X-Git-Url: https://git.exim.org/users/heiko/exim.git/blobdiff_plain/73305f2ddd22b79d59780a522e16b233228f2ad3..3695be34bdae5e69ed8188587f03b87b6e929d42:/doc/doc-docbook/spec.xfpt diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index 0ed811ab5..04678b480 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -52,7 +52,7 @@ .set I "    " .macro copyyear -2013 +2014 .endmacro . ///////////////////////////////////////////////////////////////////////////// @@ -8298,7 +8298,14 @@ Both &`+include_unknown`& and &`+ignore_unknown`& may appear in the same list. The effect of each one lasts until the next, or until the end of the list. -To explain the host/ip processing logic a different way for the same ACL: +.new +.section "Mixing wildcarded host names and addresses in host lists" &&& + "SECTmixwilhos" +.cindex "host list" "mixing names and addresses in" + +This section explains the host/ip processing logic with the same concepts +as the previous section, but specifically addresses what happens when a +wildcarded hostname is one of the items in the hostlist. .ilist If you have name lookups or wildcarded host names and @@ -8327,7 +8334,7 @@ If the first &%accept%& fails, Exim goes on to try the second one. See chapter &`+ignore_unknown`&, which was discussed in depth in the first example in this section. .endlist - +.wen .section "Temporary DNS errors when looking up host information" &&& @@ -8399,33 +8406,6 @@ See section &<>&.) -.section "Mixing wildcarded host names and addresses in host lists" &&& - "SECTmixwilhos" -.cindex "host list" "mixing names and addresses in" -If you have name lookups or wildcarded host names and IP addresses in the same -host list, you should normally put the IP addresses first. For example, in an -ACL you could have: -.code -accept hosts = 10.9.8.7 : *.friend.example -.endd -The reason for this lies in the left-to-right way that Exim processes lists. -It can test IP addresses without doing any DNS lookups, but when it reaches an -item that requires a host name, it fails if it cannot find a host name to -compare with the pattern. If the above list is given in the opposite order, the -&%accept%& statement fails for a host whose name cannot be found, even if its -IP address is 10.9.8.7. - -If you really do want to do the name check first, and still recognize the IP -address, you can rewrite the ACL like this: -.code -accept hosts = *.friend.example -accept hosts = 10.9.8.7 -.endd -If the first &%accept%& fails, Exim goes on to try the second one. See chapter -&<>& for details of ACLs. - - - .section "Address lists" "SECTaddresslist" @@ -10171,6 +10151,14 @@ number of larger units and output in Exim's normal time format, for example, .cindex "expansion" "case forcing" .cindex "&%uc%& expansion item" This forces the letters in the string into upper-case. + +.vitem &*${utf8clean:*&<&'string'&>&*}*& +.cindex "correction of invalid utf-8 sequences in strings" +.cindex "utf-8" "utf-8 sequences" +.cindex "incorrect utf-8" +.cindex "expansion" "utf-8 forcing" +.cindex "&%utf8clean%& expansion item" +This replaces any invalid utf-8 sequence in the string by the character &`?`&. .endlist @@ -10239,7 +10227,7 @@ If the ACL returns defer the result is a forced-fail. .cindex "&%bool%& expansion condition" This condition turns a string holding a true or false representation into a boolean state. It parses &"true"&, &"false"&, &"yes"& and &"no"& -(case-insensitively); also positive integer numbers map to true if non-zero, +(case-insensitively); also integer numbers map to true if non-zero, false if zero. An empty string is treated as false. Leading and trailing whitespace is ignored; @@ -11978,7 +11966,7 @@ other times, this variable is false. It is likely that you will need to coerce DNSSEC support on in the resolver library, by setting: .code -dns_use_dnssec = 1 +dns_dnssec_ok = 1 .endd Exim does not perform DNSSEC validation itself, instead leaving that to a @@ -13190,10 +13178,10 @@ See also the &'Policy controls'& section above. .row &%disable_ipv6%& "do no IPv6 processing" .row &%dns_again_means_nonexist%& "for broken domains" .row &%dns_check_names_pattern%& "pre-DNS syntax check" +.row &%dns_dnssec_ok%& "parameter for resolver" .row &%dns_ipv4_lookup%& "only v4 lookup for these domains" .row &%dns_retrans%& "parameter for resolver" .row &%dns_retry%& "parameter for resolver" -.row &%dns_use_dnssec%& "parameter for resolver" .row &%dns_use_edns0%& "parameter for resolver" .row &%hold_domains%& "hold delivery for these domains" .row &%local_interfaces%& "for routing checks" @@ -13814,6 +13802,17 @@ This option controls whether or not an IP address, given as a CSA domain, is reversed and looked up in the reverse DNS, as described in more detail in section &<>&. + +.option dns_dnssec_ok main integer -1 +.cindex "DNS" "resolver options" +.cindex "DNS" "DNSSEC" +If this option is set to a non-negative number then Exim will initialise the +DNS resolver library to either use or not use