X-Git-Url: https://git.exim.org/users/jgh/exim.git/blobdiff_plain/b10c87b38c2345d15d30da5c18c823355ac506a9..14ca5d2ac6c3536fe189435269a302ef14e972cf:/doc/doc-docbook/spec.xfpt diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index 783aeb429..32d57d027 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -2528,6 +2528,8 @@ use of Exim's filtering capabilities, you should make the document entitled If you are already running Exim on your host, building and installing a new version automatically makes it available to MUAs, or any other programs that call the MTA directly. However, if you are running an Exim daemon, you do need +.cindex restart "on HUP signal" +.cindex signal "HUP, to restart" to send it a HUP signal, to make it re-execute itself, and thereby pick up the new binary. You do not need to stop processing mail in order to install a new version of Exim. The install script does not modify an existing runtime @@ -2626,6 +2628,7 @@ supplementary group is one of those listed in the &%trusted_groups%& configuration option. Note that the Exim group is not automatically trusted. .cindex '&"From"& line' +.cindex "envelope from" .cindex "envelope sender" Trusted users are always permitted to use the &%-f%& option or a leading &"From&~"& line to specify the envelope sender of a message that is passed to @@ -2765,9 +2768,12 @@ used to specify a path on the command line if a pid file is required. The SIGHUP signal .cindex "SIGHUP" +.cindex restart "on HUP signal" +.cindex signal "HUP, to restart" .cindex "daemon" "restarting" .cindex signal "to reload configuration" .cindex daemon "reload configuration" +.cindex reload configuration can be used to cause the daemon to re-execute itself. This should be done whenever Exim's configuration file, or any file that is incorporated into it by means of the &%.include%& facility, is changed, and also whenever a new version @@ -2877,6 +2883,7 @@ separate document entitled &'Exim's interfaces to mail filtering'&. When testing a filter file, .cindex "&""From""& line" +.cindex "envelope from" .cindex "envelope sender" .oindex "&%-f%&" "for filter testing" the envelope sender can be set by the &%-f%& option, @@ -3717,6 +3724,7 @@ between &%-F%& and the <&'string'&> is optional. .cindex "sender" "address" .cindex "address" "sender" .cindex "trusted users" +.cindex "envelope from" .cindex "envelope sender" .cindex "user" "trusted" This option sets the address of the envelope sender of a locally-generated @@ -9200,6 +9208,7 @@ Many strings in Exim's runtime configuration are expanded before use. Some of them are expanded every time they are used; others are expanded only once. When a string is being expanded it is copied verbatim from left to right except +.cindex expansion "string concatenation" when a dollar or backslash character is encountered. A dollar specifies the start of a portion of the string that is interpreted and replaced as described below in section &<>& onwards. Backslash is used as an @@ -9210,7 +9219,13 @@ dependent upon the option for which a value is sought; in this documentation, options for which string expansion is performed are marked with † after the data type. ACL rules always expand strings. A couple of expansion conditions do not expand some of the brace-delimited branches, for security -reasons. +reasons, +.new +.cindex "tainted data" expansion +.cindex expansion "tainted data" +and expansion of data deriving from the sender (&"tainted data"&) +is not permitted. +.wen @@ -10956,11 +10971,15 @@ If the string is a single variable of type certificate, returns the SHA-1 hash fingerprint of the certificate. -.vitem &*${sha256:*&<&'string'&>&*}*& +.vitem &*${sha256:*&<&'string'&>&*}*& &&& + &*${sha2:*&<&'string'&>&*}*& &&& + &*${sha2_:*&<&'string'&>&*}*& .cindex "SHA-256 hash" +.cindex "SHA-2 hash" .cindex certificate fingerprint .cindex "expansion" "SHA-256 hashing" .cindex "&%sha256%& expansion item" +.cindex "&%sha2%& expansion item" The &%sha256%& operator computes the SHA-256 hash value of the string and returns it as a 64-digit hexadecimal number, in which any letters are in upper case. @@ -10968,6 +10987,15 @@ it as a 64-digit hexadecimal number, in which any letters are in upper case. If the string is a single variable of type certificate, returns the SHA-256 hash fingerprint of the certificate. +.new +The operator can also be spelled &%sha2%& and does the same as &%sha256%& +(except for certificates, which are not supported). +Finally, if an underbar +and a number is appended it specifies the output length, selecting a +member of the SHA-2 family of hash functions. +Values of 256, 384 and 512 are accepted, with 256 being the default. +.wen + .vitem &*${sha3:*&<&'string'&>&*}*& &&& &*${sha3_:*&<&'string'&>&*}*& @@ -12182,6 +12210,7 @@ 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. +This value may be overridden by the &%exim_version%& main config option. .vitem &$header_$&<&'name'&> This is not strictly an expansion variable. It is expansion syntax for @@ -12741,6 +12770,16 @@ or if not set, the value of &$qualify_domain$&. .cindex queues named The name of the spool queue in use; empty for the default queue. +.new +.vitem &$r_...