Docs: add crossref

[exim.git] / doc / doc-docbook / spec.xfpt

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 1f5e295119726d9d868533f8a335e850e3bd75c6..8164dcd745a1728ecea77bad8456e387280d46c4 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -46,7 +46,7 @@
 . Update the Copyright year (only) when changing content.
 . /////////////////////////////////////////////////////////////////////////////
 
 . Update the Copyright year (only) when changing content.
 . /////////////////////////////////////////////////////////////////////////////
 

-.set previousversion "4.96"
+.set previousversion "4.97"

 .include ./local_params
 
 .set ACL "access control lists (ACLs)"
 .include ./local_params
 
 .set ACL "access control lists (ACLs)"


@@ -55,7 +55,7 @@
 .set drivernamemax "64"
 
 .macro copyyear
 .set drivernamemax "64"
 
 .macro copyyear

-2022
+2023

 .endmacro
 
 . /////////////////////////////////////////////////////////////////////////////
 .endmacro
 
 . /////////////////////////////////////////////////////////////////////////////


@@ -996,12 +996,9 @@ contains the number of seconds since the start of the epoch (the normal Unix
 way of representing the date and time of day).
 .next
 After the first hyphen, the next
 way of representing the date and time of day).
 .next
 After the first hyphen, the next

-.new

 eleven
 eleven

-.wen

 characters are the id of the process that received the message.
 .next
 characters are the id of the process that received the message.
 .next

-.new

 There are two different possibilities for the final four characters:
 .olist
 .oindex "&%localhost_number%&"
 There are two different possibilities for the final four characters:
 .olist
 .oindex "&%localhost_number%&"


@@ -1017,7 +1014,6 @@ If &%localhost_number%& is set, it is multiplied by
 500000 (250000) and added to
 the fractional part of the time, which in this case is in units of 2 us (4 us).
 .endlist
 500000 (250000) and added to
 the fractional part of the time, which in this case is in units of 2 us (4 us).
 .endlist

-.wen

 .endlist
 
 After a message has been received, Exim waits for the clock to tick at the
 .endlist
 
 After a message has been received, Exim waits for the clock to tick at the


@@ -2846,13 +2842,11 @@ of Exim is installed. It is not necessary to do this when other files that are
 referenced from the configuration (for example, alias files) are changed,
 because these are reread each time they are used.
 
 referenced from the configuration (for example, alias files) are changed,
 because these are reread each time they are used.
 

-.new

 Either a SIGTERM or a SIGINT signal should be used to cause the daemon
 to cleanly shut down.
 Subprocesses handling recceiving or delivering messages,
 or for scanning the queue,
 will not be affected by the termination of the daemon process.
 Either a SIGTERM or a SIGINT signal should be used to cause the daemon
 to cleanly shut down.
 Subprocesses handling recceiving or delivering messages,
 or for scanning the queue,
 will not be affected by the termination of the daemon process.

-.wen

 
 .cmdopt -bdf
 This option has the same effect as &%-bd%& except that it never disconnects
 
 .cmdopt -bdf
 This option has the same effect as &%-bd%& except that it never disconnects


@@ -2890,11 +2884,14 @@ defined and macros will be expanded.
 Because macros in the config file are often used for secrets, those are only
 available to admin users.
 
 Because macros in the config file are often used for secrets, those are only
 available to admin users.
 

-.new

 The word &"set"& at the start of a line, followed by a single space,
 is recognised specially as defining a value for a variable.
 The word &"set"& at the start of a line, followed by a single space,
 is recognised specially as defining a value for a variable.

-The syntax is otherwise the same as the ACL modifier &"set ="&.
+.new
+.cindex "tainted data" "expansion testing"
+If the sequence &",t"& is inserted before the space,
+the value is marked as tainted.

 .wen
 .wen

+The syntax is otherwise the same as the ACL modifier &"set ="&.

 
 .cmdopt -bem <&'filename'&>
 .cindex "testing" "string expansion"
 
 .cmdopt -bem <&'filename'&>
 .cindex "testing" "string expansion"


@@ -4450,7 +4447,6 @@ It is only relevant when the &%-bd%& (start listening daemon) option is also
 given.
 Normally the daemon creates this socket, unless a &%-oX%& and &*no*& &%-oP%&
 option is also present.
 given.
 Normally the daemon creates this socket, unless a &%-oX%& and &*no*& &%-oP%&
 option is also present.

-.new

 If this option is given then the socket will not be created.  This is required
 if the system is running multiple daemons, in which case it should
 be used on all.
 If this option is given then the socket will not be created.  This is required
 if the system is running multiple daemons, in which case it should
 be used on all.


@@ -4464,7 +4460,6 @@ caching compiled regexes
 .next
 obtaining a current queue size
 .endlist
 .next
 obtaining a current queue size
 .endlist

-.wen

 
 .cmdopt -pd
 .cindex "Perl" "starting the interpreter"
 
 .cmdopt -pd
 .cindex "Perl" "starting the interpreter"


@@ -4569,12 +4564,10 @@ delivered down a single SMTP
 .cindex "multiple SMTP deliveries"
 connection because of the hints that were set up during the first queue scan.
 
 .cindex "multiple SMTP deliveries"
 connection because of the hints that were set up during the first queue scan.
 

-.new

 Two-phase queue runs should be used on systems which, even intermittently,
 have a large queue (such as mailing-list operators).
 They may also be useful for hosts that are connected to the Internet
 intermittently.
 Two-phase queue runs should be used on systems which, even intermittently,
 have a large queue (such as mailing-list operators).
 They may also be useful for hosts that are connected to the Internet
 intermittently.

-.wen

 
 .vitem &%-q[q]i...%&
 .oindex "&%-qi%&"
 
 .vitem &%-q[q]i...%&
 .oindex "&%-qi%&"


@@ -4660,14 +4653,12 @@ combined daemon at system boot time is to use a command such as
 Such a daemon listens for incoming SMTP calls, and also starts a queue runner
 process every 30 minutes.
 
 Such a daemon listens for incoming SMTP calls, and also starts a queue runner
 process every 30 minutes.
 

-.new

 .cindex "named queues" "queue runners"
 It is possible to set up runners for multiple named queues within one daemon,
 For example:
 .code
 exim -qGhipri/2m -q10m -qqGmailinglist/1h
 .endd
 .cindex "named queues" "queue runners"
 It is possible to set up runners for multiple named queues within one daemon,
 For example:
 .code
 exim -qGhipri/2m -q10m -qqGmailinglist/1h
 .endd

-.wen

 
 When a daemon is started by &%-q%& with a time value, but without &%-bd%&, no
 pid file is written unless one is explicitly requested by the &%-oP%& option.
 
 When a daemon is started by &%-q%& with a time value, but without &%-bd%&, no
 pid file is written unless one is explicitly requested by the &%-oP%& option.


@@ -6756,11 +6747,11 @@ Exim variables you need to construct the database query.
 
 For the string-expansion kind of lookups, the query is given in the first
 bracketed argument of the &${lookup ...}$& expansion.
 
 For the string-expansion kind of lookups, the query is given in the first
 bracketed argument of the &${lookup ...}$& expansion.

-For the list-argument kind of lookup the quury is given by the remainder of the
+For the list-argument kind of lookup the query is given by the remainder of the

 list item after the first semicolon.
 
 .cindex "tainted data" "quoting for lookups"
 list item after the first semicolon.
 
 .cindex "tainted data" "quoting for lookups"

-If tainted data is used in the query then it should be quuted by
+If tainted data is used in the query then it should be quoted by

 using the &*${quote_*&<&'lookup-type'&>&*:*&<&'string'&>&*}*& expansion operator
 appropriate for the lookup.
 .endlist
 using the &*${quote_*&<&'lookup-type'&>&*:*&<&'string'&>&*}*& expansion operator
 appropriate for the lookup.
 .endlist


@@ -6910,8 +6901,8 @@ key is found. The first key that matches is used; there is no attempt to find a
 lookup types support only literal keys.
 
 &*Warning 2*&: In a host list, you must always use &(net-iplsearch)& so that
 lookup types support only literal keys.
 
