X-Git-Url: https://git.exim.org/users/jgh/exim.git/blobdiff_plain/c5f280e20a8e3ecd5f016b8fb34a436588915ed2..3045f0503a6aacfa5feea1c9b67e7950a8c57ee7:/doc/doc-docbook/spec.xfpt diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index 13d903b16..af41e4493 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -45,14 +45,14 @@ . Update the Copyright year (only) when changing content. . ///////////////////////////////////////////////////////////////////////////// -.set previousversion "4.85" +.set previousversion "4.86" .include ./local_params .set ACL "access control lists (ACLs)" .set I "    " .macro copyyear -2014 +2015 .endmacro . ///////////////////////////////////////////////////////////////////////////// @@ -1575,7 +1575,7 @@ If a host is unreachable for a period of time, a number of messages may be waiting for it by the time it recovers, and sending them in a single SMTP connection is clearly beneficial. Whenever a delivery to a remote host is deferred, -.cindex "hints database" +.cindex "hints database" "deferred deliveries" Exim makes a note in its hints database, and whenever a successful SMTP delivery has happened, it looks to see if any other messages are waiting for the same host. If any are found, they are sent over the same SMTP @@ -1860,7 +1860,7 @@ described RFC 2047. This makes it possible to transmit characters that are not in the ASCII character set, and to label them as being in a particular character set. When Exim is inspecting header lines by means of the &%$h_%& mechanism, it decodes them, and translates them into a specified character set -(default ISO-8859-1). The translation is possible only if the operating system +(default is set at build time). The translation is possible only if the operating system supports the &[iconv()]& function. However, some of the operating systems that supply &[iconv()]& do not support @@ -1985,10 +1985,10 @@ Two different types of DNS record for handling IPv6 addresses have been defined. AAAA records (analogous to A records for IPv4) are in use, and are currently seen as the mainstream. Another record type called A6 was proposed as better than AAAA because it had more flexibility. However, it was felt to be -over-complex, and its status was reduced to &"experimental"&. It is not known -if anyone is actually using A6 records. Exim has support for A6 records, but -this is included only if you set &`SUPPORT_A6=YES`& in &_Local/Makefile_&. The -support has not been tested for some time. +over-complex, and its status was reduced to &"experimental"&. +Exim used to +have a compile option for including A6 record support but this has now been +withdrawn. @@ -2032,9 +2032,6 @@ For example, on a Sun system running Solaris 8, the directory .cindex "symbolic link" "to source files" Symbolic links to relevant source files are installed in the build directory. -&*Warning*&: The &%-j%& (parallel) flag must not be used with &'make'&; the -building process fails if it is set. - If this is the first time &'make'& has been run, it calls a script that builds a make file inside the build directory, using the configuration files from the &_Local_& directory. The new make file is then passed to another instance of @@ -3110,8 +3107,12 @@ users, the output is as in this example: .code mysql_servers = .endd -If &%configure_file%& is given as an argument, the name of the run time -configuration file is output. +If &%config%& is given as an argument, the config is +output, as it was parsed, any include file resolved, any comment removed. + +If &%config_file%& is given as an argument, the name of the run time +configuration file is output. (&%configure_file%& works too, for +backward compatibility.) If a list of configuration files was supplied, the value that is output here is the name of the file that was actually used. @@ -3551,6 +3552,9 @@ example: exim '-D ABC = something' ... .endd &%-D%& may be repeated up to 10 times on a command line. +.new +Only macro names up to 22 letters long can be set. +.wen .vitem &%-d%&<&'debug&~options'&> @@ -3811,13 +3815,11 @@ 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. -.new .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. -.wen .vitem &%-MCP%& .oindex "&%-MCP%&" @@ -4805,8 +4807,8 @@ help with this. See the comments in &_src/EDITME_& for details. Exim's configuration file is divided into a number of different parts. General option settings must always appear at the start of the file. The other parts are all optional, and may appear in any order. Each part other than the first -is introduced by the word &"begin"& followed by the name of the part. The -optional parts are: +is introduced by the word &"begin"& followed by at least one literal +space, and the name of the part. The optional parts are: .ilist &'ACL'&: Access control lists for controlling incoming SMTP mail (see chapter @@ -5011,7 +5013,8 @@ message_size_limit = 50M message_size_limit = 100M .endif .endd -sets a message size limit of 50M if the macro &`AAA`& is defined, and 100M +sets a message size limit of 50M if the macro &`AAA`& is defined +(or &`A`& or &`AA`&), and 100M otherwise. If there is more than one macro named on the line, the condition is true if any of them are defined. That is, it is an &"or"& condition. To obtain an &"and"& condition, you need to use nested &`.ifdef`&s. @@ -5233,7 +5236,7 @@ list items, it is not ignored when parsing the list. The space after the first colon in the example above is necessary. If it were not there, the list would be interpreted as the two items 127.0.0.1:: and 1. -.section "Changing list separators" "SECID53" +.section "Changing list separators" "SECTlistsepchange" .cindex "list separator" "changing" .cindex "IPv6" "addresses in lists" Doubling colons in IPv6 addresses is an unwelcome chore, so a mechanism was @@ -5599,6 +5602,13 @@ find that they send unqualified addresses. The two commented-out options: show how you can specify hosts that are permitted to send unqualified sender and recipient addresses, respectively. +The &%log_selector%& option is used to increase the detail of logging +over the default: +.code +log_selector = +smtp_protocol_error +smtp_syntax_error \ + +tls_certificate_verified +.endd + The &%percent_hack_domains%& option is also commented out: .code # percent_hack_domains = @@ -6057,8 +6067,8 @@ address_pipe: .endd This transport is used for handling deliveries to pipes that are generated by redirection (aliasing or users' &_.forward_& files). The &%return_output%& -option specifies that any output generated by the pipe is to be returned to the -sender. +option specifies that any output on stdout or stderr generated by the pipe is to +be returned to the sender. .code address_file: driver = appendfile @@ -6240,12 +6250,14 @@ cause parts of the string to be replaced by data that is obtained from the lookup. Lookups of this type are conditional expansion items. Different results can be defined for the cases of lookup success and failure. See chapter &<>&, where string expansions are described in detail. +The key for the lookup is specified as part of the string expansion. .next Lists of domains, hosts, and email addresses can contain lookup requests as a way of avoiding excessively long linear lists. In this case, the data that is returned by the lookup is often (but not always) discarded; whether the lookup succeeds or fails is what really counts. These kinds of list are described in chapter &<>&. +The key for the lookup is given by the context in which the list is expanded. .endlist String expansions, lists, and lookups interact with each other in such a way @@ -6879,19 +6891,11 @@ is used on its own as the result. If the lookup does not succeed, the &`fail`& keyword causes a &'forced expansion failure'& &-- see section &<>& for an explanation of what this means. -The supported DNS record types are A, CNAME, MX, NS, PTR, SPF, SRV, TLSA and TXT, -and, when Exim is compiled with IPv6 support, AAAA (and A6 if that is also -configured). If no type is given, TXT is assumed. When the type is PTR, -the data can be an IP address, written as normal; inversion and the addition of -&%in-addr.arpa%& or &%ip6.arpa%& happens automatically. For example: -.code -${lookup dnsdb{ptr=192.168.4.5}{$value}fail} -.endd -If the data for a PTR record is not a syntactically valid IP address, it is not -altered and nothing is added. +The supported DNS record types are A, CNAME, MX, NS, PTR, SOA, SPF, SRV, TLSA +and TXT, and, when Exim is compiled with IPv6 support, AAAA. +If no type is given, TXT is assumed. -For any record type, if multiple records are found (or, for A6 lookups, if a -single record leads to multiple addresses), the data is returned as a +For any record type, if multiple records are found, the data is returned as a concatenation, with newline as the default separator. The order, of course, depends on the DNS resolver. You can specify a different separator character between multiple records by putting a right angle-bracket followed immediately @@ -6901,21 +6905,33 @@ ${lookup dnsdb{>: a=host1.example}} .endd It is permitted to specify a space as the separator character. Further white space is ignored. +For lookup types that return multiple fields per record, +an alternate field separator can be specified using a comma after the main +separator character, followed immediately by the field separator. + +.cindex "PTR record" "in &(dnsdb)& lookup" +When the type is PTR, +the data can be an IP address, written as normal; inversion and the addition of +&%in-addr.arpa%& or &%ip6.arpa%& happens automatically. For example: +.code +${lookup dnsdb{ptr=192.168.4.5}{$value}fail} +.endd +If the data for a PTR record is not a syntactically valid IP address, it is not +altered and nothing is added. .cindex "MX record" "in &(dnsdb)& lookup" .cindex "SRV record" "in &(dnsdb)& lookup" 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. -An alternate field separator can be specified using a comma after the main -separator character, followed immediately by the field separator. +The field separator can be modified as above. .cindex "TXT record" "in &(dnsdb)& lookup" .cindex "SPF record" "in &(dnsdb)& lookup" For TXT records with multiple items of data, only the first item is returned, -unless a separator for them is specified using a comma after the separator -character followed immediately by the TXT record item separator. To concatenate -items without a separator, use a semicolon instead. For SPF records the +unless a field separator is specified. +To concatenate items without a separator, use a semicolon instead. +For SPF records the default behaviour is to concatenate multiple items without using a separator. .code ${lookup dnsdb{>\n,: txt=a.b.example}} @@ -6925,11 +6941,20 @@ ${lookup dnsdb{spf=example.org}} It is permitted to specify a space as the separator character. Further white space is ignored. +.cindex "SOA record" "in &(dnsdb)& lookup" +For an SOA lookup, while no result is obtained the lookup is redone with +successively more leading components dropped from the given domain. +Only the primary-nameserver field is returned unless a field separator is +specified. +.code +${lookup dnsdb{>:,; soa=a.b.example.com}} +.endd + .section "Dnsdb lookup modifiers" "SECTdnsdb_mod" .cindex "dnsdb modifiers" .cindex "modifiers" "dnsdb" .cindex "options" "dnsdb" -Modifiers for &(dnsdb)& lookups are givien by optional keywords, +Modifiers for &(dnsdb)& lookups are given by optional keywords, each followed by a comma, that may appear before the record type. @@ -6964,6 +6989,26 @@ The default is &"never"&. See also the &$lookup_dnssec_authenticated$& variable. +.cindex timeout "dns lookup" +.cindex "DNS" timeout +Timeout for the dnsdb lookup can be controlled by a retrans modifier. +The form is &"retrans_VAL"& where VAL is an Exim time specification +(e.g. &"5s"&). +The default value is set by the main configuration option &%dns_retrans%&. + +Retries for the dnsdb lookup can be controlled by a retry modifier. +The form if &"retry_VAL"& where VAL is an integer. +The default count is set by the main configuration option &%dns_retry%&. + +.new +.cindex cacheing "of dns lookup" +.cindex TTL "of dns lookup" +.cindex DNS TTL +Dnsdb lookup results are cached within a single process (and its children). +The cache entry lifetime is limited to the smallest time-to-live (TTL) +value of the set of returned DNS records. +.wen + .section "Pseudo dnsdb record types" "SECID66" .cindex "MX record" "in &(dnsdb)& lookup" @@ -7013,7 +7058,7 @@ The authorization code can be &"Y"& for yes, &"N"& for no, &"X"& for explicit authorization required but absent, or &"?"