$& +.vindex &$r_...$& +.cindex router variables +Values can be placed in these variables by the &%set%& option of a router. +They can be given any name that starts with &$r_$&. +The values persist for the address being handled through subsequent routers +and the eventual transport. +.wen + .vitem &$rcpt_count$& .vindex "&$rcpt_count$&" When a message is being received by SMTP, this variable contains the number of @@ -13513,7 +13552,8 @@ Otherwise, empty. .vitem &$version_number$& .vindex "&$version_number$&" -The version number of Exim. +The version number of Exim. Same as &$exim_version$&, may be overridden +by the &%exim_version%& main config option. .vitem &$warn_message_delay$& .vindex "&$warn_message_delay$&" @@ -14352,6 +14392,7 @@ See also the &'Policy controls'& section above. .row &%ignore_fromline_hosts%& "allow &""From ""& from these hosts" .row &%ignore_fromline_local%& "allow &""From ""& from local SMTP" .row &%pipelining_advertise_hosts%& "advertise pipelining to these hosts" +.row &%pipelining_connect_advertise_hosts%& "advertise pipelining to these hosts" .row &%prdr_enable%& "advertise PRDR to all hosts" .row &%smtputf8_advertise_hosts%& "advertise SMTPUTF8 to these hosts" .row &%tls_advertise_hosts%& "advertise TLS to these hosts" @@ -15142,6 +15183,11 @@ domain matches this list. This is a fudge to help with name servers that give big delays or otherwise do not work for the AAAA record type. In due course, when the world's name servers have all been upgraded, there should be no need for this option. +.new +Note that all lookups, including those done for verification, are affected; +this will result in verify failure for IPv6 connections or ones using names +only valid for IPv6 addresses. +.wen .option dns_retrans main time 0s @@ -15344,6 +15390,14 @@ not also supplied, the gid is taken from the result of &[getpwnam()]& if it is used. See chapter &<>& for a discussion of security issues. +.option exim_version main string "current version" +.cindex "Exim version" +.cindex customizing "version number" +.cindex "version number of Exim" override +This option allows to override the &$version_number$&/&$exim_version$& Exim reports in +various places. Use with care, this may fool stupid security scanners. + + .option extra_local_interfaces main "string list" unset This option defines network interfaces that are to be considered local when routing, but which are not used for listening by the daemon. See section @@ -15863,6 +15917,7 @@ and no &'Sender:'& header is ever added. If, in addition, you want to retain &'Sender:'& header lines supplied by untrusted users, you must also set &%local_sender_retain%& to be true. +.cindex "envelope from" .cindex "envelope sender" These options affect only the header lines in the message. The envelope sender is still forced to be the login id at the qualify domain unless @@ -16349,6 +16404,19 @@ for each SMTP command and response. When PIPELINING is advertised, Exim assumes that clients will use it; &"out of order"& commands that are &"expected"& do not count as protocol errors (see &%smtp_max_synprot_errors%&). +.new +.option pipelining_connect_advertise_hosts main "host list&!!" * +.cindex "pipelining" "early connection" +.cindex "pipelining" PIPE_CONNECT +If Exim is built with the SUPPORT_PIPE_CONNECT build option +this option controls which hosts the facility is advertised to +and from which pipeline early-connection (before MAIL) SMTP +commands are acceptable. +When used, the pipelining saves on roundtrip times. + +Currently the option name &"X_PIPE_CONNECT"& is used. +.wen + .option prdr_enable main boolean false .cindex "PRDR" "enabling on server" @@ -17565,7 +17633,7 @@ use when sending messages as a client, you must set the &%tls_certificate%& option in the relevant &(smtp)& transport. &*Note*&: If you use filenames based on IP addresses, change the list -separator in the usual way (&<>&) >to avoid confusion under IPv6. +separator in the usual way (&<>&) to avoid confusion under IPv6. &*Note*&: Under versions of OpenSSL preceding 1.1.1, when a list of more than one @@ -17880,6 +17948,7 @@ See &%unknown_login%&. .cindex "sender" "setting by untrusted user" .cindex "untrusted user setting sender" .cindex "user" "untrusted setting sender" +.cindex "envelope from" .cindex "envelope sender" When an untrusted user submits a message to Exim using the standard input, Exim normally creates an envelope sender address from the user's login and the @@ -18030,6 +18099,10 @@ file = ${extract{mailbox}{$address_data}} This