 &*Warning 2*&: In a host list, you must always use &(net-iplsearch)& so that

-the implicit key is the host's IP address rather than its name (see section
-&<<SECThoslispatsikey>>&).
+the implicit key is the host's IP address rather than its name
+(see section &<<SECThoslispatsikey>>&).

 
 &*Warning 3*&: Do not use an IPv4-mapped IPv6 address for a key; use the
 IPv4, in dotted-quad form. (Exim converts IPv4-mapped IPv6 addresses to this
 
 &*Warning 3*&: Do not use an IPv4-mapped IPv6 address for a key; use the
 IPv4, in dotted-quad form. (Exim converts IPv4-mapped IPv6 addresses to this


@@ -7409,10 +7400,8 @@ For example, the way to write the NIS+ query is
 [name="${quote_nisplus:$local_part}"]
 .endd
 .cindex "tainted data" "in lookups"
 [name="${quote_nisplus:$local_part}"]
 .endd
 .cindex "tainted data" "in lookups"

-.new

 &*All*& tainted data used in a query-style lookup must be quoted
 using a mechanism appropriate for the lookup type.
 &*All*& tainted data used in a query-style lookup must be quoted
 using a mechanism appropriate for the lookup type.

-.wen

 See chapter &<<CHAPexpand>>& for full coverage of string expansions. The quote
 operator can be used for all lookup types, but has no effect for single-key
 lookups, since no quoting is ever needed in their key strings.
 See chapter &<<CHAPexpand>>& for full coverage of string expansions. The quote
 operator can be used for all lookup types, but has no effect for single-key
 lookups, since no quoting is ever needed in their key strings.


@@ -8172,13 +8161,20 @@ option, you can still update it by a query of this form:
 ${lookup pgsql,servers=master/db/name/pw {UPDATE ...} }
 .endd
 
 ${lookup pgsql,servers=master/db/name/pw {UPDATE ...} }
 .endd
 

-An older syntax places the servers specification before the query,
+.new
+A now-deprecated syntax places the servers specification before the query,

 semicolon separated:
 .code
 ${lookup mysql{servers=master; UPDATE ...} }
 .endd
 semicolon separated:
 .code
 ${lookup mysql{servers=master; UPDATE ...} }
 .endd

-The new version avoids potential issues with tainted
-arguments in the query, for explicit expansion.
+The new version avoids issues with tainted
+arguments explicitly expanded as part of the query.
+The entire string within the braces becomes tainted,
+including the server sepcification - which is not permissible.
+If the older sytax is used, a warning message will be logged.
+This syntax will be removed in a future release.
+.wen
+

 &*Note*&: server specifications in list-style lookups are still problematic.
 
 
 &*Note*&: server specifications in list-style lookups are still problematic.
 
 


@@ -8234,7 +8230,7 @@ daemon as in the other SQL databases.
 .oindex &%sqlite_dbfile%&
 There are two ways of
 specifying the file.
 .oindex &%sqlite_dbfile%&
 There are two ways of
 specifying the file.

-The first is is by using the &%sqlite_dbfile%& main option.
+The first is by using the &%sqlite_dbfile%& main option.

 The second, which allows separate files for each query,
 is to use an option appended, comma-separated, to the &"sqlite"&
 lookup type word.  The option is the word &"file"&, then an equals,
 The second, which allows separate files for each query,
 is to use an option appended, comma-separated, to the &"sqlite"&
 lookup type word.  The option is the word &"file"&, then an equals,


@@ -8355,6 +8351,9 @@ type of match and is given below as the &*value*& information.
 .section "Expansion of lists" "SECTlistexpand"
 .cindex "expansion" "of lists"
 Each list is expanded as a single string before it is used.
 .section "Expansion of lists" "SECTlistexpand"
 .cindex "expansion" "of lists"
 Each list is expanded as a single string before it is used.

+.cindex "tainted data" tracking
+&*Note*&: As a result, if any componend was tainted then the
+entire result string becomes tainted.

 
 &'Exception: the router headers_remove option, where list-item
 splitting is done before string-expansion.'&
 
 &'Exception: the router headers_remove option, where list-item
 splitting is done before string-expansion.'&


@@ -9236,8 +9235,9 @@ is not used.
 
 &*Reminder*&: With this kind of pattern, you must have host &'names'& as
 keys in the file, not IP addresses. If you want to do lookups based on IP
 
 &*Reminder*&: With this kind of pattern, you must have host &'names'& as
 keys in the file, not IP addresses. If you want to do lookups based on IP

-addresses, you must precede the search type with &"net-"& (see section
-&<<SECThoslispatsikey>>&). There is, however, no reason why you could not use
+addresses, you must precede the search type with &"net-"&
+(see section &<<SECThoslispatsikey>>&).
+There is, however, no reason why you could not use

 two items in the same list, one doing an address lookup and one doing a name
 lookup, both using the same file.
 
 two items in the same list, one doing an address lookup and one doing a name
 lookup, both using the same file.
 


@@ -9550,6 +9550,9 @@ start of a portion of the string that is interpreted and replaced as described
 below in section &<<SECTexpansionitems>>& onwards. Backslash is used as an
 escape character, as described in the following section.
 
 below in section &<<SECTexpansionitems>>& onwards. Backslash is used as an
 escape character, as described in the following section.
 

+.cindex "tainted data" tracking
+If any porttion of the result string is tainted, the entire result is.
+

 Whether a string is expanded depends upon the context.  Usually this is solely
 dependent upon the option for which a value is sought; in this documentation,
 options for which string expansion is performed are marked with &dagger; after
 Whether a string is expanded depends upon the context.  Usually this is solely
 dependent upon the option for which a value is sought; in this documentation,
 options for which string expansion is performed are marked with &dagger; after


@@ -9622,7 +9625,6 @@ value. Nevertheless the &%-be%& option can be useful for checking out file and
 database lookups, and the use of expansion operators such as &%sg%&, &%substr%&
 and &%nhash%&.
 
 database lookups, and the use of expansion operators such as &%sg%&, &%substr%&
 and &%nhash%&.
 

-.new

 When reading lines from the standard input,
 macros can be defined and ACL variables can be set.
 For example:
 When reading lines from the standard input,
 macros can be defined and ACL variables can be set.
 For example:


@@ -9631,7 +9633,6 @@ MY_MACRO = foo
 set acl_m_myvar = bar
 .endd
 Such macros and variables can then be used in later input lines.
 set acl_m_myvar = bar
 .endd
 Such macros and variables can then be used in later input lines.

-.wen

 
 Exim gives up its root privilege when it is called with the &%-be%& option, and
 instead runs under the uid and gid it was called with, to prevent users from
 
 Exim gives up its root privilege when it is called with the &%-be%& option, and
 instead runs under the uid and gid it was called with, to prevent users from


@@ -9748,9 +9749,7 @@ Example use (as an ACL modifier):
       add_header = :at_start:${authresults {$primary_hostname}}
 .endd
 This is safe even if no authentication results are available
       add_header = :at_start:${authresults {$primary_hostname}}
 .endd
 This is safe even if no authentication results are available

-.new

 and would generally be placed in the DATA ACL.
 and would generally be placed in the DATA ACL.

-.wen

 
 
 .vitem "&*${certextract{*&<&'field'&>&*}{*&<&'certificate'&>&*}&&&
 
 
 .vitem "&*${certextract{*&<&'field'&>&*}{*&<&'certificate'&>&*}&&&


@@ -10010,9 +10009,7 @@ default, but the separator can be changed in the usual way (&<<SECTlistsepchange
 For each item
 in this list, its value is placed in &$item$&, and then the condition is
 evaluated.
 For each item
 in this list, its value is placed in &$item$&, and then the condition is
 evaluated.

-.new

 Any modification of &$value$& by this evaluation is discarded.
 Any modification of &$value$& by this evaluation is discarded.