& for unknown. .cindex "A+" "in &(dnsdb)& lookup" -The pseudo-type A+ performs an A6 lookup (if configured) followed by an AAAA +The pseudo-type A+ performs an AAAA and then an A lookup. All results are returned; defer processing (see below) is handled separately for each lookup. Example: .code @@ -7283,7 +7328,7 @@ The TIME parameter (also a number of seconds) is passed to the server to set a server-side limit on the time taken to complete a search. The SERVERS parameter allows you to specify an alternate list of ldap servers -to use for an individual lookup. The global ldap_servers option provides a +to use for an individual lookup. The global &%ldap_default_servers%& option provides a default list of ldap servers, and a single lookup can specify a single ldap server to use. But when you need to do a lookup with a list of servers that is different than the default list (maybe different order, maybe a completely @@ -7343,7 +7388,7 @@ SMTP authentication. See the &%ldapauth%& expansion string condition in chapter The &(ldapdn)& lookup type returns the Distinguished Name from a single entry as a sequence of values, for example .code -cn=manager, o=University of Cambridge, c=UK +cn=manager,o=University of Cambridge,c=UK .endd The &(ldap)& lookup type generates an error if more than one entry matches the search filter, whereas &(ldapm)& permits this case, and inserts a newline in @@ -7354,7 +7399,8 @@ directory. In the common case where you specify a single attribute in your LDAP query, the result is not quoted, and does not contain the attribute name. If the attribute -has multiple values, they are separated by commas. +has multiple values, they are separated by commas. Any comma that is +part of an attribute's value is doubled. If you specify multiple attributes, the result contains space-separated, quoted strings, each preceded by the attribute name and an equals sign. Within the @@ -7369,7 +7415,9 @@ same as specifying all of an entry's attributes. 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 -&%attr2%& has only one value: +&%attr2%& has only one value. Both attributes are derived from &%attr%& +(they have SUP &%attr%& in their schema definitions). + .code ldap:///o=base?attr1?sub?(uid=fred) value1.1,value1,,2 @@ -7377,6 +7425,9 @@ value1.1,value1,,2 ldap:///o=base?attr2?sub?(uid=fred) value two +ldap:///o=base?attr?sub?(uid=fred) +value1.1,value1,,2,value two + ldap:///o=base?attr1,attr2?sub?(uid=fred) attr1="value1.1,value1,,2" attr2="value two" @@ -7499,13 +7550,12 @@ a query is successfully processed. The result of a query may be that no data is found, but that is still a successful query. In other words, the list of servers provides a backup facility, not a list of different places to look. +.new The &%quote_mysql%&, &%quote_pgsql%&, and &%quote_oracle%& expansion operators convert newline, tab, carriage return, and backspace to \n, \t, \r, and \b respectively, and the characters single-quote, double-quote, and backslash -itself are escaped with backslashes. The &%quote_pgsql%& expansion operator, in -addition, escapes the percent and underscore characters. This cannot be done -for MySQL because these escapes are not recognized in contexts where these -characters are not special. +itself are escaped with backslashes. +.wen .section "Specifying the server in the query" "SECTspeserque" For MySQL and PostgreSQL lookups (but not currently for Oracle and InterBase), @@ -7551,13 +7601,17 @@ ${lookup pgsql{servers=master/db/name/pw; UPDATE ...} } .section "Special MySQL features" "SECID73" For MySQL, an empty host name or the use of &"localhost"& in &%mysql_servers%& causes a connection to the server on the local host by means of a Unix domain -socket. An alternate socket can be specified in parentheses. The full syntax of -each item in &%mysql_servers%& is: +socket. An alternate socket can be specified in parentheses. +.new +An option group name for MySQL option files can be specified in square brackets; +the default value is &"exim"&. +.wen +The full syntax of each item in &%mysql_servers%& is: .display -<&'hostname'&>::<&'port'&>(<&'socket name'&>)/<&'database'&>/&&& - <&'user'&>/<&'password'&> +<&'hostname'&>::<&'port'&>(<&'socket name'&>)[<&'option group'&>]/&&& + <&'database'&>/<&'user'&>/<&'password'&> .endd -Any of the three sub-parts of the first field can be omitted. For normal use on +Any of the four sub-parts of the first field can be omitted. For normal use on the local host it can be left blank or set to just &"localhost"&. No database need be supplied &-- but if it is absent here, it must be given in @@ -7638,6 +7692,10 @@ host, email address, or local part, respectively. In the sections below, the different types of pattern for each case are described, but first we cover some general facilities that apply to all four kinds of list. +Note that other parts of Exim use a &'string list'& which does not +support all the complexity available in +domain, host, address and local part lists. + .section "Expansion of lists" "SECID75" @@ -8420,7 +8478,7 @@ this section. .cindex "&`+ignore_defer`&" A temporary DNS lookup failure normally causes a defer action (except when &%dns_again_means_nonexist%& converts it into a permanent error). However, -host lists can include &`+ignore_defer`& and &`+include_defer`&, analagous to +host lists can include &`+ignore_defer`& and &`+include_defer`&, analogous to &`+ignore_unknown`& and &`+include_unknown`&, as described in the previous section. These options should be used with care, probably only in non-critical host lists such as whitelists. @@ -8911,7 +8969,7 @@ If the ACL returns defer the result is a forced-fail. Otherwise the expansion f .cindex "&%certextract%&" "certificate fields" .cindex "certificate" "extracting fields" The <&'certificate'&> must be a variable of type certificate. -The field name is expanded and used to retrive the relevant field from +The field name is expanded and used to retrieve the relevant field from the certificate. Supported fields are: .display &`version `& @@ -8942,11 +9000,11 @@ The field selectors marked as "RFC4514" above output a Distinguished Name string which is not quite parseable by Exim as a comma-separated tagged list -(the exceptions being elements containin commas). +(the exceptions being elements containing commas). RDN elements of a single type may be selected by a modifier of the type label; if so the expansion result is a list (newline-separated by default). -The separator may be changed by another modifer of +The separator may be changed by another modifier of a right angle-bracket followed immediately by the new separator. Recognised RDN type labels include "CN", "O", "OU" and "DC". @@ -8966,7 +9024,7 @@ The field selectors marked as "tagged" above prefix each list element with a type string and an equals sign. Elements of only one type may be selected by a modifier which is one of "dns", "uri" or "mail"; -if so the elenment tags are omitted. +if so the element tags are omitted. If not otherwise noted field values are presented in human-readable form. @@ -9008,6 +9066,30 @@ When compiling a function that is to be used in this way with gcc, you need to add &%-shared%& to the gcc command. Also, in the Exim build-time configuration, you must add &%-export-dynamic%& to EXTRALIBS. + +.vitem "&*${env{*&<&'key'&>&*}{*&<&'string1'&>&*}{*&<&'string2'&>&*}}*&" +.cindex "expansion" "extracting value from environment" +.cindex "environment" "value from" +The key is first expanded separately, and leading and trailing white space +removed. +This is then searched for as a name in the environment. +If a variable is found then its value is placed in &$value$& +and <&'string1'&> is expanded, otherwise <&'string2'&> is expanded. + +Instead of {<&'string2'&>} the word &"fail"& (not in curly brackets) can +appear, for example: +.code +${env{USER}{$value} fail } +.endd +This forces an expansion failure (see section &<>&); +{<&'string1'&>} must be present for &"fail"& to be recognized. + +If {<&'string2'&>} is omitted an empty string is substituted on +search failure. +If {<&'string1'&>} is omitted the search result is substituted on +search success. + + .vitem "&*${extract{*&<&'key'&>&*}{*&<&'string1'&>&*}{*&<&'string2'&>&*}&&& {*&<&'string3'&>&*}}*&" .cindex "expansion" "extracting substrings by key" @@ -9207,10 +9289,11 @@ by earlier ACLs are visible. Upper case and lower case letters are synonymous in header names. If the following character is white space, the terminating colon may be omitted, but this is not recommended, because you may then forget it when it is needed. When -white space terminates the header name, it is included in the expanded string. -If the message does not contain the given header, the expansion item is -replaced by an empty string. (See the &%def%& condition in section -&<>& for a means of testing for the existence of a header.) +white space terminates the header name, this white space is included in the +expanded string. If the message does not contain the given header, the +expansion item is replaced by an empty string. (See the &%def%& condition in +section &<>& for a means of testing for the existence of a +header.) If there is more than one header with the same name, they are all concatenated to form the substitution string, up to a maximum length of 64K. Unless @@ -9332,7 +9415,7 @@ yields &"42"&, and .code ${listextract{-3}{<, x,42,99,& Mailer,,/bin/bash}{result: $value}} .endd -yields &"result: 99"&. +yields &"result: 42"&. If {<&'string3'&>} is omitted, an empty string is used for string3. If {<&'string2'&>} is also omitted, the value that was @@ -9713,8 +9796,9 @@ the regular expression from string expansion. .vitem &*${sort{*&<&'string'&>&*}{*&<&'comparator'&>&*}{*&<&'extractor'&>&*}}*& -.cindex sorting a list +.cindex sorting "a list" .cindex list sorting +.cindex expansion "list sorting" After expansion, <&'string'&> is interpreted as a list, colon-separated by default, but the separator can be changed in the usual way. The <&'comparator'&> argument is interpreted as the operator @@ -9856,7 +9940,7 @@ processing lists. To clarify "list of addresses in RFC 2822 format" mentioned above, Exim follows a strict interpretation of header line formatting. Exim parses the bare, unquoted portion of an email address and if it finds a comma, treats it as an -email address seperator. For the example header line: +email address separator. For the example header line: .code From: =?iso-8859-2?Q?Last=2C_First?= .endd @@ -10040,6 +10124,27 @@ as is, and other byte values are converted to &`\xNN`&, for example a byte value 127 is converted to &`\x7f`&. +.new +.vitem &*${ipv6denorm:*&<&'string'&>&*}*& +.cindex "&%ipv6denorm%& expansion item" +.cindex "IP address" normalisation +This expands an IPv6 address to a full eight-element colon-separated set +of hex digits including leading zeroes. +A trailing ipv4-style dotted-decimal set is converted to hex. +Pure IPv4 addresses are converted to IPv4-mapped IPv6. + +.vitem &*${ipv6norm:*&<&'string'&>&*}*& +.cindex "&%ipv6norm%& expansion item" +.cindex "IP address" normalisation +.cindex "IP address" "canonical form" +This converts an IPv6 address to canonical form. +Leading zeroes of groups are omitted, and the longest +set of zero-valued groups is replaced with a double colon. +A trailing ipv4-style dotted-decimal set is converted to hex. +Pure IPv4 addresses are converted to IPv4-mapped IPv6. +.wen + + .vitem &*${lc:*&<&'string'&>&*}*& .cindex "case forcing in strings" .cindex "string" "case forcing" @@ -10202,7 +10307,7 @@ random(). .vitem &*${reverse_ip:*&<&'ipaddr'&>&*}*& .cindex "expansion" "IP address" This operator reverses an IP address; for IPv4 addresses, the result is in -dotted-quad decimal form, while for IPv6 addreses the result is in +dotted-quad decimal form, while for IPv6 addresses the result is in dotted-nibble hexadecimal form. In both cases, this is the "natural" form for DNS. For example, .code @@ -10223,7 +10328,7 @@ f.7.