X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/0762e1a4d6de4b7b0206314302297c9dd6d7ae73..37b849dca4dfd855212a763662825e:/doc/doc-docbook/spec.xfpt diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index 946f55b11..5a757c4ed 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -1,3 +1,4 @@ + . ///////////////////////////////////////////////////////////////////////////// . This is the primary source of the Exim Manual. It is an xfpt document that is . converted into DocBook XML for subsequent conversion into printable and online @@ -45,7 +46,7 @@ . Update the Copyright year (only) when changing content. . ///////////////////////////////////////////////////////////////////////////// -.set previousversion "4.96" +.set previousversion "4.97" .include ./local_params .set ACL "access control lists (ACLs)" @@ -54,7 +55,7 @@ .set drivernamemax "64" .macro copyyear -2022 +2023 .endmacro . ///////////////////////////////////////////////////////////////////////////// @@ -76,6 +77,16 @@ . --- table with four columns. For cases when the option name is given with . --- a space, so that it can be split, a fifth argument is used for the . --- index entry. +. --- Also one for multiple option def headings be grouped in a single +. --- table (but without the split capability). + +.macro otable +.itable all 0 0 4 8* left 6* center 6* center 6* right +.endmacro + +.macro orow +.row "&%$1%&" "Use: &'$2'&" "Type: &'$3'&" "Default: &'$4'&" +.endmacro .macro option .arg 5 @@ -84,8 +95,19 @@ .arg -5 .oindex "&%$1%&" .endarg -.itable all 0 0 4 8* left 6* center 6* center 6* right -.row "&%$1%&" "Use: &'$2'&" "Type: &'$3'&" "Default: &'$4'&" +.otable +.orow "$1" "$2" "$3" "$4" +.endtable +.endmacro + +.macro options +.eacharg +.oindex "&%$+1%&" +.endeach 4 +.otable +.eacharg +.orow "$+1" "$+2" "$+3" "$+4" +.endeach 4 .endtable .endmacro @@ -443,10 +465,11 @@ Please do not ask for configuration help in the bug-tracker. The following Exim mailing lists exist: .table2 140pt -.row &'exim-announce@exim.org'& "Moderated, low volume announcements list" -.row &'exim-users@exim.org'& "General discussion list" -.row &'exim-dev@exim.org'& "Discussion of bugs, enhancements, etc." -.row &'exim-cvs@exim.org'& "Automated commit messages from the VCS" +.row &'exim-announce@lists.exim.org'& "Moderated, low volume announcements list" +.row &'exim-users@lists.exim.org'& "General discussion list" +.row &'exim-users-de@lists.exim.org'& "General discussion list in German language" +.row &'exim-dev@lists.exim.org'& "Discussion of bugs, enhancements, etc." +.row &'exim-cvs@lists.exim.org'& "Automated commit messages from the VCS" .endtable You can subscribe to these lists, change your existing subscriptions, and view @@ -948,9 +971,10 @@ User filters are run as part of the routing process, described below. .cindex "base36" .cindex "Darwin" .cindex "Cygwin" -Every message handled by Exim is given a &'message id'& which is sixteen +.cindex "exim_msgdate" +Every message handled by Exim is given a &'message id'& which is 23 characters long. It is divided into three parts, separated by hyphens, for -example &`16VDhn-0001bo-D3`&. Each part is a sequence of letters and digits, +example &`16VDhn-000000001bo-D342`&. Each part is a sequence of letters and digits, normally encoding numbers in base 62. However, in the Darwin operating system (Mac OS X) and when Exim is compiled to run under Cygwin, base 36 (avoiding the use of lower case letters) is used instead, because the message @@ -971,20 +995,24 @@ started to be received, to a granularity of one second. That is, this field contains the number of seconds since the start of the epoch (the normal Unix way of representing the date and time of day). .next -After the first hyphen, the next six characters are the id of the process that -received the message. +After the first hyphen, the next +eleven +characters are the id of the process that received the message. .next -There are two different possibilities for the final two characters: +There are two different possibilities for the final four characters: .olist .oindex "&%localhost_number%&" If &%localhost_number%& is not set, this value is the fractional part of the -time of reception, normally in units of 1/2000 of a second, but for systems +time of reception, normally in units of +microseconds. +but for systems that must use base 36 instead of base 62 (because of case-insensitive file -systems), the units are 1/1000 of a second. +systems), the units are +2 us. .next -If &%localhost_number%& is set, it is multiplied by 200 (100) and added to -the fractional part of the time, which in this case is in units of 1/200 -(1/100) of a second. +If &%localhost_number%& is set, it is multiplied by +500000 (250000) and added to +the fractional part of the time, which in this case is in units of 2 us (4 us). .endlist .endlist @@ -994,6 +1022,10 @@ received by the same process, or by another process with the same (re-used) pid, it is guaranteed that the time will be different. In most cases, the clock will already have ticked while the message was being received. +The exim_msgdate utility (see section &<>&) can be +used to display the date, and optionally the process id, of an Exim +Message ID. + .section "Receiving mail" "SECID13" .cindex "receiving mail" @@ -2810,6 +2842,12 @@ of Exim is installed. It is not necessary to do this when other files that are referenced from the configuration (for example, alias files) are changed, because these are reread each time they are used. +Either a SIGTERM or a SIGINT signal should be used to cause the daemon +to cleanly shut down. +Subprocesses handling recceiving or delivering messages, +or for scanning the queue, +will not be affected by the termination of the daemon process. + .cmdopt -bdf This option has the same effect as &%-bd%& except that it never disconnects from the controlling terminal, even when no debugging is specified. @@ -2846,11 +2884,9 @@ defined and macros will be expanded. Because macros in the config file are often used for secrets, those are only available to admin users. -.new The word &"set"& at the start of a line, followed by a single space, is recognised specially as defining a value for a variable. The syntax is otherwise the same as the ACL modifier &"set ="&. -.wen .cmdopt -bem <&'filename'&> .cindex "testing" "string expansion" @@ -3258,6 +3294,12 @@ to the standard output. It is restricted to admin users, unless &%queue_list_requires_admin%& is set false. +.cmdopt -bpi +.cindex queue "list of message IDs" +This option operates like &%-bp%&, but only outputs message ids +(one per line). + + .cmdopt -bpr This option operates like &%-bp%&, but the output is not sorted into chronological order of message arrival. This can speed it up when there are @@ -3267,6 +3309,9 @@ going to be post-processed in a way that