X-Git-Url: https://git.exim.org/users/jgh/exim.git/blobdiff_plain/e9477a08d2d1f528b1f127f1d563d77e2cf24a22..01a4a5c5cbaa40ca618d3e233991ce183b551477:/doc/doc-docbook/spec.xfpt diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index 8b1a17b26..5bdf57282 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -45,7 +45,7 @@ . Update the Copyright year (only) when changing content. . ///////////////////////////////////////////////////////////////////////////// -.set previousversion "4.83" +.set previousversion "4.84" .include ./local_params .set ACL "access control lists (ACLs)" @@ -5567,7 +5567,7 @@ of an incoming SMTP connection. If you have hosts for which you trust RFC1413 and need this information, you can change this. -This line enables an efficiency SMTP option. It is negociated by clients +This line enables an efficiency SMTP option. It is negotiated by clients and not expected to cause problems but can be disabled if needed. .code prdr_enable = true @@ -6892,10 +6892,8 @@ white space is ignored. For an MX lookup, both the preference value and the host name are returned for each record, separated by a space. For an SRV lookup, the priority, weight, port, and host name are returned for each record, separated by spaces. -.new An alternate field separator can be specified using a comma after the main separator character, followed immediately by the field separator. -.wen .cindex "TXT record" "in &(dnsdb)& lookup" .cindex "SPF record" "in &(dnsdb)& lookup" @@ -6912,6 +6910,46 @@ ${lookup dnsdb{spf=example.org}} It is permitted to specify a space as the separator character. Further white space is ignored. +.section "Dnsdb lookup modifiers" "SECTdnsdb_mod" +.cindex "dnsdb modifiers" +.cindex "modifiers" "dnsdb" +.cindex "options" "dnsdb" +Modifiers for &(dnsdb)& lookups are givien by optional keywords, +each followed by a comma, +that may appear before the record type. + +The &(dnsdb)& lookup fails only if all the DNS lookups fail. If there is a +temporary DNS error for any of them, the behaviour is controlled by +a defer-option modifier. +The possible keywords are +&"defer_strict"&, &"defer_never"&, and &"defer_lax"&. +With &"strict"& behaviour, any temporary DNS error causes the +whole lookup to defer. With &"never"& behaviour, a temporary DNS error is +ignored, and the behaviour is as if the DNS lookup failed to find anything. +With &"lax"& behaviour, all the queries are attempted, but a temporary DNS +error causes the whole lookup to defer only if none of the other lookups +succeed. The default is &"lax"&, so the following lookups are equivalent: +.code +${lookup dnsdb{defer_lax,a=one.host.com:two.host.com}} +${lookup dnsdb{a=one.host.com:two.host.com}} +.endd +Thus, in the default case, as long as at least one of the DNS lookups +yields some data, the lookup succeeds. + +.cindex "DNSSEC" "dns lookup" +Use of &(DNSSEC)& is controlled by a dnssec modifier. +The possible keywords are +&"dnssec_strict"&, &"dnssec_lax"&, and &"dnssec_never"&. +With &"strict"& or &"lax"& DNSSEC information is requested +with the lookup. +With &"strict"& a response from the DNS resolver that +is not labelled as authenticated data +is treated as equivalent to a temporary DNS error. +The default is &"never"&. + +See also the &$lookup_dnssec_authenticated$& variable. + + .section "Pseudo dnsdb record types" "SECID66" .cindex "MX record" "in &(dnsdb)& lookup" By default, both the preference value and the host name are returned for @@ -6987,41 +7025,6 @@ The data from each lookup is concatenated, with newline separators by default, in the same way that multiple DNS records for a single item are handled. A different separator can be specified, as described above. -Modifiers for &(dnsdb)& lookups are givien by optional keywords, -each followed by a comma, -that may appear before the record type. - -The &(dnsdb)& lookup fails only if all the DNS lookups fail. If there is a -temporary DNS error for any of them, the behaviour is controlled by -a defer-option modifier. -The possible keywords are -&"defer_strict"&, &"defer_never"&, and &"defer_lax"&. -With &"strict"& behaviour, any temporary DNS error causes the -whole lookup to defer. With &"never"& behaviour, a temporary DNS error is -ignored, and the behaviour is as if the DNS lookup failed to find anything. -With &"lax"& behaviour, all the queries are attempted, but a temporary DNS -error causes the whole lookup to defer only if none of the other lookups -succeed. The default is &"lax"&, so the following lookups are equivalent: -.code -${lookup dnsdb{defer_lax,a=one.host.com:two.host.com}} -${lookup dnsdb{a=one.host.com:two.host.com}} -.endd -Thus, in the default case, as long as at least one of the DNS lookups -yields some data, the lookup succeeds. - -.cindex "DNSSEC" "dns lookup" -Use of &(DNSSEC)& is controlled by a dnssec modifier. -The possible keywords are -&"dnssec_strict"&, &"dnssec_lax"&, and &"dnssec_never"&. -With &"strict"& or &"lax"& DNSSEC information is requested -with the lookup. -With &"strict"& a response from the DNS resolver that -is not labelled as authenticated data -is treated as equivalent to a temporary DNS error. -The default is &"never"&. - -See also the &$lookup_dnssec_authenticated$& variable. - @@ -7342,15 +7345,12 @@ If you specify multiple attributes, the result contains space-separated, quoted strings, each preceded by the attribute name and an equals sign. Within the quotes, the quote character, backslash, and newline are escaped with backslashes, and commas are used to separate multiple values for the attribute. -.new Any commas in attribute values are doubled (permitting treatment of the values as a comma-separated list). -.wen Apart from the escaping, the string within quotes takes the same form as the output when a single attribute is requested. Specifying no attributes is the same as specifying all of an entry's attributes. -.new Here are some examples of the output format. The first line of each pair is an LDAP query, and the second is the data that is returned. The attribute called &%attr1%& has two values, one of them with an embedded comma, whereas @@ -7368,18 +7368,15 @@ attr1="value1.1,value1,,2" attr2="value two" ldap:///o=base??sub?(uid=fred) objectClass="top" attr1="value1.1,value1,,2" attr2="value two" .endd -.wen You can make use of Exim's &%-be%& option to run expansion tests and thereby check the results of LDAP lookups. The &%extract%& operator in string expansions can be used to pick out individual fields from data that consists of &'key'&=&'value'& pairs. -.new The &%listextract%& operator should be used to pick out individual values of attributes, even when only a single value is expected. The doubling of embedded commas allows you to use the returned data as a comma separated list (using the "<," syntax for changing the input list separator). -.wen @@ -9509,7 +9506,7 @@ locks out the use of this expansion item in filter files. .cindex "expansion" "inserting from a socket" .cindex "socket, use of in expansion" .cindex "&%readsocket%& expansion item" -This item inserts data from a Unix domain or Internet socket into the expanded +This item inserts data from a Unix domain or TCP socket into the expanded string. The minimal way of using it uses just two arguments, as in these examples: .code @@ -9700,7 +9697,6 @@ the regular expression from string expansion. -.new .vitem &*${sort{*&<&'string'&>&*}{*&<&'comparator'&>&*}{*&<&'extractor'&>&*}}*& .cindex sorting a list .cindex list sorting @@ -9728,7 +9724,6 @@ sorts a list of numbers, and ${sort {$lookup dnsdb{>:,,mx=example.com}} {<} {${listextract{1}{<,$item}}}} .endd will sort an MX lookup into priority order. -.wen .vitem &*${substr{*&<&'string1'&>&*}{*&<&'string2'&>&*}{*&<&'string3'&>&*}}*& @@ -11932,10 +11927,7 @@ on which interface and/or port is being used for the incoming connection. The values of &$received_ip_address$& and &$received_port$& are saved with any messages that are received, thus making these variables available at delivery time. - -&*Note:*& There are no equivalent variables for outgoing connections, because -the values are unknown (unless they are explicitly set by options of the -&(smtp)& transport). +For outbound connections see &$sending_ip_address$&. .vitem &$received_port$& .vindex "&$received_port$&" @@ -12412,9 +12404,7 @@ If TLS has not been negotiated, the value will be 0. This variable refers to the certificate presented to the peer of an inbound connection when the message was received. It is only useful as the argument of a -.new &%certextract%& expansion item, &%md5%&, &%sha1%& or &%sha256%& operator, -.wen or a &%def%& condition. .vitem &$tls_in_peercert$& @@ -12422,27 +12412,21 @@ or a &%def%& condition. This variable refers to the certificate presented by the peer of an inbound connection when the message was received. It is only useful as the argument of a -.new &%certextract%& expansion item, &%md5%&, &%sha1%& or &%sha256%& operator, -.wen or a &%def%& condition. .vitem &$tls_out_ourcert$& .vindex "&$tls_out_ourcert$&" This