-.wen

 If the condition is true, &$item$& is added to the output as an
 item in a new list; if the condition is false, the item is discarded. The
 separator used for the output list is the same as the one used for the
 If the condition is true, &$item$& is added to the output as an
 item in a new list; if the condition is false, the item is discarded. The
 separator used for the output list is the same as the one used for the


@@ -10633,7 +10630,7 @@ expansion items.
 This item inserts &"raw"& header lines. It is described with the &%header%&
 expansion item in section &<<SECTexpansionitems>>& above.
 
 This item inserts &"raw"& header lines. It is described with the &%header%&
 expansion item in section &<<SECTexpansionitems>>& above.
 

-.vitem "&*${run<&'options'&> {*&<&'command&~arg&~list'&>&*}{*&<&'string1'&>&*}&&&
+.vitem "&*${run<&'options'&> {*&<&'command&~string'&>&*}{*&<&'string1'&>&*}&&&

         {*&<&'string2'&>&*}}*&"
 .cindex "expansion" "running a command"
 .cindex "&%run%& expansion item"
         {*&<&'string2'&>&*}}*&"
 .cindex "expansion" "running a command"
 .cindex "&%run%& expansion item"


@@ -10642,8 +10639,8 @@ One option is supported after the word &'run'&, comma-separated
 and without whitespace.
 
 If the option &'preexpand'& is not used,
 and without whitespace.
 
 If the option &'preexpand'& is not used,

-the command string is split into individual arguments by spaces
-and then each argument is expanded.
+the command string before expansion is split into individual arguments by spaces
+and then each argument is separately expanded.

 Then the command is run
 in a separate process, but under the same uid and gid.  As in other command
 executions from Exim, a shell is not used by default. If the command requires
 Then the command is run
 in a separate process, but under the same uid and gid.  As in other command
 executions from Exim, a shell is not used by default. If the command requires


@@ -10655,9 +10652,9 @@ potential attacker;
 a careful assessment for security vulnerabilities should be done.
 
 If the option &'preexpand'& is used,
 a careful assessment for security vulnerabilities should be done.
 
 If the option &'preexpand'& is used,

-the command and its arguments are first expanded as one string. The result is
-split apart into individual arguments by spaces, and then the command is run
-as above.
+the command string is first expanded as a whole.
+The expansion result is split apart into individual arguments by spaces,
+and then the command is run as above.

 Since the arguments are split by spaces, when there is a variable expansion
 which has an empty result, it will cause the situation that the argument will
 simply be omitted when the program is actually executed by Exim. If the
 Since the arguments are split by spaces, when there is a variable expansion
 which has an empty result, it will cause the situation that the argument will
 simply be omitted when the program is actually executed by Exim. If the


@@ -11122,7 +11119,6 @@ abbreviation &%h%& can be used when &%hash%& is used as an operator.
 
 
 
 
 
 

-.new

 .vitem &*${headerwrap_*&<&'cols'&>&*_*&<&'limit'&>&*:*&<&'string'&>&*}*&
 .cindex header "wrapping operator"
 .cindex expansion "header wrapping"
 .vitem &*${headerwrap_*&<&'cols'&>&*_*&<&'limit'&>&*:*&<&'string'&>&*}*&
 .cindex header "wrapping operator"
 .cindex expansion "header wrapping"


@@ -11136,7 +11132,6 @@ column number is reached.
 Whitespace at a chosen wrap point is removed.
 A line-wrap consists of a newline followed by a tab,
 and the tab is counted as 8 columns.
 Whitespace at a chosen wrap point is removed.
 A line-wrap consists of a newline followed by a tab,
 and the tab is counted as 8 columns.

-.wen

 
 
 
 
 
 


@@ -12062,7 +12057,8 @@ where the first item in the list is the empty string.
 .next
 The item @[] matches any of the local host's interface addresses.
 .next
 .next
 The item @[] matches any of the local host's interface addresses.
 .next

-Single-key lookups are assumed to be like &"net-"& style lookups in host lists,
+Single-key lookups are assumed to be like &"net-"& style lookups in host lists
+(see section &<<SECThoslispatsikey>>&),

 even if &`net-`& is not specified. There is never any attempt to turn the IP
 address into a host name. The most common type of linear search for
 &*match_ip*& is likely to be &*iplsearch*&, in which the file can contain CIDR
 even if &`net-`& is not specified. There is never any attempt to turn the IP
 address into a host name. The most common type of linear search for
 &*match_ip*& is likely to be &*iplsearch*&, in which the file can contain CIDR


@@ -13436,7 +13432,6 @@ The main use of this variable is expected to be to distinguish between
 rejections of MAIL and rejections of RCPT.
 
 .tvar &$recipients$&
 rejections of MAIL and rejections of RCPT.
 
 .tvar &$recipients$&

-.new

 .tvar &$recipients_list$&
 These variables both contain the envelope recipients for a message.
 
 .tvar &$recipients_list$&
 These variables both contain the envelope recipients for a message.
 


@@ -13445,7 +13440,6 @@ The first uses a comma and a space separate the addresses in the replacement tex
 this variable is not intended for further processing.
 
 The second is a proper Exim list; colon-separated.
 this variable is not intended for further processing.
 
 The second is a proper Exim list; colon-separated.

-.wen

 
 However, the variables
 are not generally available, to prevent exposure of Bcc recipients in
 
 However, the variables
 are not generally available, to prevent exposure of Bcc recipients in


@@ -14985,6 +14979,7 @@ See also the &'Policy controls'& section above.
 .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"
 .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"

+.row &%limits_advertise_hosts%&      "advertise LIMITS to these hosts"

 .row &%pipelining_advertise_hosts%&  "advertise pipelining to these hosts"
 .row &%pipelining_connect_advertise_hosts%& "advertise pipelining to these hosts"
 .row &%prdr_enable%&                 "advertise PRDR to all hosts"
 .row &%pipelining_advertise_hosts%&  "advertise pipelining to these hosts"
 .row &%pipelining_connect_advertise_hosts%& "advertise pipelining to these hosts"
 .row &%prdr_enable%&                 "advertise PRDR to all hosts"


@@ -15732,9 +15727,9 @@ the ACL once for each signature in the message.
 See section &<<SECDKIMVFY>>&.
 
 
 See section &<<SECDKIMVFY>>&.
 
 

-.option dmarc_forensic_sender main string&!! unset
-.option dmarc_history_file main string unset
-.option dmarc_tld_file main string unset
+.option dmarc_forensic_sender main string&!! unset &&&
+        dmarc_history_file main string unset &&&
+        dmarc_tld_file main string unset

 .cindex DMARC "main section options"
 These options control DMARC processing.
 See section &<<SECDMARC>>& for details.
 .cindex DMARC "main section options"
 These options control DMARC processing.
 See section &<<SECDMARC>>& for details.


@@ -15754,10 +15749,8 @@ by a setting such as this:
 dns_again_means_nonexist = *.in-addr.arpa
 .endd
 This option applies to all DNS lookups that Exim does,
 dns_again_means_nonexist = *.in-addr.arpa
 .endd
 This option applies to all DNS lookups that Exim does,

-.new

 except for TLSA lookups (where knowing about such failures
 is security-relevant).
 except for TLSA lookups (where knowing about such failures
 is security-relevant).

-.wen

 It also applies when the
 &[gethostbyname()]& or &[getipnodebyname()]& functions give temporary errors,
 since these are most likely to be caused by DNS lookup problems. The
 It also applies when the
 &[gethostbyname()]& or &[getipnodebyname()]& functions give temporary errors,
 since these are most likely to be caused by DNS lookup problems. The


@@ -16337,10 +16330,8 @@ This option is obsolete, and retained only for backward compatibility, because
 nowadays the ACL specified by &%acl_smtp_connect%& can also reject incoming
 connections immediately.
 
 nowadays the ACL specified by &%acl_smtp_connect%& can also reject incoming
 connections immediately.
 

-.new

 If the connection is on a TLS-on-connect port then the TCP connection is
 just dropped.  Otherwise, an SMTP error is sent first.
 If the connection is on a TLS-on-connect port then the TCP connection is
 just dropped.  Otherwise, an SMTP error is sent first.

