X-Git-Url: https://git.exim.org/users/jgh/exim.git/blobdiff_plain/4f59c424dabfc69b7313d84685df68dd406d6ff9..99d03948a2265f0c96aecec3855a03618952cc14:/doc/doc-docbook/spec.xfpt?ds=inline

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index e5f307882..aece633af 100644
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -45,7 +45,7 @@
 . Update the Copyright year (only) when changing content.
 . /////////////////////////////////////////////////////////////////////////////
 
-.set previousversion "4.83"
+.set previousversion "4.84"
 .include ./local_params
 
 .set ACL "access control lists (ACLs)"
@@ -3811,6 +3811,12 @@ 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
 connection to the remote host has been authenticated.
 
+.vitem &%-MCD%&
+.oindex "&%-MCD%&"
+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.
+
 .vitem &%-MCP%&
 .oindex "&%-MCP%&"
 This option is not intended for use by external callers. It is used internally
@@ -5567,7 +5573,7 @@ of an incoming SMTP connection.
 If you have hosts for which you trust RFC1413 and need this
 information, you can change this.
 
-This line enables an efficiency SMTP option.  It is negociated by clients
+This line enables an efficiency SMTP option.  It is negotiated by clients
 and not expected to cause problems but can be disabled if needed.
 .code
 prdr_enable = true
@@ -6892,10 +6898,8 @@ white space is ignored.
 For an MX lookup, both the preference value and the host name are returned for
 each record, separated by a space. For an SRV lookup, the priority, weight,
 port, and host name are returned for each record, separated by spaces.
-.new
 An alternate field separator can be specified using a comma after the main
 separator character, followed immediately by the field separator.
-.wen
 
 .cindex "TXT record" "in &(dnsdb)& lookup"
 .cindex "SPF record" "in &(dnsdb)& lookup"
@@ -6912,6 +6916,46 @@ ${lookup dnsdb{spf=example.org}}
 It is permitted to specify a space as the separator character. Further
 white space is ignored.
 
+.section "Dnsdb lookup modifiers" "SECTdnsdb_mod"
+.cindex "dnsdb modifiers"
+.cindex "modifiers" "dnsdb"
+.cindex "options" "dnsdb"
+Modifiers for &(dnsdb)& lookups are givien by optional keywords,
+each followed by a comma,
+that may appear before the record type.
+
+The &(dnsdb)& lookup fails only if all the DNS lookups fail. If there is a
+temporary DNS error for any of them, the behaviour is controlled by
+a defer-option modifier.
+The possible keywords are
+&"defer_strict"&, &"defer_never"&, and &"defer_lax"&.
+With &"strict"& behaviour, any temporary DNS error causes the
+whole lookup to defer. With &"never"& behaviour, a temporary DNS error is
+ignored, and the behaviour is as if the DNS lookup failed to find anything.
+With &"lax"& behaviour, all the queries are attempted, but a temporary DNS
+error causes the whole lookup to defer only if none of the other lookups
+succeed. The default is &"lax"&, so the following lookups are equivalent:
+.code
+${lookup dnsdb{defer_lax,a=one.host.com:two.host.com}}
+${lookup dnsdb{a=one.host.com:two.host.com}}
+.endd
+Thus, in the default case, as long as at least one of the DNS lookups
+yields some data, the lookup succeeds.
+
+.cindex "DNSSEC" "dns lookup"
+Use of &(DNSSEC)& is controlled by a dnssec modifier.
+The possible keywords are
+&"dnssec_strict"&, &"dnssec_lax"&, and &"dnssec_never"&.
+With &"strict"& or &"lax"& DNSSEC information is requested
+with the lookup.
+With &"strict"& a response from the DNS resolver that
+is not labelled as authenticated data
+is treated as equivalent to a temporary DNS error.
+The default is &"never"&.
+
+See also the &$lookup_dnssec_authenticated$& variable.
+
+
 .section "Pseudo dnsdb record types" "SECID66"
 .cindex "MX record" "in &(dnsdb)& lookup"
 By default, both the preference value and the host name are returned for
@@ -6987,41 +7031,6 @@ The data from each lookup is concatenated, with newline separators by default,
 in the same way that multiple DNS records for a single item are handled. A
 different separator can be specified, as described above.
 
