X-Git-Url: https://git.exim.org/users/jgh/exim.git/blobdiff_plain/fef95dbbb2220e10f5a6bf7ac1b6ecdff0025bca..376d2ec0874144ee64e21ca79362793f116a381c:/doc/doc-docbook/spec.xfpt?ds=sidebyside diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index a05b41b40..5254fb8a2 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -45,7 +45,7 @@ . Update the Copyright year (only) when changing content. . ///////////////////////////////////////////////////////////////////////////// -.set previousversion "4.85" +.set previousversion "4.86" .include ./local_params .set ACL "access control lists (ACLs)" @@ -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 @@ -1986,11 +1986,9 @@ 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"&. -.new Exim used to have a compile option for including A6 record support but this has now been withdrawn. -.wen @@ -3810,13 +3808,11 @@ 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%&" @@ -4648,14 +4644,12 @@ this option. This option is interpreted by Sendmail to cause debug information to be sent to the named file. It is ignored by Exim. -.new .vitem &%-z%&&~<&'log-line'&> .oindex "&%-z%&" This option writes its argument to Exim's logfile. Use is restricted to administrators; the intent is for operational notes. Quotes should be used to maintain a multi-word item as a single argument, under most shells. -.wen .endlist .ecindex IIDclo1 @@ -4806,8 +4800,8 @@ 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 @@ -5601,14 +5595,12 @@ 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. -.new 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 -.wen The &%percent_hack_domains%& option is also commented out: .code @@ -6068,8 +6060,8 @@ 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 @@ -6251,12 +6243,14 @@ 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 @@ -6890,11 +6884,9 @@ 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. -.new 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. -.wen 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, @@ -6942,7 +6934,6 @@ ${lookup dnsdb{spf=example.org}} It is permitted to specify a space as the separator character. Further white space is ignored. -.new .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. @@ -6951,7 +6942,6 @@ specified. .code ${lookup dnsdb{>:,; soa=a.b.example.com}} .endd -.wen .section "Dnsdb lookup modifiers" "SECTdnsdb_mod" .cindex "dnsdb modifiers" @@ -6992,7 +6982,6 @@ The default is &"never"&. See also the &$lookup_dnssec_authenticated$& variable. -.new .cindex timeout "dns lookup" .cindex "DNS" timeout Timeout for the dnsdb lookup can be controlled by a retrans modifier. @@ -7003,6 +6992,14 @@ 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 @@ -7324,7 +7321,7 @@ 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 @@ -7540,13 +7537,12 @@ 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), @@ -7679,11 +7675,9 @@ 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. -.new 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. -.wen @@ -9056,7 +9050,6 @@ you need to add &%-shared%& to the gcc command. Also, in the Exim build-time configuration, you must add &%-export-dynamic%& to EXTRALIBS. -.new .vitem "&*${env{*&<&'key'&>&*}{*&<&'string1'&>&*}{*&<&'string2'&>&*}}*&" .cindex "expansion" "extracting value from environment" .cindex "environment" "value from" @@ -9078,7 +9071,6 @@ If {<&'string2'&>} is omitted an empty string is substituted on search failure. If {<&'string1'&>} is omitted the search result is substituted on search success. -.wen .vitem "&*${extract{*&<&'key'&>&*}{*&<&'string1'&>&*}{*&<&'string2'&>&*}&&& @@ -9280,10 +9272,11 @@ 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 @@ -9405,7 +9398,7 @@ yields &"42"&, and .code ${listextract{-3}{<, x,42,99,& Mailer,,/bin/bash}{result: $value}} .endd -yields &"result: 99"&. +yields &"result: 42"&. If {<&'string3'&>} is omitted, an empty string is used for string3. If {<&'string2'&>} is also omitted, the value that was @@ -11125,7 +11118,8 @@ support for TLS or the content scanning extension. When a &%match%& expansion condition succeeds, these variables contain the captured substrings identified by the regular expression during subsequent processing of the success string of the containing &%if%& expansion item. -However, they do not retain their values afterwards; in fact, their previous +In the expansion condition case +they do not retain their values afterwards; in fact, their previous values are restored at the end of processing an &%if%& item. The numerical variables may also be set externally by some other matching process which precedes the expansion of the string. For example, the commands available in @@ -11333,9 +11327,10 @@ not the same as the user id of the originator of a message (see &$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$&" @@ -11343,7 +11338,6 @@ The building process for Exim keeps a count of the number of times it has been compiled. This serves to distinguish different compilations of the same version of the program. -.new .vitem &$config_dir$& .vindex "&$config_dir$&" The directory name of the main configuration file. That is, the content of @@ -11354,7 +11348,6 @@ contain