doesn't need the sorting. .cmdopt -bpra This option is a combination of &%-bpr%& and &%-bpa%&. +.cmdopt -bpri +This option is a combination of &%-bpr%& and &%-bpi%&. + .cmdopt -bpru This option is a combination of &%-bpr%& and &%-bpu%&. @@ -3967,7 +4012,7 @@ user. This option requests Exim to give up trying to deliver the listed messages, including any that are frozen. However, if any of the messages are active, their status is not altered. For non-bounce messages, a delivery error message -is sent to the sender, containing the text &"cancelled by administrator"&. +is sent to the sender. Bounce messages are just discarded. This option can be used only by an admin user. @@ -4397,13 +4442,17 @@ It is only relevant when the &%-bd%& (start listening daemon) option is also given. Normally the daemon creates this socket, unless a &%-oX%& and &*no*& &%-oP%& option is also present. -If this option is given then the socket will not be created. This could be -required if the system is running multiple daemons. +If this option is given then the socket will not be created. This is required +if the system is running multiple daemons, in which case it should +be used on all. +The features supported by the socket will not be available in such cases. The socket is currently used for .ilist fast ramp-up of queue runner processes .next +caching compiled regexes +.next obtaining a current queue size .endlist @@ -4489,22 +4538,30 @@ every domain. Addresses are routed, local deliveries happen, but no remote transports are run. Performance will be best if the &%queue_run_in_order%& option is false. -If that is so and the &%queue_fast_ramp%& option is true then -in the first phase of the run, +If that is so and +the &%queue_fast_ramp%& option is true +and a daemon-notifier socket is available +then in the first phase of the run, once a threshold number of messages are routed for a given host, a delivery process is forked in parallel with the rest of the scan. .cindex "hints database" "remembering routing" The hints database that remembers which messages are waiting for specific hosts -is updated, as if delivery to those hosts had been deferred. After this is -complete, a second, normal queue scan happens, with routing and delivery taking -place as normal. Messages that are routed to the same host should mostly be +is updated, as if delivery to those hosts had been deferred. + +After the first queue scan complete, +a second, normal queue scan is done, with routing and delivery taking +place as normal. +Messages that are routed to the same host should mostly be delivered down a single SMTP .cindex "SMTP" "passed connection" .cindex "SMTP" "multiple deliveries" .cindex "multiple SMTP deliveries" connection because of the hints that were set up during the first queue scan. -This option may be useful for hosts that are connected to the Internet + +Two-phase queue runs should be used on systems which, even intermittently, +have a large queue (such as mailing-list operators). +They may also be useful for hosts that are connected to the Internet intermittently. .vitem &%-q[q]i...%& @@ -4591,6 +4648,13 @@ combined daemon at system boot time is to use a command such as Such a daemon listens for incoming SMTP calls, and also starts a queue runner process every 30 minutes. +.cindex "named queues" "queue runners" +It is possible to set up runners for multiple named queues within one daemon, +For example: +.code +exim -qGhipri/2m -q10m -qqGmailinglist/1h +.endd + When a daemon is started by &%-q%& with a time value, but without &%-bd%&, no pid file is written unless one is explicitly requested by the &%-oP%& option. @@ -6675,6 +6739,12 @@ version of the lookup key. The &'query-style'& type accepts a generalized database query. No particular key value is assumed by Exim for query-style lookups. You can use whichever Exim variables you need to construct the database query. + +For the string-expansion kind of lookups, the query is given in the first +bracketed argument of the &${lookup ...}$& expansion. +For the list-argument kind of lookup the quury is given by the remainder of the +list item after the first semicolon. + .cindex "tainted data" "quoting for lookups" If tainted data is used in the query then it should be quuted by using the &*${quote_*&<&'lookup-type'&>&*:*&<&'string'&>&*}*& expansion operator @@ -7265,6 +7335,11 @@ dot-separated components; a key such as &`*fict.example`& in a database file is useless, because the asterisk in a partial matching subject key is always followed by a dot. +When the lookup is done from a string-expansion, +the variables &$1$& and &$2$& contain the wild and non-wild parts of the key +during the expansion of the replacement text. +They return to their previous values at the end of the lookup item. + @@ -7315,10 +7390,13 @@ of the following form is provided: .code ${quote_:} .endd -For example, the safest way to write the NIS+ query is +For example, the way to write the NIS+ query is .code [name="${quote_nisplus:$local_part}"] .endd +.cindex "tainted data" "in lookups" +&*All*& tainted data used in a query-style lookup must be quoted +using a mechanism appropriate for the lookup type. See chapter &<>& for full coverage of string expansions. The quote operator can be used for all lookup types, but has no effect for single-key lookups, since no quoting is ever needed in their key strings. @@ -8140,7 +8218,7 @@ daemon as in the other SQL databases. .oindex &%sqlite_dbfile%& There are two ways of specifying the file. -The first is is by using the &%sqlite_dbfile%& main option. +The first is by using the &%sqlite_dbfile%& main option. The second, which allows separate files for each query, is to use an option appended, comma-separated, to the &"sqlite"& lookup type word. The option is the word &"file"&, then an equals, @@ -9528,7 +9606,6 @@ value. Nevertheless the &%-be%& option can be useful for checking out file and database lookups, and the use of expansion operators such as &%sg%&, &%substr%& and &%nhash%&. -.new When reading lines from the standard input, macros can be defined and ACL variables can be set. For example: @@ -9537,7 +9614,6 @@ MY_MACRO = foo set acl_m_myvar = bar .endd Such macros and variables can then be used in later input lines. -.wen Exim gives up its root privilege when it is called with the &%-be%& option, and instead runs under the uid and gid it was called with, to prevent users from @@ -9654,9 +9730,7 @@ Example use (as an ACL modifier): add_header = :at_start:${authresults {$primary_hostname}} .endd This is safe even if no authentication results are available -.new and would generally be placed in the DATA ACL. -.wen .vitem "&*${certextract{*&<&'field'&>&*}{*&<&'certificate'&>&*}&&& @@ -9914,11 +9988,9 @@ leading and trailing quotes are removed from the returned value. After expansion, <&'string'&> is