-Modifiers for &(dnsdb)& lookups are givien by optional keywords,
-each followed by a comma,
-that may appear before the record type.
-
-The &(dnsdb)& lookup fails only if all the DNS lookups fail. If there is a
-temporary DNS error for any of them, the behaviour is controlled by
-a defer-option modifier.
-The possible keywords are
-&"defer_strict"&, &"defer_never"&, and &"defer_lax"&.
-With &"strict"& behaviour, any temporary DNS error causes the
-whole lookup to defer. With &"never"& behaviour, a temporary DNS error is
-ignored, and the behaviour is as if the DNS lookup failed to find anything.
-With &"lax"& behaviour, all the queries are attempted, but a temporary DNS
-error causes the whole lookup to defer only if none of the other lookups
-succeed. The default is &"lax"&, so the following lookups are equivalent:
-.code
-${lookup dnsdb{defer_lax,a=one.host.com:two.host.com}}
-${lookup dnsdb{a=one.host.com:two.host.com}}
-.endd
-Thus, in the default case, as long as at least one of the DNS lookups
-yields some data, the lookup succeeds.
-
-.cindex "DNSSEC" "dns lookup"
-Use of &(DNSSEC)& is controlled by a dnssec modifier.
-The possible keywords are
-&"dnssec_strict"&, &"dnssec_lax"&, and &"dnssec_never"&.
-With &"strict"& or &"lax"& DNSSEC information is requested
-with the lookup.
-With &"strict"& a response from the DNS resolver that
-is not labelled as authenticated data
-is treated as equivalent to a temporary DNS error.
-The default is &"never"&.
-
-See also the &$lookup_dnssec_authenticated$& variable.
-
 
 
 
@@ -7342,15 +7351,12 @@ If you specify multiple attributes, the result contains space-separated, quoted
 strings, each preceded by the attribute name and an equals sign. Within the
 quotes, the quote character, backslash, and newline are escaped with
 backslashes, and commas are used to separate multiple values for the attribute.
-.new
 Any commas in attribute values are doubled
 (permitting treatment of the values as a comma-separated list).
-.wen
 Apart from the escaping, the string within quotes takes the same form as the
 output when a single attribute is requested. Specifying no attributes is the
 same as specifying all of an entry's attributes.
 
-.new
 Here are some examples of the output format. The first line of each pair is an
 LDAP query, and the second is the data that is returned. The attribute called
 &%attr1%& has two values, one of them with an embedded comma, whereas
@@ -7368,18 +7374,15 @@ attr1="value1.1,value1,,2" attr2="value two"
 ldap:///o=base??sub?(uid=fred)
 objectClass="top" attr1="value1.1,value1,,2" attr2="value two"
 .endd
-.wen
 You can
 make use of Exim's &%-be%& option to run expansion tests and thereby check the
 results of LDAP lookups.
 The &%extract%& operator in string expansions can be used to pick out
 individual fields from data that consists of &'key'&=&'value'& pairs.
-.new
 The &%listextract%& operator should be used to pick out individual values
 of attributes, even when only a single value is expected.
 The doubling of embedded commas allows you to use the returned data as a
 comma separated list (using the "<," syntax for changing the input list separator).
-.wen
 
 
 
@@ -8939,8 +8942,10 @@ a right angle-bracket followed immediately by the new separator.
 Recognised RDN type labels include "CN", "O", "OU" and "DC".
 
 The field selectors marked as "time" above
-may output a number of seconds since epoch
-if the modifier "int" is used.
+take an optional modifier of "int"
+for which the result is the number of seconds since epoch.
+Otherwise the result is a human-readable string
+in the timezone selected by the main "timezone" option.
 
 The field selectors marked as "list" above return a list,
 newline-separated by default,
@@ -9507,7 +9512,7 @@ locks out the use of this expansion item in filter files.
 .cindex "expansion" "inserting from a socket"
 .cindex "socket, use of in expansion"
 .cindex "&%readsocket%& expansion item"
-This item inserts data from a Unix domain or Internet socket into the expanded
+This item inserts data from a Unix domain or TCP socket into the expanded
 string. The minimal way of using it uses just two arguments, as in these
 examples:
 .code
@@ -9698,7 +9703,6 @@ the regular expression from string expansion.
 
 
 
-.new
 .vitem &*${sort{*&<&'string'&>&*}{*&<&'comparator'&>&*}{*&<&'extractor'&>&*}}*&
 .cindex sorting a list
 .cindex list sorting
@@ -9726,7 +9730,6 @@ sorts a list of numbers, and
 ${sort {$lookup dnsdb{>:,,mx=example.com}} {<} {${listextract{1}{<,$item}}}}
 .endd
 will sort an MX lookup into priority order.
-.wen
 
 
 .vitem &*${substr{*&<&'string1'&>&*}{*&<&'string2'&>&*}{*&<&'string3'&>&*}}*&
@@ -11257,6 +11260,17 @@ The building process for Exim keeps a count of the number
 of times it has been compiled. This serves to distinguish different
 compilations of the same version of the program.
 
+.vitem &$config_dir$&
+.vindex "&$config_dir$&"
+The directory name of the main configuration file. That is, the content of
+&$config_file$& with the last component stripped. The value does not
+contain the trailing slash. If &$config_file$& does not contain a slash,
+&$config_dir$& is ".".
+
+.vitem &$config_file$&
+.vindex "&$config_file$&"
+The name of the main configuration file Exim is using.
+
 .vitem &$demime_errorlevel$&
 .vindex "&$demime_errorlevel$&"
 This variable is available when Exim is compiled with
@@ -11364,6 +11378,13 @@ This variable contains the path to the Exim binary.
 .vindex "&$exim_uid$&"
 This variable contains the numerical value of the Exim user id.
 