-.wen

 
 The ability to give an immediate rejection (either by this option or using an
 ACL) is provided for use in unusual cases. Many hosts will just try again,
 
 The ability to give an immediate rejection (either by this option or using an
 ACL) is provided for use in unusual cases. Many hosts will just try again,


@@ -16361,10 +16352,8 @@ local processes, you must create a host list with an empty item. For example:
 .code
 hosts_connection_nolog = :
 .endd
 .code
 hosts_connection_nolog = :
 .endd

-.new

 The hosts affected by this option also do not log "no MAIL in SMTP connection"
 lines, as may commonly be produced by a monitoring system.
 The hosts affected by this option also do not log "no MAIL in SMTP connection"
 lines, as may commonly be produced by a monitoring system.

-.wen

 
 
 .option hosts_require_alpn main "host list&!!" unset
 
 
 .option hosts_require_alpn main "host list&!!" unset


@@ -16575,6 +16564,18 @@ has been built with LDAP support.
 
 
 
 
 
 

+.new
+.option limits_advertise_hosts main "host list&!!" *
+.cindex LIMITS "suppressing advertising"
+.cindex "ESMTP extensions" LIMITS
+This option can be used to suppress the advertisement of the SMTP
+LIMITS extension (RFC 9422) to specific hosts.
+If permitted, Exim as a servier will advertise in the EHLO response
+the limit for RCPT commands set by the &%recipients_max%& option (if it is set)
+and the limit for MAIL commands set by the &%smtp_accept_max_per_connection%&
+option.
+,wen
+

 .option local_from_check main boolean true
 .cindex "&'Sender:'& header line" "disabling addition of"
 .cindex "&'From:'& header line" "disabling checking of"
 .option local_from_check main boolean true
 .cindex "&'Sender:'& header line" "disabling addition of"
 .cindex "&'From:'& header line" "disabling checking of"


@@ -16672,15 +16673,21 @@ See also the ACL modifier &`control = suppress_local_fixups`&. Section
 .option localhost_number main string&!! unset
 .cindex "host" "locally unique number for"
 .cindex "message ids" "with multiple hosts"
 .option localhost_number main string&!! unset
 .cindex "host" "locally unique number for"
 .cindex "message ids" "with multiple hosts"

+.cindex multiple "systems sharing a spool"
+.cindex "multiple hosts" "sharing a spool"
+.cindex "shared spool directory"
+.cindex "spool directory" sharing

 .vindex "&$localhost_number$&"
 Exim's message ids are normally unique only within the local host. If
 .vindex "&$localhost_number$&"
 Exim's message ids are normally unique only within the local host. If

-uniqueness among a set of hosts is required, each host must set a different
+uniqueness among a set of hosts is required
+(eg. because they share a spool directory),
+each host must set a different

 value for the &%localhost_number%& option. The string is expanded immediately
 after reading the configuration file (so that a number can be computed from the
 host name, for example) and the result of the expansion must be a number in the
 range 0&--16 (or 0&--10 on operating systems with case-insensitive file
 systems). This is available in subsequent string expansions via the variable
 value for the &%localhost_number%& option. The string is expanded immediately
 after reading the configuration file (so that a number can be computed from the
 host name, for example) and the result of the expansion must be a number in the
 range 0&--16 (or 0&--10 on operating systems with case-insensitive file
 systems). This is available in subsequent string expansions via the variable

-&$localhost_number$&. When &%localhost_number is set%&, the final two
+&$localhost_number$&. When &%localhost_number%& is set, the final four

 characters of the message id, instead of just being a fractional part of the
 time, are computed from the time and the local host number as described in
 section &<<SECTmessiden>>&.
 characters of the message id, instead of just being a fractional part of the
 time, are computed from the time and the local host number as described in
 section &<<SECTmessiden>>&.


@@ -17036,7 +17043,6 @@ to be used in conjunction with &(oracle)& lookups (see section &<<SECID72>>&).
 The option is available only if Exim has been built with Oracle support.
 
 
 The option is available only if Exim has been built with Oracle support.
 
 

-.new

 .option panic_coredump main boolean false
 This option is rarely needed but can help for some debugging investigations.
 If set, when an internal error is detected by Exim which is sufficient
 .option panic_coredump main boolean false
 This option is rarely needed but can help for some debugging investigations.
 If set, when an internal error is detected by Exim which is sufficient


@@ -17047,7 +17053,6 @@ then a coredump is requested.
 Note that most systems require additional administrative configuration
 to permit write a core file for a setuid program, which is Exim's
 common installed configuration.
 Note that most systems require additional administrative configuration
 to permit write a core file for a setuid program, which is Exim's
 common installed configuration.

-.wen

 
 .option percent_hack_domains main "domain list&!!" unset
 .cindex "&""percent hack""&"
 
 .option percent_hack_domains main "domain list&!!" unset
 .cindex "&""percent hack""&"


@@ -17474,16 +17479,26 @@ or if the message was submitted locally (not using TCP/IP), and the &%-bnq%&
 option was not set.
 
 
 option was not set.
 
 

-.option recipients_max main integer 50000
+.option recipients_max main integer&!! 50000

 .cindex "limit" "number of recipients"
 .cindex "recipient" "maximum number"
 .cindex "limit" "number of recipients"
 .cindex "recipient" "maximum number"

-If this option is set greater than zero, it specifies the maximum number of
+If the value resulting from expanding this option
+is set greater than zero, it specifies the maximum number of

 original recipients for any message. Additional recipients that are generated
 by aliasing or forwarding do not count. SMTP messages get a 452 response for
 all recipients over the limit; earlier recipients are delivered as normal.
 Non-SMTP messages with too many recipients are failed, and no deliveries are
 done.
 
 original recipients for any message. Additional recipients that are generated
 by aliasing or forwarding do not count. SMTP messages get a 452 response for
 all recipients over the limit; earlier recipients are delivered as normal.
 Non-SMTP messages with too many recipients are failed, and no deliveries are
 done.
 

+.new
+For SMTP message the expansion is done after the connection is
+accepted (but before any SMTP conversation) and may depend on
+the IP addresses and port numbers of the connection.
+&*Note*&: If an expansion is used for the option,
+care should be taken that a resonable value results for
+non-SMTP messages.
+.wen
+

 .cindex "RCPT" "maximum number of incoming"
 &*Note*&: The RFCs specify that an SMTP server should accept at least 100
 RCPT commands in a single message.
 .cindex "RCPT" "maximum number of incoming"
 &*Note*&: The RFCs specify that an SMTP server should accept at least 100
 RCPT commands in a single message.


@@ -17830,10 +17845,8 @@ positive response to an SMTP connection. The default setting is:
 smtp_banner = $smtp_active_hostname ESMTP Exim \
   $version_number $tod_full
 .endd
 smtp_banner = $smtp_active_hostname ESMTP Exim \
   $version_number $tod_full
 .endd

-.new

 Failure to expand the string causes a panic error;
 a forced fail just closes the connection.
 Failure to expand the string causes a panic error;
 a forced fail just closes the connection.

-.wen

 If you want to create a
 multiline response to the initial SMTP connection, use &"\n"& in the string at
 appropriate points, but not at the end. Note that the 220 code is not included
 If you want to create a
 multiline response to the initial SMTP connection, use &"\n"& in the string at
 appropriate points, but not at the end. Note that the 220 code is not included


@@ -18579,9 +18592,7 @@ It has no effect when Exim is used with GnuTLS
 &%tls_require_ciphers%& option).
 
 After expansion it must contain
 &%tls_require_ciphers%& option).
 
 After expansion it must contain

-.new

 one or (only for OpenSSL versiona 1.1.1 onwards) more
 one or (only for OpenSSL versiona 1.1.1 onwards) more

-.wen

 EC curve names, such as &`prime256v1`&, &`secp384r1`&, or &`P-521`&.
 Consult your OpenSSL manual for valid curve names.
 
 EC curve names, such as &`prime256v1`&, &`secp384r1`&, or &`P-521`&.
 Consult your OpenSSL manual for valid curve names.
 


@@ -18589,9 +18600,7 @@ 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.
 
 &`auto`& selects &`prime256v1`&. For more recent OpenSSL versions
 &`auto`& tells the library to choose.
 