interpreted as a list, colon-separated by default, but the separator can be changed in the usual way (&<>&). For each item -in this list, its value is place in &$item$&, and then the condition is +in this list, its value is placed in &$item$&, and then the condition is evaluated. -.new Any modification of &$value$& by this evaluation is discarded. -.wen If the condition is true, &$item$& is added to the output as an item in a new list; if the condition is false, the item is discarded. The separator used for the output list is the same as the one used for the @@ -10447,6 +10519,11 @@ Defines whether or not a write-shutdown is done on the connection after sending the request. Values are &"yes"& (the default) or &"no"& (preferred, eg. by some webservers). +.next +&*sni*& +Controls the use of Server Name Identification on the connection. +Any nonempty value will be the SNI sent; TLS will be forced. + .next &*tls*& Controls the use of TLS on the connection. @@ -10534,16 +10611,17 @@ expansion items. This item inserts &"raw"& header lines. It is described with the &%header%& expansion item in section &<>& above. -.vitem "&*${run <&'options'&> {*&<&'command&~arg&~list'&>&*}{*&<&'string1'&>&*}&&& +.vitem "&*${run<&'options'&> {*&<&'command&~string'&>&*}{*&<&'string1'&>&*}&&& {*&<&'string2'&>&*}}*&" .cindex "expansion" "running a command" .cindex "&%run%& expansion item" This item runs an external command, as a subprocess. -One option is supported after the word &'run'&, comma-separated. +One option is supported after the word &'run'&, comma-separated +and without whitespace. If the option &'preexpand'& is not used, -the command string is split into individual arguments by spaces -and then each argument is expanded. +the command string before expansion is split into individual arguments by spaces +and then each argument is separately expanded. Then the command is run in a separate process, but under the same uid and gid. As in other command executions from Exim, a shell is not used by default. If the command requires @@ -10555,9 +10633,9 @@ potential attacker; a careful assessment for security vulnerabilities should be done. If the option &'preexpand'& is used, -the command and its arguments are first expanded as one string. The result is -split apart into individual arguments by spaces, and then the command is run -as above. +the command string is first expanded as a whole. +The expansion result is split apart into individual arguments by spaces, +and then the command is run as above. Since the arguments are split by spaces, when there is a variable expansion which has an empty result, it will cause the situation that the argument will simply be omitted when the program is actually executed by Exim. If the @@ -10599,6 +10677,7 @@ shell must be invoked directly, such as with: .code ${run{/bin/bash -c "/usr/bin/id >/tmp/id"}{yes}{yes}} .endd +Note that &$value$& will not persist beyond the reception of a single message. .vindex "&$runrc$&" The return code from the command is put in the variable &$runrc$&, and this @@ -11021,6 +11100,22 @@ abbreviation &%h%& can be used when &%hash%& is used as an operator. +.vitem &*${headerwrap_*&<&'cols'&>&*_*&<&'limit'&>&*:*&<&'string'&>&*}*& +.cindex header "wrapping operator" +.cindex expansion "header wrapping" +This operator line-wraps its argument in a way useful for headers. +The &'cols'& value gives the column number to wrap after, +the &'limit'& gives a limit number of result characters to truncate at. +Either just the &'limit'& and the preceding underbar, or both, can be omitted; +the defaults are 80 and 998. +Wrapping will be inserted at a space if possible before the +column number is reached. +Whitespace at a chosen wrap point is removed. +A line-wrap consists of a newline followed by a tab, +and the tab is counted as 8 columns. + + + .vitem &*${hex2b64:*&<&'hexstring'&>&*}*& .cindex "base64 encoding" "conversion from hex" .cindex "expansion" "hex to base64" @@ -11710,10 +11805,11 @@ all items in the list, the overall condition is true. .endlist Note that negation of &*forany*& means that the condition must be false for all items for the overall condition to succeed, and negation of &*forall*& means -that the condition must be false for at least one item. In this example, the -list separator is changed to a comma: +that the condition must be false for at least one item. + +Example: .code -${if forany{<, $recipients}{match{$item}{^user3@}}{yes}{no}} +${if forany{$recipients_list}{match{$item}{^user3@}}{yes}{no}} .endd The value of &$item$& is saved and restored while &%forany%& or &%forall%& is being processed, to enable these expansion items to be nested. @@ -11968,6 +12064,10 @@ Exim was built with the EXPAND_LISTMATCH_RHS option. Consult section &<>& for further details of these patterns. +The variable &$value$& will be set for a successful match and can be +used in the success clause of an &%if%& expansion item using the condition. +Any previous &$value$& is restored after the if. + .vitem &*match_local_part&~{*&<&'string1'&>&*}{*&<&'string2'&>&*}*& .cindex "domain list" "in expansion condition" .cindex "address list" "in expansion condition" @@ -13312,10 +13412,18 @@ The main use of this variable is expected to be to distinguish between rejections of MAIL and rejections of RCPT. .tvar &$recipients$& -This variable contains a list of envelope recipients for a message. A comma and -a space separate the addresses in the replacement text. However, the variable -is not generally available, to prevent exposure of Bcc recipients in -unprivileged users' filter files. You can use &$recipients$& only in these +.tvar &$recipients_list$& +These variables both contain the envelope recipients for a message. + +The first uses a comma and a space separate the addresses in the replacement text. +&*Note*&: an address can legitimately contain a comma; +this variable is not intended for further processing. + +The second is a proper Exim list; colon-separated. + +However, the variables +are not generally available, to prevent exposure of Bcc recipients in +unprivileged users' filter files. You can use either of them only in these cases: .olist @@ -13379,7 +13487,8 @@ This is an obsolete name for &$bounce_return_size_limit$&. .cindex "router" "name" .cindex "name" "of router" .vindex "&$router_name$&" -During the running of a router this variable contains its name. +During the running of a router, or a transport called, +this variable contains the router name. .vitem &$runrc$& .cindex "return code" "from &%run%& expansion" @@ -13670,6 +13779,11 @@ there actually are, because many other connections may come and go while a single connection is being processed. When a child process terminates, the daemon decrements its copy of the variable. +.vitem &$smtp_notquit_reason$& +.vindex "&$smtp_notquit_reason$&" +When the not-QUIT ACL is running, this variable is set to a string +that indicates the reason for the termination of the SMTP connection. + .vitem "&$sn0$& &-- &$sn9$&" These variables are copies of the values of the &$n0$& &-- &$n9$& accumulators that were current at the end of the system filter file. This allows a system @@ -15346,11 +15460,8 @@ $primary_hostname-$tod_epoch-testing See section &<>& for details of how this value is used. -.option check_log_inodes main integer 100 -See &%check_spool_space%& below. - - -.option check_log_space main integer 10M +.options check_log_inodes main integer 100 &&& + check_log_space main integer 10M See &%check_spool_space%& below. .oindex "&%check_rfc2047_length%&" @@ -15365,11 +15476,8 @@ of the RFC, generates overlong encoded words. If &%check_rfc2047_length%& is set false, Exim recognizes encoded words of any length. -.option check_spool_inodes main integer 100 -See &%check_spool_space%& below. - - -.option check_spool_space main integer 10M +.options check_spool_inodes main integer 100 &&& + check_spool_space main integer 10M .cindex "checking disk space" .cindex "disk space, checking" .cindex "spool directory" "checking space" @@ -15448,17 +15556,15 @@ This option specifies one or more default SMTP ports on which the Exim daemon listens. See chapter &<>& for details of how it is used. For backward compatibility, &%daemon_smtp_port%& (singular) is a synonym. -.option daemon_startup_retries main integer 9 +.options daemon_startup_retries main integer 9 &&& + daemon_startup_sleep main time 30s .cindex "daemon startup, retrying" -This option, along with &%daemon_startup_sleep%&, controls the retrying done by +These options control the retrying done by the daemon at startup when it cannot immediately bind a listening socket (typically because the socket is already in use): &%daemon_startup_retries%& defines the number of retries after the first failure, and &%daemon_startup_sleep%& defines the length of time to wait between retries. -.option daemon_startup_sleep main time 30s -See &%daemon_startup_retries%&. - .option delay_warning main "time list" 24h .cindex "warning of delay" .cindex "delay warning, specifying" @@ -15621,7 +15727,10 @@ by a setting such as this: .code dns_again_means_nonexist = *.in-addr.arpa .endd -This option applies to all DNS lookups that Exim does. It also applies when the +This option applies to all DNS lookups that Exim does, +except for TLSA lookups (where knowing about such failures +is security-relevant). +It also applies when the &[gethostbyname()]& or &[getipnodebyname()]& functions give temporary errors, since these are most likely to be caused by DNS lookup problems. The &(dnslookup)& router has some options of its own for controlling what happens @@ -15961,6 +16070,7 @@ search the file multiple times for non-existent users, and also cause delay. .option freeze_tell main "string list, comma separated" unset .cindex "freezing messages" "sending a message when freezing" +.cindex "frozen messages" "sending a message when freezing" On encountering certain errors, or when configured to do so in a system filter, ACL, or special router, Exim freezes a message. This means that no further delivery attempts take place until an administrator thaws the message, or the @@ -15976,7 +16086,8 @@ log. If you configure freezing in a filter or ACL, you must arrange for any logging that you require. -.option gecos_name main string&!! unset +.options gecos_name main string&!! unset &&& + gecos_pattern main string unset .cindex "HP-UX" .cindex "&""gecos""& field, parsing" Some operating systems, notably HP-UX, use the &"gecos"& field in the system @@ -16001,9 +16112,6 @@ gecos_pattern = ([^,]*) gecos_name = $1 .endd -.option gecos_pattern main string unset -See &%gecos_name%& above. - .option gnutls_compat_mode main boolean unset This option controls whether GnuTLS is used in compatibility mode in an Exim @@ -16201,10 +16309,8 @@ This option is obsolete, and retained only for backward compatibility, because nowadays the ACL specified by &%acl_smtp_connect%& can also reject incoming connections immediately. -.new If the connection is on a TLS-on-connect port then the TCP connection is just dropped. Otherwise, an SMTP error is sent first. -.wen The ability to give an immediate rejection (either by this option or using an ACL) is provided for use in unusual cases. Many hosts will just try again, @@ -16225,10 +16331,8 @@ local processes, you must create a host list with an empty item. For example: .code hosts_connection_nolog = : .endd -.new The hosts affected by this option also do not log "no MAIL in SMTP connection" lines, as may commonly be produced by a monitoring system. -.wen .option hosts_require_alpn main "host list&!!" unset @@ -16307,7 +16411,8 @@ dealing with other kinds of frozen message, see &%auto_thaw%& and &%timeout_frozen_after%&. -.option ignore_fromline_hosts main "host list&!!" unset +.options ignore_fromline_hosts main "host list&!!" unset &&& + ignore_fromline_local main boolean false .cindex "&""From""& line" .cindex "UUCP" "&""From""& line" Some broken SMTP clients insist on sending a UUCP-like &"From&~"& line before @@ -16319,8 +16424,6 @@ process rather than a remote host, and is using &%-bs%& to inject the messages, &%ignore_fromline_local%& must be set to achieve this effect. -.option ignore_fromline_local main boolean false -See &%ignore_fromline_hosts%& above. .option keep_environment main "string list" unset .cindex "environment" "values from" @@ -16475,7 +16578,8 @@ has more details about &'Sender:'& processing. -.option local_from_prefix main string unset +.options local_from_prefix main string unset &&& + local_from_suffix main string unset When Exim checks the &'From:'& header line of locally submitted messages for matching the login id (see &%local_from_check%& above), it can be configured to ignore certain prefixes and suffixes in the local part of the address. This is @@ -16495,10 +16599,6 @@ matches the actual sender address that is constructed from the login name and qualify domain. -.option local_from_suffix main string unset -See &%local_from_prefix%& above. - - .option local_interfaces main "string list" "see below" This option controls which network interfaces are used by the daemon for listening; they are also used to identify the local host when routing. Chapter @@ -16904,7 +17004,6 @@ to be used in conjunction with &(oracle)& lookups (see section &<>&). The option is available only if Exim has been built with Oracle support. -.new .option panic_coredump main boolean false This option is rarely needed but can help for some debugging investigations. If set, when an internal error is detected by Exim which is sufficient @@ -16915,7 +17014,6 @@ then a coredump is requested. Note that most systems require