+.vitem &$exim_version$&
+.vindex "&$exim_uid$&"
+This variable contains the version string of the Exim build.
+The first character is a major version number, currently 4.
+Then after a dot, the next group of digits is a minor version number.
+There may be other characters following the minor version.
+
 .vitem &$found_extension$&
 .vindex "&$found_extension$&"
 This variable is available when Exim is compiled with the
@@ -11930,10 +11951,7 @@ on which interface and/or port is being used for the incoming connection. The
 values of &$received_ip_address$& and &$received_port$& are saved with any
 messages that are received, thus making these variables available at delivery
 time.
-
-&*Note:*& There are no equivalent variables for outgoing connections, because
-the values are unknown (unless they are explicitly set by options of the
-&(smtp)& transport).
+For outbound connections see &$sending_ip_address$&.
 
 .vitem &$received_port$&
 .vindex "&$received_port$&"
@@ -12152,8 +12170,9 @@ the &%-bs%& or &%-bS%& options.
 
 .vitem &$sender_host_address$&
 .vindex "&$sender_host_address$&"
-When a message is received from a remote host, this variable contains that
-host's IP address. For locally submitted messages, it is empty.
+When a message is received from a remote host using SMTP,
+this variable contains that
+host's IP address. For locally non-SMTP submitted messages, it is empty.
 
 .vitem &$sender_host_authenticated$&
 .vindex "&$sender_host_authenticated$&"
@@ -12409,9 +12428,7 @@ If TLS has not been negotiated, the value will be 0.
 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
-.new
 &%certextract%& expansion item, &%md5%&, &%sha1%& or &%sha256%& operator,
-.wen
 or a &%def%& condition.
 
 .vitem &$tls_in_peercert$&
@@ -12419,27 +12436,21 @@ or a &%def%& condition.
 This variable refers to the certificate presented by the peer of an
 inbound connection when the message was received.
 It is only useful as the argument of a
-.new
 &%certextract%& expansion item, &%md5%&, &%sha1%& or &%sha256%& operator,
-.wen
 or a &%def%& condition.
 
 .vitem &$tls_out_ourcert$&
 .vindex "&$tls_out_ourcert$&"
 This variable refers to the certificate presented to the peer of an
 outbound connection.  It is only useful as the argument of a
-.new
 &%certextract%& expansion item, &%md5%&, &%sha1%& or &%sha256%& operator,
-.wen
 or a &%def%& condition.
 
 .vitem &$tls_out_peercert$&
 .vindex "&$tls_out_peercert$&"
 This variable refers to the certificate presented by the peer of an
 outbound connection.  It is only useful as the argument of a
-.new
 &%certextract%& expansion item, &%md5%&, &%sha1%& or &%sha256%& operator,
-.wen
 or a &%def%& condition.
 
 .vitem &$tls_in_certificate_verified$&
@@ -12592,6 +12603,13 @@ This variable contains the result of an expansion lookup, extraction operation,
 or external command, as described above. It is also used during a
 &*reduce*& expansion.
 
+.vitem &$verify_mode$&
+.vindex "&$verify_mode$&"
+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.
+
 .vitem &$version_number$&
 .vindex "&$version_number$&"
 The version number of Exim.
@@ -13397,6 +13415,7 @@ See also the &'Policy controls'& section above.
 .table2
 .row &%accept_8bitmime%&             "advertise 8BITMIME"
 .row &%auth_advertise_hosts%&        "advertise AUTH 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"
 .row &%pipelining_advertise_hosts%&  "advertise pipelining to these hosts"
@@ -13552,8 +13571,9 @@ This option defines the ACL that is run after an SMTP DATA command has been
 processed and the message itself has been received, but before the final
 acknowledgment is sent. See chapter &<<CHAPACL>>& for further details.
 
-.option acl_smtp_data_prdr main string&!! unset
-.cindex "DATA" "ACL for"
+.option acl_smtp_data_prdr main string&!! accept
+.cindex "PRDR" "ACL for"
+.cindex "DATA" "PRDR ACL for"
 .cindex "&ACL;" "PRDR-related"
 .cindex "&ACL;" "per-user data processing"
 This option defines the ACL that,
@@ -14137,6 +14157,18 @@ This is an obsolete option that is now a no-op. It used to affect the way Exim
 handled CR and LF characters in incoming messages. What happens now is
 described in section &<<SECTlineendings>>&.
 
