X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/578d43dc0a9276f18323ddc00ebc16679279f3c8..e8793bad207763b266bedcb9d859e238b6a3a04e:/doc/doc-docbook/spec.xfpt diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index 88308ba23..ae4d75ecb 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -52,7 +52,7 @@ .set I "    " .macro copyyear -2013 +2014 .endmacro . ///////////////////////////////////////////////////////////////////////////// @@ -10171,6 +10171,14 @@ 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 @@ -11978,7 +11986,7 @@ 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 +13198,10 @@ 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 +13822,17 @@ 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 +13863,6 @@ 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 +23027,14 @@ 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" +For OpenSSL only, 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 +23049,20 @@ 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, or when GnuTLS is used, +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" +For OpenSSL only, 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 +25964,12 @@ 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 @@ -27295,6 +27332,9 @@ after the ACL completes. Note that routers are used in verify mode. Note also that headers cannot be modified by any of the post-data ACLs (DATA, MIME and DKIM). +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. @@ -27305,7 +27345,6 @@ 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'&> @@ -27980,6 +28019,23 @@ 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" @@ -28591,6 +28647,13 @@ 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" @@ -29775,6 +29838,24 @@ 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. @@ -34021,6 +34102,7 @@ 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 @@ -34330,7 +34412,8 @@ 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. @@ -36347,7 +36430,9 @@ 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 @@ -36438,6 +36523,10 @@ 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