X-Git-Url: https://git.exim.org/users/heiko/exim.git/blobdiff_plain/595028e435015508f214f06456874a8882bfd54e..210f147e47759d98c1220a6c3b8bf185743a31df:/doc/doc-docbook/spec.xfpt?ds=inline diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index 5e76fa801..a4bbac4bf 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -1,4 +1,4 @@ -. $Cambridge: exim/doc/doc-docbook/spec.xfpt,v 1.24 2007/08/29 13:37:28 ph10 Exp $ +. $Cambridge: exim/doc/doc-docbook/spec.xfpt,v 1.28 2008/01/17 12:56:12 nm4 Exp $ . . ///////////////////////////////////////////////////////////////////////////// . This is the primary source of the Exim Manual. It is an xfpt document that is @@ -47,8 +47,8 @@ . the element must also be updated for each new edition. . ///////////////////////////////////////////////////////////////////////////// -.set previousversion "4.67" -.set version "4.68" +.set previousversion "4.69" +.set version "4.70" .set ACL "access control lists (ACLs)" .set I "    " @@ -491,13 +491,11 @@ Please ask Debian-specific questions on this list and not on the general Exim lists. .section "Exim training" "SECID4" -.new .cindex "training courses" Training courses in Cambridge (UK) used to be run annually by the author of Exim, before he retired. At the time of writing, there are no plans to run further Exim courses in Cambridge. However, if that changes, relevant information will be posted at &url(http://www-tus.csx.cam.ac.uk/courses/exim/). -.wen .section "Bug reports" "SECID5" .cindex "bug reports" @@ -539,13 +537,13 @@ 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 Philip Hazel's GPG key. The +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 &_Public-Key_&. The signatures for the tar bundles are +also a copy in the file &_nigel-pubkey.asc_&. The signatures for the tar bundles are in: .display -&_exim-n.nn.tar.gz.sig_& -&_exim-n.nn.tar.bz2.sig_& +&_exim-n.nn.tar.gz.asc_& +&_exim-n.nn.tar.bz2.asc_& .endd For each released version, the log of changes is made separately available in a separate file in the directory &_ChangeLogs_& so that it is possible to @@ -731,12 +729,12 @@ the Exim documentation, &"spool"& is always used in the first sense. A number of pieces of external code are included in the Exim distribution. .ilist -Regular expressions are supported in the main Exim program and in the Exim -monitor using the freely-distributable PCRE library, copyright © -University of Cambridge. The source is distributed in the directory -&_src/pcre_&. However, this is a cut-down version of PCRE. If you want to use -the PCRE library in other programs, you should obtain and install the full -version of the library from +Regular expressions are supported in the main Exim program and in the +Exim monitor using the freely-distributable PCRE library, copyright +© University of Cambridge. The source to a cut down version of PCRE +used to be distributed in the directory &_src/pcre_&. However, this is +no longer the case and you will need to use a system PCRE library or +obtain and install the full version of the library from &url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre). .next .cindex "cdb" "acknowledgment" @@ -1656,6 +1654,18 @@ architecture and operating system for itself, but the defaults can be overridden if necessary. +.section "PCRE library" "SECTdb" +.cindex "PCRE library" +Exim no longer has an embedded PCRE library as the vast majority of +modern systems include PCRE as a system library, although you may need +to install the PCRE or PCRE development package for your operating +system. If your system has a normal PCRE installation the Exim build +process will need no further configuration. If the library or the +headers are in an unusual location you will need to set the PCRE_LIBS +and INCLUDE directives appropriately. If your operating system has no +PCRE support then you will need to obtain and build the current PCRE +from &url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/). + .section "DBM libraries" "SECTdb" .cindex "DBM libraries" "discussion of" .cindex "hints database" "DBM files used for" @@ -3731,7 +3741,6 @@ by an admin user. This option causes the contents of the message body (-D) spool file to be written to the standard output. This option can be used only by an admin user. -.new .vitem &%-Mvc%&&~<&'message&~id'&> .oindex "&%-Mvc%&" .cindex "message" "listing in RFC 2822 format" @@ -3739,7 +3748,6 @@ written to the standard output. This option can be used only by an admin user. This option causes a copy of the complete message (header lines plus body) to be written to the standard output in RFC 2822 format. This option can be used only by an admin user. -.wen .vitem &%-Mvh%&&~<&'message&~id'&> .oindex "&%-Mvh%&" @@ -4556,13 +4564,11 @@ addresses and determine how the message is to be delivered (see chapters define mechanisms for copying messages to destinations (see chapters &<>&&--&<>&). .next -.new &'retry'&: Retry rules, for use when a message cannot be delivered immediately. If there is no retry section, or if it is empty (that is, no retry rules are defined), Exim will not retry deliveries. In this situation, temporary errors are treated the same as permanent errors. Retry rules are discussed in chapter &<>&. -.wen .next &'rewrite'&: Global address rewriting rules, for use when a message arrives and when new addresses are generated during delivery. Rewriting is discussed in @@ -5821,11 +5827,9 @@ This causes any temporarily failing address to be retried every 15 minutes for 1.5 until 16 hours have passed, then every 6 hours up to 4 days. If an address is not delivered after 4 days of temporary failure, it is bounced. -.new If the retry section is removed from the configuration, or is empty (that is, if no retry rules are defined), Exim will not retry deliveries. This turns temporary errors into permanent errors. -.wen .section "Rewriting configuration" "SECID58" @@ -6151,7 +6155,6 @@ calls using the passwords from Courier's &_/etc/userdbshadow.dat_& file. Exim's utility program for creating DBM files (&'exim_dbmbuild'&) includes the zeros by default, but has an option to omit them (see section &<>&). .next -.new .cindex "lookup" "dsearch" .cindex "dsearch lookup type" &(dsearch)&: The given file must be a directory; this is searched for an entry @@ -6161,7 +6164,6 @@ the lookup is the name of the entry, which may be a file, directory, symbolic link, or any other kind of directory entry. An example of how this lookup can be used to support virtual domains is given in section &<>&. -.wen .next .cindex "lookup" "iplsearch" .cindex "iplsearch lookup type" @@ -7170,14 +7172,12 @@ option. Here is an example where two MySQL servers are listed: hide mysql_servers = localhost/users/root/secret:\ otherhost/users/root/othersecret .endd -.new For MySQL and PostgreSQL, a host may be specified as <&'name'&>:<&'port'&> but because this is a colon-separated list, the colon has to be doubled. For each query, these parameter groups are tried in order until a connection is made and a query is successfully processed. The result of a query may be that no data is found, but that is still a successful query. In other words, the list of servers provides a backup facility, not a list of different places to look. -.wen The &%quote_mysql%&, &%quote_pgsql%&, and &%quote_oracle%& expansion operators convert newline, tab, carriage return, and backspace to \n, \t, \r, and \b @@ -7187,7 +7187,6 @@ addition, escapes the percent and underscore characters. This cannot be done for MySQL because these escapes are not recognized in contexts where these characters are not special. -.new .section "Specifying the server in the query" "SECTspeserque" For MySQL and PostgreSQL lookups (but not currently for Oracle and InterBase), it is possible to specify a list of servers with an individual query. This is @@ -7227,7 +7226,6 @@ option, you can still update it by a query of this form: .code ${lookup pgsql{servers=master/db/name/pw; UPDATE ...} .endd -.wen .section "Special MySQL features" "SECID73" @@ -7594,7 +7592,6 @@ as set by the &%primary_hostname%& option (or defaulted). This makes it possible to use the same configuration file on several different hosts that differ only in their names. .next -.new .cindex "@[] in a domain list" .cindex "domain list" "matching local IP interfaces" .cindex "domain literal" @@ -7604,7 +7601,6 @@ only if that IP address is recognized as local for email routing purposes. The &%local_interfaces%& and &%extra_local_interfaces%& options can be used to control which of a host's several IP addresses are treated as local. In today's Internet, the use of domain literals is controversial. -.wen .next .cindex "@mx_any" .cindex "@mx_primary" @@ -7666,7 +7662,6 @@ list item such as &`*key.ex`& matches &'donkey.ex'& as well as &'cipher.key.ex'&. .next -.new .cindex "regular expressions" "in domain list" .cindex "domain list" "matching regular expression" If a pattern starts with a circumflex character, it is treated as a regular @@ -7676,7 +7671,6 @@ Email domains are case-independent, so this regular expression match is by default case-independent, but you can make it case-dependent by starting it with &`(?