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2 This operator encodes text according to the rules of RFC 2047. This is an encoding that is used in header lines to encode non-ASCII characters. It is assumed that the input string is in the encoding specified by the -&%headers_charset%& option, which defaults to ISO-8859-1. If the string +&%headers_charset%& option, which gets its default at build time. If the string contains only characters in the range 33&--126, and no instances of the characters .code @@ -11051,7 +11156,8 @@ support for TLS or the content scanning extension. When a &%match%& expansion condition succeeds, these variables contain the captured substrings identified by the regular expression during subsequent processing of the success string of the containing &%if%& expansion item. -However, they do not retain their values afterwards; in fact, their previous +In the expansion condition case +they do not retain their values afterwards; in fact, their previous values are restored at the end of processing an &%if%& item. The numerical variables may also be set externally by some other matching process which precedes the expansion of the string. For example, the commands available in @@ -11259,9 +11365,10 @@ not the same as the user id of the originator of a message (see &$originator_uid$&). If Exim re-execs itself, this variable in the new incarnation normally contains the Exim uid. -.vitem &$compile_date$& -.vindex "&$compile_date$&" -The date on which the Exim binary was compiled. +.vitem &$callout_address$& +.vindex "&$callout_address$&" +After a callout for verification, spamd or malware daemon service, the +address that was connected to. .vitem &$compile_number$& .vindex "&$compile_number$&" @@ -11269,7 +11376,6 @@ 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. -.new .vitem &$config_dir$& .vindex "&$config_dir$&" The directory name of the main configuration file. That is, the content of @@ -11280,7 +11386,6 @@ contain the trailing slash. If &$config_file$& does not contain a slash, .vitem &$config_file$& .vindex "&$config_file$&" The name of the main configuration file Exim is using. -.wen .vitem &$demime_errorlevel$& .vindex "&$demime_errorlevel$&" @@ -11294,6 +11399,34 @@ This variable is available when Exim is compiled with the content-scanning extension and the obsolete &%demime%& condition. For details, see section &<>&. +.vitem &$dkim_cur_signer$& &&& + &$dkim_verify_status$& &&& + &$dkim_verify_reason$& &&& + &$dkim_domain$& &&& + &$dkim_identity$& &&& + &$dkim_selector$& &&& + &$dkim_algo$& &&& + &$dkim_canon_body$& &&& + &$dkim_canon_headers$& &&& + &$dkim_copiedheaders$& &&& + &$dkim_bodylength$& &&& + &$dkim_created$& &&& + &$dkim_expires$& &&& + &$dkim_headernames$& &&& + &$dkim_key_testing$& &&& + &$dkim_key_nosubdomains$& &&& + &$dkim_key_srvtype$& &&& + &$dkim_key_granularity$& &&& + &$dkim_key_notes$& +These variables are only available within the DKIM ACL. +For details see chapter &<>&. + +.vitem &$dkim_signers$& +.vindex &$dkim_signers$& +When a message has been received this variable contains +a colon-separated list of signer domains and identities for the message. +For details see chapter &<>&. + .vitem &$dnslist_domain$& &&& &$dnslist_matched$& &&& &$dnslist_text$& &&& @@ -11389,14 +11522,12 @@ This variable contains the path to the Exim binary. .vindex "&$exim_uid$&" This variable contains the numerical value of the Exim user id. -.new .vitem &$exim_version$& -.vindex "&$exim_uid$&" +.vindex "&$exim_version$&" 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. -.wen .vitem &$found_extension$& .vindex "&$found_extension$&" @@ -11657,9 +11788,13 @@ the space value is -1. See also the &%check_log_space%& option. .vindex "&$lookup_dnssec_authenticated$&" This variable is set after a DNS lookup done by a dnsdb lookup expansion, dnslookup router or smtp transport. +.cindex "DNS" "DNSSEC" It will be empty if &(DNSSEC)& was not requested, &"no"& if the result was not labelled as authenticated data and &"yes"& if it was. +Results that are labelled as authoritative answer that match +the &%dns_trust_aa%& configuration variable count also +as authenticated data. .vitem &$mailstore_basename$& .vindex "&$mailstore_basename$&" @@ -11892,6 +12027,13 @@ a single-component name, Exim calls &[gethostbyname()]& (or qualified host name. See also &$smtp_active_hostname$&. +.new +.vitem &$prdr_requested$& +.cindex "PRDR" "variable for" +This variable is set to &"yes"& if PRDR was requested by the client for the +current message, otherwise &"no"&. +.wen + .vitem &$prvscheck_address$& This variable is used in conjunction with the &%prvscheck%& expansion item, which is described in sections &<>& and @@ -12070,6 +12212,12 @@ increases for each accepted recipient. It can be referenced in an ACL. This variable is set to contain the matching regular expression after a &%regex%& ACL condition has matched (see section &<>&). +.vitem "&$regex1$&, &$regex2$&, etc" +.cindex "regex submatch variables (&$1regex$& &$2regex$& etc)" +When a &%regex%& or &%mime_regex%& ACL condition succeeds, +these variables contain the +captured substrings identified by the regular expression. + .vitem &$reply_address$& .vindex "&$reply_address$&" @@ -12174,6 +12322,12 @@ verification either failed or was not requested. A host name in parentheses is the argument of a HELO or EHLO command. This is omitted if it is identical to the verified host name or to the host's IP address in square brackets. +.vitem &$sender_helo_dnssec$& +.vindex "&$sender_helo_dnssec$&" +This boolean variable is true if a successful HELO verification was +.cindex "DNS" "DNSSEC" +done using DNS information the resolver library stated was authenticated data. + .vitem &$sender_helo_name$& .vindex "&$sender_helo_name$&" When a message is received from a remote host that has issued a HELO or EHLO @@ -12199,9 +12353,11 @@ received. It is empty if there was no successful authentication. See also If an attempt to populate &$sender_host_name$& has been made (by reference, &%hosts_lookup%& or otherwise) then this boolean will have been set true if, and only if, the -resolver library states that the reverse DNS was authenticated data. At all +resolver library states that both +the reverse and forward DNS were authenticated data. At all other times, this variable is false. +.cindex "DNS" "DNSSEC" It is likely that you will need to coerce DNSSEC support on in the resolver library, by setting: .code @@ -12209,10 +12365,7 @@ dns_dnssec_ok = 1 .endd Exim does not perform DNSSEC validation itself, instead leaving that to a -validating resolver (eg, unbound, or bind with suitable configuration). - -Exim does not (currently) check to see if the forward DNS was also secured -with DNSSEC, only the reverse DNS. +validating resolver (e.g. unbound, or bind with suitable configuration). If you have changed &%host_lookup_order%& so that &`bydns`& is not the first mechanism in the list, then this variable will be false. @@ -12451,6 +12604,8 @@ inbound connection when the message was received. It is only useful as the argument of a &%certextract%& expansion item, &%md5%&, &%sha1%& or &%sha256%& operator, or a &%def%& condition. +If certificate verification fails it may refer to a failing chain element +which is not the leaf. .vitem &$tls_out_ourcert$& .vindex "&$tls_out_ourcert$&" @@ -12465,13 +12620,15 @@ This variable refers to the certificate presented by the peer of an outbound connection. It is only useful as the argument of a &%certextract%& expansion item, &%md5%&, &%sha1%& or &%sha256%& operator, or a &%def%& condition. +If certificate verification fails it may refer to a failing chain element +which is not the leaf. .vitem &$tls_in_certificate_verified$& .vindex "&$tls_in_certificate_verified$&" This variable is set to &"1"& if a TLS certificate was verified when the message was received, and &"0"& otherwise. -The deprecated &$tls_certificate_verfied$& variable refers to the inbound side +The deprecated &$tls_certificate_verified$& variable refers to the inbound side except when used in the context of an outbound SMTP delivery, when it refers to the outbound. @@ -12528,6 +12685,8 @@ When a message is received from a remote host over an encrypted SMTP connection, and Exim is configured to request a certificate from the client, the value of the Distinguished Name of the certificate is made available in the &$tls_in_peerdn$& during subsequent processing. +If certificate verification fails it may refer to a failing chain element +which is not the leaf. The deprecated &$tls_peerdn$& variable refers to the inbound side except when used in the context of an outbound SMTP delivery, when it refers to @@ -12539,6 +12698,8 @@ When a message is being delivered to a remote host over an encrypted SMTP connection, and Exim is configured to request a certificate from the server, the value of the Distinguished Name of the certificate is made available in the &$tls_out_peerdn$& during subsequent processing. +If certificate verification fails it may refer to a failing chain element +which is not the leaf. .vitem &$tls_in_sni$& .vindex "&$tls_in_sni$&" @@ -13169,6 +13330,7 @@ listed in more than one group. .row &%message_logs%& "create per-message logs" .row &%preserve_message_logs%& "after message completion" .row &%process_log_path%& "for SIGUSR1 and &'exiwhat'&" +.row &%slow_lookup_log%& "control logging of slow DNS lookups" .row &%syslog_duplication%& "controls duplicate log lines on syslog" .row &%syslog_facility%& "set syslog &""facility""& field" .row &%syslog_processname%& "set syslog &""ident""& field" @@ -13282,6 +13444,7 @@ listed in more than one group. .row &%acl_smtp_mail%& "ACL for MAIL" .row &%acl_smtp_mailauth%& "ACL for AUTH on MAIL command" .row &%acl_smtp_mime%& "ACL for MIME parts" +.row &%acl_smtp_notquit%& "ACL for non-QUIT terminations" .row &%acl_smtp_predata%& "ACL for start of data" .row &%acl_smtp_quit%& "ACL for QUIT" .row &%acl_smtp_rcpt%& "ACL for RCPT" @@ -13335,6 +13498,7 @@ listed in more than one group. .row &%tls_crl%& "certificate revocation list" .row &%tls_dh_max_bits%& "clamp D-H bit count suggestion" .row &%tls_dhparam%& "DH parameters for server" +.row &%tls_eccurve%& "EC curve selection for server" .row &%tls_ocsp_file%& "location of server certificate status proof" .row &%tls_on_connect_ports%& "specify SSMTP (SMTPS) ports" .row &%tls_privatekey%& "location of server private key" @@ -13389,6 +13553,7 @@ listed in more than one group. See also the &'Policy controls'& section above. .table2 +.row &%dkim_verify_signers%& "DKIM domain for which DKIM ACL is run" .row &%host_lookup%& "host name looked up for these hosts" .row &%host_lookup_order%& "order of DNS and local name lookups" .row &%recipient_unqualified_hosts%& "may send unqualified recipients" @@ -13482,6 +13647,7 @@ See also the &'Policy controls'& section above. .row &%dns_ipv4_lookup%& "only v4 lookup for these domains" .row &%dns_retrans%& "parameter for resolver" .row &%dns_retry%& "parameter for resolver" +.row &%dns_trust_aa%& "DNS zones trusted as authentic" .row &%dns_use_edns0%& "parameter for resolver" .row &%hold_domains%& "hold delivery for these domains" .row &%local_interfaces%& "for routing checks" @@ -13584,19 +13750,23 @@ 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 &<>& for further details. -.new .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" -.wen This option defines the ACL that, if the PRDR feature has been negotiated, is run for each recipient after an SMTP DATA command has been processed and the message itself has been received, but before the acknowledgment is sent. See chapter &<>& for further details. +.option acl_smtp_dkim main string&!! unset +.cindex DKIM "ACL for" +This option defines the ACL that is run for each DKIM signature +of a received message. +See chapter &<>& for further details. + .option acl_smtp_etrn main string&!! unset .cindex "ETRN" "ACL for" This option defines the ACL that is run when an SMTP ETRN command is @@ -13631,6 +13801,12 @@ This option is available when Exim is built with the content-scanning extension. It defines the ACL that is run for each MIME part in a message. See section &<>& for details. +.option acl_smtp_notquit main string&!! unset +.cindex "not-QUIT, ACL for" +This option defines the ACL that is run when an SMTP session +ends without a QUIT command being received. +See chapter &<>& for further details. + .option acl_smtp_predata main string&!! unset This option defines the ACL that is run when an SMTP DATA command is received, before the message itself is received. See chapter &<>& for @@ -13687,7 +13863,7 @@ the local host's IP addresses. It appears that more and more DNS zone administrators are breaking the rules and putting domain names that look like IP addresses on the right hand side of MX records. Exim follows the rules and rejects this, giving an error message -that explains the mis-configuration. However, some other MTAs support this +that explains the misconfiguration. However, some other MTAs support this practice, so to avoid &"Why can't Exim do this?"