X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/d7148a072a5fee80ffa8d1aeebf9bc05d0e903b4..c027f5ce4024679cf010976e6da8a01c8a08160e:/doc/doc-docbook/spec.xfpt diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index 0cdc98657..92d0a2287 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -41,16 +41,19 @@ .book . ///////////////////////////////////////////////////////////////////////////// -. These definitions set some parameters and save some typing. Remember that -. the element must also be updated for each new edition. +. These definitions set some parameters and save some typing. +. Update the Copyright year (only) when changing content. . ///////////////////////////////////////////////////////////////////////////// .set previousversion "4.80" -.set version "4.80" +.include ./local_params .set ACL "access control lists (ACLs)" .set I "    " +.macro copyyear +2012 +.endmacro . ///////////////////////////////////////////////////////////////////////////// . Additional xfpt markup used by this document, over and above the default @@ -170,15 +173,23 @@ Specification of the Exim Mail Transfer Agent The Exim MTA -17 May 2012 + +.fulldate + EximMaintainers EM - 4.80 - 17 May 2012 + +.version + + +.fulldate + EM -2012University of Cambridge + +.copyyear + University of Cambridge .literal off @@ -367,7 +378,7 @@ contributors. .new .cindex "documentation" -This edition of the Exim specification applies to version &version; of Exim. +This edition of the Exim specification applies to version &version() of Exim. Substantive changes from the &previousversion; edition are marked in some renditions of the document; this paragraph is so marked if the rendition is capable of showing a change indicator. @@ -533,10 +544,23 @@ The &_.bz2_& file is usually a lot smaller than the &_.gz_& file. .cindex "distribution" "signing details" .cindex "distribution" "public key" .cindex "public key for signed distribution" -The distributions are currently signed with Nigel Metheringham's GPG key. The -corresponding public key is available from a number of keyservers, and there is -also a copy in the file &_nigel-pubkey.asc_&. The signatures for the tar bundles are -in: +.new +The distributions will be PGP signed by an individual key of the Release +Coordinator. This key will have a uid containing an email address in the +&'exim.org'& domain and will have signatures from other people, including +other Exim maintainers. We expect that the key will be in the "strong set" of +PGP keys. There should be a trust path to that key from Nigel Metheringham's +PGP key, a version of which can be found in the release directory in the file +&_nigel-pubkey.asc_&. All keys used will be available in public keyserver pools, +such as &'pool.sks-keyservers.net'&. + +At time of last update, releases were being made by Phil Pennock and signed with +key &'0x403043153903637F'&, although that key is expected to be replaced in 2013. +A trust path from Nigel's key to Phil's can be observed at +&url(https://www.security.spodhuis.org/exim-trustpath). +.wen + +The signatures for the tar bundles are in: .display &_exim-n.nn.tar.gz.asc_& &_exim-n.nn.tar.bz2.asc_& @@ -1348,6 +1372,8 @@ Setting the &%verify%& option actually sets two options, &%verify_sender%& and &%verify_recipient%&, which independently control the use of the router for sender and recipient verification. You can set these options directly if you want a router to be used for only one type of verification. +Note that cutthrough delivery is classed as a recipient verification +for this purpose. .next If the &%address_test%& option is set false, the router is skipped when Exim is run with the &%-bt%& option to test an address routing. This can be helpful @@ -1357,6 +1383,7 @@ having to simulate the effect of the scanner. .next Routers can be designated for use only when verifying an address, as opposed to routing it for delivery. The &%verify_only%& option controls this. +Again, cutthrough delibery counts as a verification. .next Individual routers can be explicitly skipped when running the routers to check an address given in the SMTP EXPN command (see the &%expn%& option). @@ -1602,7 +1629,7 @@ for only a short time (see &%timeout_frozen_after%& and .section "Unpacking" "SECID23" Exim is distributed as a gzipped or bzipped tar file which, when unpacked, creates a directory with the name of the current release (for example, -&_exim-&version;_&) into which the following files are placed: +&_exim-&version()_&) into which the following files are placed: .table2 140pt .irow &_ACKNOWLEDGMENTS_& "contains some acknowledgments" @@ -1936,7 +1963,7 @@ in your &_/etc/hosts.allow_& file allows connections from the local host, from the subnet 192.168.1.0/24, and from all hosts in &'friendly.domain.example'&. All other connections are denied. The daemon name used by &'tcpwrappers'& can be changed at build time by setting TCP_WRAPPERS_DAEMON_NAME in -in &_Local/Makefile_&, or by setting tcp_wrappers_daemon_name in the +&_Local/Makefile_&, or by setting tcp_wrappers_daemon_name in the configure file. Consult the &'tcpwrappers'& documentation for further details. @@ -2298,7 +2325,7 @@ INFO_DIRECTORY, as described in section &<>& below. For the utility programs, old versions are renamed by adding the suffix &_.O_& to their names. The Exim binary itself, however, is handled differently. It is installed under a name that includes the version number and the compile number, -for example &_exim-&version;-1_&. The script then arranges for a symbolic link +for example &_exim-&version()-1_&. The script then arranges for a symbolic link called &_exim_& to point to the binary. If you are updating a previous version of Exim, the script takes care to ensure that the name &_exim_& is never absent from the directory (as seen by other processes). @@ -2978,7 +3005,7 @@ way to guarantee a correct response. .oindex "&%-bm%&" .cindex "local message reception" This option runs an Exim receiving process that