additional administrative configuration to permit write a core file for a setuid program, which is Exim's common installed configuration. -.wen .option percent_hack_domains main "domain list&!!" unset .cindex "&""percent hack""&" @@ -16938,16 +17036,11 @@ a good idea to reject recipient addresses with percent characters in their local parts. Exim's default configuration does this. -.option perl_at_start main boolean false -.cindex "Perl" -This option is available only when Exim is built with an embedded Perl -interpreter. See chapter &<>& for details of its use. - - -.option perl_startup main string unset +.options perl_at_start main boolean false &&& + perl_startup main string unset .cindex "Perl" -This option is available only when Exim is built with an embedded Perl -interpreter. See chapter &<>& for details of its use. +These options are available only when Exim is built with an embedded Perl +interpreter. See chapter &<>& for details of their use. .option perl_taintmode main boolean false .cindex "Perl" @@ -17159,7 +17252,7 @@ and &%-odi%& command line options override &%queue_only%& unless &%queue_only_load%&, and &%smtp_accept_queue%&. -.option queue_only_file main string unset +.option queue_only_file main "string list" unset .cindex "queueing incoming messages" .cindex "message" "queueing by file existence" This option can be set to a colon-separated list of absolute path names, each @@ -17703,10 +17796,8 @@ positive response to an SMTP connection. The default setting is: smtp_banner = $smtp_active_hostname ESMTP Exim \ $version_number $tod_full .endd -.new Failure to expand the string causes a panic error; a forced fail just closes the connection. -.wen If you want to create a multiline response to the initial SMTP connection, use &"\n"& in the string at appropriate points, but not at the end. Note that the 220 code is not included @@ -17842,7 +17933,9 @@ non-SMTP command lines are sent first. -.option smtp_ratelimit_hosts main "host list&!!" unset +.options smtp_ratelimit_hosts main "host list&!!" unset &&& + smtp_ratelimit_mail main string unset &&& + smtp_ratelimit_rcpt main string unset .cindex "SMTP" "rate limiting" .cindex "limit" "rate of message arrival" .cindex "RCPT" "rate limiting" @@ -17885,13 +17978,6 @@ seconds, increasing by a factor of 1.05 each time. The second setting applies delays to RCPT commands when more than four occur in a single message. -.option smtp_ratelimit_mail main string unset -See &%smtp_ratelimit_hosts%& above. - - -.option smtp_ratelimit_rcpt main string unset -See &%smtp_ratelimit_hosts%& above. - .option smtp_receive_timeout main time&!! 5m .cindex "timeout" "for SMTP input" @@ -18292,7 +18378,7 @@ is not required the &%tls_advertise_hosts%& option should be set empty. .cindex ALPN "set acceptable names for server" If this option is set, the TLS library supports ALPN, -and the client offers either more than +and the client offers either more than one ALPN name or a name which does not match the list, the TLS connection is declined. @@ -18449,20 +18535,23 @@ prior to the 4.80 release, as Debian used to patch Exim to raise the minimum acceptable bound from 1024 to 2048. -.option tls_eccurve main string&!! &`auto`& +.option tls_eccurve main string list&!! &`auto`& .cindex TLS "EC cryptography" -This option selects a EC curve for use by Exim when used with OpenSSL. -It has no effect when Exim is used with GnuTLS. +This option selects EC curves for use by Exim when used with OpenSSL. +It has no effect when Exim is used with GnuTLS +(the equivalent can be done using a priority string for the +&%tls_require_ciphers%& option). -After expansion it must contain a valid EC curve parameter, such as -&`prime256v1`&, &`secp384r1`&, or &`P-512`&. Consult your OpenSSL manual -for valid selections. +After expansion it must contain +one or (only for OpenSSL versiona 1.1.1 onwards) more +EC curve names, such as &`prime256v1`&, &`secp384r1`&, or &`P-521`&. +Consult your OpenSSL manual for valid curve names. For OpenSSL versions before (and not including) 1.0.2, the string &`auto`& selects &`prime256v1`&. For more recent OpenSSL versions &`auto`& tells the library to choose. -If the option expands to an empty string, no EC curves will be enabled. +If the option expands to an empty string, the effect is undefined. .option tls_ocsp_file main string&!! unset @@ -19056,12 +19145,25 @@ This applies to all of the SRV, MX, AAAA, A lookup sequence. .cindex "router" "restricting to specific domains" .vindex "&$domain_data$&" If this option is set, the router is skipped unless the current domain matches -the list. If the match is achieved by means of a file lookup, the data that the -lookup returned for the domain is placed in &$domain_data$& for use in string +the list. +The data returned by the list check +is placed in &$domain_data$& for use in string expansions of the driver's private options and in the transport. See section &<>& for a list of the order in which preconditions are evaluated. +A complex example, using a file like: +.code +alice@dom1 +bill@dom1 +maggie@dom1 +.endd +and checking both domain and local_part +.code +domains = ${domain:${lookup {$local_part@$domain} lseach,ret=key {/path/to/accountsfile}}} +local_parts = ${local_part:${lookup {$local_part@$domain} lseach,ret=key {/path/to/accountsfile}}} +.endd + .option driver routers string unset @@ -19425,7 +19527,7 @@ example: local_parts = dbm;/usr/local/specials/$domain_data .endd .vindex "&$local_part_data$&" -If the match is achieved by a lookup, the data that the lookup returned +the data returned by the list check for the local part is placed in the variable &$local_part_data$& for use in expansions of the router's private options or in the transport. You might use this option, for @@ -22690,8 +22792,11 @@ If unset, or expanding to an empty string, no filtering is done. When the message is about to be written out, the command specified by &%transport_filter%& is started up in a separate, parallel process, and the entire message, including the header lines, is passed to it on its standard -input (this in fact is done from a third process, to avoid deadlock). The -command must be specified as an absolute path. +input (this in fact is done from a third process, to avoid deadlock). +The command must be specified as an absolute path. + +The process run by the command must use its standard input as the message +data to be transformed, and write the results on its standard output. The lines of the message that are written to the transport filter are terminated by newline (&"\n"&). The message is passed to the filter before any @@ -22761,7 +22866,17 @@ example: transport_filter = '/bin/cmd${if eq{$host}{a.b.c}{1}{2}}' .endd This runs the command &(/bin/cmd1)& if the host name is &'a.b.c'&, and -&(/bin/cmd2)& otherwise. If double quotes