the trailing slash. If &$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$&" @@ -11368,7 +11361,6 @@ This variable is available when Exim is compiled with the content-scanning extension and the obsolete &%demime%& condition. For details, see section &<>&. -.new .vitem &$dkim_cur_signer$& &&& &$dkim_verify_status$& &&& &$dkim_verify_reason$& &&& @@ -11396,7 +11388,6 @@ For details see chapter &<>&. When a message has been received this variable contains a colon-separated list of signer domains and identities for the message. For details see chapter &<>&. -.wen .vitem &$dnslist_domain$& &&& &$dnslist_matched$& &&& @@ -11493,14 +11484,12 @@ This variable contains the path to the Exim binary. .vindex "&$exim_uid$&" This variable contains the numerical value of the Exim user id. -.new .vitem &$exim_version$& .vindex "&$exim_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$&" @@ -11765,11 +11754,9 @@ a dnsdb lookup expansion, dnslookup router or smtp transport. It will be empty if &(DNSSEC)& was not requested, &"no"& if the result was not labelled as authenticated data and &"yes"& if it was. -.new Results that are labelled as authoritative answer that match the &%dns_trust_aa%& configuration variable count also as authenticated data. -.wen .vitem &$mailstore_basename$& .vindex "&$mailstore_basename$&" @@ -12180,6 +12167,12 @@ increases for each accepted recipient. It can be referenced in an ACL. This variable is set to contain the matching regular expression after a &%regex%& ACL condition has matched (see section &<>&). +.vitem "&$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 "&$reply_address$&" @@ -12284,13 +12277,11 @@ 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. -.new .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. -.wen .vitem &$sender_helo_name$& .vindex "&$sender_helo_name$&" @@ -12568,10 +12559,8 @@ 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. -.new If certificate verification fails it may refer to a failing chain element which is not the leaf. -.wen .vitem &$tls_out_ourcert$& .vindex "&$tls_out_ourcert$&" @@ -12586,10 +12575,8 @@ 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. -.new If certificate verification fails it may refer to a failing chain element which is not the leaf. -.wen .vitem &$tls_in_certificate_verified$& .vindex "&$tls_in_certificate_verified$&" @@ -12653,10 +12640,8 @@ 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. -.new If certificate verification fails it may refer to a failing chain element which is not the leaf. -.wen 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 @@ -12668,10 +12653,8 @@ 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. -.new If certificate verification fails it may refer to a failing chain element which is not the leaf. -.wen .vitem &$tls_in_sni$& .vindex "&$tls_in_sni$&" @@ -13722,26 +13705,22 @@ 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. -.new .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. -.wen .option acl_smtp_etrn main string&!! unset .cindex "ETRN" "ACL for" @@ -13777,13 +13756,11 @@ 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. -.new .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. -.wen .option acl_smtp_predata main string&!! unset This option defines the ACL that is run when an SMTP DATA command is @@ -14220,14 +14197,12 @@ etc. are ignored. If IP literals are enabled, the &(ipliteral)& router declines to handle IPv6 literal addresses. -.new .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 &<>&. -.wen .option dns_again_means_nonexist main "domain list&!!" unset @@ -14316,16 +14291,13 @@ 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. -.new See also the &%slow_lookup_log%& option. -.wen .option dns_retry main integer 0 See &%dns_retrans%& above. -.new .option dns_trust_aa main "domain list&!!" unset .cindex "DNS" "resolver options" .cindex "DNS" "DNSSEC" @@ -14350,7 +14322,6 @@ 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. -.wen .cindex "DNS" "resolver options" .option dns_use_edns0 main integer -1 @@ -14369,7 +14340,6 @@ 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" @@ -14381,7 +14351,6 @@ 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" @@ -14507,7 +14476,7 @@ 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%&" @@ -15879,7 +15848,6 @@ 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" @@ -15887,11 +15855,8 @@ 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, @@ -15910,7 +15875,6 @@ it qualifies them only if the message came from a host that matches using TCP/IP), and the &%-bnq%& option was not set. -.new .option slow_lookup_log main integer 0 .cindex "logging" "slow lookups" .cindex "dns" "logging slow lookups" @@ -15918,7 +15882,6 @@ 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. -.wen @@ -16312,11 +16275,9 @@ SMTP data timeout on connection from... The former means that Exim was expecting to read an SMTP command; the latter means that it was in the DATA phase, reading the contents of a message. -.new If the first character of the option is a &"$"& the option is expanded before use and may depend on &$sender_host_name$&, &$sender_host_address$& and &$sender_host_port$&. -.wen .oindex "&%-os%&" @@ -16703,7 +16664,6 @@ prior to the 4.80 release, as Debian used to patch Exim to raise the minimum acceptable bound from 1024 to 2048. -.new .option tls_eccurve main string&!! prime256v1 .cindex TLS "EC cryptography" If built with a recent-enough version of OpenSSL, @@ -16715,7 +16675,6 @@ 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. -.wen .option tls_ocsp_file main string&!! unset @@ -16726,6 +16685,10 @@ 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 @@ -16776,7 +16739,6 @@ 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" @@ -16799,7 +16761,6 @@ 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 @@ -17239,7 +17200,6 @@ 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. -.new .option dnssec_request_domains routers "domain list&!!" unset .cindex "MX record" "security" .cindex "DNSSEC" "MX lookup" @@ -17258,7 +17218,6 @@ 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. -.wen .option domains routers&!? "domain list&!!" unset @@ -17277,7 +17236,6 @@ 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" @@ -17285,7 +17243,6 @@ 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 @@ -17410,9 +17367,7 @@ and the discussion in chapter &<>&. .cindex "header lines" "adding" .cindex "router" "adding header lines" This option specifies a list of text headers, -.new newline-separated (by default, changeable in the usual way), -.wen 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 @@ -17450,9 +17405,7 @@ avoided. The &%repeat_use%& option of the &%redirect%& router may be of help. .cindex "header lines" "removing" .cindex "router" "removing header lines" This option specifies a list of text headers, -.new colon-separated (by default, changeable in the usual way), -.wen 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 @@ -17478,11 +17431,9 @@ 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. -.new &*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 (&<>&). -.wen @@ -18238,10 +18189,8 @@ 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%&. -.new The router will defer rather than decline if the domain is found in the &%fail_defer_domains%& router option. -.wen Reasons for a &(dnslookup)& router to decline currently include: .ilist @@ -18322,7 +18271,6 @@ when there is a DNS lookup error. -.new .option fail_defer_domains dnslookup "domain list&!!" unset .cindex "MX record" "not found" DNS lookups for domains matching &%fail_defer_domains%& @@ -18332,7 +18280,6 @@ 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. -.wen .option mx_domains dnslookup "domain list&!!" unset @@ -19303,12 +19250,10 @@ 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 @@ -20503,9 +20448,7 @@ value that the router supplies, and also overriding any value associated with .cindex "header lines" "adding in transport" .cindex "transport" "header lines; adding" This option specifies a list of text headers, -.new newline-separated (by default, changeable in the usual way), -.wen 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 @@ -20531,9 +20474,7 @@ checked, since this option does not automatically suppress them. .cindex "header lines" "removing" .cindex "transport" "header lines; removing" This option specifies a list of header names, -.new colon-separated (by default, changeable in the usual way); -.wen these headers are omitted from the message as it is transported, as described in section &<>&. Header removal can also be specified by routers. @@ -20597,6 +20538,32 @@ 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" @@ -22494,6 +22461,10 @@ 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 @@ -22758,6 +22729,7 @@ 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. @@ -22768,27 +22740,29 @@ 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 @@ -23425,13 +23399,11 @@ 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. -.new .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. -.wen .option hosts_max_try smtp integer 5 @@ -23528,14 +23500,12 @@ 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" @@ -23602,11 +23572,9 @@ 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$&. -.wen .option port smtp string&!! "see below" .cindex "port" "sending TCP/IP" @@ -23653,9 +23621,7 @@ However, in some dialup environments hosts are assigned a different IP address each time they connect. In this situation the use of the IP address as part of the retry key leads to undesirable behaviour. Setting this option false causes Exim to use only the host name. -.new Since it is expanded it can be made to depend on the host or domain. -.wen .option serialize_hosts smtp "host list&!!" unset @@ -23681,6 +23647,10 @@ start with &_misc_& and they are kept in the &_spool/db_& directory. There may be one or two files, depending on the type of DBM in use. The same files are used for ETRN serialization. +.new +See also the &%max_parallel%& generic transport option. +.wen + .option size_addition smtp integer 1024 .cindex "SMTP" "SIZE" @@ -23793,9 +23763,7 @@ unknown state), opens a new one to the same host, and then tries the delivery in clear. -.new .option tls_try_verify_hosts smtp "host list&!!" * -.wen .cindex "TLS" "server certificate verification" .cindex "certificate" "verification of server" This option gives a list of hosts for which, on encrypted connections, @@ -23808,7 +23776,6 @@ The &$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" @@ -23820,10 +23787,8 @@ 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" @@ -23842,7 +23807,6 @@ must be specified. 