variable refers to the certificate presented to the peer of an outbound connection. It is only useful as the argument of a -.new &%certextract%& expansion item, &%md5%&, &%sha1%& or &%sha256%& operator, -.wen or a &%def%& condition. .vitem &$tls_out_peercert$& .vindex "&$tls_out_peercert$&" This variable refers to the certificate presented by the peer of an outbound connection. It is only useful as the argument of a -.new &%certextract%& expansion item, &%md5%&, &%sha1%& or &%sha256%& operator, -.wen or a &%def%& condition. .vitem &$tls_in_certificate_verified$& @@ -13562,8 +13546,9 @@ This option defines the ACL that is run after an SMTP DATA command has been processed and the message itself has been received, but before the final acknowledgment is sent. See chapter &<>& for further details. -.option acl_smtp_data_prdr main string&!! unset -.cindex "DATA" "ACL for" +.option acl_smtp_data_prdr main string&!! accept +.cindex "PRDR" "ACL for" +.cindex "DATA" "PRDR ACL for" .cindex "&ACL;" "PRDR-related" .cindex "&ACL;" "per-user data processing" This option defines the ACL that, @@ -16505,12 +16490,17 @@ directory containing certificate files. For earlier versions of GnuTLS the option must be set to the name of a single file. +With OpenSSL the certificates specified +explicitly +either by file or directory +are added to those given by the system default location. + These certificates should be for the certificate authorities trusted, rather than the public cert of individual clients. With both OpenSSL and GnuTLS, if the value is a file then the certificates are sent by Exim as a server to connecting clients, defining the list of accepted certificate authorities. Thus the values defined should be considered public data. To avoid this, -use OpenSSL with a directory. +use the explicit directory version. See &<>& for discussion of when this option might be re-expanded. @@ -16879,7 +16869,6 @@ If the expansion fails (other than forced failure) delivery is deferred. Some of the other precondition options are common special cases that could in fact be specified using &%condition%&. -.new Historical note: We have &%condition%& on ACLs and on Routers. Routers are far older, and use one set of semantics. ACLs are newer and when they were created, the ACL &%condition%& process was given far stricter @@ -16919,7 +16908,6 @@ true, as the result of expansion is a non-empty string which doesn't match an explicit false value. This can be tricky to debug. By contrast, in an ACL either of those strings will always result in an expansion error because the result doesn't look sufficiently boolean. -.wen .option debug_print routers string&!! unset @@ -23175,11 +23163,12 @@ connects. If authentication fails, Exim will try to transfer the message unauthenticated. See also &%hosts_require_auth%&, and chapter &<>& for details of authentication. -.option hosts_try_prdr smtp "host list&!!" unset +.option hosts_try_prdr smtp "host list&!!" * .cindex "PRDR" "enabling, optional in client" This option provides a list of servers to which, provided they announce PRDR support, Exim will attempt to negotiate PRDR for multi-recipient messages. +The option can usually be left as default. .option interface smtp "string list&!!" unset .cindex "bind IP address" @@ -23237,7 +23226,7 @@ so can cause parallel connections to the same host if &%remote_max_parallel%& permits this. -.option multi_domain smtp boolean true +.option multi_domain smtp boolean&!! true .vindex "&$domain$&" When this option is set, the &(smtp)& transport can handle a number of addresses containing a mixture of different domains provided they all resolve @@ -23246,6 +23235,9 @@ handling only one domain at a time. This is useful if you want to use &$domain$& in an expansion for the transport, because it is set only when there is a single domain involved in a remote delivery. +It is expanded per-address and can depend on any of +&$address_data$&, &$domain_data$&, &$local_part_data$&, +&$host$&, &$host_address$& and &$host_port$&. .option port smtp string&!! "see below" .cindex "port" "sending TCP/IP" @@ -23281,7 +23273,7 @@ connecting, as an outbound SSL-on-connect, instead of using STARTTLS to upgrade. The Internet standards bodies strongly discourage use of this mode. -.option retry_include_ip_address smtp boolean true +.option retry_include_ip_address smtp boolean&!! true Exim normally includes both the host name and the IP address in the key it constructs for indexing retry data after a temporary delivery failure. This