had been used, they would have been +&(/bin/cmd2)& otherwise. + +Option strings in general have any fully-surrounding double quote wrapping +removed early in parsing (see &<>&). +Then, for this option, quotes protect against whitespace being +regarded as a separator while splitting into the command argument vector. +Either double or single quotes can be used here; +the former interprets backlash-quoted charachters +and the latter does not. + +If double quotes had been used in this example, they would have been stripped by Exim when it read the option's value. When the value is used, if the single quotes were missing, the line would be split into two items, &`/bin/cmd${if`& and &`eq{$host}{a.b.c}{1}{2}`&, and an error would occur when @@ -25631,11 +25746,9 @@ Exim will request a Certificate Status on a TLS session for any host that matches this list. &%tls_verify_certificates%& should also be set for the transport. -.new The default is &"**"& if DANE is not in use for the connection, or if DANE-TA us used. It is empty if DANE-EE is used. -.wen .option hosts_require_alpn smtp "host list&!!" unset .cindex ALPN "require negotiation in client" @@ -25781,16 +25894,12 @@ has advertised support for IGNOREQUOTA in its response to the LHLO command. .option max_rcpt smtp integer&!! 100 .cindex "RCPT" "maximum number of outgoing" This option, -.new after expansion, -.wen limits the number of RCPT commands that are sent in a single SMTP message transaction. A value setting of zero disables the limit. -.new If a constant is given, -.wen each set of addresses is treated independently, and so can cause parallel connections to the same host if &%remote_max_parallel%& permits this. @@ -26066,7 +26175,8 @@ This option give a list of hosts for which, while verifying the server certificate, checks will be included on the host name (note that this will generally be the result of a DNS MX lookup) -versus Subject and Subject-Alternate-Name fields. Wildcard names are permitted +versus the Subject-Alternate-Name (or, if none, Subject-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. @@ -27600,7 +27710,6 @@ no successful authentication. Successful authentication sets up information used by the &%authresults%& expansion item. -.new .cindex authentication "failure event, server" If an authenticator is run and does not succeed, an event (see &<>&) of type "auth:fail" is raised. @@ -27611,7 +27720,6 @@ will be valid. If the event is serviced and a string is returned then the string will be logged instead of the default log line. See <> for details on events. -.wen .section "Testing server authentication" "SECID169" @@ -27690,7 +27798,6 @@ Exim abandons trying to send the message to the host for the moment. It will try again later. If there are any backup hosts available, they are tried in the usual way. -.new .next .cindex authentication "failure event, client" If the response to authentication is a permanent error (5&'xx'& code), @@ -27700,7 +27807,6 @@ While the event is being processed the variable will be valid. If the event is serviced and a string is returned then the string will be logged. See <> for details on events. -.wen .next If the response to authentication is a permanent error (5&'xx'& code), Exim @@ -28257,7 +28363,7 @@ Dovecot 2 POP/IMAP server, which can support a number of authentication methods. Note that Dovecot must be configured to use auth-client not auth-userdb. If you are using Dovecot to authenticate POP/IMAP clients, it might be helpful to use the same mechanisms for SMTP authentication. This is a server -authenticator only. There is only one option: +authenticator only. There is only one non-generic option: .option server_socket dovecot string unset @@ -28269,6 +28375,7 @@ authenticators for different mechanisms. For example: dovecot_plain: driver = dovecot public_name = PLAIN + server_advertise_condition = ${if def:tls_in_cipher} server_socket = /var/run/dovecot/auth-client server_set_id = $auth1 @@ -28278,6 +28385,11 @@ dovecot_ntlm: server_socket = /var/run/dovecot/auth-client server_set_id = $auth1 .endd + +&*Note*&: plaintext authentication methods such as PLAIN and LOGIN +should not be advertised on cleartext SMTP connections. +See the discussion in section &<>&. + If the SMTP connection is encrypted, or if &$sender_host_address$& is equal to &$received_ip_address$& (that is, the connection is local), the &"secured"& option is passed in the Dovecot authentication command. If, for a TLS @@ -28876,9 +28988,10 @@ for which it must have been requested via the (see &<>&). If an authenticator of this type is configured it is -run before any SMTP-level communication is done, +run immediately after a TLS connection being negotiated +(due to either STARTTLS or TLS-on-connect) and can authenticate the connection. -If it does, SMTP authentication is not offered. +If it does, SMTP authentication is not subsequently offered. A maximum of one authenticator of this type may be present. @@ -29084,8 +29197,8 @@ When using OpenSSL, this option is ignored. (If an API is found to let OpenSSL be configured in this way, let the Exim Maintainers know and we'll likely use it). .next -With GnuTLS, if an explicit list is used for the &%tls_privatekey%& main option -main option, it must be ordered to match the &%tls_certificate%& list. +With GnuTLS, if an explicit list is used for the &%tls_privatekey%& main option, +it must be ordered to match the &%tls_certificate%& list. .next Some other recently added features may only be available in one or the other. This should be documented with the feature. If the documentation does not @@ -29535,10 +29648,10 @@ A HUP signal is sufficient for this. The value &"system"& results in no caching under GnuTLS. The macro _HAVE_TLS_CA_CACHE will be defined if the suffix for "system" -is acceptable in configurations for the Exim executavble. +is acceptable in configurations for the Exim executable. Caching of the system Certificate Authorities bundle can -save siginificant time and processing on every TLS connection +save significant time and processing on every TLS connection accepted by Exim. @@ -29708,10 +29821,10 @@ A HUP signal is sufficient for this. The value &"system"& results in no caching under GnuTLS. The macro _HAVE_TLS_CA_CACHE will be defined if the suffix for "system" -is acceptable in configurations for the Exim executavble. +is acceptable in configurations for the Exim executable. Caching of the system Certificate Authorities bundle can -save siginificant time and processing on every TLS connection +save significant time and processing on every TLS connection initiated by Exim. @@ -30179,7 +30292,7 @@ DNSSEC. .next Add TLSA DNS records. These say what the server certificate for a TLS connection should be. .next -Offer a server certificate, or certificate chain, in TLS connections which