+.option dsn_advertise_hosts main "host list&!!" unset
+.cindex "bounce messages" "success"
+.cindex "DSN" "success"
+.cindex "Delivery Status Notification" "success"
+DSN extensions (RFC3461) will be advertised in the EHLO message to,
+and accepted from, these hosts.
+Hosts may use the NOTIFY and ENVID options on RCPT TO commands,
+and RET and ORCPT options on MAIL FROM commands.
+A NOTIFY=SUCCESS option requests success-DSN messages.
+A NOTIFY= option with no argument requests that no delay or failure DSNs
+are sent.
+
 .option dsn_from main "string&!!" "see below"
 .cindex "&'From:'& header line" "in bounces"
 .cindex "bounce messages" "&'From:'& line, specifying"
@@ -15054,16 +15086,21 @@ yourself in the foot in various unpleasant ways.  This option should not be
 adjusted lightly.  An unrecognised item will be detected at startup, by
 invoking Exim with the &%-bV%& flag.
 
+The option affects Exim operating both as a server and as a client.
+
 Historical note: prior to release 4.80, Exim defaulted this value to
 "+dont_insert_empty_fragments", which may still be needed for compatibility
 with some clients, but which lowers security by increasing exposure to
 some now infamous attacks.
 
-An example:
+Examples:
 .code
 # Make both old MS and old Eudora happy:
 openssl_options = -all +microsoft_big_sslv3_buffer \
                        +dont_insert_empty_fragments
+
+# Disable older protocol versions:
+openssl_options = +no_sslv2 +no_sslv3
 .endd
 
 Possible options may include:
@@ -15624,13 +15661,15 @@ the time of delivery. They are normally used only for final local deliveries.
 This option is an obsolete synonym for &%bounce_return_size_limit%&.
 
 
-.option rfc1413_hosts main "host list&!!" *
+.option rfc1413_hosts main "host list&!!" @[]
 .cindex "RFC 1413"
 .cindex "host" "for RFC 1413 calls"
-RFC 1413 identification calls are made to any client host which matches an item
-in the list.
+RFC 1413 identification calls are made to any client host which matches
+an item in the list.
+The default value specifies just this host, being any local interface
+for the system.
 
-.option rfc1413_query_timeout main time 5s
+.option rfc1413_query_timeout main time 0s
 .cindex "RFC 1413" "query timeout"
 .cindex "timeout" "for RFC 1413 call"
 This sets the timeout on RFC 1413 identification calls. If it is set to zero,
@@ -16478,22 +16517,40 @@ preference order of the available ciphers. Details are given in sections
 See &%tls_verify_hosts%& below.
 
 
-.option tls_verify_certificates main string&!! unset
+.option tls_verify_certificates main string&!! system
 .cindex "TLS" "client certificate verification"
 .cindex "certificate" "verification of client"
-The value of this option is expanded, and must then be the absolute path to
-a file containing permitted certificates for clients that
-match &%tls_verify_hosts%& or &%tls_try_verify_hosts%&. Alternatively, if you
-are using OpenSSL, you can set &%tls_verify_certificates%& to the name of a
-directory containing certificate files. This does not work with GnuTLS; the
-option must be set to the name of a single file if you are using GnuTLS.
+The value of this option is expanded, and must then be either the
+word "system"
+or the absolute path to
+a file or directory containing permitted certificates for clients that
+match &%tls_verify_hosts%& or &%tls_try_verify_hosts%&.
+
+The "system" value for the option will use a
+system default location compiled into the SSL library.
+This is not available for GnuTLS versions preceding 3.0.20,
+and will be taken as empty; an explicit location
+must be specified.
+
+The use of a directory for the option value is not avilable for GnuTLS versions
+preceding 3.3.6 and a single file must be used.
+
+With OpenSSL the certificates specified
+explicitly
+either by file or directory
+are added to those given by the system default location.
+
+With OpenSSL the certificates specified
+explicitly
+either by file or directory
+are added to those given by the system default location.
 
 These certificates should be for the certificate authorities trusted, rather
 than the public cert of individual clients.  With both OpenSSL and GnuTLS, if
 the value is a file then the certificates are sent by Exim as a server to
 connecting clients, defining the list of accepted certificate authorities.
 Thus the values defined should be considered public data.  To avoid this,
-use OpenSSL with a directory.
+use the explicit directory version.
 
 See &<<SECTtlssni>>& for discussion of when this option might be re-expanded.
 
@@ -16862,7 +16919,6 @@ If the expansion fails (other than forced failure) delivery is deferred. Some
 of the other precondition options are common special cases that could in fact
 be specified using &%condition%&.
 
-.new
 Historical note: We have &%condition%& on ACLs and on Routers.  Routers
 are far older, and use one set of semantics.  ACLs are newer and when
 they were created, the ACL &%condition%& process was given far stricter
@@ -16902,7 +16958,6 @@ true, as the result of expansion is a non-empty string which doesn't
 match an explicit false value.  This can be tricky to debug.  By
 contrast, in an ACL either of those strings will always result in an
 expansion error because the result doesn't look sufficiently boolean.
-.wen
 
 
 .option debug_print routers string&!! unset
@@ -16945,6 +17000,15 @@ This option must always be set. It specifies which of the available routers is
 to be used.
 
