X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/089fc87a02b0c682ace3afc2f597f5e5b3b8f076..exim-4_86:/doc/doc-docbook/spec.xfpt diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index a598ec08b..a05b41b40 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -52,7 +52,7 @@ .set I "    " .macro copyyear -2014 +2015 .endmacro . ///////////////////////////////////////////////////////////////////////////// @@ -1985,9 +1985,12 @@ 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"&. Exim used to +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 +.new +Exim used to have a compile option for including A6 record support but this has now been withdrawn.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 @@ -2031,9 +2034,6 @@ 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 @@ -4648,12 +4648,14 @@ 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 @@ -5010,7 +5012,8 @@ 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. @@ -5232,7 +5235,7 @@ 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 @@ -5598,6 +5601,15 @@ 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 # percent_hack_domains = @@ -6878,9 +6890,11 @@ 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. +.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, @@ -6928,6 +6942,7 @@ ${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. @@ -6936,12 +6951,13 @@ specified. .code ${lookup dnsdb{>:,; soa=a.b.example.com}} .endd +.wen .section "Dnsdb lookup modifiers" "SECTdnsdb_mod" .cindex "dnsdb modifiers" .cindex "modifiers" "dnsdb" .cindex "options" "dnsdb" -Modifiers for &(dnsdb)& lookups are givien by optional keywords, +Modifiers for &(dnsdb)& lookups are given by optional keywords, each followed by a comma, that may appear before the record type. @@ -6976,16 +6992,18 @@ The default is &"never"&. See also the &$lookup_dnssec_authenticated$& variable. +.new .cindex timeout "dns lookup" .cindex "DNS" timeout Timeout for the dnsdb lookup can be controlled by a retrans modifier. The form is &"retrans_VAL"& where VAL is an Exim time specification -(eg &"5s"&). +(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%&. +.wen .section "Pseudo dnsdb record types" "SECID66" @@ -7661,6 +7679,12 @@ 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 + .section "Expansion of lists" "SECID75" @@ -8443,7 +8467,7 @@ 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. @@ -8934,7 +8958,7 @@ 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 `& @@ -8969,7 +8993,7 @@ parseable by Exim as a comma-separated tagged list 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". @@ -8989,7 +9013,7 @@ 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. @@ -9032,6 +9056,7 @@ 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" @@ -9049,10 +9074,11 @@ ${env{USER}{$value} fail } 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 +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 "&*${extract{*&<&'key'&>&*}{*&<&'string1'&>&*}{*&<&'string2'&>&*}&&& @@ -9904,7 +9930,7 @@ processing lists. To clarify "list of addresses in RFC 2822 format" mentioned above, Exim follows a strict interpretation of header line formatting. Exim parses the bare, unquoted portion of an email address and if it finds a comma, treats it as an -email address seperator. For the example header line: +email address separator. For the example header line: .code From: =?iso-8859-2?Q?Last=2C_First?= .endd @@ -10250,7 +10276,7 @@ random(). .vitem &*${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 @@ -11342,6 +11368,36 @@ This variable is available when Exim is compiled with the content-scanning extension and the obsolete &%demime%& condition. For details, see section &<>&. +.new +.vitem &$dkim_cur_signer$& &&& + &$dkim_verify_status$& &&& + &$dkim_verify_reason$& &&& + &$dkim_domain$& &&& + &$dkim_identity$& &&& + &$dkim_selector$& &&& + &$dkim_algo$& &&& + &$dkim_canon_body$& &&& + &$dkim_canon_headers$& &&& + &$dkim_copiedheaders$& &&& + &$dkim_bodylength$& &&& + &$dkim_created$& &&& + &$dkim_expires$& &&& + &$dkim_headernames$& &&& + &$dkim_key_testing$& &&& + &$dkim_key_nosubdomains$& &&& + &$dkim_key_srvtype$& &&& + &$dkim_key_granularity$& &&& + &$dkim_key_notes$& +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 &<>&. +.wen + .vitem &$dnslist_domain$& &&& &$dnslist_matched$& &&& &$dnslist_text$& &&& @@ -11709,6 +11765,11 @@ 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 "&$mailstore_basename$&" @@ -12228,7 +12289,7 @@ the verified host name or to the host's IP address in square brackets. .