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 @@ -24610,14 +24574,12 @@ 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. -.new .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%&. -.wen .vitem &%refused_MX%& A connection to a host obtained from an MX record was refused. @@ -25045,10 +25007,8 @@ 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. -.new The eighth is an Exim authenticator but not an SMTP one; instead it can use information from a TLS negotiation. -.wen The authenticators are configured using the same syntax as other drivers (see section &<>&). If no authenticators are required, no @@ -26258,7 +26218,6 @@ msn: . //////////////////////////////////////////////////////////////////////////// . //////////////////////////////////////////////////////////////////////////// -.new .chapter "The tls authenticator" "CHAPtlsauth" .scindex IIDtlsauth1 "&(tls)& authenticator" .scindex IIDtlsauth2 "authenticators" "&(tls)&" @@ -26321,7 +26280,6 @@ tls: .endd .ecindex IIDtlsauth1 .ecindex IIDtlsauth2 -.wen Note that because authentication is traditionally an SMTP operation, @@ -26775,9 +26733,7 @@ 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%&. @@ -26853,7 +26809,9 @@ 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%&. @@ -26940,9 +26898,7 @@ 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, depending on library version, a directory, must name a file or, @@ -27454,10 +27410,8 @@ the feature was not requested by the client. 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. -.new For this reason, it may only accept or warn as its final result. -.wen 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 @@ -28374,10 +28328,8 @@ 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 received via smtp and routed to an smtp transport, -.new and only one transport, interface, destination host and port combination is used for all recipients of the message, -.wen then the delivery connection is made while the receiving connection is open and data is copied from one to the other. @@ -28385,9 +28337,7 @@ 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 -.new any subsequent recipients and the data, -.wen otherwise one is made after the initial RCPT ACL completes. Note that routers are used in verify mode, @@ -28399,9 +28349,7 @@ 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. -.new It is not supported for messages received with the SMTP PRDR option in use. -.wen Should the ultimate destination system positively accept or reject the mail, a corresponding indication is given to the source system and nothing is queued. @@ -29139,7 +29087,8 @@ 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. @@ -29210,10 +29159,8 @@ Verification ensures that the host name obtained from a reverse DNS lookup, or one of its aliases, does, when it is itself looked up in the DNS, yield the original IP address. -.new There is one possible option, &`defer_ok`&. If this is present and a DNS operation returns a temporary error, the verify condition succeeds. -.wen If this condition is used for a locally generated message (that is, when there is no client host involved), it always succeeds. @@ -29303,9 +29250,15 @@ 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). @@ -30762,10 +30715,8 @@ 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 @@ -30784,7 +30735,6 @@ 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 @@ -30816,7 +30766,6 @@ $ socat UNIX:/var/run/avast/scan.sock STDIO: SENSITIVITY PACK .endd -.wen .vitem &%aveserver%& @@ -31032,9 +30981,7 @@ 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 @@ -31048,17 +30995,14 @@ 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: @@ -31066,7 +31010,10 @@ 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 @@ -31117,13 +31064,11 @@ deny message = This message contains malware ($malware_name) .cindex "Rspamd" The &%spam%& ACL condition calls SpamAssassin's &%spamd%& daemon to get a spam score and a report for the message. -.new Support is also provided for Rspamd. For more information about installation and configuration of SpamAssassin or Rspamd refer to their respective websites at &url(http://spamassassin.apache.org) and &url(http://www.rspamd.com) -.wen SpamAssassin can be installed with CPAN by running: .code @@ -31143,14 +31088,12 @@ configuration as follows (example): spamd_address = 192.168.99.45 387 .endd -.new To use Rspamd (which by default listens on all local addresses on TCP port 11333) you should add &%variant=rspamd%& after the address/port pair, for example: .code spamd_address = 127.0.0.1 11333 variant=rspamd .endd -.wen As of version 2.60, &%SpamAssassin%& also supports communication over UNIX sockets. If you want to us these, supply &%spamd_address%& with an absolute @@ -31172,7 +31115,6 @@ When a server fails to respond to the connection attempt, all other servers are tried