accepts an incoming, -locally-generated message on the current input. The recipients are given as the +locally-generated message on the standard input. The recipients are given as the command arguments (except when &%-t%& is also present &-- see below). Each argument can be a comma-separated list of RFC 2822 addresses. This is the default option for selecting the overall action of an Exim call; it is assumed @@ -4094,8 +4121,8 @@ message. Provided this error message is successfully sent, the Exim receiving process exits with a return code of zero. If not, the return code is 2 if the problem -is that the original message has no recipients, or 1 any other error. This is -the default &%-oe%&&'x'& option if Exim is called as &'rmail'&. +is that the original message has no recipients, or 1 for any other error. +This is the default &%-oe%&&'x'& option if Exim is called as &'rmail'&. .vitem &%-oem%& .oindex "&%-oem%&" @@ -4515,7 +4542,7 @@ has &'f'& or &'ff'& in its flags, the associated action is taken. .vitem &%-Tqt%&&~<&'times'&> .oindex "&%-Tqt%&" -This an option that is exclusively for use by the Exim testing suite. It is not +This is an option that is exclusively for use by the Exim testing suite. It is not recognized when Exim is run normally. It allows for the setting up of explicit &"queue times"& so that various warning/retry features can be tested. @@ -6911,6 +6938,14 @@ has two space-separated fields: an authorization code and a target host name. The authorization code can be &"Y"& for yes, &"N"& for no, &"X"& for explicit authorization required but absent, or &"?"& for unknown. +.cindex "A+" "in &(dnsdb)& lookup" +The pseudo-type A+ performs an A6 lookup (if configured) followed by an AAAA +and then an A lookup. All results are returned; defer processing +(see below) is handled separately for each lookup. Example: +.code +${lookup dnsdb {>; a+=$sender_helo_name}} +.endd + .section "Multiple dnsdb lookups" "SECID67" In the previous sections, &(dnsdb)& lookups for a single domain are described. @@ -8144,7 +8179,7 @@ case the IP address is used on its own. There are several types of pattern that require Exim to know the name of the remote host. These are either wildcard patterns or lookups by name. (If a complete hostname is given without any wildcarding, it is used to find an IP -address to match against, as described in the section &<>& +address to match against, as described in section &<>& above.) If the remote host name is not already known when Exim encounters one of these @@ -8313,7 +8348,7 @@ use masked IP addresses in database queries, you can use the &%mask%& expansion operator. If the query contains a reference to &$sender_host_name$&, Exim automatically -looks up the host name if has not already done so. (See section +looks up the host name if it has not already done so. (See section &<>& for comments on finding host names.) Historical note: prior to release 4.30, Exim would always attempt to find a @@ -8513,7 +8548,7 @@ but the separating colon must still be included at line breaks. White space surrounding the colons is ignored. For example: .code aol.com: spammer1 : spammer2 : ^[0-9]+$ : -spammer3 : spammer4 + spammer3 : spammer4 .endd As in all colon-separated lists in Exim, a colon can be included in an item by doubling. @@ -8758,6 +8793,23 @@ string easier to understand. This item inserts &"basic"& header lines. It is described with the &%header%& expansion item below. + +.vitem "&*${acl{*&<&'name'&>&*}{*&<&'arg'&>&*}...}*&" +.cindex "expansion" "calling an acl" +.cindex "&%acl%&" "call from expansion" +The name and zero to nine argument strings are first expanded separately. The expanded +arguments are assigned to the variables &$acl_arg1$& to &$acl_arg9$& in order. +Any unused are made empty. The variable &$acl_narg$& is set to the number of +arguments. The named ACL (see chapter &<>&) is called +and may use the variables; if another acl expansion is used the values +are restored after it returns. If the ACL sets +a value using a "message =" modifier and returns accept or deny, the value becomes +the result of the expansion. +If no message is set and the ACL returns accept or deny +the expansion result is an empty string. +If the ACL returns defer the result is a forced-fail. Otherwise the expansion fails. + + .vitem "&*${dlfunc{*&<&'file'&>&*}{*&<&'function'&>&*}{*&<&'arg'&>&*}&&& {*&<&'arg'&>&*}...}*&" .cindex &%dlfunc%& @@ -9388,6 +9440,20 @@ can be the word &"fail"& (not in braces) to force expansion failure if the command does not succeed. If both strings are omitted, the result is contents of the standard output/error on success, and nothing on failure. +.vindex "&$run_in_acl$&" +The standard output/error of the command is put in the variable &$value$&. +In this ACL example, the output of a command is logged for the admin to +troubleshoot: +.code +warn condition = ${run{/usr/bin/id}{yes}{no}} + log_message = Output of id: $value +.endd +If the command requires shell idioms, such as the > redirect operator, the +shell must be invoked directly, such as with: +.code +${run{/bin/bash -c "/usr/bin/id >/tmp/id"}{yes}{yes}} +.endd + .vindex "&$runrc$&" The return code from the command is put in the variable &$runrc$&, and this remains set afterwards, so in a filter file you can do things like this: @@ -9567,6 +9633,7 @@ environments where Exim uses base 36 instead of base 62 for its message identifiers, base-36 digits. The number is converted to decimal and output as a string. + .vitem &*${domain:*&<&'string'&>&*}*& .cindex "domain" "extraction" .cindex "expansion" "domain extraction" @@ -9726,6 +9793,25 @@ See the description of the general &%length%& item above for details. Note that when &%length%& is used as an operator. +.vitem &*${listcount:*&<&'string'&>&*}*& +.cindex "expansion" "list item count" +.cindex "list" "item count" +.cindex "list" "count of items" +.cindex "&%listcount%& expansion item" +The string is interpreted as a list and the number of items