-.new

 If the option expands to an empty string, the effect is undefined.
 If the option expands to an empty string, the effect is undefined.

-.wen

 
 
 .option tls_ocsp_file main string&!! unset
 
 
 .option tls_ocsp_file main string&!! unset


@@ -22832,8 +22841,11 @@ If unset, or expanding to an empty string, no filtering is done.
 When the message is about to be written out, the command specified by
 &%transport_filter%& is started up in a separate, parallel process, and
 the entire message, including the header lines, is passed to it on its standard
 When the message is about to be written out, the command specified by
 &%transport_filter%& is started up in a separate, parallel process, and
 the entire message, including the header lines, is passed to it on its standard

-input (this in fact is done from a third process, to avoid deadlock). The
-command must be specified as an absolute path.
+input (this in fact is done from a third process, to avoid deadlock).
+The command must be specified as an absolute path.
+
+The process run by the command must use its standard input as the message
+data to be transformed, and write the results on its standard output.

 
 The lines of the message that are written to the transport filter are
 terminated by newline (&"\n"&). The message is passed to the filter before any
 
 The lines of the message that are written to the transport filter are
 terminated by newline (&"\n"&). The message is passed to the filter before any


@@ -24868,7 +24880,7 @@ Exim, and each argument is separately expanded, as described in section
 No part of the resulting command may be tainted.
 
 
 No part of the resulting command may be tainted.
 
 

-.option environment pipe string&!! unset
+.option environment pipe "string list&!!" unset

 .cindex "&(pipe)& transport" "environment for command"
 .cindex "environment" "&(pipe)& transport"
 This option is used to add additional variables to the environment in which the
 .cindex "&(pipe)& transport" "environment for command"
 .cindex "environment" "&(pipe)& transport"
 This option is used to add additional variables to the environment in which the


@@ -25374,6 +25386,13 @@ over a single TCP/IP connection. If the value is zero, there is no limit.
 For testing purposes, this value can be overridden by the &%-oB%& command line
 option.
 
 For testing purposes, this value can be overridden by the &%-oB%& command line
 option.
 

+.new
+.cindex "ESMTP extensions" LIMITS
+If the peer advertises a LIMITS extension with a MAILMAX value,
+and either TLSS is in use or was not advertised,
+that value also constrains the result of this option.
+.wen
+

 
 .option dane_require_tls_ciphers smtp string&!! unset
 .cindex "TLS" "requiring specific ciphers for DANE"
 
 .option dane_require_tls_ciphers smtp string&!! unset
 .cindex "TLS" "requiring specific ciphers for DANE"


@@ -25586,15 +25605,24 @@ load-balancer, matching the session stored in the client's cache.
 
 Exim can pull out a server name, if there is one, from the response to the
 client's SMTP EHLO command.
 
 Exim can pull out a server name, if there is one, from the response to the
 client's SMTP EHLO command.

-The default value of this option:
+For normal STARTTLS use, the default value of this option:

 .code
     ${if and { {match {$host} {.outlook.com\$}} \
                {match {$item} {\N^250-([\w.]+)\s\N}} \
             } {$1}}
 .endd
 suffices for one known case.
 .code
     ${if and { {match {$host} {.outlook.com\$}} \
                {match {$item} {\N^250-([\w.]+)\s\N}} \
             } {$1}}
 .endd
 suffices for one known case.

+

 During the expansion of this option the &$item$& variable will have the
 server's EHLO response.
 During the expansion of this option the &$item$& variable will have the
 server's EHLO response.

+
+.new
+For TLS-on-connect connections we do not have an EHLO
+response to use. Because of this the default value of this option is
+set to a static string for those cases, meaning that resumption will
+always be attempted if permitted by the &%tls_resumption_hosts%& option.
+.wen
+

 The result of the option expansion is included in the key used to store and
 retrieve the TLS session, for session resumption.
 
 The result of the option expansion is included in the key used to store and
 retrieve the TLS session, for session resumption.
 


@@ -25783,11 +25811,9 @@ Exim will request a Certificate Status on a
 TLS session for any host that matches this list.
 &%tls_verify_certificates%& should also be set for the transport.
 
 TLS session for any host that matches this list.
 &%tls_verify_certificates%& should also be set for the transport.
 

-.new

 The default is &"**"& if DANE is not in use for the connection,
 or if DANE-TA us used.
 It is empty if DANE-EE is used.
 The default is &"**"& if DANE is not in use for the connection,
 or if DANE-TA us used.
 It is empty if DANE-EE is used.

-.wen

 
 .option hosts_require_alpn smtp "host list&!!" unset
 .cindex ALPN "require negotiation in client"
 
 .option hosts_require_alpn smtp "host list&!!" unset
 .cindex ALPN "require negotiation in client"


@@ -25933,25 +25959,30 @@ has advertised support for IGNOREQUOTA in its response to the LHLO command.
 .option max_rcpt smtp integer&!! 100
 .cindex "RCPT" "maximum number of outgoing"
 This option,
 .option max_rcpt smtp integer&!! 100
 .cindex "RCPT" "maximum number of outgoing"
 This option,

-.new

 after expansion,
 after expansion,

-.wen

 limits the number of RCPT commands that are sent in a single
 SMTP message transaction.
 A value setting of zero disables the limit.
 
 limits the number of RCPT commands that are sent in a single
 SMTP message transaction.
 A value setting of zero disables the limit.
 

-.new

 If a constant is given,
 If a constant is given,

-.wen

 each set of addresses is treated independently, and
 so can cause parallel connections to the same host if &%remote_max_parallel%&
 permits this.
 
 each set of addresses is treated independently, and
 so can cause parallel connections to the same host if &%remote_max_parallel%&
 permits this.
 

+.new
+.cindex "ESMTP extensions" LIMITS
+If the peer advertises a LIMITS extension with a RCPTMAX value,
+and either TLSS is in use or was not advertised,
+that value also constrains the result of this option
+and no parallel connections will be caused on meeting the RCPTMAX limit.
+.wen
+

 
 .option message_linelength_limit smtp integer 998
 .cindex "line length" limit
 This option sets the maximum line length, in bytes, that the transport
 will send.  Any messages with lines exceeding the given value
 
 .option message_linelength_limit smtp integer 998
 .cindex "line length" limit
 This option sets the maximum line length, in bytes, that the transport
 will send.  Any messages with lines exceeding the given value

+(before a transport filter, if any)

 will fail and a failure-DSN ("bounce") message will if possible be returned
 to the sender.
 The default value is that defined by the SMTP standards.
 will fail and a failure-DSN ("bounce") message will if possible be returned
 to the sender.
 The default value is that defined by the SMTP standards.


@@ -25977,6 +26008,14 @@ If the connection is DANE-enabled then this option is ignored;
 only messages having the domain used for the DANE TLSA lookup are
 sent on the connection.
 
 only messages having the domain used for the DANE TLSA lookup are
 sent on the connection.
 

+.new
+.cindex "ESMTP extensions" LIMITS
+If the peer advertises a LIMITS extension with a RCPTDOMAINMAX value,
+and either TLSS is in use or was not advertised,
+this option is regarded as being false.
+.wen
+
+

 .option port smtp string&!! "see below"
 .cindex "port" "sending TCP/IP"
 .cindex "TCP/IP" "setting outgoing port"
 .option port smtp string&!! "see below"
 .cindex "port" "sending TCP/IP"
 .cindex "TCP/IP" "setting outgoing port"


@@ -27753,7 +27792,6 @@ no successful authentication.
 Successful authentication sets up information used by the
 &%authresults%& expansion item.
 
 Successful authentication sets up information used by the
 &%authresults%& expansion item.
 

-.new

 .cindex authentication "failure event, server"
 If an authenticator is run and does not succeed,
 an event (see &<<CHAPevents>>&) of type "auth:fail" is raised.
 .cindex authentication "failure event, server"
 If an authenticator is run and does not succeed,
 an event (see &<<CHAPevents>>&) of type "auth:fail" is raised.