DNSSEC, overriding the system +default. A value of 0 coerces DNSSEC off, a value of 1 coerces DNSSEC on. + +If the resolver library does not support DNSSEC then this option has no effect. + + .option dns_ipv4_lookup main "domain list&!!" unset .cindex "IPv6" "DNS lookup for AAAA records" .cindex "DNS" "IPv6 lookup for AAAA records" @@ -13844,16 +13843,6 @@ to set in them. See &%dns_retrans%& above. -.option dns_use_dnssec main integer -1 -.cindex "DNS" "resolver options" -.cindex "DNS" "DNSSEC" -If this option is set to a non-negative number then Exim will initialise the -DNS resolver library to either use or not use DNSSEC, overriding the system -default. A value of 0 coerces DNSSEC off, a value of 1 coerces DNSSEC on. - -If the resolver library does not support DNSSEC then this option has no effect. - - .option dns_use_edns0 main integer -1 .cindex "DNS" "resolver options" .cindex "DNS" "EDNS0" @@ -23018,6 +23007,14 @@ 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 +.cindex "TLS" "server certificate verification" +.cindex "certificate" "verification of server" +This option gives a list of hosts for which, on encrypted connections, +certificate verification will be tried but need not succeed. +The &%tls_verify_certificates%& option must also be set. + + .option tls_verify_certificates smtp string&!! unset .cindex "TLS" "server certificate verification" .cindex "certificate" "verification of server" @@ -23032,6 +23029,20 @@ single file if you are using GnuTLS. 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. +For back-compatability, +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 +.cindex "TLS" "server certificate verification" +.cindex "certificate" "verification of server" +This option gives a list of hosts for which. on encrypted connections, +certificate verification must succeed. +The &%tls_verify_certificates%& option must also be set. +If both this option and &%tls_try_verify_hosts%& are unset +operation is as if this option selected all hosts. + @@ -25933,6 +25944,12 @@ for OpenSSL only (not GnuTLS), a directory, that contains a collection of expected server certificates. The client verifies the server's certificate against this collection, taking into account any revoked certificates that are in the list defined by &%tls_crl%&. +Failure to verify fails the TLS connection unless either of the +&%tls_verify_hosts%& or &%tls_try_verify_hosts%& options are set. + +The &%tls_verify_hosts%& and &%tls_try_verify_hosts%& options restrict +certificate verification to the listed servers. Verification either must +or need not succeed respectively. If &%tls_require_ciphers%& is set on the &(smtp)& transport, it must contain a @@ -27292,7 +27309,16 @@ 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. -Note that routers are used in verify mode. + +Note that routers are used in verify mode, +and cannot depend on content of received headers. +Note also that headers cannot be +modified by any of the post-data ACLs (DATA, MIME and DKIM). +Headers may be modified by routers (subject to the above) and transports. + +Cutthrough delivery is not supported via transport-filters or when DKIM signing +of outgoing messages is done, because it sends data to the ultimate destination +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. @@ -27303,7 +27329,6 @@ line. 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. -Cutthrough delivery is not supported via transport-filters. .vitem &*control&~=&~debug/*&<&'options'&> @@ -27547,12 +27572,15 @@ warn dnslists = sbl.spamhaus.org : \ add_header = X-blacklisted-at: $dnslist_domain .endd The &%add_header%& modifier is permitted in the MAIL, RCPT, PREDATA, DATA, -MIME, and non-SMTP ACLs (in other words, those that are concerned with +MIME, DKIM, and non-SMTP ACLs (in other words, those that are concerned with receiving a message). The message must ultimately be accepted for &%add_header%& to have any significant effect. You can use &%add_header%& with any ACL verb, including &%deny%& (though this is potentially useful only in a RCPT ACL). +Headers will not be added to the message if the modifier is used in +DATA, MIME or DKIM ACLs for messages delivered by cutthrough routing. + Leading and trailing newlines are removed from the data for the &%add_header%& modifier; if it then contains one or more newlines that @@ -27646,12 +27674,15 @@ 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 +MIME, DKIM, 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. +Headers will not be removed to the message if the modifier is used in +DATA, MIME or DKIM ACLs for messages delivered by cutthrough routing. + More than one header can be removed at the same time by using a colon separated list of header names. The header matching is case insensitive. Wildcards are not permitted, nor is list expansion performed, so you cannot use hostlists to @@ -27972,6 +28003,23 @@ This condition checks whether the sending host (the client) is authorized to send email. Details of how