is returned. + + +.vitem &*${listnamed:*&<&'name'&>&*}*&&~and&~&*${list_*&<&'type'&>&*name*&>&*}*& +.cindex "expansion" "named list" +.cindex "&%listnamed%& expansion item" +The name is interpreted as a named list and the content of the list is returned, +expanding any referenced lists, re-quoting as needed for colon-separation. +If the optional type if given it must be one of "a", "d", "h" or "l" +and selects address-, domain-, host- or localpart- lists to search among respectively. +Otherwise all types are searched in an undefined order and the first +matching list is returned. + + .vitem &*${local_part:*&<&'string'&>&*}*& .cindex "expansion" "local part extraction" .cindex "&%local_part%& expansion item" @@ -9848,12 +9934,12 @@ dotted-nibble hexadecimal form. In both cases, this is the "natural" form for DNS. For example, .code ${reverse_ip:192.0.2.4} -${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3} +${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.127} .endd returns .code 4.2.0.192 -3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2 +f.7.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2 .endd @@ -10023,6 +10109,21 @@ In all cases, a relative comparator OP is testing if <&'string1'&> OP 10M, not if 10M is larger than &$message_size$&. +.vitem &*acl&~{{*&<&'name'&>&*}{*&<&'arg1'&>&*}&&& + {*&<&'arg2'&>&*}...}*& +.cindex "expansion" "calling an acl" +.cindex "&%acl%&" "expansion condition" +The name and zero to nine argument strings are first expanded separately. The expanded +arguments are assigned to the variables &$acl_arg1$& to &$acl_arg9$& in order. +Any unused are made empty. The variable &$acl_narg$& is set to the number of +arguments. The named ACL (see chapter &<>&) is called +and may use the variables; if another acl expansion is used the values +are restored after it returns. If the ACL sets +a value using a "message =" modifier the variable $value becomes +the result of the expansion, otherwise it is empty. +If the ACL returns accept the condition is true; if deny, false. +If the ACL returns defer the result is a forced-fail. + .vitem &*bool&~{*&<&'string'&>&*}*& .cindex "expansion" "boolean parsing" .cindex "&%bool%& expansion condition" @@ -10973,6 +11074,12 @@ inserting the message header line with the given name. Note that the name must be terminated by colon or white space, because it may contain a wide variety of characters. Note also that braces must &'not'& be used. +.vitem &$headers_added$& +.vindex "&$headers_added$&" +Within an ACL this variable contains the headers added so far by +the ACL modifier add_header (section &<>&). +The headers are a newline-separated list. + .vitem &$home$& .vindex "&$home$&" When the &%check_local_user%& option is set for a router, the user's home @@ -11643,6 +11750,12 @@ envelope sender. .vindex "&$return_size_limit$&" This is an obsolete name for &$bounce_return_size_limit$&. +.vitem &$router_name$& +.cindex "router" "name" +.cindex "name" "of router" +.vindex "&$router_name$&" +During the running of a router this variable contains its name. + .vitem &$runrc$& .cindex "return code" "from &%run%& expansion" .vindex "&$runrc$&" @@ -12097,6 +12210,12 @@ This variable contains the numerical value of the local timezone, for example: This variable contains the UTC date and time in &"Zulu"& format, as specified by ISO 8601, for example: 20030221154023Z. +.vitem &$transport_name$& +.cindex "transport" "name" +.cindex "name" "of transport" +.vindex "&$transport_name$&" +During the running of a transport, this variable contains its name. + .vitem &$value$& .vindex "&$value$&" This variable contains the result of an expansion lookup, extraction operation, @@ -12508,7 +12627,7 @@ local_interfaces = 0.0.0.0 : 127.0.0.1.26 .endd To specify listening on the default port on specific interfaces only: .code -local_interfaces = 192.168.34.67 : 192.168.34.67 +local_interfaces = 10.0.0.67 : 192.168.34.67 .endd &*Warning*&: Such a setting excludes listening on the loopback interfaces. @@ -12805,6 +12924,7 @@ listed in more than one group. .section "TLS" "SECID108" .table2 .row &%gnutls_compat_mode%& "use GnuTLS compatibility mode" +.row &%gnutls_enable_pkcs11%& "allow GnuTLS to autoload PKCS11 modules" .row &%openssl_options%& "adjust OpenSSL compatibility options" .row &%tls_advertise_hosts%& "advertise TLS to these hosts" .row &%tls_certificate%& "location of server certificate" @@ -12954,9 +13074,7 @@ 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" -.new .row &%dns_use_dnssec%& "parameter for resolver" -.wen .row &%dns_use_edns0%& "parameter for resolver" .row &%hold_domains%& "hold delivery for these domains" .row &%local_interfaces%& "for routing checks" @@ -13004,6 +13122,8 @@ Those options that undergo string expansion before use are marked with .option accept_8bitmime main boolean true .cindex "8BITMIME" .cindex "8-bit characters" +.cindex "log" "selectors" +.cindex "log" "8BITMIME" This option causes Exim to send 8BITMIME in its response to an SMTP EHLO command, and to accept the BODY= parameter on MAIL commands. However, though Exim is 8-bit clean, it is not a protocol converter, and it @@ -13017,6 +13137,11 @@ A more detailed analysis of the issues is provided by Dan Bernstein: &url(http://cr.yp.to/smtp/8bitmime.html) .endd +To log received 8BITMIME status use +.code +log_selector = +8bitmime +.endd + .option acl_not_smtp main string&!! unset .cindex "&ACL;" "for non-SMTP messages" .cindex "non-SMTP messages" "ACLs for" @@ -13833,6 +13958,19 @@ This option controls whether GnuTLS is used in compatibility mode in an Exim server. This reduces security slightly, but improves interworking with older implementations of TLS. + +.new +option gnutls_enable_pkcs11 main boolean unset +This option will let GnuTLS (2.12.0 or later) autoload PKCS11 modules with +the p11-kit configuration files in &_/etc/pkcs11/modules/_&. + +See +&url(http://www.gnu.org/software/gnutls/manual/gnutls.html#Smart-cards-and-HSMs) +for