& complaints, &%allow_mx_to_ip%& exists, in order to enable this heinous activity. It is not recommended, except when you have no other choice. @@ -14066,6 +14242,14 @@ etc. are ignored. If IP literals are enabled, the &(ipliteral)& router declines to handle IPv6 literal addresses. +.option dkim_verify_signers main "domain list&!!" $dkim_signers +.cindex DKIM "controlling calls to the ACL" +This option gives a list of DKIM domains for which the DKIM ACL is run. +It is expanded after the message is received; by default it runs +the ACL once for each signature in the message. +See chapter &<>&. + + .option dns_again_means_nonexist main "domain list&!!" unset .cindex "DNS" "&""try again""& response; overriding" DNS lookups give a &"try again"& response for the DNS errors @@ -14141,6 +14325,8 @@ servers have all been upgraded, there should be no need for this option. .option dns_retrans main time 0s .cindex "DNS" "resolver options" +.cindex timeout "dns lookup" +.cindex "DNS" timeout The options &%dns_retrans%& and &%dns_retry%& can be used to set the retransmission and retry parameters for DNS lookups. Values of zero (the defaults) leave the system default settings unchanged. The first value is the @@ -14150,12 +14336,39 @@ take. I haven't found any documentation about timeouts on DNS lookups; these parameter values are available in the external resolver interface structure, but nowhere does it seem to describe how they are used or what you might want to set in them. +See also the &%slow_lookup_log%& option. .option dns_retry main integer 0 See &%dns_retrans%& above. +.option dns_trust_aa main "domain list&!!" unset +.cindex "DNS" "resolver options" +.cindex "DNS" "DNSSEC" +If this option is set then lookup results marked with the AA bit +(Authoritative Answer) are trusted the same way as if they were +DNSSEC-verified. The authority section's name of the answer must +match with this expanded domain list. + +Use this option only if you talk directly to a resolver that is +authoritative for some zones and does not set the AD (Authentic Data) +bit in the answer. Some DNS servers may have an configuration option to +mark the answers from their own zones as verified (they set the AD bit). +Others do not have this option. It is considered as poor practice using +a resolver that is an authoritative server for some zones. + +Use this option only if you really have to (e.g. if you want +to use DANE for remote delivery to a server that is listed in the DNS +zones that your resolver is authoritative for). + +If the DNS answer packet has the AA bit set and contains resource record +in the answer section, the name of the first NS record appearing in the +authority section is compared against the list. If the answer packet is +authoritative but the answer section is empty, the name of the first SOA +record in the authoritative section is used instead. + +.cindex "DNS" "resolver options" .option dns_use_edns0 main integer -1 .cindex "DNS" "resolver options" .cindex "DNS" "EDNS0" @@ -14172,7 +14385,6 @@ 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 &<>&. -.new .option dsn_advertise_hosts main "host list&!!" unset .cindex "bounce messages" "success" .cindex "DSN" "success" @@ -14184,7 +14396,6 @@ 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. -.wen .option dsn_from main "string&!!" "see below" .cindex "&'From:'& header line" "in bounces" @@ -14203,7 +14414,7 @@ panic is logged, and the default value is used. Exim's transports have an option for adding an &'Envelope-to:'& header to a message when it is delivered, in exactly the same way as &'Return-path:'& is handled. &'Envelope-to:'& records the original recipient address from the -messages's envelope that caused the delivery to happen. Such headers should not +message's envelope that caused the delivery to happen. Such headers should not be present in incoming messages, and this option causes them to be removed at the time the message is received, to avoid any problems that might occur when a delivered message is subsequently sent on to some other recipient. @@ -14310,7 +14521,7 @@ routing, but which are not used for listening by the daemon. See section . Allow this long option name to split; give it unsplit as a fifth argument . for the automatic .oindex that is generated by .option. -.option "extract_addresses_remove_ &~&~arguments" main boolean true &&& +.option "extract_addresses_remove_arguments" main boolean true &&& extract_addresses_remove_arguments .oindex "&%-t%&" .cindex "command line" "addresses with &%-t%&" @@ -14494,14 +14705,17 @@ is an IP literal matching the calling address of the host, or matches the host name that Exim obtains by doing a reverse lookup of the calling host address, or .next -when looked up using &[gethostbyname()]& (or &[getipnodebyname()]& when -available) yields the calling host address. +when looked up in DNS yields the calling host address. .endlist However, the EHLO or HELO command is not rejected if any of the checks fail. Processing continues, but the result of the check is remembered, and can be detected later in an ACL by the &`verify = helo`& condition. +If DNS was used for successful verification, the variable +.cindex "DNS" "DNSSEC" +&$helo_verify_dnssec$& records the DNSSEC status of the lookups. + .option helo_verify_hosts main "host list&!!" unset .cindex "HELO verifying" "mandatory" .cindex "EHLO" "verifying, mandatory" @@ -14875,8 +15089,9 @@ section &<>&. This option sets the path which is used to determine the names of Exim's log files, or indicates that logging is to be to syslog, or both. It is expanded when Exim is entered, so it can, for example, contain a reference to the host -name. If no specific path is set for the log files at compile or run time, they -are written in a sub-directory called &_log_& in Exim's spool directory. +name. If no specific path is set for the log files at compile or run time, +or if the option is unset at run time (i.e. &`log_file_path = `&) +they are written in a sub-directory called &_log_& in Exim's spool directory. Chapter &<>& contains further details about Exim's logging, and section &<>& describes how the contents of &%log_file_path%& are used. If this string is fixed at your installation (contains no expansion @@ -15023,7 +15238,7 @@ If you use a virus-scanner and set this option to to a value larger than the maximum size that your virus-scanner is configured to support, you may get failures triggered by large mails. The right size to configure for the virus-scanner depends upon what data is passed and the options in use but it's -probably safest to just set it to a little larger than this value. Eg, with a +probably safest to just set it to a little larger than this value. E.g., with a default Exim message size of 50M and a default ClamAV StreamMaxLength of 10M, some problems may result. @@ -15263,9 +15478,9 @@ not count as protocol errors (see &%smtp_max_synprot_errors%&). This option can be used to enable the Per-Recipient Data Response extension to SMTP, defined by Eric Hall. If the option is set, PRDR is advertised by Exim when operating as a server. -If the client requests PRDR, and more than one recipient, for a message +If the client requests PRDR, and more than one recipient, for a message an additional ACL is called for each recipient after the message content -is recieved. See section &<>&. +is received. See section &<>&. .option preserve_message_logs main boolean false .cindex "message logs" "preserving" @@ -15678,7 +15893,6 @@ the time of delivery. They are normally used only for final local deliveries. This option is an obsolete synonym for &%bounce_return_size_limit%&. -.new .option rfc1413_hosts main "host list&!!" @[] .cindex "RFC 1413" .cindex "host" "for RFC 1413 calls" @@ -15686,11 +15900,8 @@ 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. -.wen -.new .option rfc1413_query_timeout main time 0s -.wen .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, @@ -15709,6 +15920,16 @@ it qualifies them only if the message came from a host that matches using TCP/IP), and the &%-bnq%& option was not set. +.option slow_lookup_log main integer 0 +.cindex "logging" "slow lookups" +.cindex "dns" "logging slow lookups" +This option controls logging of slow lookups. +If the value is nonzero it is taken as a number of milliseconds +and lookups taking longer than this are logged. +Currently this applies only to DNS lookups. + + + .option smtp_accept_keepalive main boolean true .cindex "keepalive" "on incoming connection" This option controls the setting of the SO_KEEPALIVE option on incoming @@ -16375,7 +16596,9 @@ runs. This is appropriate behaviour for obtaining wall-clock time on some, but unfortunately not all, operating systems. -.option tls_advertise_hosts main "host list&!!" unset +.new +.option tls_advertise_hosts main "host list&!!" * +.wen .cindex "TLS" "advertising" .cindex "encryption" "on SMTP connection" .cindex "SMTP" "encrypted connection" @@ -16383,6 +16606,11 @@ When Exim is built with support for TLS encrypted connections, the availability of the STARTTLS command to set up an encrypted session is advertised in response to EHLO only to those client hosts that match this option. See chapter &<>& for details of Exim's support for TLS. +.new +Note that the default value requires that a certificate be supplied +using the &%tls_certificate%& option. If no certificate is available then +the &%tls_advertise_hosts%& option should be set empty. +.wen .option tls_certificate main string&!! unset @@ -16488,14 +16716,35 @@ prior to the 4.80 release, as Debian used to patch Exim to raise the minimum acceptable bound from 1024 to 2048. +.option tls_eccurve main string&!! prime256v1 +.cindex TLS "EC cryptography" +If built with a recent-enough version of OpenSSL, +this option selects a EC curve for use by Exim. + +Curve names of the form &'prime256v1'& are accepted. +For even more-recent library versions, names of the form &'P-512'& +are also accepted, plus the special value &'auto'& +which tell the library to choose. + +If the option is set to an empty string, no EC curves will be enabled. + + .option tls_ocsp_file main string&!! unset +.cindex TLS "certificate status" +.cindex TLS "OCSP proof file" This option must if set expand to the absolute path to a file which contains a current status proof for the server's certificate, as obtained from the Certificate Authority. +.new +Usable for GnuTLS 3.4.4 or 3.3.17 or OpenSSL 1.1.0 (or later). +.wen + .option tls_on_connect_ports main "string list" unset +.cindex SSMTP +.cindex SMTPS This option specifies a list of incoming SSMTP (aka SMTPS) ports that should operate the obsolete SSMTP (SMTPS) protocol, where a TLS session is immediately set up without waiting for the client to issue a STARTTLS command. For @@ -16542,7 +16791,6 @@ preference order of the available ciphers. Details are given in sections See &%tls_verify_hosts%& below. -.new .option tls_verify_certificates main string&!! system .cindex "TLS" "client certificate verification" .cindex "certificate" "verification of client" @@ -16558,14 +16806,13 @@ 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 +The use of a directory for the option value is not available 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. -.wen These certificates should be for the certificate authorities trusted, rather than the public cert of individual clients. With both OpenSSL and GnuTLS, if @@ -17005,6 +17252,25 @@ or for any deliveries caused by this router. You should not set this option unless you really, really know what you are doing. See also the generic transport option of the same name. +.option dnssec_request_domains routers "domain list&!!" unset +.cindex "MX record" "security" +.cindex "DNSSEC" "MX lookup" +.cindex "security" "MX lookup" +.cindex "DNS" "DNSSEC" +DNS lookups for domains matching &%dnssec_request_domains%& will be done with +the dnssec request bit set. +This applies to all of the SRV, MX, AAAA, A lookup sequence. + +.option dnssec_require_domains routers "domain list&!!" unset +.cindex "MX record" "security" +.cindex "DNSSEC" "MX lookup" +.cindex "security" "MX lookup" +.cindex "DNS" "DNSSEC" +DNS lookups for domains matching &%dnssec_request_domains%& will be done with +the dnssec request bit set. Any returns not having the Authenticated Data bit +(AD bit) set will be ignored and logged as a host-lookup failure. +This applies to all of the SRV, MX, AAAA, A lookup sequence. + .option domains routers&!? "domain list&!!" unset .cindex "router" "restricting to specific domains" @@ -17022,7 +17288,6 @@ This option must always be set. It specifies which of the available routers is to be used. -.new .option dsn_lasthop routers boolean false .cindex "DSN" "success" .cindex "Delivery Status Notification" "success" @@ -17030,7 +17295,6 @@ 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. -.wen @@ -17154,7 +17418,8 @@ and the discussion in chapter &<>&. .option headers_add routers list&!! unset .cindex "header lines" "adding" .cindex "router" "adding header lines" -This option specifies a list of text headers, newline-separated, +This option specifies a list of text headers, +newline-separated (by default, changeable in the usual way), that is associated with any addresses that are accepted by the router. Each item is separately expanded, at routing time. However, this option has no effect when an address is just being verified. The way in which @@ -17191,7 +17456,8 @@ avoided. The &%repeat_use%& option of the &%redirect%& router may be of help. .option headers_remove routers list&!! unset .cindex "header lines" "removing" .cindex "router" "removing header lines" -This option specifies a list of text headers, colon-separated, +This option specifies a list of text headers, +colon-separated (by default, changeable in the usual way), that is associated with any addresses