-i)`&. References to descriptions of the syntax of regular expressions are given in chapter &<>&. -.wen &*Warning*&: Because domain lists are expanded before being processed, you must escape any backslash and dollar characters in the regular expression, or @@ -7919,7 +7913,6 @@ mask, and this is used as the lookup key. For example, if the host's IP address is 192.168.34.6, the key that is looked up for the above example is &"192.168.34.0/24"&. -.new When an IPv6 address is converted to a string, dots are normally used instead of colons, so that keys in &(lsearch)& files need not contain colons (which terminate &(lsearch)& keys). This was implemented some time before the ability @@ -7934,7 +7927,6 @@ Ideally, it would be nice to tidy up this anomalous situation by changing to colons in all cases, given that quoting is now available for &(lsearch)&. However, this would be an incompatible change that might break some existing configurations. -.wen &*Warning*&: Specifying &%net32-%& (for an IPv4 address) or &%net128-%& (for an IPv6 address) is not the same as specifying just &%net-%& without a number. In @@ -7990,7 +7982,6 @@ the host name. For example, &`*.b.c`& matches all hosts whose names end in requirement. Other kinds of wildcarding require the use of a regular expression. .next -.new .cindex "regular expressions" "in host list" .cindex "host list" "regular expression in" If the item starts with &"^"& it is taken to be a regular expression which is @@ -7999,7 +7990,6 @@ expression match is by default case-independent, but you can make it case-dependent by starting it with &`(?-i)`&. References to descriptions of the syntax of regular expressions are given in chapter &<>&. For example, -.wen .code ^(a|b)\.c\.d$ .endd @@ -8027,10 +8017,8 @@ name (see section &<>&), or it may need to look up a host name from an IP address (see section &<>&). In either case, the behaviour when it fails to find the information it is seeking is the same. -.new &*Note*&: This section applies to permanent lookup failures. It does &'not'& apply to temporary DNS errors, whose handling is described in the next section. -.wen .cindex "&`+include_unknown`&" .cindex "&`+ignore_unknown`&" @@ -8066,7 +8054,6 @@ list. The effect of each one lasts until the next, or until the end of the list. -.new .section "Temporary DNS errors when looking up host information" &&& "SECTtemdnserr" .cindex "host" "lookup failures, temporary" @@ -8078,7 +8065,6 @@ host lists can include &`+ignore_defer`& and &`+include_defer`&, analagous to &`+ignore_unknown`& and &`+include_unknown`&, as described in the previous section. These options should be used with care, probably only in non-critical host lists such as whitelists. -.wen @@ -9658,11 +9644,9 @@ bytes are replaced by question marks. Characters are converted into the character set defined by &%headers_charset%&. Overlong RFC 2047 &"words"& are not recognized unless &%check_rfc2047_length%& is set false. -.new &*Note*&: If you use &%$header%&_&'xxx'&&*:*& (or &%$h%&_&'xxx'&&*:*&) to access a header line, RFC 2047 decoding is done automatically. You do not need to use this operator as well. -.wen @@ -9992,7 +9976,6 @@ The substring is first expanded, and then tested to see if it has the form of an IP address. Both IPv4 and IPv6 addresses are valid for &%isip%&, whereas &%isip4%& and &%isip6%& test specifically for IPv4 or IPv6 addresses. -.new For an IPv4 address, the test is for four dot-separated components, each of which consists of from one to three digits. For an IPv6 address, up to eight colon-separated components are permitted, each containing from one to four @@ -10007,7 +9990,6 @@ host names, or between IPv4 and