means that when one of several IP addresses for a host is failing, it gets @@ -23291,9 +23283,8 @@ addresses is not affected. However, in some dialup environments hosts are assigned a different IP address each time they connect. In this situation the use of the IP address as part of the retry key leads to undesirable behaviour. Setting this option false causes -Exim to use only the host name. This should normally be done on a separate -instance of the &(smtp)& transport, set up specially to handle the dialup -hosts. +Exim to use only the host name. +Since it is expanded it can be made to depend on the host or domain. .option serialize_hosts smtp "host list&!!" unset @@ -23431,7 +23422,7 @@ unknown state), opens a new one to the same host, and then tries the delivery in clear. -.option tls_try_verify_hosts smtp "host list&!! unset +.option tls_try_verify_hosts smtp "host list&!!" unset .cindex "TLS" "server certificate verification" .cindex "certificate" "verification of server" This option gives a list of hosts for which, on encrypted connections, @@ -23439,11 +23430,24 @@ certificate verification will be tried but need not succeed. The &%tls_verify_certificates%& option must also be set. Note that unless the host is in this list TLS connections will be denied to hosts using self-signed certificates -when &%tls_verify_certificates%& is set. +when &%tls_verify_certificates%& is matched. The &$tls_out_certificate_verified$& variable is set when certificate verification succeeds. +.option tls_verify_cert_hostnames smtp "host list&!!" * +.cindex "TLS" "server certificate hostname verification" +.cindex "certificate" "verification of server" +This option give a list of hosts for which, +while verifying the server certificate, +checks will be included on the host name +(note that this will generally be the result of a DNS MX lookup) +versus Subject and Subject-Alternate-Name fields. Wildcard names are permitted +limited to being the initial component of a 3-or-more component FQDN. + +There is no equivalent checking on client certificates. + + .option tls_verify_certificates smtp string&!! unset .cindex "TLS" "server certificate verification" .cindex "certificate" "verification of server" @@ -23458,6 +23462,12 @@ you can set files. For earlier versions of GnuTLS the option must be set to the name of a single file. + +With OpenSSL the certificates specified +explicitly +either by file or directory +are added to those given by the system default location. + The values of &$host$& and &$host_address$& are set to the name and address of the server during the expansion of this option. See chapter &<>& for details of TLS. @@ -23467,7 +23477,7 @@ if neither tls_verify_hosts nor tls_try_verify_hosts are set and certificate verification fails the TLS connection is closed. -.option tls_verify_hosts smtp "host list&!! unset +.option tls_verify_hosts smtp "host list&!!" unset .cindex "TLS" "server certificate verification" .cindex "certificate" "verification of server" This option gives a list of hosts for which. on encrypted connections, @@ -26565,7 +26575,7 @@ during TLS session handshake, to permit alternative values to be chosen: &%tls_verify_certificates%& .next .vindex "&%tls_ocsp_file%&" -&%tls_verify_certificates%& +&%tls_ocsp_file%& .endlist Great care should be taken to deal with matters of case, various injection @@ -26924,6 +26934,7 @@ This ACL is evaluated after &%acl_smtp_dkim%& but before &%acl_smtp_data%&. .section "The SMTP PRDR ACL" "SECTPRDRACL" +.cindex "PRDR" "ACL for" .oindex "&%prdr_enable%&" The &%acl_smtp_data_prdr%& ACL is available only when Exim is compiled with PRDR support enabled (which is the default). @@ -26932,8 +26943,9 @@ client and server for a message, and more than one recipient has been accepted. The ACL test specfied by &%acl_smtp_data_prdr%& happens after a message -has been recieved, and is executed for each recipient of the message. -The test may accept or deny for inividual recipients. +has been recieved, and is executed once for each recipient of the message +with &$local_part$& and &$domain$& valid. +The test may accept, defer or deny for inividual recipients. The &%acl_smtp_data%& will still be called after this ACL and can reject the message overall, even if this ACL has accepted it for some or all recipients. @@ -27762,10 +27774,8 @@ anyway. If the message contains newlines, this gives rise to a multi-line SMTP response. .vindex "&$acl_verify_message$&" -.new For ACLs that are called by an &%acl =%& ACL condition, the message is stored in &$acl_verify_message$&, from which the calling ACL may use it. -.wen If &%message%& is used on a statement that verifies an address, the message specified overrides any message that is generated by the verification process. @@ -27874,10 +27884,16 @@ is what is wanted for subsequent tests. .