that are accepted by the router. Each item is separately expanded, at routing time. However, this option has no effect when an address is just being verified. The way in which @@ -17217,6 +17483,11 @@ removal requests are deleted when the address is passed on to subsequent routers, and this can lead to problems with duplicates -- see the similar warning for &%headers_add%& above. +&*Warning 3*&: Because of the separate expansion of the list items, +items that contain a list separator must have it doubled. +To avoid this, change the list separator (&<>&). + + .option ignore_target_hosts routers "host list&!!" unset .cindex "IP address" "discarding" @@ -17948,7 +18219,7 @@ happens is controlled by the generic &%self%& option. .section "Problems with DNS lookups" "SECTprowitdnsloo" There have been problems with DNS servers when SRV records are looked up. -Some mis-behaving servers return a DNS error or timeout when a non-existent +Some misbehaving servers return a DNS error or timeout when a non-existent SRV record is sought. Similar problems have in the past been reported for MX records. The global &%dns_again_means_nonexist%& option can help with this problem, but it is heavy-handed because it is a global option. @@ -17970,6 +18241,9 @@ There are a few cases where a &(dnslookup)& router will decline to accept an address; if such a router is expected to handle "all remaining non-local domains", then it is important to set &%no_more%&. +The router will defer rather than decline if the domain +is found in the &%fail_defer_domains%& router option. + Reasons for a &(dnslookup)& router to decline currently include: .ilist The domain does not exist in DNS @@ -18048,27 +18322,16 @@ when there is a DNS lookup error. -.option dnssec_request_domains dnslookup "domain list&!!" unset -.cindex "MX record" "security" -.cindex "DNSSEC" "MX lookup" -.cindex "security" "MX lookup" -.cindex "DNS" "DNSSEC" -DNS lookups for domains matching &%dnssec_request_domains%& will be done with -the dnssec request bit set. -This applies to all of the SRV, MX A6, AAAA, A lookup sequence. - - - -.option dnssec_require_domains dnslookup "domain list&!!" unset -.cindex "MX record" "security" -.cindex "DNSSEC" "MX lookup" -.cindex "security" "MX lookup" -.cindex "DNS" "DNSSEC" -DNS lookups for domains matching &%dnssec_request_domains%& will be done with -the dnssec request bit set. Any returns not having the Authenticated Data bit -(AD bit) set wil be ignored and logged as a host-lookup failure. -This applies to all of the SRV, MX A6, AAAA, A lookup sequence. +.option fail_defer_domains dnslookup "domain list&!!" unset +.cindex "MX record" "not found" +DNS lookups for domains matching &%fail_defer_domains%& +which find no matching record will cause the router to defer +rather than the default behaviour of decline. +This maybe be useful for queueing messages for a newly created +domain while the DNS configuration is not ready. +However, it will result in any message with mistyped domains +also being queued. .option mx_domains dnslookup "domain list&!!" unset @@ -19039,12 +19302,10 @@ 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. -.new 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. -.wen @@ -19312,7 +19573,7 @@ the router to decline. Instead, the alias item .cindex "black hole" .cindex "abandoning mail" &':blackhole:'& can be used. It does what its name implies. No delivery is -done, and no error message is generated. This has the same effect as specifing +done, and no error message is generated. This has the same effect as specifying &_/dev/null_& as a destination, but it can be independently disabled. &*Warning*&: If &':blackhole:'& appears anywhere in a redirection list, no @@ -20238,7 +20499,8 @@ value that the router supplies, and also overriding any value associated with .option headers_add transports list&!! unset .cindex "header lines" "adding in transport" .cindex "transport" "header lines; adding" -This option specifies a list of text headers, newline-separated, +This option specifies a list of text headers, +newline-separated (by default, changeable in the usual way), which are (separately) expanded and added to the header portion of a message as it is transported, as described in section &<>&. Additional header lines can also be specified by @@ -20263,7 +20525,8 @@ checked, since this option does not automatically suppress them. .option headers_remove transports list&!! unset .cindex "header lines" "removing" .cindex "transport" "header lines; removing" -This option specifies a list of header names, colon-separated; +This option specifies a list of header names, +colon-separated (by default, changeable in the usual way); these headers are omitted from the message as it is transported, as described in section &<>&. Header removal can also be specified by routers. @@ -20275,6 +20538,10 @@ errors and cause the delivery to be deferred. Unlike most options, &%headers_remove%& can be specified multiple times for a router; all listed headers are removed. +&*Warning*&: Because of the separate expansion of the list items, +items that contain a list separator must have it doubled. +To avoid this, change the list separator (&<>&). + .option headers_rewrite transports string unset @@ -20323,6 +20590,32 @@ transport, the &[initgroups()]& function is called when running the transport to ensure that any additional groups associated with the uid are set up. +.new +.option max_parallel transports integer&!! unset +.cindex limit "transport parallelism" +.cindex transport "parallel processes" +.cindex transport "concurrency limit" +.cindex "delivery" "parallelism for transport" +If this option is set and expands to an integer greater than zero +it limits the number of concurrent runs of the transport. +The control does not apply to shadow transports. + +.cindex "hints database" "transport concurrency control" +Exim implements this control by means of a hints database in which a record is +incremented whenever a transport process is beaing created. The record +is decremented and possibly removed when the process terminates. +Obviously there is scope for +records to get left lying around if there is a system or program crash. To +guard against this, Exim ignores any records that are more than six hours old. + +If you use this option, you should also arrange to delete the +relevant hints database whenever your system reboots. The names of the files +start with &_misc_& and they are kept in the &_spool/db_& directory. There +may be one or two files, depending on the type of DBM in use. The same files +are used for ETRN and smtp transport serialization. +.wen + + .option message_size_limit transports string&!! 0 .cindex "limit" "message size per transport" .cindex "size" "of message, limit" @@ -20469,6 +20762,9 @@ headers that some sites insist on. This option sets up a filtering (in the Unix shell sense) process for messages at transport time. It should not be confused with mail filtering as set up by individual users or via a system filter. +.new +If unset, or expanding to an empty string, no filtering is done. +.wen When the message is about to be written out, the command specified by &%transport_filter%& is started up in a separate, parallel process, and @@ -22220,6 +22516,10 @@ If two messages arrive at almost the same time, and both are routed to a pipe delivery, the two pipe transports may be run concurrently. You must ensure that any pipe commands you set up are robust against this happening. If the commands write to a file, the &%exim_lock%& utility might be of use. +.new +Alternatively the &%max_parallel%& option could be used with a value +of "1" to enforce serialization. +.wen @@ -22484,6 +22784,7 @@ Note that &$address_pipe$& is handled specially in &%command%& when &%force_command%& is set, expanding out to the original argument vector as separate items, similarly to a Unix shell &`"$@"`& construct. + .option ignore_status pipe boolean false If this option is true, the status returned by the subprocess that is set up to run the command is ignored, and Exim behaves as if zero had been returned. @@ -22494,27 +22795,29 @@ from the transport unless the status value is one of those listed in &*Note*&: This option does not apply to timeouts, which do not return a status. See the &%timeout_defer%& option for how timeouts are handled. + .option log_defer_output pipe boolean false .cindex "&(pipe)& transport" "logging output" If this option is set, and the status returned by the command is one of the codes listed in &%temp_errors%& (that is, delivery was deferred), -and any output was produced, the first line of it is written to the main log. +and any output was produced on stdout or stderr, the first line of it is +written to the main log. .option log_fail_output pipe boolean false -If this option is set, and the command returns any output, and also ends with a -return code that is neither zero nor one of the return codes listed in -&%temp_errors%& (that is, the delivery failed), the first line of output is -written to the main log. This option and &%log_output%& are mutually exclusive. -Only one of them may be set. - +If this option is set, and the command returns any output on stdout or +stderr, and also ends with a return code that is neither zero nor one of +the return codes listed in &%temp_errors%& (that is, the delivery +failed), the first line of output is written to the main log. This +option and &%log_output%& are mutually exclusive. Only one of them may +be set. .option log_output pipe boolean false -If this option is set and the command returns any output, the first line of -output is written to the main log, whatever the return code. This option and -&%log_fail_output%& are mutually exclusive. Only one of them may be set. - +If this option is set and the command returns any output on stdout or +stderr, the first line of output is written to the main log, whatever +the return code. This option and &%log_fail_output%& are mutually +exclusive. Only one of them may be set. .option max_output pipe integer 20K @@ -22988,7 +23291,7 @@ details. .cindex "DNS" "DNSSEC" DNS lookups for domains matching &%dnssec_request_domains%& will be done with the dnssec request bit set. -This applies to all of the SRV, MX A6, AAAA, A lookup sequence. +This applies to all of the SRV, MX, AAAA, A lookup sequence. @@ -22999,8 +23302,8 @@ This applies to all of the SRV, MX A6, AAAA, A lookup sequence. .cindex "DNS" "DNSSEC" DNS lookups for domains matching &%dnssec_request_domains%& will be done with the dnssec request bit set. Any returns not having the Authenticated Data bit -(AD bit) set wil be ignored and logged as a host-lookup failure. -This applies to all of the SRV, MX A6, AAAA, A lookup sequence. +(AD bit) set will be ignored and logged as a host-lookup failure. +This applies to all of the SRV, MX, AAAA, A lookup sequence. @@ -23151,12 +23454,11 @@ that matches this list, even if the server host advertises PIPELINING support. Exim will not try to start a TLS session when delivering to any host that matches this list. See chapter &<>& for details of TLS. -.option hosts_verify_avoid_tls smtp "host list&!!" * +.option hosts_verify_avoid_tls smtp "host list&!!" unset .cindex "TLS" "avoiding for certain hosts" Exim will not try to start a TLS session for a verify callout, or when delivering in cutthrough mode, to any host that matches this list. -Note that the default is to not use TLS. .option hosts_max_try smtp integer 5 @@ -23253,14 +23555,12 @@ connects. If authentication fails, Exim will try to transfer the message unauthenticated. See also &%hosts_require_auth%&, and chapter &<>& for details of authentication. -.new .