IPv6 addresses. For example, you could use ${if isip4{$sender_host_address}... .endd to test which IP version an incoming SMTP connection is using. -.wen .vitem &*ldapauth&~{*&<&'ldap&~query'&>&*}*& .cindex "LDAP" "use for authentication" @@ -10574,7 +10556,6 @@ This variable is available when Exim is compiled with the content-scanning extension and the obsolete &%demime%& condition. For details, see section &<>&. -.new .vitem &$dnslist_domain$& &&& &$dnslist_matched$& &&& &$dnslist_text$& &&& @@ -10588,7 +10569,6 @@ When a DNS (black) list lookup succeeds, these variables are set to contain the following data from the lookup: the list's domain name, the key that was looked up, the contents of any associated TXT record, and the value from the main A record. See section &<>& for more details. -.wen .vitem &$domain$& .vindex "&$domain$&" @@ -10930,7 +10910,6 @@ This variable is available when Exim is compiled with the content-scanning extension. It is set to the name of the virus that was found when the ACL &%malware%& condition is true (see section &<>&). -.new .vitem &$max_received_linelength$& .vindex "&$max_received_linelength$&" .cindex "maximum" "line length" @@ -10938,7 +10917,6 @@ when the ACL &%malware%& condition is true (see section &<>&). This variable contains the number of bytes in the longest line that was received as part of the message, not counting the line termination character(s). -.wen .vitem &$message_age$& .cindex "message" "age of" @@ -10958,13 +10936,11 @@ being delivered, and is intended mainly for use in filter files. The maximum number of characters of the body that are put into the variable is set by the &%message_body_visible%& configuration option; the default is 500. -.new .oindex "&%message_body_newlines%&" By default, newlines are converted into spaces in &$message_body$&, to make it easier to search for phrases that might be split over a line break. However, this can be disabled by setting &%message_body_newlines%& to be true. Binary zeros are always converted into spaces. -.wen .vitem &$message_body_end$& .cindex "body of message" "expansion variable" @@ -11645,7 +11621,6 @@ This variable is set to &"1"& if a TLS certificate was verified when the message was received, and &"0"& otherwise. .vitem &$tls_cipher$& -.new .vindex "&$tls_cipher$&" When a message is received from a remote host over an encrypted SMTP connection, this variable is set to the cipher suite that was negotiated, for @@ -11660,7 +11635,6 @@ case, &$tls_cipher$& is cleared before any outgoing SMTP connection is made, and then set to the outgoing cipher suite if one is negotiated. See chapter &<>& for details of TLS support and chapter &<>& for details of the &(smtp)& transport. -.wen .vitem &$tls_peerdn$& .vindex "&$tls_peerdn$&" @@ -13628,13 +13602,11 @@ chapter &<>&, which contains a discussion about local network interfaces and recognizing the local host. -.new .option ibase_servers main "string list" unset .cindex "InterBase" "server list" This option provides a list of InterBase servers and associated connection data, to be used in conjunction with &(ibase)& lookups (see section &<>&). The option is available only if Exim has been built with InterBase support. -.wen @@ -13888,7 +13860,6 @@ this option is set greater than zero, any attempt to call &[getpwnam()]& with an argument that is longer behaves as if &[getpwnam()]& failed. -.new .option message_body_newlines main bool false .cindex "message body" "newlines in variables" .cindex "newline" "in message body variables" @@ -13897,7 +13868,6 @@ an argument that is longer behaves as if &[getpwnam()]& failed. By default, newlines in the message body are replaced by spaces when setting the &$message_body$& and &$message_body_end$& expansion variables. If this option is set true, this no longer happens. -.wen .option message_body_visible main integer 500 @@ -14234,7 +14204,6 @@ causes Exim to behave as if &%queue_smtp_domains%& were set to &"*"& whenever .option queue_only_load main fixed-point unset -.new .cindex "load average" .cindex "queueing incoming messages" .cindex "message" "queueing by load" @@ -14244,7 +14213,6 @@ happens during local or remote SMTP input, all subsequent messages received on the same SMTP connection are queued by default, whatever happens