makes the configuration file less messy, and also reduces the number of lookups (though Exim does cache lookups). +.new +See also the &%set%& option below. +.wen + .vindex "&$sender_address_data$&" .vindex "&$address_data$&" The &%address_data%& facility is also useful as a means of passing information @@ -18282,6 +18355,7 @@ Not effective on redirect routers. .option errors_to routers string&!! unset +.cindex "envelope from" .cindex "envelope sender" .cindex "router" "changing address for errors" If a router successfully handles an address, it may assign the address to a @@ -18943,6 +19017,32 @@ SMTP VRFY command is enabled, it must be used after MAIL if the sender address matters. +.new +.option set routers "string list" unset +.cindex router variables +This option may be used multiple times on a router; +because of this the list aspect is mostly irrelevant. +The list separator is a semicolon but can be changed in the +usual way. + +Each list-element given must be of the form $"name = value"$ +and the names used must start with the string &"r_"&. +Values containing a list-separator should have them doubled. +When a router runs, the strings are evaluated in order, +to create variables which are added to the set associated with +the address. +The variable is set with the expansion of the value. +The variables can be used by the router options +(not including any preconditions) +and by the transport. +Later definitions of a given named variable will override former ones. +Varible use is via the usual &$r_...$& syntax. + +This is similar to the &%address_data%& option, except that +many independent variables can be used, with choice of naming. +.wen + + .option translate_ip_address routers string&!! unset .cindex "IP address" "translating" .cindex "packet radio" @@ -21728,6 +21828,7 @@ on a remote transport in the current implementation. .option return_path transports string&!! unset .cindex "envelope sender" +.cindex "envelope from" .cindex "transport" "return path; changing" .cindex "return path" "changing in transport" If this option is set, the string is expanded at transport time and replaces @@ -22774,6 +22875,7 @@ percentage. .option use_bsmtp appendfile boolean false +.cindex "envelope from" .cindex "envelope sender" If this option is set true, &(appendfile)& writes messages in &"batch SMTP"& format, with the envelope sender and recipient(s) included as SMTP commands. If @@ -23658,7 +23760,7 @@ inserted in the argument list at that point &'as a separate argument'&. This avoids any problems with spaces or shell metacharacters, and is of use when a &(pipe)& transport is handling groups of addresses in a batch. -If &%force_command%& is enabled on the transport, Special handling takes place +If &%force_command%& is enabled on the transport, special handling takes place for an argument that consists of precisely the text &`$address_pipe`&. It is handled similarly to &$pipe_addresses$& above. It is expanded and each argument is inserted in the argument list at that point @@ -24529,6 +24631,30 @@ facilities such as AUTH, PIPELINING, SIZE, and STARTTLS. Exim will not use the SMTP PIPELINING extension when delivering to any host that matches this list, even if the server host advertises PIPELINING support. +.new +.option hosts_pipe_connect smtp "host list&!!" unset +.cindex "pipelining" "early connection" +.cindex "pipelining" PIPE_CONNECT +If Exim is built with the SUPPORT_PIPE_CONNECT build option +this option controls which to hosts the facility watched for +and recorded, and used for subsequent connections. + +The retry hints database is used for the record, +and records are subject to the &%retry_data_expire%& option. +When used, the pipelining saves on roundtrip times. +It also turns SMTP into a client-first protocol +so combines well with TCP Fast Open. + +Note: +When the facility is used, the transport &%helo_data%& option +will be expanded before the &$sending_ip_address$& variable +is filled in. +A check is made for the use of that variable, without the +presence of a &"def:"& test on it, but suitably complex coding +can avoid the check and produce unexpected results. +You have been warned. +.wen + .option hosts_avoid_tls smtp "host list&!!" unset .cindex "TLS" "avoiding for certain hosts" @@ -24568,13 +24694,15 @@ been started will not be passed to a new delivery process for sending another message on the same connection. See section &<>& for an explanation of when this might be needed. -.option hosts_noproxy_tls smtp "host list&!!" * +.new +.option hosts_noproxy_tls smtp "host list&!!" unset .cindex "TLS" "passing connection" .cindex "multiple SMTP deliveries" .cindex "TLS" "multiple message deliveries" For any host that matches this list, a TLS session which has been started will not be passed to a new delivery process for sending another