@@ -27764,7 +27802,6 @@ will be valid.
 If the event is serviced and a string is returned then the string will be logged
 instead of the default log line.
 See <<CHAPevents>> for details on events.
 If the event is serviced and a string is returned then the string will be logged
 instead of the default log line.
 See <<CHAPevents>> for details on events.

-.wen

 
 
 .section "Testing server authentication" "SECID169"
 
 
 .section "Testing server authentication" "SECID169"


@@ -27843,7 +27880,6 @@ Exim abandons trying to send the message to the host for the moment. It will
 try again later. If there are any backup hosts available, they are tried in the
 usual way.
 
 try again later. If there are any backup hosts available, they are tried in the
 usual way.
 

-.new

 .next
 .cindex authentication "failure event, client"
 If the response to authentication is a permanent error (5&'xx'& code),
 .next
 .cindex authentication "failure event, client"
 If the response to authentication is a permanent error (5&'xx'& code),


@@ -27853,7 +27889,6 @@ While the event is being processed the variable
 will be valid.
 If the event is serviced and a string is returned then the string will be logged.
 See <<CHAPevents>> for details on events.
 will be valid.
 If the event is serviced and a string is returned then the string will be logged.
 See <<CHAPevents>> for details on events.

-.wen

 
 .next
 If the response to authentication is a permanent error (5&'xx'& code), Exim
 
 .next
 If the response to authentication is a permanent error (5&'xx'& code), Exim


@@ -28433,11 +28468,9 @@ dovecot_ntlm:
   server_set_id = $auth1
 .endd
 
   server_set_id = $auth1
 .endd
 

-.new

 &*Note*&: plaintext authentication methods such as PLAIN and LOGIN
 should not be advertised on cleartext SMTP connections.
 See the discussion in section &<<SECTplain_TLS>>&.
 &*Note*&: plaintext authentication methods such as PLAIN and LOGIN
 should not be advertised on cleartext SMTP connections.
 See the discussion in section &<<SECTplain_TLS>>&.

-.wen

 
 If the SMTP connection is encrypted, or if &$sender_host_address$& is equal to
 &$received_ip_address$& (that is, the connection is local), the &"secured"&
 
 If the SMTP connection is encrypted, or if &$sender_host_address$& is equal to
 &$received_ip_address$& (that is, the connection is local), the &"secured"&


@@ -29246,8 +29279,8 @@ When using OpenSSL, this option is ignored.
 (If an API is found to let OpenSSL be configured in this way,
 let the Exim Maintainers know and we'll likely use it).
 .next
 (If an API is found to let OpenSSL be configured in this way,
 let the Exim Maintainers know and we'll likely use it).
 .next

-With GnuTLS, if an explicit list is used for the &%tls_privatekey%& main option
-main option, it must be ordered to match the &%tls_certificate%& list.
+With GnuTLS, if an explicit list is used for the &%tls_privatekey%& main option,
+it must be ordered to match the &%tls_certificate%& list.

 .next
 Some other recently added features may only be available in one or the other.
 This should be documented with the feature.  If the documentation does not
 .next
 Some other recently added features may only be available in one or the other.
 This should be documented with the feature.  If the documentation does not


@@ -30341,7 +30374,7 @@ DNSSEC.
 .next
 Add TLSA DNS records.  These say what the server certificate for a TLS connection should be.
 .next
 .next
 Add TLSA DNS records.  These say what the server certificate for a TLS connection should be.
 .next

-Offer a server certificate, or certificate chain, in TLS connections which is is anchored by one of the TLSA records.
+Offer a server certificate, or certificate chain, in TLS connections which is anchored by one of the TLSA records.

 .endlist
 
 There are no changes to Exim specific to server-side operation of DANE.
 .endlist
 
 There are no changes to Exim specific to server-side operation of DANE.


@@ -30670,11 +30703,9 @@ accepted by an &%accept%& verb that has a &%message%& modifier, the contents of
 the message override the banner message that is otherwise specified by the
 &%smtp_banner%& option.
 
 the message override the banner message that is otherwise specified by the
 &%smtp_banner%& option.
 

-.new

 For tls-on-connect connections, the ACL is run before the TLS connection
 is accepted; if the ACL does not accept then the TCP connection is dropped without
 any TLS startup attempt and without any SMTP response being transmitted.
 For tls-on-connect connections, the ACL is run before the TLS connection
 is accepted; if the ACL does not accept then the TCP connection is dropped without
 any TLS startup attempt and without any SMTP response being transmitted.

-.wen

 
 
 .subsection "The EHLO/HELO ACL" SECID192
 
 
 .subsection "The EHLO/HELO ACL" SECID192


@@ -30741,6 +30772,10 @@ and the &%acl_smtp_mime%& ACLs.
 The &%acl_smtp_dkim%& ACL is available only when Exim is compiled with DKIM support
 enabled (which is the default).
 
 The &%acl_smtp_dkim%& ACL is available only when Exim is compiled with DKIM support
 enabled (which is the default).
 

+If, for a specific message, an ACL control
+&*dkim_disable_verify*&
+has been set, this &%acl_smtp_dkim%& ACL is not called.
+

 The ACL test specified by &%acl_smtp_dkim%& happens after a message has been
 received, and is executed for each DKIM signature found in a message.  If not
 otherwise specified, the default action is to accept.
 The ACL test specified by &%acl_smtp_dkim%& happens after a message has been
 received, and is executed for each DKIM signature found in a message.  If not
 otherwise specified, the default action is to accept.


@@ -31038,7 +31073,8 @@ option to do this.)
 .section "Format of an ACL" "SECID199"
 .cindex "&ACL;" "format of"
 .cindex "&ACL;" "verbs, definition of"
 .section "Format of an ACL" "SECID199"
 .cindex "&ACL;" "format of"
 .cindex "&ACL;" "verbs, definition of"

-An individual ACL consists of a number of statements. Each statement starts
+An individual ACL definition consists of a number of statements.
+Each statement starts

 with a verb, optionally followed by a number of conditions and &"modifiers"&.
 Modifiers can change the way the verb operates, define error and log messages,
 set variables, insert delays, and vary the processing of accepted messages.
 with a verb, optionally followed by a number of conditions and &"modifiers"&.
 Modifiers can change the way the verb operates, define error and log messages,
 set variables, insert delays, and vary the processing of accepted messages.


@@ -31057,6 +31093,9 @@ happens then depends on the verb (and in one case, on a special modifier). Not
 all the conditions make sense at every testing point. For example, you cannot
 test a sender address in the ACL that is run for a VRFY command.
 
 all the conditions make sense at every testing point. For example, you cannot
 test a sender address in the ACL that is run for a VRFY command.
 

+The definition of an ACL ends where another starts,
+or a different configuration section starts.
+

 
 .section "ACL verbs" "SECID200"
 The ACL verbs are as follows:
 
 .section "ACL verbs" "SECID200"
 The ACL verbs are as follows:


@@ -32211,7 +32250,6 @@ DATA, MIME or DKIM ACLs for a message delivered by cutthrough routing.
 
 More than one header can be removed at the same time by using a colon separated
 list of header specifiers.
 
 More than one header can be removed at the same time by using a colon separated
 list of header specifiers.

-.new

 If a specifier does not start with a circumflex (^)
 then it is treated as a header name.
 The header name matching is case insensitive.
 If a specifier does not start with a circumflex (^)
 then it is treated as a header name.
 The header name matching is case insensitive.


@@ -32225,7 +32263,6 @@ Example:
 .code
 remove_header = \N^(?i)Authentication-Results\s*::\s*example.org;\N
 .endd
 .code
 remove_header = \N^(?i)Authentication-Results\s*::\s*example.org;\N
 .endd

-.wen

 
 List expansion is not performed, so you cannot use hostlists to
 create a list of headers, however both connection and message variable expansion
 
 List expansion is not performed, so you cannot use hostlists to
 create a list of headers, however both connection and message variable expansion


@@ -35379,9 +35416,10 @@ The arguments are as follows:
 (the -D file). The file is open for reading and writing, but updating it is not
 recommended. &*Warning*&: You must &'not'& close this file descriptor.
 