documentation. +.wen + + + .option headers_charset main string "see below" This option sets a default character set for translating from encoded MIME &"words"& in header lines, when referenced by an &$h_xxx$& expansion item. The @@ -15928,6 +16066,9 @@ use OpenSSL with a directory. See &<>& for discussion of when this option might be re-expanded. +A forced expansion failure or setting to an empty string is equivalent to +being unset. + .option tls_verify_hosts main "host list&!!" unset .cindex "TLS" "client certificate verification" @@ -16265,7 +16406,7 @@ router is skipped, and the address is offered to the next one. If the result is any other value, the router is run (as this is the last precondition to be evaluated, all the other preconditions must be true). -This option is unique in that multiple &%condition%& options may be present. +This option is unusual in that multiple &%condition%& options may be present. All &%condition%& options must succeed. The &%condition%& option provides a means of applying custom conditions to the @@ -16294,7 +16435,8 @@ be specified using &%condition%&. .option debug_print routers string&!! unset .cindex "testing" "variables in drivers" If this option is set and debugging is enabled (see the &%-d%& command line -option), the string is expanded and included in the debugging output. +option) or in address-testing mode (see the &%-bt%& command line option), +the string is expanded and included in the debugging output. If expansion of the string fails, the error message is written to the debugging output, and Exim carries on processing. This option is provided to help with checking out the values of variables and @@ -16303,6 +16445,7 @@ option appears not to be working, &%debug_print%& can be used to output the variables it references. The output happens after checks for &%domains%&, &%local_parts%&, and &%check_local_user%& but before any other preconditions are tested. A newline is added to the text if it does not end with one. +The variable &$router_name$& contains the name of the router. @@ -16464,6 +16607,9 @@ The &%headers_add%& option is expanded after &%errors_to%&, but before the expansion is forced to fail, the option has no effect. Other expansion failures are treated as configuration errors. +Unlike most options, &%headers_add%& can be specified multiple times +for a router; all listed headers are added. + &*Warning 1*&: The &%headers_add%& option cannot be used for a &(redirect)& router that has the &%one_time%& option set. @@ -16497,6 +16643,9 @@ The &%headers_remove%& option is expanded after &%errors_to%& and the option has no effect. Other expansion failures are treated as configuration errors. +Unlike most options, &%headers_remove%& can be specified multiple times +for a router; all listed headers are removed. + &*Warning 1*&: The &%headers_remove%& option cannot be used for a &(redirect)& router that has the &%one_time%& option set. @@ -17133,7 +17282,8 @@ Setting this option has the effect of setting &%verify_sender%& and .cindex "EXPN" "with &%verify_only%&" .oindex "&%-bv%&" .cindex "router" "used only when verifying" -If this option is set, the router is used only when verifying an address or +If this option is set, the router is used only when verifying an address, +delivering in cutthrough mode or testing with the &%-bv%& option, not when actually doing a delivery, testing with the &%-bt%& option, or running the SMTP EXPN command. It can be further restricted to verifying only senders or recipients by means of @@ -17147,7 +17297,8 @@ user or group. .option verify_recipient routers&!? boolean true If this option is false, the router is skipped when verifying recipient -addresses +addresses, +delivering in cutthrough mode or testing recipient verification using &%-bv%&. See section &<>& for a list of the order in which preconditions are evaluated. @@ -19455,6 +19606,8 @@ so on when debugging driver configurations. For example, if a &%headers_add%& option is not working properly, &%debug_print%& could be used to output the variables it references. A newline is added to the text if it does not end with one. +The variables &$transport_name$& and &$router_name$& contain the name of the +transport and the router that called it. .option delivery_date_add transports boolean false @@ -19500,6 +19653,9 @@ routers. If the result of the expansion is an empty string, or if the expansion is forced to fail, no action is taken. Other expansion failures are treated as errors and cause the delivery to be deferred. +Unlike most options, &%headers_add%& can be specified multiple times +for a transport; all listed headers are added. + .option headers_only transports boolean false @@ -19522,6 +19678,9 @@ routers. If the result of the expansion is an empty string, or if the expansion is forced to fail, no action is taken. Other expansion failures are treated as 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 added. + .option headers_rewrite transports string unset @@ -19826,7 +19985,7 @@ message, which happens if the &%return_message%& option is set. .option transport_filter_timeout transports time 5m .cindex "transport" "filter, timeout" -When Exim is reading the output of a transport filter, it a applies a timeout +When Exim is reading the output of a transport filter, it applies a timeout that can be set by this option. Exceeding the timeout is normally treated as a temporary delivery failure. However, if a transport filter is used with a &(pipe)& transport, a timeout in the transport filter is treated in the same @@ -23943,6 +24102,12 @@ client_condition = ${if !eq{$tls_out_cipher}{}} .endd +.