to the load in the meantime, but this can be changed by setting &%queue_only_load_latch%& false. -.wen Deliveries will subsequently be performed by queue runner processes. This option has no effect on ancient operating systems on which Exim cannot @@ -14252,7 +14220,6 @@ determine the load average. See also &%deliver_queue_load_max%& and &%smtp_load_reserve%&. -.new .option queue_only_load_latch main boolean true .cindex "load average" "re-evaluating per message" When this option is true (the default), once one message has been queued @@ -14265,7 +14232,6 @@ circumstances such as very long-lived connections from scanning appliances where this is not the best strategy. In such cases, &%queue_only_load_latch%& should be set false. This causes the value of the load average to be re-evaluated for each message. -.wen .option queue_only_override main boolean true @@ -14628,7 +14594,6 @@ doing this processing, it cannot accept any other incoming connections. .option smtp_accept_queue main integer 0 -.new .cindex "SMTP" "incoming connection count" .cindex "queueing incoming messages" .cindex "message" "queueing by SMTP connection count" @@ -14638,7 +14603,6 @@ on the queue; no delivery processes are started automatically. The count is fixed at the start of an SMTP connection. It cannot be updated in the subprocess that receives messages, and so the queueing or not queueing applies to all messages received in the same connection. -.wen A value of zero implies no limit, and clearly any non-zero value is useful only if it is less than the &%smtp_accept_max%& value (unless that is zero). See @@ -15295,7 +15259,6 @@ certificates from clients. The expected certificates are defined by either &%tls_verify_hosts%& or &%tls_try_verify_hosts%& is set and &%tls_verify_certificates%& is not set. -.new Any client that matches &%tls_verify_hosts%& is constrained by &%tls_verify_certificates%&. When the client initiates a TLS session, it must present one of the listed certificates. If it does not, the connection is @@ -15303,7 +15266,6 @@ aborted. &*Warning*&: Including a host in &%tls_verify_hosts%& does not require the host to use TLS. It can still send SMTP commands through unencrypted connections. Forcing a client to use TLS has to be done separately using an ACL to reject inappropriate commands when the connection is not encrypted. -.wen A weaker form of checking is provided by &%tls_try_verify_hosts%&. If a client matches this option (but not &%tls_verify_hosts%&), Exim requests a @@ -15954,14 +15916,12 @@ real_localuser: check_local_user transport = local_delivery .endd -.new For security, it would probably be a good idea to restrict the use of this router to locally-generated messages, using a condition such as this: .code condition = ${if match {$sender_host_address}\ {\N^(|127\.0\.0\.1)$\N}} .endd -.wen If both &%local_part_prefix%& and &%local_part_suffix%& are set for a router, both conditions must be met if not optional. Care must be taken if wildcards @@ -16071,7 +16031,6 @@ applies to all of them. .option pass_router routers string unset -.new .cindex "router" "go to after &""pass""&" Routers that recognize the generic &%self%& option (&(dnslookup)&, &(ipliteral)&, and &(manualroute)&) are able to return &"pass"&, forcing @@ -16082,7 +16041,6 @@ of another router. However (unlike &%redirect_router%&) the named router must be below the current router, to avoid loops. Note that this option applies only to the special case of &"pass"&. It does not apply when a router returns &"decline"& because it cannot handle an address. -.wen @@ -18503,14 +18461,12 @@ real_localuser: local_part_prefix = real- transport = local_delivery .endd -.new For security, it would probably be a good idea to restrict the use of this router to locally-generated messages, using a condition such as this: .code condition = ${if match {$sender_host_address}\ {\N^(|127\.0\.0\.1)$\N}} .endd -.wen .option syntax_errors_text redirect string&!! unset @@ -19805,10 +19761,8 @@ in which case it is: message_prefix = "From ${if def:return_path{$return_path}\ {MAILER-DAEMON}} $tod_bsdinbox\n" .endd -.new &*Note:*& If you set &%use_crlf%& true, you must change any occurrences of &`\n`& to &`\r\n`& in &%message_prefix%&. -.wen .option message_suffix appendfile