message on the same session. +.wen The traditional implementation closes down TLS and re-starts it in the new process, on the same open TCP connection, for each successive message @@ -24670,7 +24798,7 @@ This option provides a list of servers to which, provided they announce CHUNKING support, Exim will attempt to use BDAT commands rather than DATA. BDAT will not be used in conjunction with a transport filter. -.option hosts_try_dane smtp "host list&!!" unset +.option hosts_try_dane smtp "host list&!!" * .cindex DANE "transport options" .cindex DANE "attempting for certain servers" If built with DANE support, Exim will lookup a @@ -24680,7 +24808,7 @@ a DANE-verified TLS connection is made to that host; there will be no fallback to in-clear communication. See section &<>&. -.option hosts_try_fastopen smtp "host list&!!" unset +.option hosts_try_fastopen smtp "host list&!!" * .cindex "fast open, TCP" "enabling, in client" .cindex "TCP Fast Open" "enabling, in client" .cindex "RFC 7413" "TCP Fast Open" @@ -25243,6 +25371,7 @@ When an address is being routed, either for delivery or for verification, rewriting is applied immediately to child addresses that are generated by redirection, unless &%no_rewrite%& is set on the router. +.cindex "envelope from" .cindex "envelope sender" "rewriting at transport time" .cindex "rewriting" "at transport time" .cindex "header lines" "rewriting at transport time" @@ -28359,6 +28488,13 @@ transport provide the client with a certificate, which is passed to the server if it requests it. If the server is Exim, it will request a certificate only if &%tls_verify_hosts%& or &%tls_try_verify_hosts%& matches the client. +.new +Do not use a certificate which has the OCSP-must-staple extension, +for client use (they are usable for server use). +As TLS has no means for the client to staple before TLS 1.3 it will result +in failed connections. +.wen + If the &%tls_verify_certificates%& option is set on the &(smtp)& transport, it specifies a collection of expected server certificates. These may be @@ -30838,7 +30974,7 @@ client host, and its contents have been verified. If there has been no previous attempt to verify the HELO/EHLO contents, it is carried out when this condition is encountered. See the description of the &%helo_verify_hosts%& and &%helo_try_verify_hosts%& options for details of how to request verification -independently of this condition. +independently of this condition, and for detail of the verification. For SMTP input that does not come over TCP/IP (the &%-bs%& command line option), this condition is always true. @@ -34346,6 +34482,7 @@ headers remove "Old-Subject" .section "Setting an errors address in a system filter" "SECID217" +.cindex "envelope from" .cindex "envelope sender" In a system filter, if a &%deliver%& command is followed by .code @@ -34579,6 +34716,7 @@ other words, such qualification is also controlled by .cindex "sender" "address" .oindex "&%uucp_from_pattern%&" .oindex "&%uucp_from_sender%&" +.cindex "envelope from" .cindex "envelope sender" .cindex "Sendmail compatibility" "&""From""& line" Messages that have come from UUCP (and some other applications) often begin @@ -36027,6 +36165,7 @@ the address, giving a suitable error message. .section "Variable Envelope Return Paths (VERP)" "SECTverp" .cindex "VERP" .cindex "Variable Envelope Return Paths" +.cindex "envelope from" .cindex "envelope sender" Variable Envelope Return Paths &-- see &url(https://cr.yp.to/proto/verp.txt) &-- are a way of helping mailing list administrators discover which subscription @@ -37354,6 +37493,15 @@ The field is a single "L". On accept lines, where PIPELINING was offered but not used by the client, the field has a minus appended. + +.new +.cindex "pipelining" "early connection" +If Exim is built with the SUPPORT_PIPE_CONNECT build option +accept "L" fields have a period appended if the feature was +offered but not used, or an asterisk appended if used. +Delivery "L" fields have an asterisk appended if used. +.wen + .next .cindex "log" "queue run" .cindex "queue runner" "logging" @@ -37709,6 +37857,11 @@ Match only frozen messages. .vitem &*-x*& Match only non-frozen messages. + +.new +.vitem &*-G*&&~<&'queuename'&> +Match only messages in the given queue. Without this, the default queue is searched. +.wen .endlist The following options control the format of the output: @@ -39396,6 +39549,11 @@ was received from the client, this records the Distinguished Name from that certificate. .endlist +.new +Any of the above may have an extra hyphen prepended, to indicate the the +corresponding data is untrusted. +.wen + Following the options there is a list of those addresses to which the message is not to be delivered. This set of addresses is initialized from the command line when the &%-t%& option is used and &%extract_addresses_remove_arguments%&