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. +Typically it will be the user name used for authentication. + + .option driver authenticators string unset This option must always be set. It specifies which of the available authenticators is to be used. @@ -25786,6 +25951,8 @@ install if the receiving end is a client MUA that can interact with a user. .cindex "certificate" "self-signed" You can create a self-signed certificate using the &'req'& command provided with OpenSSL, like this: +. ==== Do not shorten the duration here without reading and considering +. ==== the text below. Please leave it at 9999 days. .code openssl req -x509 -newkey rsa:1024 -keyout file1 -out file2 \ -days 9999 -nodes @@ -25798,6 +25965,22 @@ that you are prompted for, and any use that is made of the key causes more prompting for the passphrase. This is not helpful if you are going to use this certificate and key in an MTA, where prompting is not possible. +. ==== I expect to still be working 26 years from now. The less technical +. ==== debt I create, in terms of storing up trouble for my later years, the +. ==== happier I will be then. We really have reached the point where we +. ==== should start, at the very least, provoking thought and making folks +. ==== pause before proceeding, instead of leaving all the fixes until two +. ==== years before 2^31 seconds after the 1970 Unix epoch. +. ==== -pdp, 2012 +NB: we are now past the point where 9999 days takes us past the 32-bit Unix +epoch. If your system uses unsigned time_t (most do) and is 32-bit, then +the above command might produce a date in the past. Think carefully about +the lifetime of the systems you're deploying, and either reduce the duration +of the certificate or reconsider your platform deployment. (At time of +writing, reducing the duration is the most likely choice, but the inexorable +progression of time takes us steadily towards an era where this will not +be a sensible resolution). + A self-signed certificate made in this way is sufficient for testing, and may be adequate for all your requirements if you are mainly interested in encrypting transfers, and not in secure identification. @@ -25996,6 +26179,9 @@ before or after the data) correctly &-- they keep the message on their queues and try again later, but that is their problem, though it does waste some of your resources. +The &%acl_smtp_data%& ACL is run after both the &%acl_smtp_dkim%& and +the &%acl_smtp_mime%& ACLs. + .section "The SMTP DKIM ACL" "SECTDKIMACL" The &%acl_smtp_dkim%& ACL is available only when Exim is compiled with DKIM support @@ -26005,13 +26191,17 @@ The ACL test specified by &%acl_smtp_dkim%& happens after a message has been received, and is executed for each DKIM signature found in a message. If not otherwise specified, the default action is to accept. -For details on the operation of DKIM, see chapter &<>&. +This ACL is evaluated before &%acl_smtp_mime%& and &%acl_smtp_data%&. + +For details on the operation of DKIM, see chapter &<>&. .section "The SMTP MIME ACL" "SECID194" The &%acl_smtp_mime%& option is available only when Exim is compiled with the content-scanning extension. For details, see chapter &<>&. +This ACL is evaluated after &%acl_smtp_dkim%& but before &%acl_smtp_data%&. + .section "The QUIT ACL" "SECTQUITACL" .cindex "QUIT, ACL for" @@ -26042,7 +26232,7 @@ connection is closed. In these special cases, the QUIT ACL does not run. .section "The not-QUIT ACL" "SECTNOTQUITACL" .vindex &$acl_smtp_notquit$& The not-QUIT ACL, specified by &%acl_smtp_notquit%&, is run in most cases when -an SMTP session ends without sending QUIT. However, when Exim itself is is bad +an SMTP session ends without sending QUIT. However, when Exim itself is in bad trouble, such as being unable to write to its log files, this ACL is not run, because it might try to do things (such as write to log files) that make the situation even worse. @@ -26396,8 +26586,8 @@ duplicates to be written, use the &%logwrite%& modifier instead. If &%log_message%& is not present, a &%warn%& verb just checks its conditions and obeys any &"immediate"& modifiers (such as &%control%&, &%set%&, -&%logwrite%&, and &%add_header%&) that appear before the first failing -condition. There is more about adding header lines in section +&%logwrite%&, &%add_header%&, and &%remove_header%&) that appear before the +first failing condition. There is more about adding header lines in section &<>&. If any condition on a &%warn%& statement cannot be completed (that is, there is @@ -26515,7 +26705,7 @@ others specify text for messages that are used when access is denied or a warning is generated. The &%control%& modifier affects the way an incoming message is handled. -The positioning of the modifiers in an ACL statement important, because the +The positioning of the modifiers in an ACL statement is important, because the processing of a verb ceases as soon as its outcome is known. Only those modifiers that have already been encountered will take effect. For example, consider this use of the &%message%& modifier: @@ -26636,12 +26826,12 @@ If you want to apply a control unconditionally, you can use it with a .vitem &*delay*&&~=&~<&'time'&> .cindex "&%delay%& ACL modifier" .oindex "&%-bh%&" -This modifier may appear in any ACL. It causes Exim to wait for the time -interval before proceeding. However, when testing Exim using the &%-bh%& -option, the delay is not actually imposed (an appropriate message is output -instead). The time is given in the usual Exim notation, and the delay happens -as soon as the modifier is processed. In an SMTP session, pending output is -flushed before the delay is imposed. +This modifier may appear in any ACL except notquit. It causes Exim to wait for +the time interval before proceeding. However, when testing Exim using the +&%-bh%& option, the delay is not actually imposed (an appropriate message is +output instead). The time is given in the usual Exim notation, and the delay +happens as soon as the modifier is processed. In an SMTP session, pending +output is flushed before the delay is imposed. Like &%control%&, &%delay%& can be used with &%accept%& or &%deny%&, for example: @@ -26839,6 +27029,12 @@ all the conditions are true, wherever it appears in an ACL command, whereas effect. +.vitem &*remove_header*&&~=&~<&'text'&> +This