 only supports using the same canonicalization method for both headers and body.
 
 .option dkim_strict smtp string&!! unset
-OPTIONAL:
 This  option  defines  how  Exim  behaves  when  signing a message that
 should be signed fails for some reason.  When the expansion evaluates to
 either "1" or "true", Exim will defer. Otherwise Exim will send the message
@@ -38105,11 +38560,10 @@ unsigned. You can use the &%$dkim_domain%& and &%$dkim_selector%& expansion
 variables here.
 
 .option dkim_sign_headers smtp string&!! unset
-OPTIONAL:
-When set, this option must expand to (or be specified as) a colon-separated
+If set, this option must expand to (or be specified as) a colon-separated
 list of header names. Headers with these names will be included in the message
-signature. When unspecified, the header names recommended in RFC4871 will be
-used.
+signature.
+When unspecified, the header names recommended in RFC4871 will be used.
 
 
 .section "Verifying DKIM signatures in incoming mail" "SECID514"
@@ -38168,6 +38622,7 @@ available (from most to least important):
 The signer that is being evaluated in this ACL run. This can be a domain or
 an identity. This is one of the list items from the expanded main option
 &%dkim_verify_signers%& (see above).
+
 .vitem &%$dkim_verify_status%&
 A string describing the general status of the signature. One of
 .ilist
@@ -38182,6 +38637,7 @@ available in &%$dkim_verify_reason%&.
 .next
 &%pass%&: The signature passed verification. It is valid.
 .endlist
+
 .vitem &%$dkim_verify_reason%&
 A string giving a little bit more detail when &%$dkim_verify_status%& is either
 "fail" or "invalid". One of
@@ -38201,51 +38657,71 @@ could not be verified. This may mean that headers were modified,
 re-written or otherwise changed in a way which is incompatible with
 DKIM verification. It may of course also mean that the signature is forged.
 .endlist
+
 .vitem &%$dkim_domain%&
 The signing domain. IMPORTANT: This variable is only populated if there is
 an actual signature in the message for the current domain or identity (as
 reflected by &%$dkim_cur_signer%&).
+
 .vitem &%$dkim_identity%&
 The signing identity, if present. IMPORTANT: This variable is only populated
 if there is an actual signature in the message for the current domain or
 identity (as reflected by &%$dkim_cur_signer%&).
+
 .vitem &%$dkim_selector%&
 The key record selector string.
+
 .vitem &%$dkim_algo%&
 The algorithm used. One of 'rsa-sha1' or 'rsa-sha256'.
+
 .vitem &%$dkim_canon_body%&
 The body canonicalization method. One of 'relaxed' or 'simple'.
-.vitem &%dkim_canon_headers%&
+
+.vitem &%$dkim_canon_headers%&
 The header canonicalization method. One of 'relaxed' or 'simple'.
+
 .vitem &%$dkim_copiedheaders%&
 A transcript of headers and their values which are included in the signature
 (copied from the 'z=' tag of the signature).
+Note that RFC6376 requires that verification fail if the From: header is
+not included in the signature.  Exim does not enforce this; sites wishing
+strict enforcement should code the check explicitly.
+
 .vitem &%$dkim_bodylength%&
 The number of signed body bytes. If zero ("0"), the body is unsigned. If no
 limit was set by the signer, "9999999999999" is returned. This makes sure
 that this variable always expands to an integer value.
+
 .vitem &%$dkim_created%&
 UNIX timestamp reflecting the date and time when the signature was created.
 When this was not specified by the signer, "0" is returned.
+
 .vitem &%$dkim_expires%&
 UNIX timestamp reflecting the date and time when the signer wants the
 signature to be treated as "expired". When this was not specified by the
 signer, "9999999999999" is returned. This makes it possible to do useful
 integer size comparisons against this value.
+
 .vitem &%$dkim_headernames%&
 A colon-separated list of names of headers included in the signature.
+
 .vitem &%$dkim_key_testing%&
 "1" if the key record has the "testing" flag set, "0" if not.
+
 .vitem &%$dkim_key_nosubdomains%&
 "1" if the key record forbids subdomaining, "0" otherwise.
+
 .vitem &%$dkim_key_srvtype%&
 Service type (tag s=) from the key record. Defaults to "*" if not specified
 in the key record.
+
 .vitem &%$dkim_key_granularity%&
 Key granularity (tag g=) from the key record. Defaults to "*" if not specified
 in the key record.
+
 .vitem &%$dkim_key_notes%&
 Notes from the key record (tag n=).
+
 .vitem &%$dkim_key_length%&
 Number of bits in the key.
 .endlist
@@ -38260,13 +38736,16 @@ for a match against the domain or identity that the ACL is currently verifying
 verb to a group of domains or identities. For example:
 
 .code
-# Warn when Mail purportedly from GMail has no signature at all
-warn log_message = GMail sender without DKIM signature
+# Warn when Mail purportedly from GMail has no gmail signature
+warn log_message = GMail sender without gmail.com DKIM signature
      sender_domains = gmail.com
      dkim_signers = gmail.com
      dkim_status = none
 .endd
 
+Note that the above does not check for a total lack of DKIM signing;
+for that check for empty &$h_DKIM-Signature:$& in the data ACL.
+
 .vitem &%dkim_status%&
 ACL condition that checks a colon-separated list of possible DKIM verification
 results against the actual result of verification. This is typically used
@@ -38308,9 +38787,9 @@ To include this support, include &"SUPPORT_PROXY=yes"&
 in Local/Makefile.
 