 
+.option dsn_lasthop routers boolean false
+.cindex "DSN" "success"
+.cindex "Delivery Status Notification" "success"
+If this option is set true, and extended DSN (RFC3461) processing is in effect,
+Exim will not pass on DSN requests to downstream DSN-aware hosts but will
+instead send a success DSN as if the next hop does not support DSN.
+Not effective on redirect routers.
+
+
 
 .option errors_to routers string&!! unset
 .cindex "envelope sender"
@@ -17777,6 +17841,7 @@ delivering in cutthrough mode
 or testing recipient verification using &%-bv%&.
 See section &<<SECTrouprecon>>& for a list of the order in which preconditions
 are evaluated.
+See also the &$verify_mode$& variable.
 
 
 .option verify_sender routers&!? boolean true
@@ -17784,6 +17849,7 @@ If this option is false, the router is skipped when verifying sender addresses
 or testing sender verification using &%-bvs%&.
 See section &<<SECTrouprecon>>& for a list of the order in which preconditions
 are evaluated.
+See also the &$verify_mode$& variable.
 .ecindex IIDgenoprou1
 .ecindex IIDgenoprou2
 
@@ -18949,6 +19015,11 @@ However, there are some private options which define transports for delivery to
 files and pipes, and for generating autoreplies. See the &%file_transport%&,
 &%pipe_transport%& and &%reply_transport%& descriptions below.
 
+If success DSNs have been requested
+.cindex "DSN" "success"
+.cindex "Delivery Status Notification" "success"
+redirection triggers one and the DSN options are not passed any further.
+
 
 
 .section "Redirection data" "SECID124"
@@ -23156,11 +23227,12 @@ 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_prdr smtp "host list&!!" unset
+.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
 PRDR support, Exim will attempt to negotiate PRDR
 for multi-recipient messages.
+The option can usually be left as default.
 
 .option interface smtp "string list&!!" unset
 .cindex "bind IP address"
@@ -23218,7 +23290,7 @@ so can cause parallel connections to the same host if &%remote_max_parallel%&
 permits this.
 
 
-.option multi_domain smtp boolean true
+.option multi_domain smtp boolean&!! true
 .vindex "&$domain$&"
 When this option is set, the &(smtp)& transport can handle a number of
 addresses containing a mixture of different domains provided they all resolve
@@ -23227,6 +23299,9 @@ handling only one domain at a time. This is useful if you want to use
 &$domain$& in an expansion for the transport, because it is set only when there
 is a single domain involved in a remote delivery.
 
+It is expanded per-address and can depend on any of
+&$address_data$&, &$domain_data$&, &$local_part_data$&,
+&$host$&, &$host_address$& and &$host_port$&.
 
 .option port smtp string&!! "see below"
 .cindex "port" "sending TCP/IP"
@@ -23262,7 +23337,7 @@ connecting, as an outbound SSL-on-connect, instead of using STARTTLS to upgrade.
 The Internet standards bodies strongly discourage use of this mode.
 
 
-.option retry_include_ip_address smtp boolean true
+.option retry_include_ip_address smtp boolean&!! true
 Exim normally includes both the host name and the IP address in the key it
 constructs for indexing retry data after a temporary delivery failure. This
 means that when one of several IP addresses for a host is failing, it gets
@@ -23272,9 +23347,8 @@ addresses is not affected.
 However, in some dialup environments hosts are assigned a different IP address
 each time they connect. In this situation the use of the IP address as part of
 the retry key leads to undesirable behaviour. Setting this option false causes
-Exim to use only the host name. This should normally be done on a separate
-instance of the &(smtp)& transport, set up specially to handle the dialup
-hosts.
+Exim to use only the host name.
+Since it is expanded it can be made to depend on the host or domain.
 
 
 .option serialize_hosts smtp "host list&!!" unset
@@ -23412,7 +23486,7 @@ unknown state), opens a new one to the same host, and then tries the delivery
 in clear.
 
 
-.option tls_try_verify_hosts smtp "host list&!! unset
+.option tls_try_verify_hosts smtp "host list&!!" *
 .cindex "TLS" "server certificate verification"
 .cindex "certificate" "verification of server"
 This option gives a list of hosts for which, on encrypted connections,
@@ -23420,31 +23494,59 @@ certificate verification will be tried but need not succeed.
 The &%tls_verify_certificates%& option must also be set.
 Note that unless the host is in this list
 TLS connections will be denied to hosts using self-signed certificates
-when &%tls_verify_certificates%& is set.
+when &%tls_verify_certificates%& is matched.
 The &$tls_out_certificate_verified$& variable is set when
 certificate verification succeeds.
 