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 authenticatied data. +done using DNS information the resolver library stated was authenticated data. .wen .vitem &$sender_helo_name$& @@ -12268,7 +12329,7 @@ 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). +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. @@ -12507,8 +12568,10 @@ 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 "&$tls_out_ourcert$&" @@ -12523,15 +12586,17 @@ 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 "&$tls_in_certificate_verified$&" 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. @@ -12588,8 +12653,10 @@ 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 @@ -12601,8 +12668,10 @@ 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 "&$tls_in_sni$&" @@ -13401,6 +13470,7 @@ 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" @@ -13455,6 +13525,7 @@ 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" @@ -13548,6 +13619,7 @@ 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" @@ -13663,6 +13735,14 @@ 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" This option defines the ACL that is run when an SMTP ETRN command is @@ -13697,11 +13777,13 @@ 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 @@ -13759,7 +13841,7 @@ 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. @@ -14138,6 +14220,16 @@ 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 .cindex "DNS" "&""try again""& response; overriding" DNS lookups give a &"try again"& response for the DNS errors @@ -14224,13 +14316,43 @@ 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" +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. +.wen + +.cindex "DNS" "resolver options" .option dns_use_edns0 main integer -1 .cindex "DNS" "resolver options" .cindex "DNS" "EDNS0" @@ -14278,7 +14400,7 @@ 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. @@ -14953,8 +15075,9 @@ 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 @@ -15101,7 +15224,7 @@ 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. @@ -15341,9 +15464,9 @@ 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" @@ -15787,6 +15910,7 @@ 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" @@ -15794,6 +15918,7 @@ 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 @@ -16187,9 +16312,11 @@ 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%&" @@ -16576,7 +16703,24 @@ 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, +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. +.wen + + .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 @@ -16584,6 +16728,8 @@ Certificate Authority. .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 @@ -16646,7 +16792,7 @@ 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 @@ -17093,6 +17239,7 @@ 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" @@ -17111,6 +17258,7 @@ 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 @@ -17330,6 +17478,13 @@ 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 + + .option ignore_target_hosts routers "host list&!!" unset .cindex "IP address" "discarding" @@ -18061,7 +18216,7 @@ 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. @@ -18083,8 +18238,10 @@ 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 @@ -18165,6 +18322,7 @@ 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%& @@ -18174,6 +18332,7 @@ 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 @@ -19417,7 +19576,7 @@ 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 @@ -20386,6 +20545,10 @@ 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 @@ -23110,7 +23273,7 @@ This applies to all of the SRV, MX, 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. +(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. @@ -23473,7 +23636,7 @@ 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. @@ -23677,7 +23840,7 @@ 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 @@ -23690,7 +23853,7 @@ 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. @@ -24447,12 +24610,14 @@ 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. @@ -24865,6 +25030,7 @@ 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 @@ -24879,6 +25045,10 @@ 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 @@ -24950,7 +25120,7 @@ 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. @@ -25598,7 +25768,7 @@ 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 = $auth1 .endd @@ -25968,7 +26138,7 @@ The value should be a pathname, with no &"file:"& prefix. .option server_service heimdal_gssapi string&!! "smtp" This option specifies the service identifier used, in conjunction with -&%server_hostname%&, for building the identifer for finding credentials +&%server_hostname%&, for building the identifier for finding credentials from the keytab. @@ -26085,6 +26255,81 @@ msn: +. //////////////////////////////////////////////////////////////////////////// +. //////////////////////////////////////////////////////////////////////////// + +.new +.chapter "The tls authenticator" "CHAPtlsauth" +.scindex IIDtlsauth1 "&(tls)& authenticator" +.scindex IIDtlsauth2 "authenticators" "&(tls)&" +.cindex "authentication" "Client Certificate" +.cindex "authentication" "X509" +.cindex "Certificate-based authentication" +The &(tls)& authenticator provides server support for +authentication based on client certificates. + +It is not an SMTP authentication mechanism and is not +advertised by the server as part of the SMTP EHLO response. +It is an Exim authenticator in the sense that it affects +the protocol element of the log line, can be tested for +by the &%authenticated%& ACL condition, and can set +the &$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 +.wen + + +Note that because authentication is traditionally an SMTP operation, +the &%authenticated%& ACL condition cannot be used in +a connect- or helo-ACL. + + + . //////////////////////////////////////////////////////////////////////////// . //////////////////////////////////////////////////////////////////////////// @@ -26699,7 +26944,7 @@ specifies a collection of expected server certificates. 