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. -.wen .option interface smtp "string list&!!" unset .cindex "bind IP address" @@ -23327,11 +23627,9 @@ 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. -.new It is expanded per-address and can depend on any of &$address_data$&, &$domain_data$&, &$local_part_data$&, &$host$&, &$host_address$& and &$host_port$&. -.wen .option port smtp string&!! "see below" .cindex "port" "sending TCP/IP" @@ -23361,7 +23659,7 @@ protocol (RFC 2033) instead of SMTP. This protocol is sometimes used for local deliveries into closed message stores. Exim also has support for running LMTP over a pipe to a local process &-- see chapter &<>&. -If this option is set to &"smtps"&, the default vaule for the &%port%& option +If this option is set to &"smtps"&, the default value for the &%port%& option changes to &"smtps"&, and the transport initiates TLS immediately after connecting, as an outbound SSL-on-connect, instead of using STARTTLS to upgrade. The Internet standards bodies strongly discourage use of this mode. @@ -23378,9 +23676,7 @@ 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. -.new Since it is expanded it can be made to depend on the host or domain. -.wen .option serialize_hosts smtp "host list&!!" unset @@ -23406,6 +23702,10 @@ start with &_misc_& and they are kept in the &_spool/db_& directory. There may be one or two files, depending on the type of DBM in use. The same files are used for ETRN serialization. +.new +See also the &%max_parallel%& generic transport option. +.wen + .option size_addition smtp integer 1024 .cindex "SMTP" "SIZE" @@ -23518,9 +23818,7 @@ unknown state), opens a new one to the same host, and then tries the delivery in clear. -.new .option tls_try_verify_hosts smtp "host list&!!" * -.wen .cindex "TLS" "server certificate verification" .cindex "certificate" "verification of server" This option gives a list of hosts for which, on encrypted connections, @@ -23533,7 +23831,6 @@ The &$tls_out_certificate_verified$& variable is set when certificate verification succeeds. -.new .option tls_verify_cert_hostnames smtp "host list&!!" * .cindex "TLS" "server certificate hostname verification" .cindex "certificate" "verification of server" @@ -23545,10 +23842,8 @@ 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. -.wen -.new .option tls_verify_certificates smtp string&!! system .cindex "TLS" "server certificate verification" .cindex "certificate" "verification of server" @@ -23565,9 +23860,8 @@ 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 +The use of a directory for the option value is not available for GnuTLS versions preceding 3.3.6 and a single file must be used. -.wen With OpenSSL the certificates specified explicitly @@ -23578,7 +23872,7 @@ 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 &<>& for details of TLS. -For back-compatability, +For back-compatibility, 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. @@ -24063,7 +24357,7 @@ replaced, not just the working part. The replacement must be a complete RFC 2822 address, including the angle brackets if necessary. If text outside angle brackets contains a character whose value is greater than 126 or less than 32 (except for tab), the text is encoded according to RFC 2047. The character set -is taken from &%headers_charset%&, which defaults to ISO-8859-1. +is taken from &%headers_charset%&, which gets its default at build time. When the &"w"& flag is set on a rule that causes an envelope address to be rewritten, all but the working part of the replacement address is discarded. @@ -24335,6 +24629,13 @@ A server unexpectedly closed the SMTP connection. There may, of course, legitimate reasons for this (host died, network died), but if it repeats a lot for the same host, it indicates something odd. +.vitem &%lookup%& +A DNS lookup for a host failed. +Note that a &%dnslookup%& router will need to have matched +its &%fail_defer_domains%& option for this retry type to be usable. +Also note that a &%manualroute%& router will probably need +its &%host_find_failed%& option set to &%defer%&. + .vitem &%refused_MX%& A connection to a host obtained from an MX record was refused. @@ -24746,6 +25047,7 @@ AUTH_GSASL=yes AUTH_HEIMDAL_GSSAPI=yes AUTH_PLAINTEXT=yes AUTH_SPA=yes +AUTH_TLS=yes .endd in &_Local/Makefile_&, respectively. The first of these supports the CRAM-MD5 authentication mechanism (RFC 2195), and the second provides an interface to @@ -24760,6 +25062,8 @@ The sixth can be configured to support the PLAIN authentication mechanism (RFC 2595) or the LOGIN mechanism, which is not formally documented, but used by several MUAs. The seventh authenticator supports Microsoft's &'Secure Password Authentication'& mechanism. +The eighth is an Exim authenticator but not an SMTP one; +instead it can use information from a TLS negotiation. The authenticators are configured using the same syntax as other drivers (see section &<>&). If no authenticators are required, no @@ -24831,7 +25135,7 @@ client_condition = ${if !eq{$tls_out_cipher}{}} .option client_set_id authenticators string&!! unset When client authentication succeeds, this condition is expanded; the -result is used in the log lines for outbound messasges. +result is used in the log lines for outbound messages. Typically it will be the user name used for authentication. @@ -25479,7 +25783,7 @@ cyrusless_crammd5: driver = cram_md5 public_name = CRAM-MD5 server_secret = ${lookup{$auth1:mail.example.org:userPassword}\ - dbmjz{/etc/sasldb2}} + dbmjz{/etc/sasldb2}{$value}fail} server_set_id = $auth1 .endd @@ -25849,7 +26153,7 @@ The value should be a pathname, with no &"file:"& prefix. .option server_service heimdal_gssapi string&!! "smtp" This option specifies the service identifier used, in conjunction with -&%server_hostname%&, for building the identifer for finding credentials +&%server_hostname%&, for building the identifier for finding credentials from the keytab. @@ -25966,6 +26270,79 @@ msn: +. //////////////////////////////////////////////////////////////////////////// +. //////////////////////////////////////////////////////////////////////////// + +.chapter "The tls authenticator" "CHAPtlsauth" +.scindex IIDtlsauth1 "&(tls)& authenticator" +.scindex IIDtlsauth2 "authenticators" "&(tls)&" +.cindex "authentication" "Client Certificate" +.cindex "authentication" "X509" +.cindex "Certificate-based authentication" +The &(tls)& authenticator provides server support for +authentication based on client certificates. + +It is not an SMTP authentication mechanism and is not +advertised by the server as part of the SMTP EHLO response. +It is an Exim authenticator in the sense that it affects +the protocol element of the log line, can be tested for +by the &%authenticated%& ACL condition, and can set +the &$authenticated_id$& variable. + +The client must present a verifiable certificate, +for which it must have been requested via the +&%tls_verify_hosts%& or &%tls_try_verify_hosts%& main options +(see &<>&). + +If an authenticator of this type is configured it is +run before any SMTP-level communication is done, +and can authenticate the connection. +If it does, SMTP authentication is not offered. + +A maximum of one authenticator of this type may be present. + + +.cindex "options" "&(tls)& authenticator (server)" +The &(tls)& authenticator has three server options: + +.option server_param1 tls string&!! unset +.cindex "variables (&$auth1$& &$auth2$& etc)" "in &(tls)& authenticator" +This option is expanded after the TLS negotiation and +the result is placed in &$auth1$&. +If the expansion is forced to fail, authentication fails. Any other expansion +failure causes a temporary error code to be returned. + +.option server_param2 tls string&!! unset +.option server_param3 tls string&!! unset +As above, for &$auth2$& and &$auth3$&. + +&%server_param1%& may also be spelled &%server_param%&. + + +Example: +.code +tls: + driver = tls + server_param1 = ${certextract {subj_altname,mail,>:} \ + {$tls_in_peercert}} + server_condition = ${if forany {$auth1} \ + {!= {0} \ + {${lookup ldap{ldap:///\ + mailname=${quote_ldap_dn:${lc:$item}},\ + ou=users,LDAP_DC?mailid} {$value}{0} \ + } } } } + server_set_id = ${if = {1}{${listcount:$auth1}} {$auth1}{}} +.endd +.ecindex IIDtlsauth1 +.ecindex IIDtlsauth2 + + +Note that because authentication is traditionally an SMTP operation, +the &%authenticated%& ACL condition cannot be used in +a connect- or helo-ACL. + + + . //////////////////////////////////////////////////////////////////////////// . //////////////////////////////////////////////////////////////////////////// @@ -26411,9 +26788,7 @@ 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. -.new These may be the system default set (depending on library version), -.wen an explicit file or, depending on library version, a directory, identified by &%tls_verify_certificates%&. @@ -26489,7 +26864,9 @@ starts retrying to fetch an OCSP proof some time before its current proof expires. The downside is that it requires server support. Unless Exim is built with the support disabled, -or with GnuTLS earlier than version 3.1.3, +.new +or with GnuTLS earlier than version 3.3.16 / 3.4.8 +.wen support for OCSP stapling is included. There is a global option called &%tls_ocsp_file%&. @@ -26576,11 +26953,9 @@ if it requests it. If the server is Exim, it will request a certificate only if If the &%tls_verify_certificates%& option is set on the &(smtp)& transport, it specifies a collection of expected server certificates. -.new These may be the system default set (depending on library version), -.wen a file or, -depnding on liibrary version, a directory, +depending on library version, a directory, must name a file or, for OpenSSL only (not GnuTLS), a directory. The client verifies the server's certificate @@ -26650,7 +27025,7 @@ client in the initial handshake, so that the server can examine the servername within and possibly choose to use different certificates and keys (and more) for this session. -This is analagous to HTTP's &"Host:"& header, and is the main mechanism by +This is analogous to HTTP's &"Host:"& header, and is the main mechanism by which HTTPS-enabled web-sites can be virtual-hosted, many sites to one IP address. @@ -26704,7 +27079,7 @@ arbitrary unverified data provided prior to authentication. The Exim developers are proceeding cautiously and so far no other TLS options are re-expanded. -When Exim is built againt OpenSSL, OpenSSL must have been built with support +When Exim is built against OpenSSL, OpenSSL must have been built with support for TLS Extensions. This holds true for OpenSSL 1.0.0+ and 0.9.8+ with enable-tlsext in EXTRACONFIGURE. If you invoke &(openssl s_client -h)& and see &`-servername`& in the output, then OpenSSL has support. @@ -26894,6 +27269,7 @@ options in the main part of the configuration. These options are: .cindex "EXPN" "ACL for" .cindex "HELO" "ACL for" .cindex "EHLO" "ACL for" +.cindex "DKIM" "ACL for" .cindex "MAIL" "ACL for" .cindex "QUIT, ACL for" .cindex "RCPT" "ACL for" @@ -26912,6 +27288,7 @@ options in the main part of the configuration. These options are: .irow &%acl_smtp_connect%& "ACL for start of SMTP connection" .irow &%acl_smtp_data%& "ACL after DATA is complete" .irow &%acl_smtp_data_prdr%& "ACL for each recipient, after DATA is complete" +.irow &%acl_smtp_dkim%& "ACL for each DKIM signer" .irow &%acl_smtp_etrn%& "ACL for ETRN" .irow &%acl_smtp_expn%& "ACL for EXPN" .irow &%acl_smtp_helo%& "ACL for HELO or EHLO" @@ -27060,10 +27437,10 @@ It becomes active only when the PRDR feature is negotiated between 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 once for each recipient of the message +The ACL test specified by &%acl_smtp_data_prdr%& happens after a message +has been received, 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 test may accept, defer or deny for individual 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. @@ -27071,10 +27448,14 @@ for some or all recipients. PRDR may be used to support per-user content filtering. Without it one must defer any recipient after the first that has a different content-filter configuration. With PRDR, the RCPT-time check -for this can be disabled when the MAIL-time $smtp_command included -"PRDR". Any required difference in behaviour of the main DATA-time +.new +.cindex "PRDR" "variable for" +for this can be disabled when the variable &$prdr_requested$& +is &"yes"&. +.wen +Any required difference in behaviour of the main DATA-time ACL should however depend on the PRDR-time ACL having run, as Exim -will avoid doing so in some situations (eg. single-recipient mails). +will avoid doing so in some situations (e.g. single-recipient mails). See also the &%prdr_enable%& global option and the &%hosts_try_prdr%& smtp transport option. @@ -27087,8 +27468,9 @@ the feature was not requested by the client. .cindex "QUIT, ACL for" The ACL for the SMTP QUIT command is anomalous, in that the outcome of the ACL does not affect the response code to QUIT, which is always 221. Thus, the ACL -does not in fact control any access. For this reason, the only verbs that are -permitted are &%accept%& and &%warn%&. +does not in fact control any access. +For this reason, it may only accept +or warn as its final result. This ACL can be used for tasks such as custom logging at the end of an SMTP session. For example, you can use ACL variables in other ACLs to count @@ -28004,7 +28386,7 @@ is what is wanted for subsequent tests. This option requests delivery be attempted while the item is being received. The option is usable in the RCPT ACL. -If enabled for a message recieved via smtp and routed to an smtp transport, +If enabled for a message received via smtp and routed to an smtp transport, and only one transport, interface, destination host and port combination is used for all recipients of the message, then the delivery connection is made while the receiving connection is open @@ -28014,7 +28396,7 @@ An attempt to set this option for any recipient but the first for a mail will be quietly ignored. If a recipient-verify callout connection is