this works are given in section &<>&. +.new +.vitem &*verify&~=&~header_names_ascii*& +.cindex "&%verify%& ACL condition" +.cindex "&ACL;" "verifying header names only ASCII" +.cindex "header lines" "verifying header names only ASCII" +.cindex "verifying" "header names only ASCII" +This condition is relevant only in an ACL that is run after a message has been +received, that is, in an ACL specified by &%acl_smtp_data%& or +&%acl_not_smtp%&. It checks all header names (not the content) to make sure +there are no non-ASCII characters, also excluding control characters. The +allowable characters are decimal ASCII values 33 through 126. + +Exim itself will handle headers with non-ASCII characters, but it can cause +problems for downstream applications, so this option will allow their +detection and rejection in the DATA ACL's. +.wen + .vitem &*verify&~=&~header_sender/*&<&'options'&> .cindex "&%verify%& ACL condition" .cindex "&ACL;" "verifying sender in the header" @@ -28583,6 +28631,13 @@ deny condition = ${if isip4{$sender_host_address}} dnslists = some.list.example .endd +If an explicit key is being used for a DNS lookup and it may be an IPv6 +address you should specify alternate list separators for both the outer +(DNS list name) list and inner (lookup keys) list: +.code + dnslists = <; dnsbl.example.com/<|$acl_m_addrslist +.endd + .section "Rate limiting incoming messages" "SECTratelimiting" .cindex "rate limiting" "client sending" .cindex "limiting client sending rates" @@ -28964,6 +29019,7 @@ router that does not set up hosts routes to an &(smtp)& transport with a &%hosts%& setting, the transport's hosts are used. If an &(smtp)& transport has &%hosts_override%& set, its hosts are always used, whether or not the router supplies a host list. +Callouts are only supported on &(smtp)& transports. The port that is used is taken from the transport, if it is specified and is a remote transport. (For routers that do verification only, no transport need be @@ -29767,6 +29823,24 @@ av_scanner = mksd:2 .endd You can safely omit this option (the default value is 1). +.vitem &%sock%& +.cindex "virus scanners" "simple socket-connected" +This is a general-purpose way of talking to simple scanner daemons +running on the local machine. +There are four options: +an address (which may be an IP addres and port, or the path of a Unix socket), +a commandline to send (may include a single %s which will be replaced with +the path to the mail file to be scanned), +an RE to trigger on from the returned data, +an RE to extract malware_name from the returned data. +For example: +.code +av_scanner = sock:127.0.0.1 6001:%s:(SPAM|VIRUS):(.*)\$ +.endd +Default for the socket specifier is &_/tmp/malware.sock_&. +Default for the commandline is &_%s\n_&. +Both regular-expressions are required. + .vitem &%sophie%& .cindex "virus scanners" "Sophos and Sophie" Sophie is a daemon that uses Sophos' &%libsavi%& library to scan for viruses. @@ -34013,6 +34087,7 @@ the following table: &`R `& on &`<=`& lines: reference for local bounce &` `& on &`=>`& &`**`& and &`==`& lines: router name &`S `& size of message +&`SNI `& server name indication from TLS client hello &`ST `& shadow transport name &`T `& on &`<=`& lines: message subject (topic) &` `& on &`=>`& &`**`& and &`==`& lines: transport name @@ -34322,7 +34397,8 @@ The message that is written is &"spool file is locked"&. .next .cindex "log" "smtp confirmation" .cindex "SMTP" "logging confirmation" -&%smtp_confirmation%&: The response to the final &"."& in the SMTP dialogue for +.cindex "LMTP" "logging confirmation" +&%smtp_confirmation%&: The response to the final &"."& in the SMTP or LMTP dialogue for outgoing messages is added to delivery log lines in the form &`C=`&<&'text'&>. A number of MTAs (including Exim) return an identifying string in this response. @@ -36339,7 +36415,9 @@ disabled by setting DISABLE_DKIM=yes in Local/Makefile. Exim's DKIM implementation allows to .olist Sign outgoing messages: This function is implemented in the SMTP transport. -It can co-exist with all other Exim features, including transport filters. +It can co-exist with all other Exim features +(including transport filters) +except cutthrough delivery. .next Verify signatures in incoming messages: This is implemented by an additional ACL (acl_smtp_dkim), which can be called several times per message, with @@ -36430,6 +36508,10 @@ used. Verification of DKIM signatures in incoming email is implemented via the &%acl_smtp_dkim%& ACL. By default, this ACL is called once for each syntactically(!) correct signature in the incoming message. +A missing ACL definition defaults to accept. +If any ACL call does not acccept, the message is not accepted. +If a cutthrough delivery was in progress for the message it is +summarily dropped (having wasted the transmission effort). To evaluate the signature in the ACL a large number of expansion variables containing the signature status and its details are set up during the