 
-.option tls_verify_certificates smtp string&!! unset
+.option tls_verify_cert_hostnames smtp "host list&!!" *
+.cindex "TLS" "server certificate hostname verification"
+.cindex "certificate" "verification of server"
+This option give a list of hosts for which,
+while verifying the server certificate,
+checks will be included on the host name
+(note that this will generally be the result of a DNS MX lookup)
+versus Subject and Subject-Alternate-Name fields.  Wildcard names are permitted
+limited to being the initial component of a 3-or-more component FQDN.
+
+There is no equivalent checking on client certificates.
+
+
+.option tls_verify_certificates smtp string&!! system
 .cindex "TLS" "server certificate verification"
 .cindex "certificate" "verification of server"
 .vindex "&$host$&"
 .vindex "&$host_address$&"
-The value of this option must be the absolute path to a file containing
-permitted server certificates, for use when setting up an encrypted connection.
-Alternatively, if you are using OpenSSL, you can set
-&%tls_verify_certificates%& to the name of a directory containing certificate
-files. This does not work with GnuTLS; the option must be set to the name of a
-single file if you are using GnuTLS. The values of &$host$& and
+The value of this option must be either the
+word "system"
+or the absolute path to
+a file or directory containing permitted certificates for servers,
+for use when setting up an encrypted connection.
+
+The "system" value for the option will use a location compiled into the SSL library.
+This is not available for GnuTLS versions preceding 3.0.20; a value of "system"
+is taken as empty and an explicit location
+must be specified.
+
+The use of a directory for the option value is not avilable for GnuTLS versions
+preceding 3.3.6 and a single file must be used.
+
+With OpenSSL the certificates specified
+explicitly
+either by file or directory
+are added to those given by the system default location.
+
+The values of &$host$& and
 &$host_address$& are set to the name and address of the server during the
 expansion of this option. See chapter &<<CHAPTLS>>& for details of TLS.
 
 For back-compatability,
 if neither tls_verify_hosts nor tls_try_verify_hosts are set
+(a single-colon empty list counts as being set)
 and certificate verification fails the TLS connection is closed.
 
 
-.option tls_verify_hosts smtp "host list&!! unset
+.option tls_verify_hosts smtp "host list&!!" unset
 .cindex "TLS" "server certificate verification"
 .cindex "certificate" "verification of server"
 This option gives a list of hosts for which. on encrypted connections,
@@ -25916,8 +26018,10 @@ include files and libraries for GnuTLS can be found.
 There are some differences in usage when using GnuTLS instead of OpenSSL:
 
 .ilist
-The &%tls_verify_certificates%& option must contain the name of a file, not the
-name of a directory (for OpenSSL it can be either).
+The &%tls_verify_certificates%& option
+cannot be the path of a directory
+for GnuTLS versions before 3.3.6
+(for later versions, or OpenSSL, it can be either).
 .next
 The default value for &%tls_dhparam%& differs for historical reasons.
 .next
@@ -26114,7 +26218,8 @@ The GnuTLS library allows the caller to provide a "priority string", documented
 as part of the &[gnutls_priority_init]& function.  This is very similar to the
 ciphersuite specification in OpenSSL.
 
-The &%tls_require_ciphers%& option is treated as the GnuTLS priority string.
+The &%tls_require_ciphers%& option is treated as the GnuTLS priority string
+and controls both protocols and ciphers.
 
 The &%tls_require_ciphers%& option is available both as an global option,
 controlling how Exim behaves as a server, and also as an option of the
@@ -26131,6 +26236,12 @@ installed on your system.  If you are using GnuTLS 3,
 &url(http://www.gnutls.org/manual/gnutls.html#Listing-the-ciphersuites-in-a-priority-string, then the example code)
 on that site can be used to test a given string.
 
+For example:
+.code
+# Disable older versions of protocols
+tls_require_ciphers = NORMAL:%LATEST_RECORD_VERSION:-VERS-SSL3.0
+.endd
+
 Prior to Exim 4.80, an older API of GnuTLS was used, and Exim supported three
 additional options, "&%gnutls_require_kx%&", "&%gnutls_require_mac%&" and
 "&%gnutls_require_protocols%&".  &%tls_require_ciphers%& was an Exim list.
@@ -26181,8 +26292,11 @@ tls_privatekey = /some/file/name
 These options are, in fact, expanded strings, so you can make them depend on
 the identity of the client that is connected if you wish. The first file
 contains the server's X509 certificate, and the second contains the private key
-that goes with it. These files need to be readable by the Exim user, and must
-always be given as full path names. They can be the same file if both the
+that goes with it. These files need to be
+PEM format and readable by the Exim user, and must
+always be given as full path names.
+The key must not be password-protected.
+They can be the same file if both the
 certificate and the key are contained within it. If &%tls_privatekey%& is not
 set, or if its expansion is forced to fail or results in an empty string, this
 is assumed to be the case. The certificate file may also contain intermediate
@@ -26258,8 +26372,10 @@ session with a client, you must set either &%tls_verify_hosts%& or
 apply to all TLS connections. For any host that matches one of these options,
 Exim requests a certificate as part of the setup of the TLS session. The
 contents of the certificate are verified by comparing it with a list of
-expected certificates. These must be available in a file or,
-for OpenSSL only (not GnuTLS), a directory, identified by
+expected certificates.
+These may be the system default set (depending on library version),
+an explicit file or,
+depending on library version, a directory, identified by
 &%tls_verify_certificates%&.
 