subsequently requested in the same ACL it is held open and used for -any subsequent receipients and the data, +any subsequent recipients and the data, otherwise one is made after the initial RCPT ACL completes. Note that routers are used in verify mode, @@ -28026,7 +28408,7 @@ Headers may be modified by routers (subject to the above) and transports. Cutthrough delivery is not supported via transport-filters or when DKIM signing of outgoing messages is done, because it sends data to the ultimate destination before the entire message has been received from the source. -It is not supported for messages recieved with the SMTP PRDR option in use. +It is not supported for messages received with the SMTP PRDR option in use. Should the ultimate destination system positively accept or reject the mail, a corresponding indication is given to the source system and nothing is queued. @@ -28764,7 +29146,8 @@ This condition is relevant only in an ACL that is run after a message has been received, that is, in an ACL specified by &%acl_smtp_data%& or &%acl_not_smtp%&. It checks the syntax of all header lines that can contain lists of addresses (&'Sender:'&, &'From:'&, &'Reply-To:'&, &'To:'&, &'Cc:'&, -and &'Bcc:'&). Unqualified addresses (local parts without domains) are +and &'Bcc:'&), returning true if there are no problems. +Unqualified addresses (local parts without domains) are permitted only in locally generated messages and from hosts that match &%sender_unqualified_hosts%& or &%recipient_unqualified_hosts%&, as appropriate. @@ -28926,9 +29309,15 @@ deny dnslists = blackholes.mail-abuse.org warn message = X-Warn: sending host is on dialups list dnslists = dialups.mail-abuse.org .endd -DNS list lookups are cached by Exim for the duration of the SMTP session, +.cindex cacheing "of dns lookup" +.cindex DNS TTL +DNS list lookups are cached by Exim for the duration of the SMTP session +.new +(but limited by the DNS return TTL value), +.wen so a lookup based on the IP address is done at most once for any incoming -connection. Exim does not share information between multiple incoming +connection (assuming long-enough TTL). +Exim does not share information between multiple incoming connections (but your local name server cache should be active). @@ -29441,7 +29830,7 @@ The &%per_rcpt%& option causes Exim to limit the rate at which recipients are accepted. It can be used in the &%acl_smtp_rcpt%&, &%acl_smtp_predata%&, &%acl_smtp_mime%&, &%acl_smtp_data%&, or &%acl_smtp_rcpt%& ACLs. In &%acl_smtp_rcpt%& the rate is updated one recipient at a time; in the other -ACLs the rate is updated with the total recipient count in one go. Note that +ACLs the rate is updated with the total (accepted) recipient count in one go. Note that in either case the rate limiting engine will see a message with many recipients as a large high-speed burst. @@ -30385,10 +30774,8 @@ It supports a &"generic"& interface to scanners called via the shell, and specialized interfaces for &"daemon"& type virus scanners, which are resident in memory and thus are much faster. -.new A timeout of 2 minutes is applied to a scanner call (by default); if it expires then a defer action is taken. -.wen .oindex "&%av_scanner%&" You can set the &%av_scanner%& option in the main part of the configuration @@ -30407,11 +30794,10 @@ The usual list-parsing of the content (see &<>&) applies. The following scanner types are supported in this release: .vlist -.new .vitem &%avast%& .cindex "virus scanners" "avast" This is the scanner daemon of Avast. It has been tested with Avast Core -Security (currenty at version 1.1.7). +Security (currently at version 1.1.7). You can get a trial version at &url(http://www.avast.com) or for Linux at &url(http://www.avast.com/linux-server-antivirus). This scanner type takes one option, @@ -30432,14 +30818,13 @@ is used. If you use a remote host, you need to make Exim's spool directory available to it, as the scanner is passed a file path, not file contents. -For information about available commands and their options you may use +For information about available commands and their options you may use .code $ socat UNIX:/var/run/avast/scan.sock STDIO: FLAGS SENSITIVITY PACK .endd -.wen .vitem &%aveserver%& @@ -30458,17 +30843,39 @@ av_scanner = aveserver:/var/run/aveserver This daemon-type scanner is GPL and free. You can get it at &url(http://www.clamav.net/). Some older versions of clamd do not seem to unpack MIME containers, so it used to be recommended to unpack MIME attachments -in the MIME ACL. This no longer believed to be necessary. One option is -required: either the path and name of a UNIX socket file, or a hostname or IP -number, and a port, separated by space, as in the second of these examples: +in the MIME ACL. This is no longer believed to be necessary. + +The options are a list of server specifiers, which may be +a UNIX socket specification, +a TCP socket specification, +or a (global) option. + +A socket specification consists of a space-separated list. +For a Unix socket the first element is a full path for the socket, +for a TCP socket the first element is the IP address +and the second a port number, +Any further elements are per-server (non-global) options. +These per-server options are supported: +.code +retry= Retry on connect fail +.endd + +The &`retry`& option specifies a time after which a single retry for +a failed connect is made. The default is to not retry. + +If a Unix socket file is specified, only one server is supported. + +Examples: .code av_scanner = clamd:/opt/clamd/socket av_scanner = clamd:192.0.2.3 1234 av_scanner = clamd:192.0.2.3 1234:local +av_scanner = clamd:192.0.2.3 1234 retry=10s av_scanner = clamd:192.0.2.3 1234 : 192.0.2.4 1234 .endd -If the value of av_scanner points to a UNIX socket file or contains the local -keyword, then the ClamAV interface will pass a filename containing the data +If the value of av_scanner points to a UNIX socket file or contains the +&`local`& +option, then the ClamAV interface will pass a filename containing the data to be scanned, which will should normally result in less I/O happening and be more efficient. Normally in the TCP case, the data is streamed to ClamAV as Exim does not assume that there is a common filesystem with the remote host. @@ -30594,7 +31001,7 @@ You can safely omit this option (the default value is 1). This is a general-purpose way of talking to simple scanner daemons running on the local machine. There are four options: -an address (which may be an IP addres and port, or the path of a Unix socket), +an address (which may be an IP address and port, or the path of a Unix socket), a commandline to send (may include a single %s which will be replaced with the path to the mail file to be scanned), an RE to trigger on from the returned data, @@ -30633,9 +31040,7 @@ which case each use of the &%malware%& condition causes a new scan of the message. The &%malware%& condition takes a right-hand argument that is expanded before -.new use and taken as a list, slash-separated by default. -.wen The first element can then be one of .ilist @@ -30649,17 +31054,14 @@ the condition fails immediately. A regular expression, in which case the message is scanned for viruses. The condition succeeds if a virus is found and its name matches the regular expression. This allows you to take special actions on certain types of virus. -.new Note that &"/"& characters in the RE must be doubled due to the list-processing, unless the separator is changed (in the usual way). -.wen .endlist You can append a &`defer_ok`& element to the &%malware%& argument list to accept messages even if there is a problem with the virus scanner. Otherwise, such a problem causes the ACL to defer. -.new You can append a &`tmo=`& element to the &%malware%& argument list to specify a non-default timeout. The default is two minutes. For example: @@ -30667,7 +31069,10 @@ For example: malware = * / defer_ok / tmo=10s .endd A timeout causes the ACL to defer. -.wen + +.vindex "&$callout_address$&" +When a connection is made to the scanner the expansion variable &$callout_address$& +is set to record the actual address used. .vindex "&$malware_name$&" When a virus is found, the condition sets up an expansion variable called @@ -30718,14 +31123,11 @@ deny message = This message contains malware ($malware_name) .cindex "Rspamd" The &%spam%& ACL condition calls SpamAssassin's &%spamd%& daemon to get a spam score and a report for the message. -.new -Support is also provided for Rspamd (which can speak SpamAssassin's protocol but -provides reduced functionality when used in this mode). +Support is also provided for Rspamd. -For more information about installation and configuration of SpamAssassin or +For more information about installation and configuration of SpamAssassin or Rspamd refer to their respective websites at &url(http://spamassassin.apache.org) and &url(http://www.rspamd.com) -.wen SpamAssassin can be installed with CPAN by running: .code @@ -30736,7 +31138,7 @@ documentation to see how you can tweak it. The default installation should work nicely, however. .oindex "&%spamd_address%&" -By default, SpamAssassin listens on 127.0.0.1, TCP port 783 and if you +By default, SpamAssassin listens on 127.0.0.1, TCP port 783 and if you intend to use an instance running on the local host you do not need to set &%spamd_address%&. If you intend to use another host or port for SpamAssassin, you must set the &%spamd_address%& option in the global part of the Exim @@ -30745,43 +31147,87 @@ configuration as follows (example): spamd_address = 192.168.99.45 387 .endd -.new To use Rspamd (which by default listens on all local addresses on TCP port 11333) you should add &%variant=rspamd%& after the address/port pair, for example: .code spamd_address = 127.0.0.1 11333 variant=rspamd .endd -.wen As of version 2.60, &%SpamAssassin%& also supports communication over UNIX sockets. If you want to us these, supply &%spamd_address%& with an absolute -file name instead of a address/port pair: +file name instead of an address/port pair: .code spamd_address = /var/run/spamd_socket .endd You can have multiple &%spamd%& servers to improve scalability. These can reside on other hardware reachable over the network. To specify multiple &%spamd%& servers, put multiple address/port pairs in the &%spamd_address%& -option, separated with colons: +option, separated with colons (the separator can be changed in the usual way): .code spamd_address = 192.168.2.10 783 : \ 192.168.2.11 783 : \ 192.168.2.12 783 .endd -Up to 32 &%spamd%& servers are supported. The servers are queried in a random -fashion. When a server fails to respond to the connection attempt, all other +Up to 32 &%spamd%& servers are supported. +When a server fails to respond to the connection attempt, all other servers are tried until one succeeds. If no server responds, the &%spam%& condition defers. -&*Warning*&: It is not possible to use the UNIX socket connection method with -multiple &%spamd%& servers. +Unix and TCP socket specifications may be mixed in any order. +Each element of the list is a list itself, space-separated by default +and changeable in the usual way. + +For TCP socket specifications a host name or IP (v4 or v6, but +subject to list-separator quoting rules) address can be used, +and the port can be one or a dash-separated pair. +In the latter case, the range is tried in strict order. + +Elements after the first for Unix sockets, or second for TCP socket, +are options. +The supported options are: +.code +pri= Selection priority +weight= Selection bias +time=- Use only between these times of day +retry= Retry on connect fail +tmo= Connection time limit +variant=rspamd Use Rspamd rather than SpamAssassin protocol +.endd + +The &`pri`& option specifies a priority for the server within the list, +higher values being tried first. +The default priority is 1. + +The &`weight`& option specifies a selection bias. +Within a priority set +servers are queried in a random fashion, weighted by this value. +The default value for selection bias is 1. + +Time specifications for the &`time`& option are .. +in the local time zone; each element being one or more digits. +Either the seconds or both minutes and seconds, plus the leading &`.