until one succeeds. If no server responds, the &%spam%& condition defers. -.new Unix and TCP socket specifications may be mixed in any order. Each element of the list is a list itself, space-separated by default and changeable in the usual way. @@ -31184,7 +31126,7 @@ In the latter case, the range is tried in strict order. Elements after the first for Unix sockets, or second for TCP socket, are options. -The supported option are: +The supported options are: .code pri= Selection priority weight= Selection bias @@ -31217,13 +31159,16 @@ The default value is two minutes. The &`retry`& option specifies a time after which a single retry for a failed connect is made. The default is to not retry. -.wen The &%spamd_address%& variable is expanded before use if it starts with a dollar sign. In this case, the expansion may return a string that is used as the list so that multiple spamd servers can be the result of an expansion. +.vindex "&$callout_address$&" +When a connection is made to the server the expansion variable &$callout_address$& +is set to record the actual address used. + .section "Calling SpamAssassin from an Exim ACL" "SECID206" Here is a simple example of the use of the &%spam%& condition in a DATA ACL: .code @@ -31234,10 +31179,8 @@ The right-hand side of the &%spam%& condition specifies a name. This is relevant if you have set up multiple SpamAssassin profiles. If you do not want to scan using a specific profile, but rather use the SpamAssassin system-wide default profile, you can scan for an unknown name, or simply use &"nobody"&. -.new Rspamd does not use this setting. However, you must put something on the right-hand side. -.wen The name allows you to use per-domain or per-user antispam profiles in principle, but this is not straightforward in practice, because a message may @@ -31245,14 +31188,12 @@ have multiple recipients, not necessarily all in the same domain. Because the &%spam%& condition has to be called from a DATA-time ACL in order to be able to read the contents of the message, the variables &$local_part$& and &$domain$& are not set. -.new Careful enforcement of single-recipient messages (e.g. by responding with defer in the recipient ACL for all recipients after the first), or the use of PRDR, .cindex "PRDR" "use for per-user SpamAssassin profiles" are needed to use this feature. -.wen The right-hand side of the &%spam%& condition is expanded before being used, so you can put lookups or conditions there. When the right-hand side evaluates to @@ -31277,9 +31218,7 @@ it always return &"true"& by appending &`:true`& to the username. .cindex "spam scanning" "returned variables" When the &%spam%& condition is run, it sets up a number of expansion variables. -.new Except for &$spam_report$&, -.wen these variables are saved with the received message so are available for use at delivery time. @@ -31298,21 +31237,18 @@ The integer value is useful for numeric comparisons in conditions. A string consisting of a number of &"+"& or &"-"& characters, representing the integer part of the spam score value. A spam score of 4.4 would have a &$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$& A multiline text table, containing the full SpamAssassin report for the message. Useful for inclusion in headers or reject messages. -.new This variable is only usable in a DATA-time ACL. -.wen -.new .vitem &$spam_action$& For SpamAssassin either 'reject' or 'no action' depending on the spam score versus threshold. For Rspamd, the recommended action. -.wen .endlist @@ -31500,9 +31436,7 @@ This is perhaps the most important of the MIME variables. It contains a proposed filename for an attachment, if one was found in either the &'Content-Type:'& or &'Content-Disposition:'& headers. The filename will be RFC2047 -.new or RFC2231 -.wen decoded, but no additional sanity checks are done. If no filename was found, this variable contains the empty string. @@ -31593,6 +31527,8 @@ deny message = contains blacklisted regex ($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. @@ -34102,10 +34038,8 @@ 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 @@ -35444,11 +35378,12 @@ selection marked by asterisks: &`*etrn `& ETRN commands &`*host_lookup_failed `& as it says &` ident_timeout `& timeout for ident connection -.new &` incoming_interface `& local interface on <= and => lines -.wen &` 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 @@ -35471,9 +35406,7 @@ selection marked by asterisks: &` 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 @@ -35481,6 +35414,9 @@ 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 @@ -35573,10 +35509,10 @@ 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 +added to other SMTP log lines, for example &"SMTP connection from"&, to +rejection lines, and (despite the name) to outgoing &"=>"& and &"->"& lines. .new -and (despite the name) the local interface is added to &"=>"& lines.. +The latter can be disabled by turning off the &%outgoing_interface%& option. .wen .next .cindex "log" "incoming remote port" @@ -35595,13 +35531,30 @@ 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" @@ -36345,6 +36298,9 @@ 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