string&!! "see below" The string specified here is expanded and output at the end of every message. @@ -19818,10 +19772,8 @@ setting .code message_suffix = .endd -.new &*Note:*& If you set &%use_crlf%& true, you must change any occurrences of &`\n`& to &`\r\n`& in &%message_suffix%&. -.wen .option mode appendfile "octal integer" 0600 If the output file is created, it is given this mode. If it already exists and @@ -20003,14 +19955,12 @@ This option causes lines to be terminated with the two-character CRLF sequence of batched SMTP, the byte sequence written to the file is then an exact image of what would be sent down a real SMTP connection. -.new &*Note:*& The contents of the &%message_prefix%& and &%message_suffix%& options (which are used to supply the traditional &"From&~"& and blank line separators in Berkeley-style mailboxes) are written verbatim, so must contain their own carriage return characters if these are needed. In cases where these options have non-empty defaults, the values end with a single linefeed, so they must be changed to end with &`\r\n`& if &%use_crlf%& is set. -.wen .option use_fcntl_lock appendfile boolean "see below" @@ -21058,10 +21008,8 @@ setting .code message_prefix = .endd -.new &*Note:*& If you set &%use_crlf%& true, you must change any occurrences of &`\n`& to &`\r\n`& in &%message_prefix%&. -.wen .option message_suffix pipe string&!! "see below" @@ -21071,10 +21019,8 @@ The suffix can be suppressed by setting .code message_suffix = .endd -.new &*Note:*& If you set &%use_crlf%& true, you must change any occurrences of &`\n`& to &`\r\n`& in &%message_suffix%&. -.wen .option path pipe string "see below" @@ -21184,13 +21130,11 @@ This option causes lines to be terminated with the two-character CRLF sequence of batched SMTP, the byte sequence written to the pipe is then an exact image of what would be sent down a real SMTP connection. -.new The contents of the &%message_prefix%& and &%message_suffix%& options are written verbatim, so must contain their own carriage return characters if these are needed. When &%use_bsmtp%& is not set, the default values for both &%message_prefix%& and &%message_suffix%& end with a single linefeed, so their values must be changed to end with &`\r\n`& if &%use_crlf%& is set. -.wen .option use_shell pipe boolean false @@ -21337,7 +21281,6 @@ that are in force when the &%helo_data%&, &%hosts_try_auth%&, &%interface%&, &%serialize_hosts%&, and the various TLS options are expanded. -.new .section "Use of $tls_cipher and $tls_peerdn" "usecippeer" .vindex &$tls_cipher$& .vindex &$tls_peerdn$& @@ -21349,7 +21292,6 @@ variables are emptied. If TLS is subsequently started, they are set to the appropriate values for the outgoing connection, and these are the values that are in force when any authenticators are run and when the &%authenticated_sender%& option is expanded. -.wen .section "Private options for smtp" "SECID146" @@ -21386,12 +21328,10 @@ forced to fail, the option is ignored. Other expansion failures cause delivery to be deferred. If the result of expansion is an empty string, that is also ignored. -.new The expansion happens after the outgoing connection has been made and TLS started, if required. This means that the &$host$&, &$host_address$&, &$tls_cipher$&, and &$tls_peerdn$& variables are set according to the particular connection. -.wen If the SMTP session is not authenticated, the expansion of &%authenticated_sender%& still happens (and can cause the delivery to be @@ -22342,6 +22282,12 @@ rewriting rule is skipped unless the relevant addresses are being processed. &`s`& rewrite the &'Sender:'& header &`t`& rewrite the &'To:'& header .endd +.new +"All headers" means all of the headers listed above that can be selected +individually, plus their &'Resent-'& versions. It does not include +other headers such as &'Subject:'& etc. +.wen + You should be particularly careful about rewriting &'Sender:'& headers, and restrict this to special known cases in your own domains. @@ -22475,7 +22421,6 @@ can be done on the rewritten addresses. .chapter "Retry configuration" "CHAPretry" .scindex IIDretconf1 "retry" "configuration, description of" .scindex IIDregconf2 "configuration file" "retry section" -.new The &"retry"& section of the runtime configuration file contains