`& +characters, may be omitted and will be taken as zero. + +Timeout specifications for the &`retry`& and &`tmo`& options +are the usual Exim time interval standard, e.g. &`20s`& or &`1m`&. + +The &`tmo`& option specifies an overall timeout for communication. +The default value is two minutes. + +The &`retry`& option specifies a time after which a single retry for +a failed connect is made. +The default is to not retry. The &%spamd_address%& variable is expanded before use if it starts with a dollar sign. In this case, the expansion may return a string that is used as the list so that multiple spamd servers can be the result of an expansion. +.vindex "&$callout_address$&" +When a connection is made to the server the expansion variable &$callout_address$& +is set to record the actual address used. + .section "Calling SpamAssassin from an Exim ACL" "SECID206" Here is a simple example of the use of the &%spam%& condition in a DATA ACL: .code @@ -30792,17 +31238,21 @@ The right-hand side of the &%spam%& condition specifies a name. This is relevant if you have set up multiple SpamAssassin profiles. If you do not want to scan using a specific profile, but rather use the SpamAssassin system-wide default profile, you can scan for an unknown name, or simply use &"nobody"&. -.new Rspamd does not use this setting. However, you must put something on the right-hand side. -.wen The name allows you to use per-domain or per-user antispam profiles in principle, but this is not straightforward in practice, because a message may have multiple recipients, not necessarily all in the same domain. Because the -&%spam%& condition has to be called from a DATA ACL in order to be able to +&%spam%& condition has to be called from a DATA-time ACL in order to be able to read the contents of the message, the variables &$local_part$& and &$domain$& are not set. +Careful enforcement of single-recipient messages +(e.g. by responding with defer in the recipient ACL for all recipients +after the first), +or the use of PRDR, +.cindex "PRDR" "use for per-user SpamAssassin profiles" +are needed to use this feature. The right-hand side of the &%spam%& condition is expanded before being used, so you can put lookups or conditions there. When the right-hand side evaluates to @@ -30826,7 +31276,9 @@ it always return &"true"& by appending &`:true`& to the username. .cindex "spam scanning" "returned variables" When the &%spam%& condition is run, it sets up a number of expansion -variables. These variables are saved with the received message, thus they are +variables. +Except for &$spam_report$&, +these variables are saved with the received message so are available for use at delivery time. .vlist @@ -30844,18 +31296,18 @@ The integer value is useful for numeric comparisons in conditions. A string consisting of a number of &"+"& or &"-"& characters, representing the integer part of the spam score value. A spam score of 4.4 would have a &$spam_bar$& value of &"++++"&. This is useful for inclusion in warning -headers, since MUAs can match on such strings. +headers, since MUAs can match on such strings. The maximum length of the +spam bar is 50 characters. .vitem &$spam_report$& A multiline text table, containing the full SpamAssassin report for the message. Useful for inclusion in headers or reject messages. +This variable is only usable in a DATA-time ACL. -.new .vitem &$spam_action$& For SpamAssassin either 'reject' or 'no action' depending on the spam score versus threshold. For Rspamd, the recommended action. -.wen .endlist @@ -31042,7 +31494,10 @@ containing the decoded data. This is perhaps the most important of the MIME variables. It contains a proposed filename for an attachment, if one was found in either the &'Content-Type:'& or &'Content-Disposition:'& headers. The filename will be -RFC2047 decoded, but no additional sanity checks are done. If no filename was +RFC2047 +or RFC2231 +decoded, but no additional sanity checks are done. + If no filename was found, this variable contains the empty string. .vitem &$mime_is_coverletter$& @@ -31131,6 +31586,8 @@ deny message = contains blacklisted regex ($regex_match_string) The conditions returns true if any one of the regular expressions matches. The &$regex_match_string$& expansion variable is then set up and contains the matching regular expression. +The expansion variables &$regex1$& &$regex2$& etc +are set to any substrings captured by the regular expression. &*Warning*&: With large messages, these conditions can be fairly CPU-intensive. @@ -33640,10 +34097,8 @@ 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 -.new The fourth, fifth and sixth items will be ignored and may be empty. The fields exist for back-compatibility -.wen .endlist The default state (&%bounce_message_file%& unset) is equivalent to the @@ -34480,8 +34935,9 @@ equivalent to the setting: .code log_file_path = $spool_directory/log/%slog .endd -If you do not specify anything at build time or run time, that is where the -logs are written. +If you do not specify anything at build time or run time, +or if you unset the option at run time (i.e. &`log_file_path = `&), +that is where the logs are written. A log file path may also contain &`%D`& or &`%M`& if datestamped log file names are in use &-- see section &<>& below. @@ -34750,7 +35206,7 @@ data when a message is received. See section &<>& below. .cindex "log" "delivery line" The format of the single-line entry in the main log that is written for every delivery is shown in one of the examples below, for local and remote -deliveries, respectively. Each example has been split into two lines in order +deliveries, respectively. Each example has been split into multiple lines in order to fit it on the page: .code 2002-10-31 08:59:13 16ZCW1-0005MB-00 => marv @@ -34984,6 +35440,9 @@ selection marked by asterisks: &` incoming_interface `& local interface on <= and => lines &` incoming_port `& remote port on <= lines &`*lost_incoming_connection `& as it says (includes timeouts) +.new +&` outgoing_interface `& local interface on => lines +.wen &` outgoing_port `& add remote port to => lines &`*queue_run `& start and end queue runs &` queue_time `& time on queue for one recipient @@ -34999,16 +35458,14 @@ selection marked by asterisks: &`*size_reject `& rejection because too big &`*skip_delivery `& delivery skipped in a queue run &`*smtp_confirmation `& SMTP confirmation on => lines -&` smtp_connection `& SMTP connections +&` smtp_connection `& incoming SMTP connections &` smtp_incomplete_transaction`& incomplete SMTP transactions &` smtp_mailauth `& AUTH argument to MAIL commands &` smtp_no_mail `& session with no MAIL commands &` smtp_protocol_error `& SMTP protocol errors &` smtp_syntax_error `& SMTP syntax errors &` subject `& contents of &'Subject:'& on <= lines -.new &`*tls_certificate_verified `& certificate verification status -.wen &`*tls_cipher `& TLS cipher suite on <= and => lines &` tls_peerdn `& TLS peer DN on <= and => lines &` tls_sni `& TLS SNI on <= lines @@ -35016,6 +35473,9 @@ selection marked by asterisks: &` all `& all of the above .endd +See also the &%slow_lookup_log%& main configuration option, +section &<>& + More details on each of these items follows: .ilist @@ -35108,9 +35568,11 @@ client's ident port times out. &%incoming_interface%&: The interface on which a message was received is added to the &"<="& line as an IP address in square brackets, tagged by I= and followed by a colon and the port number. The local interface and port are also -added to other SMTP log lines, for example &"SMTP connection from"& and to -rejection lines -and (despite the name) the local interface is added to &"=>"& lines.. +added to other SMTP log lines, for example &"SMTP connection from"&, to +rejection lines, and (despite the name) to outgoing &"=>"& and &"->"& lines. +.new +The latter can be disabled by turning off the &%outgoing_interface%& option. +.wen .next .cindex "log" "incoming remote port" .cindex "port" "logging remote" @@ -35128,13 +35590,30 @@ important with the widening use of NAT (see RFC 2505). &%lost_incoming_connection%&: A log line is written when an incoming SMTP connection is unexpectedly dropped. .next +.cindex "log" "outgoing interface" +.cindex "log" "local interface" +.cindex "log" "local address and port" +.cindex "TCP/IP" "logging local address and port" +.cindex "interface" "logging" +.new +&%outgoing_interface%&: If &%incoming_interface%& is turned on, then the +interface on which a message was sent is added to delivery lines as an I= tag +followed by IP address in square brackets. You can disable this by turning +off the &%outgoing_interface%& option. +.wen +.next .cindex "log" "outgoing remote port" .cindex "port" "logging outgoint remote" .cindex "TCP/IP" "logging ougtoing remote port" &%outgoing_port%&: The remote port number is added to delivery log lines (those -containing => tags) following the IP address. This option is not included in -the default setting, because for most ordinary configurations, the remote port -number is always 25 (the SMTP port). +containing => tags) following the IP address. +.new +The local port is also added if &%incoming_interface%& and +&%outgoing_interface%& are both enabled. +.wen +This option is not included in the default setting, because for most ordinary +configurations, the remote port number is always 25 (the SMTP port), and the +local port is a random ephemeral port. .next .cindex "log" "process ids in" .cindex "pid (process id)" "in log lines" @@ -35225,7 +35704,7 @@ response. .next .cindex "log" "SMTP connections" .cindex "SMTP" "logging connections" -&%smtp_connection%&: A log line is written whenever an SMTP connection is +&%smtp_connection%&: A log line is written whenever an incoming SMTP connection is established or closed, unless the connection is from a host that matches &%hosts_connection_nolog%&. (In contrast, &%lost_incoming_connection%& applies only when the closure is unexpected.) This applies to connections from local @@ -35274,7 +35753,7 @@ C=EHLO,QUIT shows that the client issued QUIT straight after EHLO. If there were fewer than 20 commands, they are all listed. If there were more than 20 commands, the last 20 are listed, preceded by &"..."&. However, with the default -setting of 10 for &%smtp_accep_max_nonmail%&, the connection will in any case +setting of 10 for &%smtp_accept_max_nonmail%&, the connection will in any case have been aborted before 20 non-mail commands are processed. .next &%smtp_mailauth%&: A third subfield with the authenticated sender, @@ -35454,7 +35933,7 @@ exim -bp The &*-C*& option is used to specify an alternate &_exim.conf_& which might contain alternate exim configuration the queue management might be using. -to obtain a queue listing, and then greps the output to select messages +to obtain a queue listing, and then greps the output to select messages that match given criteria. The following selection options are available: .vlist @@ -35465,7 +35944,7 @@ tested is enclosed in angle brackets, so you can test for bounce messages with exiqgrep -f '^<>$' .endd .vitem &*-r*&&~<&'regex'&> -Match a recipient address using a case-insensitve search. The field that is +Match a recipient address using a case-insensitive search. The field that is tested is not enclosed in angle brackets. .vitem &*-s*&&~<&'regex'&> @@ -35597,6 +36076,8 @@ search term. If the location of a &'zcat'& command is known from the definition of ZCAT_COMMAND in &_Local/Makefile_&, &'exigrep'& automatically passes any file whose name ends in COMPRESS_SUFFIX through &'zcat'& as it searches it. +If the ZCAT_COMMAND is not executable, &'exigrep'& tries to use +autodetection of some well known compression extensions. .section "Selecting messages by various criteria (exipick)" "SECTexipick" @@ -35876,6 +36357,9 @@ Serializing ETRN runs (when &%smtp_etrn_serialize%& is set) .next Serializing delivery to a specific host (when &%serialize_hosts%& is set in an &(smtp)& transport) +.next +Limiting the concurrency of specific transports (when &%max_parallel%& is set +in a transport) .endlist @@ -36736,7 +37220,7 @@ Such invocations should be viewed with prejudicial suspicion. Administrators who use embedded Perl are advised to explore how Perl's taint checking might apply to their usage. .next -Use of &%${expand...}%& is somewhat analagous to shell's eval builtin and +Use of &%${expand...}%& is somewhat analogous to shell's eval builtin and administrators are well advised to view its use with suspicion, in case (for instance) it allows a local-part to contain embedded Exim directives. .next @@ -37351,7 +37835,7 @@ Verification of DKIM signatures in incoming email is implemented via the &%acl_smtp_dkim%& ACL. By default, this ACL is called once for each syntactically(!) correct signature in the incoming message. A missing ACL definition defaults to accept. -If any ACL call does not acccept, the message is not accepted. +If any ACL call does not accept, the message is not accepted. If a cutthrough delivery was in progress for the message it is summarily dropped (having wasted the transmission effort). @@ -37415,7 +37899,7 @@ available in &%$dkim_verify_reason%&. &%pass%&: The signature passed verification. It is valid. .endlist .vitem &%$dkim_verify_reason%& -A string giving a litte bit more detail when &%$dkim_verify_status%& is either +A string giving a little bit more detail when &%$dkim_verify_status%& is either "fail" or "invalid". One of .ilist &%pubkey_unavailable%& (when &%$dkim_verify_status%&="invalid"): The public