 A file can contain multiple certificates, concatenated end to end. If a
@@ -26419,9 +26535,13 @@ if it requests it. If the server is Exim, it will request a certificate only if
 &%tls_verify_hosts%& or &%tls_try_verify_hosts%& matches the client.
 
 If the &%tls_verify_certificates%& option is set on the &(smtp)& transport, it
+specifies a collection of expected server certificates.
+These may be the system default set (depeding on library version),
+a file or,
+depnding on liibrary version, a directory,
 must name a file or,
-for OpenSSL only (not GnuTLS), a directory, that contains a collection of
-expected server certificates. The client verifies the server's certificate
+for OpenSSL only (not GnuTLS), a directory.
+The client verifies the server's certificate
 against this collection, taking into account any revoked certificates that are
 in the list defined by &%tls_crl%&.
 Failure to verify fails the TLS connection unless either of the
@@ -26531,7 +26651,7 @@ during TLS session handshake, to permit alternative values to be chosen:
 &%tls_verify_certificates%&
 .next
 .vindex "&%tls_ocsp_file%&"
-&%tls_verify_certificates%&
+&%tls_ocsp_file%&
 .endlist
 
 Great care should be taken to deal with matters of case, various injection
@@ -26890,6 +27010,7 @@ This ACL is evaluated after &%acl_smtp_dkim%& but before &%acl_smtp_data%&.
 
 
 .section "The SMTP PRDR ACL" "SECTPRDRACL"
+.cindex "PRDR" "ACL for"
 .oindex "&%prdr_enable%&"
 The &%acl_smtp_data_prdr%& ACL is available only when Exim is compiled
 with PRDR support enabled (which is the default).
@@ -26898,8 +27019,9 @@ client and server for a message, and more than one recipient
 has been accepted.
 
 The ACL test specfied by &%acl_smtp_data_prdr%& happens after a message
-has been recieved, and is executed for each recipient of the message.
-The test may accept or deny for inividual recipients.
+has been recieved, and is executed once for each recipient of the message
+with &$local_part$& and &$domain$& valid.
+The test may accept, defer or deny for inividual recipients.
 The &%acl_smtp_data%& will still be called after this ACL and
 can reject the message overall, even if this ACL has accepted it
 for some or all recipients.
@@ -27728,10 +27850,8 @@ anyway. If the message contains newlines, this gives rise to a multi-line SMTP
 response.
 
 .vindex "&$acl_verify_message$&"
-.new
 For ACLs that are called by an &%acl =%& ACL condition, the message is
 stored in &$acl_verify_message$&, from which the calling ACL may use it.
-.wen
 
 If &%message%& is used on a statement that verifies an address, the message
 specified overrides any message that is generated by the verification process.
@@ -27840,10 +27960,16 @@ is what is wanted for subsequent tests.
 .cindex "&ACL;" "cutthrough routing"
 .cindex "cutthrough" "requesting"
 This option requests delivery be attempted while the item is being received.
-It is usable in the RCPT ACL and valid only for single-recipient mails forwarded
-from one SMTP connection to another.  If a recipient-verify callout connection is
-requested in the same ACL it is held open and used for the data, otherwise one is made
-after the ACL completes.
+
+The option usable in the RCPT ACL.
+If enabled for a message recieved via smtp and routed to an smtp transport,
+and the message has only one recipient,
+then the delivery connection is made while the receiving connection is open
+and data is copied from one to the other.
+
+If a recipient-verify callout connection is subsequently
+requested in the same ACL it is held open and used for the data,
+otherwise one is made after the initial RCPT ACL completes.
 
 Note that routers are used in verify mode,
 and cannot depend on content of received headers.
@@ -27858,11 +27984,12 @@ before the entire message has been received from the source.
 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 the log line
-is tagged with ">>" rather than "=>" and appears before the acceptance "<="
-line.
+usual fashion. If the item is successfully delivered in cutthrough mode
+the log line is tagged with ">>" rather than "=>" and appears
+before the acceptance "<=" line.
 
-Delivery in this mode avoids the generation of a bounce mail to a (possibly faked)
+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.
 
 
@@ -28307,6 +28434,8 @@ can be appended; they appear within the called ACL in $acl_arg1 to $acl_arg9,
 and $acl_narg is set to the count of values.
 Previous values of these variables are restored after the call returns.
 The name and values are expanded separately.
+Note that spaces in complex expansions which are used as arguments
+will act as argument separators.
 