a list of retry rules that control how often Exim tries to deliver messages that cannot be delivered at the first attempt. If there are no retry rules (the section is @@ -22484,7 +22429,6 @@ errors are treated as permanent. The default configuration contains a single, general-purpose retry rule (see section &<>&). The &%-brt%& command line option can be used to test which retry rule will be used for a given address, domain and error. -.wen The most common cause of retries is temporary failure to deliver to a remote host because the host is down, or inaccessible because of a network problem. @@ -23130,7 +23074,6 @@ in Exim. .cindex "authentication" "generic options" .cindex "options" "generic; for authenticators" -.new .option client_condition authenticators string&!! unset When Exim is authenticating as a client, it skips any authenticator whose &%client_condition%& expansion yields &"0"&, &"no"&, or &"false"&. This can be @@ -23142,7 +23085,6 @@ client_condition = ${if !eq{$tls_cipher}{}} (Older documentation incorrectly states that &$tls_cipher$& contains the cipher used for incoming messages. In fact, during SMTP delivery, it contains the cipher used for the delivery.) -.wen .option driver authenticators string unset @@ -24412,14 +24354,12 @@ condition can be used to test for specific cipher suites in ACLs. &new("(For outgoing SMTP deliveries, &$tls_cipher$& is reset &-- see section &<>&.)") -.new Once TLS has been established, the ACLs that run for subsequent SMTP commands can check the name of the cipher suite and vary their actions accordingly. The cipher suite names vary, depending on which TLS library is being used. For example, OpenSSL uses the name DES-CBC3-SHA for the cipher suite which in other contexts is known as TLS_RSA_WITH_3DES_EDE_CBC_SHA. Check the OpenSSL or GnuTLS documentation for more details. -.wen .section "Requesting and verifying client certificates" "SECID183" @@ -24545,7 +24485,6 @@ All the TLS options in the &(smtp)& transport are expanded before use, with which the client is connected. Forced failure of an expansion causes Exim to behave as if the relevant option were unset. -.new .vindex &$tls_cipher$& .vindex &$tls_peerdn$& Before an SMTP connection is established, the &$tls_cipher$& and &$tls_peerdn$& @@ -24553,7 +24492,6 @@ variables are emptied. (Until the first connection, they contain the values that were set when the message was received.) If STARTTLS is subsequently successfully obeyed, these variables are set to the relevant values for the outgoing connection. -.wen @@ -24875,7 +24813,6 @@ connection is closed. In these special cases, the QUIT ACL does not run. -.new .section "The not-QUIT ACL" "SECTNOTQUITACL" The not-QUIT ACL, specified by &%smtp_notquit_acl%&, is run in most cases when an SMTP session ends without sending QUIT. However, when Exim itself is is bad @@ -24910,7 +24847,6 @@ With the exception of the &`acl-drop`& case, the default message can be overridden by the &%message%& modifier in the not-QUIT ACL. In the case of a &%drop%& verb in another ACL, it is the message from the other ACL that is used. -.wen .section "Finding an ACL to use" "SECID195" @@ -26587,10 +26523,8 @@ dnslists = sbl.spahmaus.org/<|192.168.2.3|192.168.5.6|... Thus, this example checks whether or not the IP addresses of the sender domain's mail servers are on the Spamhaus black list. -.new The key that was used for a successful DNS list lookup is put into the variable &$dnslist_matched$& (see section &<>&). -.wen @@ -26616,7 +26550,6 @@ see section &<>& for details of how they are checked. .section "Variables set from DNS lists" "SECID204" -.new .cindex "expansion" "variables, set from DNS list" .cindex "DNS list" "variables set from" .vindex "&$dnslist_domain$&" @@ -26642,7 +26575,6 @@ deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|... .endd If this condition succeeds, the value in &$dnslist_matched$& might be &`192.168.6.7`& (for example). -.wen If more than one address record is returned by the DNS lookup, all the IP addresses are included in &$dnslist_value$&, separated by commas and spaces. @@ -26941,11 +26873,9 @@ user, independent of the computer they are sending from, set the key to example, &$authenticated_id$& is only meaningful if the client has authenticated, and