modifier specifies one or more header names in a colon-separated list + that are to be removed from an incoming message, assuming, of course, that +the message is ultimately accepted. For details, see section &<>&. + + .vitem &*set*&&~<&'acl_name'&>&~=&~<&'value'&> .cindex "&%set%& ACL modifier" This modifier puts a value into one of the ACL variables (see section @@ -26908,11 +27104,12 @@ is what is wanted for subsequent tests. .new .vitem &*control&~=&~cutthrough_delivery*& .cindex "&ACL;" "cutthrough routing" +.cindex "cutthrough" "requesting" This option requests delivery be attempted while the item is being received. It is usable in the RCPT ACL and valid only for single-recipient mails forwarded from one SMTP connection to another. If a recipient-verify callout connection is requested in the same ACL it is held open and used for the data, otherwise one is made -after the ACL completes. +after the ACL completes. Note that routers are used in verify mode. Should the ultimate destination system positively accept or reject the mail, a corresponding indication is given to the source system and nothing is queued. @@ -26927,24 +27124,6 @@ sender when the destination system is doing content-scan based rejection. .new -.vitem &*control&~=&~dscp/*&<&'value'&> -.cindex "&ACL;" "setting DSCP value" -.cindex "DSCP" "inbound" -This option causes the DSCP value associated with the socket for the inbound -connection to be adjusted to a given value, given as one of a number of fixed -strings or to numeric value. -The &%-bI:dscp%& option may be used to ask Exim which names it knows of. -Common values include &`throughput`&, &`mincost`&, and on newer systems -&`ef`&, &`af41`&, etc. Numeric values may be in the range 0 to 0x3F. - -The outbound packets from Exim will be marked with this value in the header -(for IPv4, the TOS field; for IPv6, the TCLASS field); there is no guarantee -that these values will have any effect, not be stripped by networking -equipment, or do much of anything without cooperation with your Network -Engineer and those of all network operators between the source and destination. -.wen - - .vitem &*control&~=&~debug/*&<&'options'&> .cindex "&ACL;" "enabling debug logging" .cindex "debugging" "enabling from an ACL" @@ -26961,6 +27140,35 @@ contexts): control = debug/opts=+expand+acl control = debug/tag=.$message_exim_id/opts=+expand .endd +.wen + + +.new +.vitem &*control&~=&~dkim_disable_verify*& +.cindex "disable DKIM verify" +.cindex "DKIM" "disable verify" +This control turns off DKIM verification processing entirely. For details on +the operation and configuration of DKIM, see chapter &<>&. +.wen + + +.new +.vitem &*control&~=&~dscp/*&<&'value'&> +.cindex "&ACL;" "setting DSCP value" +.cindex "DSCP" "inbound" +This option causes the DSCP value associated with the socket for the inbound +connection to be adjusted to a given value, given as one of a number of fixed +strings or to numeric value. +The &%-bI:dscp%& option may be used to ask Exim which names it knows of. +Common values include &`throughput`&, &`mincost`&, and on newer systems +&`ef`&, &`af41`&, etc. Numeric values may be in the range 0 to 0x3F. + +The outbound packets from Exim will be marked with this value in the header +(for IPv4, the TOS field; for IPv6, the TCLASS field); there is no guarantee +that these values will have any effect, not be stripped by networking +equipment, or do much of anything without cooperation with your Network +Engineer and those of all network operators between the source and destination. +.wen .vitem &*control&~=&~enforce_sync*& &&& @@ -27153,7 +27361,7 @@ Remotely submitted, fixups applied: use &`control = submission`&. .section "Adding header lines in ACLs" "SECTaddheadacl" .cindex "header lines" "adding in an ACL" .cindex "header lines" "position of added lines" -.cindex "&%message%& ACL modifier" +.cindex "&%add_header%& ACL modifier" The &%add_header%& modifier can be used to add one or more extra header lines to an incoming message, as in this example: .code @@ -27168,7 +27376,9 @@ receiving a message). The message must ultimately be accepted for any ACL verb, including &%deny%& (though this is potentially useful only in a RCPT ACL). -If the data for the &%add_header%& modifier contains one or more newlines that +Leading and trailing newlines are removed from +the data for the &%add_header%& modifier; if it then +contains one or more newlines that are not followed by a space or a tab, it is assumed to contain multiple header lines. Each one is checked for valid syntax; &`X-ACL-Warn:`& is added to the front of any line that is not a valid header line. @@ -27186,7 +27396,9 @@ message is rejected after DATA or by the non-SMTP ACL, all added header lines are included in the entry that is written to the reject log. .cindex "header lines" "added; visibility of" -Header lines are not visible in string expansions until they are added to the +Header lines are not visible in string expansions +of message headers +until they are added to the message. It follows that header lines defined in the MAIL, RCPT, and predata ACLs are not visible until the DATA ACL and MIME ACLs are run. Similarly, header lines that are added by the DATA or MIME ACLs are not visible in those @@ -27195,7 +27407,9 @@ passing data between (for example) the MAIL and RCPT ACLs. If you want to do this, you can use ACL variables, as described in section &<>&. -The &%add_header%& modifier acts immediately it is encountered during the +The list of headers yet to be added is given by the &%$headers_added%& variable. + +The &%add_header%& modifier acts immediately as it is encountered during the processing of an ACL. Notice the difference between these two cases: .display &`accept add_header = ADDED: some text`& @@ -27244,10 +27458,81 @@ system filter or in a router or transport. +.section "Removing header lines in ACLs" "SECTremoveheadacl" +.cindex "header lines" "removing in an ACL" +.cindex "header lines" "position of