 (the -D file). The file is open for reading and writing, but updating it is not
 recommended. &*Warning*&: You must &'not'& close this file descriptor.
 

-The descriptor is positioned at character 19 of the file, which is the first
-character of the body itself, because the first 19 characters are the message
-id followed by &`-D`& and a newline. If you rewind the file, you should use the
+The descriptor is positioned at character 26 of the file, which is the first
+character of the body itself, because the first 26 characters (19 characters
+before Exim  4.97) are the message id followed by &`-D`& and a newline.
+If you rewind the file, you should use the

 macro SPOOL_DATA_START_OFFSET to reset to the start of the data, just in
 case this changes in some future version.
 .next
 macro SPOOL_DATA_START_OFFSET to reset to the start of the data, just in
 case this changes in some future version.
 .next


@@ -36497,8 +36535,6 @@ other MTAs, the way Exim handles line endings for all messages is now as
 follows:
 
 .ilist
 follows:
 
 .ilist

-LF not preceded by CR is treated as a line ending.
-.next

 CR is treated as a line ending; if it is immediately followed by LF, the LF
 is ignored.
 .next
 CR is treated as a line ending; if it is immediately followed by LF, the LF
 is ignored.
 .next


@@ -36513,7 +36549,10 @@ people trying to play silly games.
 .next
 If the first header line received in a message ends with CRLF, a subsequent
 bare LF in a header line is treated in the same way as a bare CR in a header
 .next
 If the first header line received in a message ends with CRLF, a subsequent
 bare LF in a header line is treated in the same way as a bare CR in a header

-line.
+line and a bare LF in a body line is replaced with a space.
+.next
+If the first header line received in a message does not end with CRLF, a subsequent
+LF not preceded by CR is treated as a line ending.

 .endlist
 
 
 .endlist
 
 


@@ -39096,7 +39135,7 @@ selection marked by asterisks:
 .irow &`deliver_time`&                 &nbsp; "time taken to attempt delivery"
 .irow &`delivery_size`&                        &nbsp; "add &`S=`&&'nnn'& to => lines"
 .irow &`dkim`&                         *       "DKIM verified domain on <= lines"
 .irow &`deliver_time`&                 &nbsp; "time taken to attempt delivery"
 .irow &`delivery_size`&                        &nbsp; "add &`S=`&&'nnn'& to => lines"
 .irow &`dkim`&                         *       "DKIM verified domain on <= lines"

-.irow &`dkim_verbose`&                 &nbsp; "separate full DKIM verification result line, per signature"
+.irow &`dkim_verbose`&                 &nbsp; "separate full DKIM verification result line, per signature; DKIM signing"

 .irow &`dnslist_defer`&                        *       "defers of DNS list (aka RBL) lookups"
 .irow &`dnssec`&                       &nbsp; "DNSSEC secured lookups"
 .irow &`etrn`&                         *       "ETRN commands"
 .irow &`dnslist_defer`&                        *       "defers of DNS list (aka RBL) lookups"
 .irow &`dnssec`&                       &nbsp; "DNSSEC secured lookups"
 .irow &`etrn`&                         *       "ETRN commands"


@@ -39140,7 +39179,7 @@ selection marked by asterisks:
 .irow &`tls_peerdn`&                   &nbsp; "TLS peer DN on <= and => lines"
 .irow &`tls_resumption`&               &nbsp; "append * to cipher field"
 .irow &`tls_sni`&                      &nbsp; "TLS SNI on <= lines"
 .irow &`tls_peerdn`&                   &nbsp; "TLS peer DN on <= and => lines"
 .irow &`tls_resumption`&               &nbsp; "append * to cipher field"
 .irow &`tls_sni`&                      &nbsp; "TLS SNI on <= lines"

-.irow &`unknown_in_list`&              &nbsp; "DNS lookup failed in list match"
+.irow &`unknown_in_list`&              &nbsp; "lookup failed in list match"

 .irow &`all`&                          &nbsp; "&*all of the above*&"
 .endtable
 See also the &%slow_lookup_log%& main configuration option,
 .irow &`all`&                          &nbsp; "&*all of the above*&"
 .endtable
 See also the &%slow_lookup_log%& main configuration option,


@@ -39187,12 +39226,10 @@ only way to log such cases is to interpose a script such as &_util/logargs.sh_&
 between the caller and Exim.
 .next
 .cindex "log" "connection identifier"
 between the caller and Exim.
 .next
 .cindex "log" "connection identifier"

-.new

 &%connection_identifier%&: An identifier for the accepted connection is added to
 connection start and end lines and to message accept lines.
 The identifier is tagged by Ci=.
 The value is PID-based, so will reset on reboot and will wrap.
 &%connection_identifier%&: An identifier for the accepted connection is added to
 connection start and end lines and to message accept lines.
 The identifier is tagged by Ci=.
 The value is PID-based, so will reset on reboot and will wrap.

-.wen

 .next
 .cindex "log" "connection rejections"
 &%connection_reject%&: A log entry is written whenever an incoming SMTP
 .next
 .cindex "log" "connection rejections"
 &%connection_reject%&: A log entry is written whenever an incoming SMTP


@@ -39224,6 +39261,10 @@ verifies successfully a tag of DKIM is added, with one of the verified domains.
 .cindex log "DKIM verification"
 .cindex DKIM "verification logging"
 &%dkim_verbose%&: A log entry is written for each attempted DKIM verification.
 .cindex log "DKIM verification"
 .cindex DKIM "verification logging"
 &%dkim_verbose%&: A log entry is written for each attempted DKIM verification.

+.new
+Also, on message delivery lines signing information (domain and selector)
+is added, tagged with DKIM=.
+.wen

 .next
 .cindex "log" "dnslist defer"
 .cindex "DNS list" "logging defer"
 .next
 .cindex "log" "dnslist defer"
 .cindex "DNS list" "logging defer"


@@ -39561,7 +39602,8 @@ added to the log line, preceded by SNI=.
 .next
 .cindex "log" "DNS failure in list"
 &%unknown_in_list%&: This setting causes a log entry to be written when the
 .next
 .cindex "log" "DNS failure in list"
 &%unknown_in_list%&: This setting causes a log entry to be written when the

-result of a list match is failure because a DNS lookup failed.
+result of a list match is failure because a DNS lookup failed, or because
+a bad IP address was in the list.

 .endlist
 
 
 .endlist
 
 


@@ -41569,8 +41611,11 @@ Exim's DKIM implementation allows for
 .olist
 Signing outgoing messages: This function is implemented in the SMTP transport.
 It can co-exist with all other Exim features
 .olist
 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.
+(including transport filters) except cutthrough delivery.
+.new
+However, signing options may not depend on headers modified by
+routers, the transport or a transport filter.
+.wen

 .next
 Verifying signatures in incoming messages: This is implemented by an additional
 ACL (acl_smtp_dkim), which can be called several times per message, with
 .next
 Verifying signatures in incoming messages: This is implemented by an additional
 ACL (acl_smtp_dkim), which can be called several times per message, with


@@ -41756,7 +41801,7 @@ variables here.
 .option dkim_sign_headers smtp string&!! "see below"
 If set, this option must expand to a colon-separated
 list of header names.
 .option dkim_sign_headers smtp string&!! "see below"
 If set, this option must expand to a colon-separated
 list of header names.

-Headers with these names, or the absence or such a header, will be included
+Headers with these names, or the absence of such a header, will be included

 in the message signature.
 When unspecified, the header names listed in RFC4871 will be used,
 whether or not each header is present in the message.
 in the message signature.
 When unspecified, the header names listed in RFC4871 will be used,
 whether or not each header is present in the message.


@@ -41778,10 +41823,11 @@ name will be appended.
 .option dkim_timestamps smtp integer&!! unset
 This option controls the inclusion of timestamp information in the signature.
 If not set, no such information will be included.
 .option dkim_timestamps smtp integer&!! unset
 This option controls the inclusion of timestamp information in the signature.
 If not set, no such information will be included.