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. + +The option usable in the RCPT ACL. +If enabled for a message recieved via smtp and routed to an smtp transport, +and the message has only one recipient, +then the delivery connection is made while the receiving connection is open +and data is copied from one to the other. + +If a recipient-verify callout connection is subsequently +requested in the same ACL it is held open and used for the data, +otherwise one is made after the initial RCPT ACL completes. Note that routers are used in verify mode, and cannot depend on content of received headers. @@ -27892,11 +27908,12 @@ before the entire message has been received from the source. Should the ultimate destination system positively accept or reject the mail, a corresponding indication is given to the source system and nothing is queued. If there is a temporary error the item is queued for later delivery in the -usual fashion. If the item is successfully delivered in cutthrough mode the log line -is tagged with ">>" rather than "=>" and appears before the acceptance "<=" -line. +usual fashion. If the item is successfully delivered in cutthrough mode +the log line is tagged with ">>" rather than "=>" and appears +before the acceptance "<=" line. -Delivery in this mode avoids the generation of a bounce mail to a (possibly faked) +Delivery in this mode avoids the generation of a bounce mail to a +(possibly faked) sender when the destination system is doing content-scan based rejection. @@ -30348,9 +30365,13 @@ av_scanner = cmdline:\ .endd .vitem &%drweb%& .cindex "virus scanners" "DrWeb" -The DrWeb daemon scanner (&url(http://www.sald.com/)) interface takes one -argument, either a full path to a UNIX socket, or an IP address and port -separated by white space, as in these examples: +The DrWeb daemon scanner (&url(http://www.sald.com/)) interface +takes one option, +either a full path to a UNIX socket, +or host and port specifiers separated by white space. +The host may be a name or an IP address; the port is either a +single number or a pair of numbers with a dash between. +For example: .code av_scanner = drweb:/var/run/drwebd.sock av_scanner = drweb:192.168.2.20 31337 @@ -30358,6 +30379,17 @@ av_scanner = drweb:192.168.2.20 31337 If you omit the argument, the default path &_/usr/local/drweb/run/drwebd.sock_& is used. Thanks to Alex Miller for contributing the code for this scanner. +.vitem &%f-protd%& +.cindex "virus scanners" "f-protd" +The f-protd scanner is accessed via HTTP over TCP. +One argument is taken, being a space-separated hostname and port number +(or port-range). +For example: +.code +av_scanner = f-protd:localhost 10200-10204 +.endd +If you omit the argument, the default values show above are used. + .vitem &%fsecure%& .cindex "virus scanners" "F-Secure" The F-Secure daemon scanner (&url(http://www.f-secure.com)) takes one @@ -35312,11 +35344,9 @@ given message, or all mail for a given user, or for a given host, for example. The input files can be in Exim log format or syslog format. If a matching log line is not associated with a specific message, it is included in &'exigrep'&'s output without any additional lines. The usage is: -.new .display &`exigrep [-t<`&&'n'&&`>] [-I] [-l] [-M] [-v] <`&&'pattern'&&`> [<`&&'log file'&&`>] ...`& .endd -.wen If no log file names are given on the command line, the standard input is read. The &%-t%& argument specifies a number of seconds. It adds an additional @@ -35336,7 +35366,6 @@ regular expression. The &%-v%& option inverts the matching condition. That is, a line is selected if it does &'not'& match the pattern. -.new The &%-M%& options means &"related messages"&. &'exigrep'& will show messages that are generated as a result/response to a message that &'exigrep'& matched normally. @@ -35349,7 +35378,6 @@ the second (bounce) message will be displayed. Using &%-M%& with &'exigrep'& when searching for &"user_a"& will show both messages since the bounce is &"related"& to or a &"result"& of the first message that was found by the search term. -.wen If the location of a &'zcat'& command is known from the definition of ZCAT_COMMAND in &_Local/Makefile_&, &'exigrep'& automatically passes any file