is is anchored by one of the TLSA records. +Offer a server certificate, or certificate chain, in TLS connections which is anchored by one of the TLSA records. .endlist There are no changes to Exim specific to server-side operation of DANE. @@ -30508,11 +30621,9 @@ accepted by an &%accept%& verb that has a &%message%& modifier, the contents of the message override the banner message that is otherwise specified by the &%smtp_banner%& option. -.new For tls-on-connect connections, the ACL is run before the TLS connection is accepted; if the ACL does not accept then the TCP connection is dropped without any TLS startup attempt and without any SMTP response being transmitted. -.wen .subsection "The EHLO/HELO ACL" SECID192 @@ -31438,8 +31549,11 @@ the message modifier cannot override the 221 response code. The text in a &%message%& modifier is literal; any quotes are taken as literals, but because the string is expanded, backslash escapes are processed -anyway. If the message contains newlines, this gives rise to a multi-line SMTP +anyway. +If the message contains newlines, this gives rise to a multi-line SMTP response. +A long message line will also be split into multi-line SMTP responses, +on word boundaries if possible. .vindex "&$acl_verify_message$&" While the text is being expanded, the &$acl_verify_message$& variable @@ -31733,6 +31847,7 @@ work with. .vitem &*control&~=&~fakedefer/*&<&'message'&> .cindex "fake defer" .cindex "defer, fake" +.cindex fakedefer This control works in exactly the same way as &%fakereject%& (described below) except that it causes an SMTP 450 response after the message data instead of a 550 response. You must take care when using &%fakedefer%& because it causes the @@ -31742,6 +31857,7 @@ use &%fakedefer%& if the message is to be delivered normally. .vitem &*control&~=&~fakereject/*&<&'message'&> .cindex "fake rejection" .cindex "rejection, fake" +.cindex fakereject This control is permitted only for the MAIL, RCPT, and DATA ACLs, in other words, only when an SMTP message is being received. If Exim accepts the message, instead the final 250 response, a 550 rejection message is sent. @@ -32043,8 +32159,22 @@ Headers will not be removed from the message if the modifier is used in DATA, MIME or DKIM ACLs for a message delivered by cutthrough routing. More than one header can be removed at the same time by using a colon separated -list of header names. The header matching is case insensitive. Wildcards are -not permitted, nor is list expansion performed, so you cannot use hostlists to +list of header specifiers. +If a specifier does not start with a circumflex (^) +then it is treated as a header name. +The header name matching is case insensitive. +If it does, then it is treated as a (front-anchored) +regular expression applied to the whole header. + +&*Note*&: The colon terminating a header name will need to be doubled +if used in an RE, and there can legitimately be whitepace before it. + +Example: +.code +remove_header = \N^(?i)Authentication-Results\s*::\s*example.org;\N +.endd + +List expansion is not performed, so you cannot use hostlists to create a list of headers, however both connection and message variable expansion are performed (&%$acl_c_*%& and &%$acl_m_*%&), illustrated in this example: .code @@ -32053,14 +32183,14 @@ warn hosts = +internal_hosts warn message = Remove internal headers remove_header = $acl_c_ihdrs .endd -Header names for removal are accumulated during the MAIL, RCPT, and predata ACLs. +Header specifiers for removal are accumulated during the MAIL, RCPT, and predata ACLs. Matching header lines are removed from the message before processing the DATA and MIME ACLs. If multiple header lines match, all are removed. There is no harm in attempting to remove the same header twice nor in removing -a non-existent header. Further header lines to be removed may be accumulated -during the DATA and MIME ACLs, after which they are removed from the message, -if present. In the case of non-SMTP messages, headers to be removed are -accumulated during the non-SMTP ACLs, and are removed from the message after +a non-existent header. Further header specifiers for removal may be accumulated +during the DATA and MIME ACLs, after which matching headers are removed +if present. In the case of non-SMTP messages, remove specifiers are +accumulated during the non-SMTP ACLs, and are acted on after all the ACLs have run. If a message is rejected after DATA or by the non-SMTP ACL, there really is no effect because there is no logging of what headers would have been removed. @@ -38804,6 +38934,7 @@ the following table: .display &`A `& authenticator name (and optional id and sender) &`C `& SMTP confirmation on delivery +&`Ci `& connection identifier &` `& command list for &"no mail in SMTP session"& &`CV `& certificate verification status &`D `& duration of &"no mail in SMTP session"& @@ -38892,7 +39023,7 @@ logging and the message has a DKIM signature header. .section "Reducing or increasing what is logged" "SECTlogselector" .cindex "log" "selectors" By setting the &%log_selector%& global option, you can disable some of Exim's -default logging, or you can request additional logging. The value of +default logging to the main log, or you can request additional logging. The value of &%log_selector%& is made up of names preceded by plus or minus characters. For example: .code @@ -38906,6 +39037,7 @@ selection marked by asterisks: .irow &`address_rewrite`&   "address rewriting" .irow &`all_parents`&   "all parents in => lines" .irow &`arguments`&   "command line arguments" +.irow &`connection_id`&   "connection identifier" .irow &`connection_reject`& * "connection rejections" .irow &`delay_delivery`& * "immediate delivery delayed" .irow &`deliver_time`&   "time taken to attempt delivery" @@ -39001,6 +39133,12 @@ because the arguments are checked before the configuration file is read. The only way to log such cases is to interpose a script such as &_util/logargs.sh_& between the caller and Exim. .next +.cindex "log" "connection identifier" +&%connection_identifier%&: An identifier for the accepted connection is added to +connection start and end lines and to message accept lines. +The identifier is tagged by Ci=. +The value is PID-based, so will reset on reboot and will wrap. +.next .cindex "log" "connection rejections" &%connection_reject%&: A log entry is written whenever an incoming SMTP connection is rejected, for whatever reason. @@ -39422,6 +39560,7 @@ the next chapter. The utilities described here are: .irow &<>& &'exim_tidydb'& "clean up a hints database" .irow &<>& &'exim_fixdb'& "patch a hints database" .irow &<>& &'exim_lock'& "lock a mailbox file" +.irow &<>& &'exim_msgdate'& "Message Ids for humans (exim_msgdate)" .endtable Another utility that might be of use to sites with many MTAs is