you can check with the &%authenticated%& ACL condition. -.new If you want to limit the rate at which a recipient receives messages, you can use the key &`$local_part@$domain`& with the &%per_rcpt%& option (see below) in a RCPT ACL. -.wen Internally, Exim includes the smoothing constant &'p'& and the options in the lookup key because they alter the meaning of the stored data. This is not true @@ -26953,14 +26883,12 @@ for the limit &'m'&, so you can alter the configured maximum rate and Exim will still remember clients' past behaviour, but if you alter the other ratelimit parameters Exim forgets past behaviour. -.new Each &%ratelimit%& condition can have up to three options. One option specifies what Exim measures the rate of, and the second specifies how Exim handles excessively fast clients. The third option can be &`noupdate`&, to disable updating of the ratelimiting database (see section &<>&). The options are separated by a slash, like the other parameters. They may appear in any order. -.wen .section "Ratelimit options for what is being measured" "ratoptmea" The &%per_conn%& option limits the client's connection rate. @@ -26974,12 +26902,23 @@ relies on the SIZE parameter on the MAIL command, which may be inaccurate or completely missing. You can follow the limit &'m'& in the configuration with K, M, or G to specify limits in kilobytes, megabytes, or gigabytes, respectively. +.new +The &%per_rcpt%& option causes Exim to limit the rate at which +recipients are accepted. To be effective, it would need to be used in +either the &%acl_smtp_rcpt%& or the &%acl_not_smtp%& ACL. In the +&%acl_smtp_rcpt%& ACL, the number of recipients is incremented by one. +In the case of a locally submitted message in the &%acl_not_smtp%& ACL, +the number of recipients incremented is equal to &%$recipients_count%& +for the entire message. Note that in either case the rate limiting +engine will see a message with many recipients as a large high-speed +burst. + The &%per_cmd%& option causes Exim to recompute the rate every time the -condition is processed. This can be used to limit the SMTP command rate. The -alias &%per_rcpt%& is provided for use in the RCPT ACL instead of &%per_cmd%& -to make it clear that the effect is to limit the rate at which recipients are -accepted. Note that in this case the rate limiting engine will see a message -with many recipients as a large high-speed burst. +condition is processed. This can be used to limit the SMTP command rate. +This command is essentially an alias of &%per_rcpt%& to make it clear +that the effect is to limit the rate at which individual commands, +rather than recipients, are accepted. +.wen .section "Ratelimit options for handling fast clients" "ratophanfas" If a client's average rate is greater than the maximum, the rate limiting @@ -27051,7 +26990,6 @@ this means that Exim will lose its hints data after a reboot (including retry hints, the callout cache, and ratelimit data). -.new .section "Reading ratelimit data without updating" "rearatdat" .cindex "rate limitint" "reading data without updating" If the &%noupdate%& option is present on a &%ratelimit%& ACL condition, Exim @@ -27080,7 +27018,6 @@ acl_check_mail: In this example, the rate is tested and used to deny access (when it is too high) in the connect ACL, but the actual computation of the remembered rate happens later, on a per-command basis, in another ACL. -.wen @@ -28783,23 +28720,19 @@ out the values of all the &[local_scan()]& options. .section "Available Exim variables" "SECID208" -.new .cindex "&[local_scan()]& function" "available Exim variables" The header &_local_scan.h_& gives you access to a number of C variables. These are the only ones that are guaranteed to be maintained from release to release. Note, however, that you can obtain the value of any Exim expansion variable, including &$recipients$&, by calling &'expand_string()'&. The exported C variables are as follows: -.wen .vlist .vitem &*int&~body_linecount*& -.new This variable contains the number of lines in the message's body. .vitem &*int&~body_zerocount*& This variable contains the number of binary zero bytes in the message's body. -.wen .vitem &*unsigned&~int&~debug_selector*& This variable is set to zero when no debugging is taking place. Otherwise, it