removed lines" +.cindex "&%remove_header%& ACL modifier" +The &%remove_header%& modifier can be used to remove one or more header lines +from an incoming message, as in this example: +.code +warn message = Remove internal headers + remove_header = x-route-mail1 : x-route-mail2 +.endd +The &%remove_header%& modifier is permitted in the MAIL, RCPT, PREDATA, DATA, +MIME, and non-SMTP ACLs (in other words, those that are concerned with +receiving a message). The message must ultimately be accepted for +&%remove_header%& to have any significant effect. You can use &%remove_header%& +with any ACL verb, including &%deny%&, though this is really not useful for +any verb that doesn't result in a delivered message. + +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 +create a list of headers, however both connection and message variable expansion +are performed (&%$acl_c_*%& and &%$acl_m_*%&), illustrated in this example: +.code +warn hosts = +internal_hosts + set acl_c_ihdrs = x-route-mail1 : x-route-mail2 +warn message = Remove internal headers + remove_header = $acl_c_ihdrs +.endd +Removed header lines are accumulated during the MAIL, RCPT, and predata ACLs. +They are removed from the message before processing the DATA and MIME ACLs. +There is no harm in attempting to remove the same header twice nor is 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 +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. + +.cindex "header lines" "removed; visibility of" +Header lines are not visible in string expansions until the DATA phase when it +is received. Any header lines removed in the MAIL, RCPT, and predata ACLs are +not visible in the DATA ACL and MIME ACLs. Similarly, header lines that are +removed by the DATA or MIME ACLs are still visible in those ACLs. Because of +this restriction, you cannot use header lines as a way of controlling data +passed between (for example) the MAIL and RCPT ACLs. If you want to do this, +you should instead use ACL variables, as described in section +&<>&. + +The &%remove_header%& modifier acts immediately as it is encountered during the +processing of an ACL. Notice the difference between these two cases: +.display +&`accept remove_header = X-Internal`& +&` `&<&'some condition'&> + +&`accept `&<&'some condition'&> +&` remove_header = X-Internal`& +.endd +In the first case, the header line is always removed, whether or not the +condition is true. In the second case, the header line is removed only if the +condition is true. Multiple occurrences of &%remove_header%& may occur in the +same ACL statement. All those that are encountered before a condition fails +are honoured. + +&*Warning*&: This facility currently applies only to header lines that are +present during ACL processing. It does NOT remove header lines that are added +in a system filter or in a router or transport. + + + + .section "ACL conditions" "SECTaclconditions" .cindex "&ACL;" "conditions; list of" -Some of conditions listed in this section are available only when Exim is +Some of the conditions listed in this section are available only when Exim is compiled with the content-scanning extension. They are included here briefly for completeness. More detailed descriptions can be found in the discussion on content scanning in chapter &<>&. @@ -27265,6 +27550,7 @@ The conditions are as follows: .vitem &*acl&~=&~*&<&'name&~of&~acl&~or&~ACL&~string&~or&~file&~name&~'&> .cindex "&ACL;" "nested" .cindex "&ACL;" "indirect" +.cindex "&ACL;" "arguments" .cindex "&%acl%& ACL condition" The possible values of the argument are the same as for the &%acl_smtp_%&&'xxx'& options. The named or inline ACL is run. If it returns @@ -27274,6 +27560,12 @@ condition is on a &%warn%& verb. In that case, a &"defer"& return makes the condition false. This means that further processing of the &%warn%& verb ceases, but processing of the ACL continues. +If the argument is a named ACL, up to nine space-separated optional values +can be appended; they appear within the called ACL in $acl_arg1 to $acl_arg9, +and $acl_narg is set to the count of values. +Previous values of these variables are restored after the call returns. +The name and values are expanded separately. + If the nested &%acl%& returns &"drop"& and the outer condition denies access, the connection is dropped. If it returns &"discard"&, the verb must be &%accept%& or &%discard%&, and the action is taken immediately &-- no further @@ -27362,7 +27654,7 @@ encrypted = * .endd -.vitem &*hosts&~=&~*&<&'&~host&~list'&> +.vitem &*hosts&~=&~*&<&'host&~list'&> .cindex "&%hosts%& ACL condition" .cindex "host" "ACL checking" .cindex "&ACL;" "testing the client host" @@ -28022,7 +28314,7 @@ dnslists = a.b.c!&0.0.0.1 If the DNS lookup yields both 127.0.0.1 and 127.0.0.2, the condition is false because 127.0.0.1 matches. .next -If &`!==`& or &`!=&&`& is used, the condition is true there is at least one +If &`!==`& or &`!=&&`& is used, the condition is true if there is at least one looked up IP address that does not match. Consider: .code dnslists = a.b.c!=&0.0.0.1 @@ -31408,6 +31700,10 @@ headers_add = X-added-header: added by $primary_hostname\n\ .endd Exim does not check the syntax of these added header lines. +Multiple &%headers_add%& options for a single router or transport can be +specified; the values will be concatenated (with a separating newline +added) before expansion. + The result of expanding &%headers_remove%& must consist of a colon-separated list of header names. This is confusing, because header names themselves are often terminated by colons. In this case, the colons are the list separators, @@ -31415,6 +31711,11 @@ not part of the names. For example: .code headers_remove = return-receipt-to:acknowledge-to .endd + +Multiple &%headers_remove%& options for a single router or transport can be +specified; the values will be concatenated (with a separating colon +added) before expansion. + When &%headers_add%& or &%headers_remove%& is specified on a router, its