Tom Kistner's @@ -39930,6 +40069,8 @@ Serializing delivery to a specific host (when &%serialize_hosts%& is set in an .next Limiting the concurrency of specific transports (when &%max_parallel%& is set in a transport) +.next +Recording EHLO-time facilities advertised by hosts .endlist @@ -40145,9 +40286,16 @@ exim_lock -q /var/spool/mail/spqr \ .endd Note that if a command is supplied, it must be entirely contained within the second argument &-- hence the quotes. -.ecindex IIDutils +.section "Message Ids for humans (exim_msgdate)" "SECTexim_msgdate" +.cindex "exim_msgdate" +The &'exim_msgdate'& utility is written by Andrew Aitchison and included in the Exim distribution. +This Perl script converts an Exim Mesage ID back into a human readable form. +For details of &'exim_msgdate'&'s options, run &'exim_msgdate'& with the &%--help%& option. + +Section &<>& (Message identification) describes Exim Mesage IDs. +.ecindex IIDutils . //////////////////////////////////////////////////////////////////////////// . //////////////////////////////////////////////////////////////////////////// @@ -41588,8 +41736,9 @@ RFC 6376 lists these tags as RECOMMENDED. Verification of DKIM signatures in SMTP incoming email is done for all messages for which an ACL control &%dkim_disable_verify%& has not been set. + .cindex DKIM "selecting signature algorithms" -Individual classes of signature algorithm can be ignored by changing +Individual classes of DKIM signature algorithm can be ignored by changing the main options &%dkim_verify_hashes%& or &%dkim_verify_keytypes%&. The &%dkim_verify_minimal%& option can be set to cease verification processing for a message once the first passing signature is found. @@ -41602,7 +41751,7 @@ For most purposes the default option settings suffice and the remainder of this section can be ignored. The results of verification are made available to the -&%acl_smtp_dkim%& ACL, which can examine and modify them. +&%acl_smtp_dkim%& ACL, which (for complex needs) can examine and modify them. A missing ACL definition defaults to accept. By default, the ACL is called once for each syntactically(!) correct signature in the incoming message. @@ -41667,6 +41816,12 @@ an identity. This is one of the list items from the expanded main option &%dkim_verify_signers%& (see above). .vitem &%$dkim_verify_status%& +So long as a DKIM ACL is defined +(it need do no more than accept, which is the default), +after all the DKIM ACL runs have completed, the value becomes a +colon-separated list of the values after each run. +The value is maintained for the MIME, PRDR and DATA ACLs. + Within the DKIM ACL, a string describing the general status of the signature. One of .ilist @@ -41695,11 +41850,6 @@ hash-method or key-size: set dkim_verify_reason = hash too weak or key too short .endd -So long as a DKIM ACL is defined (it need do no more than accept), -after all the DKIM ACL runs have completed, the value becomes a -colon-separated list of the values after each run. -This is maintained for the mime, prdr and data ACLs. - .vitem &%$dkim_verify_reason%& A string giving a little bit more detail when &%$dkim_verify_status%& is either "fail" or "invalid". One of @@ -41830,7 +41980,9 @@ In addition, two ACL conditions are provided: .vitem &%dkim_signers%& ACL condition that checks a colon-separated list of domains or identities for a match against the domain or identity that the ACL is currently verifying -(reflected by &%$dkim_cur_signer%&). This is typically used to restrict an ACL +(reflected by &%$dkim_cur_signer%&). +This condition is only usable in a DKIM ACL. +This is typically used to restrict an ACL verb to a group of domains or identities. For example: .code @@ -41846,7 +41998,18 @@ for that check for empty &$h_DKIM-Signature:$& in the data ACL. .vitem &%dkim_status%& ACL condition that checks a colon-separated list of possible DKIM verification -results against the actual result of verification. This is typically used +results against the actual result of verification, +given by &$dkim_verify_status$& if that is non-empty or "none" if empty. +.new +This condition may be used in DKIM, MIME, PRDR and DATA ACLs. +.wen + +A basic verification might be: +.code +deny !dkim_status = pass:none:invalid +.endd + +A more complex use could be to restrict an ACL verb to a list of verification outcomes, for example: .code @@ -41859,6 +42022,12 @@ deny sender_domains = paypal.com:paypal.de The possible status keywords are: 'none','invalid','fail' and 'pass'. Please see the documentation of the &%$dkim_verify_status%& expansion variable above for more information of what they mean. + +The condition is true if the status +.new +(or any of the list of status values) +.wen +is any one of the supplied list. .endlist @@ -42092,18 +42261,28 @@ encoding operation. If this value is empty the the expansion result will be empty. The third argument should be the recipient domain of the message when it arrived at this system. +All arguments are expanded before use. + +The result of the expansion is the replacement envelope-from (return path) +to be used. .endlist .cindex SRS decoding To decode an address use this expansion condition: .vlist .vitem &*inbound_srs&~{*&<&'local&~part'&>&*}{*&<&'secret'&>&*}*& -The first argument should be the recipient local prt as is was received. +The first argument should be the recipient local part as it was received. The second argument is the site secret. +Both arguments are expanded before use. If the messages is not for an SRS-encoded recipient the condition will -return false. If it is, the condition will return true and the variable +return false. +If it is, the condition will return true and the variable &$srs_recipient$& will be set to the decoded (original) value. + +If the second argument is empty then the condition returns true if +the first argument is in valid SRS formet, else false. +The variable &$srs_recipient$& is not set for this case. .endlist Example usage: @@ -42145,8 +42324,9 @@ Example usage: # one, plus the max_rcpt and return_path options remote_forwarded_smtp: driver = smtp - # modify the envelope from, for mails that we forward + # single-recipient so that $original_domain is valid max_rcpt = 1 + # modify the envelope from, for mails that we forward return_path = ${srs_encode {SRS_SECRET} {$return_path} {$original_domain}} .endd @@ -42801,8 +42981,8 @@ All other message types ignore the result string, and no other use is made of it. For a tcp:connect event, if the connection is being made to a proxy -then the address and port variables will be that of the proxy and not -the target system. +then the &$host_address$& and &$host_port$& variables +will be that of the proxy and not the target system. For tls:cert events, if GnuTLS is in use this will trigger only per chain element received on the connection.