 It was built on specifications from:
-http://haproxy.1wt.eu/download/1.5/doc/proxy-protocol.txt
+(&url(http://haproxy.1wt.eu/download/1.5/doc/proxy-protocol.txt)).
 That URL was revised in May 2014 to version 2 spec:
-http://git.1wt.eu/web?p=haproxy.git;a=commitdiff;h=afb768340c9d7e50d8e
+(&url(http://git.1wt.eu/web?p=haproxy.git;a=commitdiff;h=afb768340c9d7e50d8e)).
 
 The purpose of this facility is so that an application load balancer,
 such as HAProxy, can sit in front of several Exim servers
@@ -38324,21 +38803,26 @@ recorded in an ACL (example is below).
 Use of a proxy is enabled by setting the &%hosts_proxy%&
 main configuration option to a hostlist; connections from these
 hosts will use Proxy Protocol.
+Exim supports both version 1 and version 2 of the Proxy Protocol and
+automatically determines which version is in use.
+
+The Proxy Protocol header is the first data received on a TCP connection
+and is inserted before any TLS-on-connect handshake from the client; Exim
+negotiates TLS between Exim-as-server and the remote client, not between
+Exim and the proxy server.
 
-.new
 The following expansion variables are usable
 (&"internal"& and &"external"& here refer to the interfaces
 of the proxy):
 .display
 &'proxy_external_address   '& IP of host being proxied or IP of remote interface of proxy
 &'proxy_external_port      '& Port of host being proxied or Port on remote interface of proxy
-&'proxy_local_address '& IP of proxy server inbound or IP of local interface of proxy
-&'proxy_local_port    '& Port of proxy server inbound or Port on local interface of proxy
-&'proxy_session        '& boolean: SMTP connection via proxy
+&'proxy_local_address      '& IP of proxy server inbound or IP of local interface of proxy
+&'proxy_local_port         '& Port of proxy server inbound or Port on local interface of proxy
+&'proxy_session            '& boolean: SMTP connection via proxy
 .endd
 If &$proxy_session$& is set but &$proxy_external_address$& is empty
 there was a protocol error.
-.wen
 
 Since the real connections are all coming from the proxy, and the
 per host connection tracking is done before Proxy Protocol is
@@ -38446,6 +38930,10 @@ Exim has support for Internationalised mail names.
 To include this it must be built with SUPPORT_I18N and the libidn library.
 Standards supported are RFCs 2060, 5890, 6530 and 6533.
 
+If Exim is built with SUPPORT_I18N_2008 (in addition to SUPPORT_I18N, not
+instead of it) then IDNA2008 is supported; this adds an extra library
+requirement, upon libidn2.
+
 .section "MTA operations" SECTi18nMTA
 .cindex SMTPUTF8 "ESMTP option"
 The main configuration option &%smtputf8_advertise_hosts%& specifies
@@ -38559,7 +39047,7 @@ must be representable in UTF-16.
 .cindex events
 
 The events mechanism in Exim can be used to intercept processing at a number
-of points.  It was originally invented to giave a way to do customised logging
+of points.  It was originally invented to give a way to do customised logging
 actions (for example, to a database) but can also be used to modify some
 processing actions.
 
@@ -38598,7 +39086,7 @@ The current list of events is:
 &`msg:rcpt:host:defer    after    transport  `& per recipient per host
 &`msg:rcpt:defer         after    transport  `& per recipient
 &`msg:host:defer         after    transport  `& per attempt
-&`msg:fail:delivery      after    main       `& per recipient
+&`msg:fail:delivery      after    transport  `& per recipient
 &`msg:fail:internal      after    main       `& per recipient
 &`tcp:connect            before   transport  `& per connection
 &`tcp:close              after    transport  `& per connection
@@ -38615,10 +39103,15 @@ The second column in the table above describes whether the event fires
 before or after the action is associates with.  Those which fire before
 can be used to affect that action (more on this below).
 
+.new
+The third column in the table above says what section of the configumration
+should define the event action.
+.wen
+
 An additional variable, &$event_data$&, is filled with information varying
 with the event type:
 .display
-&`msg:delivery         `& smtp confirmation mssage
+&`msg:delivery         `& smtp confirmation message
 &`msg:rcpt:host:defer  `& error string
 &`msg:rcpt:defer       `& error string
 &`msg:host:defer       `& error string
@@ -38629,7 +39122,7 @@ with the event type:
 The :defer events populate one extra variable: &$event_defer_errno$&.
 
 For complex operations an ACL expansion can be used in &%event_action%&
-however due to the multiple contextx that Exim operates in during
+however due to the multiple contexts that Exim operates in during
 the course of its processing:
 .ilist
 variables set in transport events will not be visible outside that