value is expanded at routing time, and then associated with all addresses that are accepted by that router, and also with any new addresses that it generates. If @@ -33278,6 +33579,7 @@ timestamp. The flags are: &`<=`& message arrival &`=>`& normal message delivery &`->`& additional address in same delivery +&`>>`& cutthrough message delivery &`*>`& delivery suppressed by &%-N%& &`**`& delivery failed; address bounced &`==`& delivery deferred; temporary problem @@ -33377,6 +33679,11 @@ intermediate address(es) exist between the original and the final address, the last of these is given in parentheses after the final address. The R and T fields record the router and transport that were used to process the address. +If SMTP AUTH was used for the delivery there is an additional item A= +followed by the name of the authenticator that was used. +If an authenticated identification was set up by the authenticator's &%client_set_id%& +option, this is logged too, separated by a colon from the authenticator name. + If a shadow transport was run after a successful local delivery, the log line for the successful delivery has an item added on the end, of the form .display @@ -33392,6 +33699,12 @@ flagged with &`->`& instead of &`=>`&. When two or more messages are delivered down a single SMTP connection, an asterisk follows the IP address in the log lines for the second and subsequent messages. +.cindex "delivery" "cutthrough; logging" +.cindex "cutthrough" "logging" +When delivery is done in cutthrough mode it is flagged with &`>>`& and the log +line precedes the reception line, since cutthrough waits for a possible +rejection from the destination in case it can reject the sourced item. + The generation of a reply message by a filter file gets logged as a &"delivery"& to the addressee, preceded by &">"&. @@ -33484,7 +33797,7 @@ at the end of its processing. A summary of the field identifiers that are used in log lines is shown in the following table: .display -&`A `& authenticator name (and optional id) +&`A `& authenticator name (and optional id and sender) &`C `& SMTP confirmation on delivery &` `& command list for &"no mail in SMTP session"& &`CV `& certificate verification status @@ -33568,6 +33881,7 @@ log_selector = +arguments -retry_defer The list of optional log items is in the following table, with the default selection marked by asterisks: .display +&` 8bitmime `& received 8BITMIME status &`*acl_warn_skipped `& skipped &%warn%& statement in ACL &` address_rewrite `& address rewriting &` all_parents `& all parents in => lines @@ -33597,9 +33911,10 @@ selection marked by asterisks: &`*sender_verify_fail `& sender verification failures &`*size_reject `& rejection because too big &`*skip_delivery `& delivery skipped in a queue run -&` smtp_confirmation `& SMTP confirmation on => lines +&`*smtp_confirmation `& SMTP confirmation on => lines &` smtp_connection `& SMTP connections &` smtp_incomplete_transaction`& incomplete SMTP transactions +&` smtp_mailauth `& AUTH argument to MAIL commands &` smtp_no_mail `& session with no MAIL commands &` smtp_protocol_error `& SMTP protocol errors &` smtp_syntax_error `& SMTP syntax errors @@ -33615,6 +33930,14 @@ selection marked by asterisks: More details on each of these items follows: .ilist +.cindex "8BITMIME" +.cindex "log" "8BITMIME" +&%8bitmime%&: This causes Exim to log any 8BITMIME status of received messages, +which may help in tracking down interoperability issues with ancient MTAs +that are not 8bit clean. This is added to the &"<="& line, tagged with +&`M8S=`& and a value of &`0`&, &`7`& or &`8`&, corresponding to "not given", +&`7BIT`& and &`8BITMIME`& respectively. +.next .cindex "&%warn%& ACL verb" "log when skipping" &%acl_warn_skipped%&: When an ACL &%warn%& statement is skipped because one of its conditions cannot be evaluated, a log line to this effect is written if @@ -33860,6 +34183,11 @@ 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 have been aborted before 20 non-mail commands are processed. .next +&%smtp_mailauth%&: A third subfield with the authenticated sender, +colon-separated, is appended to the A= item for a message arrival or delivery +log line, if an AUTH argument to the SMTP MAIL command (see &<>&) +was accepted or used. +.next .cindex "log" "SMTP protocol error" .cindex "SMTP" "logging protocol error" &%smtp_protocol_error%&: A log line is written for every SMTP protocol error @@ -35719,7 +36047,7 @@ unqualified domain &'foundation'&. . //////////////////////////////////////////////////////////////////////////// . //////////////////////////////////////////////////////////////////////////// -.chapter "Support for DKIM (DomainKeys Identified Mail)" "CHID12" &&& +.chapter "Support for DKIM (DomainKeys Identified Mail)" "CHAPdkim" &&& "DKIM Support" .cindex "DKIM" @@ -35970,7 +36298,7 @@ warn log_message = GMail sender without DKIM signature .vitem &%dkim_status%& ACL condition that checks a colon-separated list of possible DKIM verification -results agains the actual result of verification. This is typically used +results against the actual result of verification. This is typically used to restrict an ACL verb to a list of verification outcomes, for example: .code @@ -36016,6 +36344,12 @@ Add to &_src/config.h.defaults_& the line: Edit &_src/drtables.c_&, adding conditional code to pull in the private header and create a table entry as is done for all the other drivers and lookup types. .next +Edit &_scripts/lookups-Makefile_& if this is a new lookup; there is a for-loop +near the bottom, ranging the &`name_mod`& variable over a list of all lookups. +Add your &`NEWDRIVER`& to that list. +As long as the dynamic module would be named &_newdriver.so_&, you can use the +simple form that most lookups have. +.next Edit &_Makefile_& in the appropriate sub-directory (&_src/routers_&, &_src/transports_&, &_src/auths_&, or &_src/lookups_&); add a line for the new driver or lookup type and add it to the definition of OBJ.