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 @@ -26769,7 +27014,7 @@ 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. @@ -26823,7 +27068,7 @@ 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. @@ -27013,6 +27258,7 @@ 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" @@ -27031,6 +27277,7 @@ 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" @@ -27179,10 +27426,10 @@ 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. @@ -27193,7 +27440,7 @@ 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 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. @@ -27206,8 +27453,11 @@ 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, it may only accept +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 @@ -28123,9 +28373,11 @@ 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, +.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. @@ -28133,7 +28385,9 @@ 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, +.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, @@ -28145,7 +28399,9 @@ 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. +.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. @@ -28954,8 +29210,10 @@ 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. @@ -29560,7 +29818,7 @@ 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. @@ -30530,7 +30788,7 @@ The following scanner types are supported in this release: .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, @@ -30551,7 +30809,7 @@ 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 @@ -30735,7 +30993,7 @@ 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, @@ -30862,7 +31120,7 @@ score and a report for the message. .new 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 @@ -30876,7 +31134,7 @@ 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 @@ -30938,7 +31196,7 @@ variant=rspamd Use Rspamd rather than SpamAssassin protocol The &`pri`& option specifies a priority for the server within the list, higher values being tried first. -The deafult priority is 1. +The default priority is 1. The &`weight`& option specifies a selection bias. Within a priority set @@ -30951,7 +31209,7 @@ 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, eg. &`20s`& or &`1m`&. +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. @@ -30984,15 +31242,17 @@ right-hand side. 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. +.new Careful enforcement of single-recipient messages -(eg. by responding with defer in the recipient ACL for all recipients +(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 @@ -31016,7 +31276,11 @@ 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. +.new +Except for &$spam_report$&, +.wen +these variables are saved with the received message so are available for use at delivery time. .vlist @@ -31039,6 +31303,9 @@ headers, since MUAs can match on such strings. .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 &$spam_action$& @@ -31232,7 +31499,11 @@ 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 or RFC2231 decoded, but no additional sanity checks are done. +RFC2047 +.new +or RFC2231 +.wen +decoded, but no additional sanity checks are done. If no filename was found, this variable contains the empty string. @@ -34671,8 +34942,9 @@ 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. @@ -35172,7 +35444,9 @@ 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) &` outgoing_port `& add remote port to => lines @@ -35190,7 +35464,7 @@ 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 @@ -35301,7 +35575,9 @@ 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 +.new and (despite the name) the local interface is added to &"=>"& lines.. +.wen .next .cindex "log" "incoming remote port" .cindex "port" "logging remote" @@ -35416,7 +35692,7 @@ 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 @@ -35465,7 +35741,7 @@ 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, @@ -35645,7 +35921,7 @@ 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 @@ -35656,7 +35932,7 @@ 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'&> @@ -36929,7 +37205,7 @@ 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 @@ -37544,7 +37820,7 @@ 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). @@ -37608,7 +37884,7 @@ 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