-Otherwise, must be an unsigned number giving an offset in seconds from the current time
-for the expiry tag
-(eg. 1209600 for two weeks);
-both creation (t=) and expiry (x=) tags will be included.
+.new
+Otherwise, must be an unsigned number giving an offset in seconds from the
+current time for the expiry tag (e.g. 1209600 for two weeks); both creation
+(t=) and expiry (x=) tags will be included unless the offset is 0 (no expiry).
+.wen

 
 RFC 6376 lists these tags as RECOMMENDED.
 
 
 RFC 6376 lists these tags as RECOMMENDED.
 


@@ -41791,8 +41837,9 @@ RFC 6376 lists these tags as RECOMMENDED.
 
 Verification of DKIM signatures in SMTP incoming email is done for all
 messages for which an ACL control &%dkim_disable_verify%& has not been set.
 
 Verification of DKIM signatures in SMTP incoming email is done for all
 messages for which an ACL control &%dkim_disable_verify%& has not been set.

+

 .cindex DKIM "selecting signature algorithms"
 .cindex DKIM "selecting signature algorithms"

-Individual classes of signature algorithm can be ignored by changing
+Individual classes of DKIM signature algorithm can be ignored by changing

 the main options &%dkim_verify_hashes%& or &%dkim_verify_keytypes%&.
 The &%dkim_verify_minimal%& option can be set to cease verification
 processing for a message once the first passing signature is found.
 the main options &%dkim_verify_hashes%& or &%dkim_verify_keytypes%&.
 The &%dkim_verify_minimal%& option can be set to cease verification
 processing for a message once the first passing signature is found.


@@ -41805,7 +41852,7 @@ For most purposes the default option settings suffice and the remainder
 of this section can be ignored.
 
 The results of verification are made available to the
 of this section can be ignored.
 
 The results of verification are made available to the

-&%acl_smtp_dkim%& ACL, which can examine and modify them.
+&%acl_smtp_dkim%& ACL, which (for complex needs) can examine and modify them.

 A missing ACL definition defaults to accept.
 By default, the ACL is called once for each
 syntactically(!) correct signature in the incoming message.
 A missing ACL definition defaults to accept.
 By default, the ACL is called once for each
 syntactically(!) correct signature in the incoming message.


@@ -41870,6 +41917,12 @@ an identity. This is one of the list items from the expanded main option
 &%dkim_verify_signers%& (see above).
 
 .vitem &%$dkim_verify_status%&
 &%dkim_verify_signers%& (see above).
 
 .vitem &%$dkim_verify_status%&

+So long as a DKIM ACL is defined
+(it need do no more than accept, which is the default),
+after all the DKIM ACL runs have completed, the value becomes a
+colon-separated list of the values after each run.
+The value is maintained for the MIME, PRDR and DATA ACLs.
+

 Within the DKIM ACL,
 a string describing the general status of the signature. One of
 .ilist
 Within the DKIM ACL,
 a string describing the general status of the signature. One of
 .ilist


@@ -41898,11 +41951,6 @@ hash-method or key-size:
        set dkim_verify_reason = hash too weak or key too short
 .endd
 
        set dkim_verify_reason = hash too weak or key too short
 .endd
 

-So long as a DKIM ACL is defined (it need do no more than accept),
-after all the DKIM ACL runs have completed, the value becomes a
-colon-separated list of the values after each run.
-This is maintained for the mime, prdr and data ACLs.
-

 .vitem &%$dkim_verify_reason%&
 A string giving a little bit more detail when &%$dkim_verify_status%& is either
 "fail" or "invalid". One of
 .vitem &%$dkim_verify_reason%&
 A string giving a little bit more detail when &%$dkim_verify_status%& is either
 "fail" or "invalid". One of


@@ -42027,13 +42075,15 @@ option.
 
 .endlist
 
 
 .endlist
 

-In addition, two ACL conditions are provided, usable only in a DKIM ACL:
+In addition, two ACL conditions are provided:

 
 .vlist
 .vitem &%dkim_signers%&
 ACL condition that checks a colon-separated list of domains or identities
 for a match against the domain or identity that the ACL is currently verifying
 
 .vlist
 .vitem &%dkim_signers%&
 ACL condition that checks a colon-separated list of domains or identities
 for a match against the domain or identity that the ACL is currently verifying

-(reflected by &%$dkim_cur_signer%&). This is typically used to restrict an ACL
+(reflected by &%$dkim_cur_signer%&).
+This condition is only usable in a DKIM ACL.
+This is typically used to restrict an ACL

 verb to a group of domains or identities. For example:
 
 .code
 verb to a group of domains or identities. For example:
 
 .code


@@ -42049,7 +42099,18 @@ 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
 
 .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
+results against the actual result of verification,
+given by &$dkim_verify_status$& if that is non-empty or "none" if empty.
+.new
+This condition may be used in DKIM, MIME, PRDR and DATA ACLs.
+.wen
+
+A basic verification might be:
+.code
+deny !dkim_status = pass:none:invalid
+.endd
+
+A more complex use could be

 to restrict an ACL verb to a list of verification outcomes, for example:
 
 .code
 to restrict an ACL verb to a list of verification outcomes, for example:
 
 .code


@@ -42062,6 +42123,12 @@ deny sender_domains = paypal.com:paypal.de
 The possible status keywords are: 'none','invalid','fail' and 'pass'. Please
 see the documentation of the &%$dkim_verify_status%& expansion variable above
 for more information of what they mean.
 The possible status keywords are: 'none','invalid','fail' and 'pass'. Please
 see the documentation of the &%$dkim_verify_status%& expansion variable above
 for more information of what they mean.

+
+The condition is true if the status
+.new
+(or any of the list of status values)
+.wen
+is any one of the supplied list.

 .endlist
 
 
 .endlist
 
 


@@ -42258,10 +42325,16 @@ The lookup will return the same result strings as can appear in
 
 .subsection "SRS (Sender Rewriting Scheme)" SECTSRS
 .cindex SRS "sender rewriting scheme"
 
 .subsection "SRS (Sender Rewriting Scheme)" SECTSRS
 .cindex SRS "sender rewriting scheme"

+.cindex VERP "variable envelope return path"

 
 SRS can be used to modify sender addresses when forwarding so that
 SPF verification does not object to them.
 
 SRS can be used to modify sender addresses when forwarding so that
 SPF verification does not object to them.

-It operates by encoding the original envelope sender in a new
+It can also be used to identify a received bounce message as
+likely (or not) having been trigged by a message from the
+local system, and for identifying dead addresses in mailing lists.
+It is one implementation of a VERP (Variable Envelope Return Path) method.
+
+SRS operates by encoding the original envelope sender in a new

 sender local part and using a domain run by the forwarding site
 as the new domain for the sender.  Any DSN message should be returned
 to this new sender at the forwarding site, which can extract the
 sender local part and using a domain run by the forwarding site
 as the new domain for the sender.  Any DSN message should be returned
 to this new sender at the forwarding site, which can extract the


@@ -42314,11 +42387,9 @@ return false.
 If it is, the condition will return true and the variable
 &$srs_recipient$& will be set to the decoded (original) value.
 
 If it is, the condition will return true and the variable
 &$srs_recipient$& will be set to the decoded (original) value.
 

-.new

 If the second argument is empty then the condition returns true if
 the first argument is in valid SRS formet, else false.
 The variable &$srs_recipient$& is not set for this case.
 If the second argument is empty then the condition returns true if
 the first argument is in valid SRS formet, else false.
 The variable &$srs_recipient$& is not set for this case.

-.wen

 .endlist
 
 Example usage:
 .endlist
 
 Example usage:


@@ -43017,8 +43088,8 @@ All other message types ignore the result string, and
 no other use is made of it.
 
 For a tcp:connect event, if the connection is being made to a proxy
 no other use is made of it.
 
 For a tcp:connect event, if the connection is being made to a proxy

-then the address and port variables will be that of the proxy and not
-the target system.
+then the &$host_address$& and &$host_port$& variables
+will be that of the proxy and not the target system.

 
 For tls:cert events, if GnuTLS is in use this will trigger only per
 chain element received on the connection.
 
 For tls:cert events, if GnuTLS is in use this will trigger only per
 chain element received on the connection.