 If the nested &%acl%& returns &"drop"& and the outer condition denies access,
 the connection is dropped. If it returns &"discard"&, the verb must be
@@ -30312,9 +30441,13 @@ av_scanner = cmdline:\
 .endd
 .vitem &%drweb%&
 .cindex "virus scanners" "DrWeb"
-The DrWeb daemon scanner (&url(http://www.sald.com/)) interface takes one
-argument, either a full path to a UNIX socket, or an IP address and port
-separated by white space, as in these examples:
+The DrWeb daemon scanner (&url(http://www.sald.com/)) interface
+takes one option,
+either a full path to a UNIX socket,
+or host and port specifiers separated by white space.
+The host may be a name or an IP address; the port is either a
+single number or a pair of numbers with a dash between.
+For example:
 .code
 av_scanner = drweb:/var/run/drwebd.sock
 av_scanner = drweb:192.168.2.20 31337
@@ -30322,6 +30455,17 @@ av_scanner = drweb:192.168.2.20 31337
 If you omit the argument, the default path &_/usr/local/drweb/run/drwebd.sock_&
 is used. Thanks to Alex Miller for contributing the code for this scanner.
 
+.vitem &%f-protd%&
+.cindex "virus scanners" "f-protd"
+The f-protd scanner is accessed via HTTP over TCP.
+One argument is taken, being a space-separated hostname and port number
+(or port-range).
+For example:
+.code
+av_scanner = f-protd:localhost 10200-10204
+.endd
+If you omit the argument, the default values show above are used.
+
 .vitem &%fsecure%&
 .cindex "virus scanners" "F-Secure"
 The F-Secure daemon scanner (&url(http://www.f-secure.com)) takes one
@@ -32520,6 +32664,9 @@ headers_remove = return-receipt-to:acknowledge-to
 Multiple &%headers_remove%& options for a single router or transport can be
 specified; the arguments will append to a single header-names list.
 Each item is separately expanded.
+Note that colons in complex expansions which are used to
+form all or part of a &%headers_remove%& list
+will act as list separators.
 
 When &%headers_add%& or &%headers_remove%& is specified on a router,
 items are expanded at routing time,
@@ -33357,13 +33504,8 @@ failing addresses with their error messages.
 The third item is used to introduce any text from pipe transports that is to be
 returned to the sender. It is omitted if there is no such text.
 .next
-The fourth item is used to introduce the copy of the message that is returned
-as part of the error report.
-.next
-The fifth item is added after the fourth one if the returned message is
-truncated because it is bigger than &%return_size_limit%&.
-.next
-The sixth item is added after the copy of the original message.
+The fourth, fifth and sixth items will be ignored and may be empty.
+The fields exist for back-compatibility
 .endlist
 
 The default state (&%bounce_message_file%& unset) is equivalent to the
@@ -34726,7 +34868,7 @@ selection marked by asterisks:
 &` smtp_protocol_error        `&  SMTP protocol errors
 &` smtp_syntax_error          `&  SMTP syntax errors
 &` subject                    `&  contents of &'Subject:'& on <= lines
-&` tls_certificate_verified   `&  certificate verification status
+&`*tls_certificate_verified   `&  certificate verification status
 &`*tls_cipher                 `&  TLS cipher suite on <= and => lines
 &` tls_peerdn                 `&  TLS peer DN on <= and => lines
 &` tls_sni                    `&  TLS SNI on <= lines
@@ -35273,11 +35415,9 @@ given message, or all mail for a given user, or for a given host, for example.
 The input files can be in Exim log format or syslog format.
 If a matching log line is not associated with a specific message, it is
 included in &'exigrep'&'s output without any additional lines. The usage is:
-.new
 .display
 &`exigrep [-t<`&&'n'&&`>] [-I] [-l] [-M] [-v] <`&&'pattern'&&`> [<`&&'log file'&&`>] ...`&
 .endd
-.wen
 If no log file names are given on the command line, the standard input is read.
 
 The &%-t%& argument specifies a number of seconds. It adds an additional
@@ -35297,7 +35437,6 @@ regular expression.
 The &%-v%& option inverts the matching condition. That is, a line is selected
 if it does &'not'& match the pattern.
 
-.new
 The &%-M%& options means &"related messages"&. &'exigrep'& will show messages
 that are generated as a result/response to a message that &'exigrep'& matched
 normally.
@@ -35310,7 +35449,6 @@ the second (bounce) message will be displayed. Using &%-M%& with &'exigrep'&
 when searching for &"user_a"& will show both messages since the bounce is
 &"related"& to or a &"result"& of the first message that was found by the
 search term.
-.wen
 
 If the location of a &'zcat'& command is known from the definition of
 ZCAT_COMMAND in &_Local/Makefile_&, &'exigrep'& automatically passes any file