X-Git-Url: https://git.exim.org/users/jgh/exim.git/blobdiff_plain/0e66b3b655cefaf20e3ce7347b45e158c3427831..5ef5dd52d1ded8b0ffdf4708e1d00e4ef458b86a:/doc/doc-txt/experimental-spec.txt diff --git a/doc/doc-txt/experimental-spec.txt b/doc/doc-txt/experimental-spec.txt index e7a0d0668..74614cd3f 100644 --- a/doc/doc-txt/experimental-spec.txt +++ b/doc/doc-txt/experimental-spec.txt @@ -448,6 +448,17 @@ spf_guess = v=spf1 a/16 mx/16 ptr ?all would relax host matching rules to a broader network range. +A lookup expansion is also available. It takes an email +address as the key and an IP address as the database: + + $lookup (username@domain} spf {ip.ip.ip.ip}} + +The lookup will return the same result strings as they can appear in +$spf_result (pass,fail,softfail,neutral,none,err_perm,err_temp). +Currently, only IPv4 addresses are supported. + + + SRS (Sender Rewriting Scheme) Support -------------------------------------------------------------- @@ -469,6 +480,7 @@ in your Local/Makefile. DCC Support -------------------------------------------------------------- +Distributed Checksum Clearinghouse; http://www.rhyolite.com/dcc/ *) Building exim @@ -623,10 +635,10 @@ exim will send these forensic emails. It's also advised that you configure a dmarc_forensic_sender because the default sender address construction might be inadequate. - control = dmarc_forensic_enable + control = dmarc_enable_forensic (AGAIN: You can choose not to send these forensic reports by simply -not putting the dmarc_forensic_enable control line at any point in +not putting the dmarc_enable_forensic control line at any point in your exim config. If you don't tell it to send them, it will not send them.) @@ -755,15 +767,16 @@ b. Configure, somewhere before the DATA ACL, the control option to deny dmarc_status = reject !authenticated = * - message = Message from $domain_used_domain failed sender's DMARC policy, REJECT + message = Message from $dmarc_used_domain failed sender's DMARC policy, REJECT -Transport post-delivery actions +Event Actions -------------------------------------------------------------- -An arbitrary per-transport string can be expanded upon various transport events -and (for SMTP transports) a second string on deferrals caused by a host error. +(Renamed from TPDA, Transport post-delivery actions) + +An arbitrary per-transport string can be expanded upon various transport events. Additionally a main-section configuration option can be expanded on some per-message events. This feature may be used, for example, to write exim internal log information @@ -771,41 +784,49 @@ This feature may be used, for example, to write exim internal log information In order to use the feature, you must compile with -EXPERIMENTAL_TPDA=yes +EXPERIMENTAL_EVENT=yes in your Local/Makefile and define one or both of -- the tpda_event_action option in the transport -- the delivery_event_action +- the event_action option in the transport +- the event_action main option to be expanded when the event fires. -A new variable, $tpda_event, is set to the event type when the +A new variable, $event_name, is set to the event type when the expansion is done. The current list of events is: - msg:complete main per message - msg:delivery transport per recipient - msg:host:defer transport per attempt - msg:fail:delivery main per recipient - msg:fail:internal main per recipient - tcp:connect transport per connection - tcp:close transport per connection - tls:cert transport per certificate in verification chain - smtp:connect transport per connection - -The expansion is called for all event types, and should use the $tpda_event -value to decide when to act. The variable data is a colon-separated -list, describing an event tree. - -There is an auxilary variable, $tpda_data, for which the + msg:complete after main per message + msg:delivery after transport per recipient + msg:rcpt:host:defer after transport per recipient per host + msg:rcpt:defer after transport per recipient + msg:host:defer after transport per attempt + msg:fail:delivery after main per recipient + msg:fail:internal after main per recipient + tcp:connect before transport per connection + tcp:close after transport per connection + tls:cert before both per certificate in verification chain + smtp:connect after transport per connection + +The expansion is called for all event types, and should use the $event_name +variable to decide when to act. The value of the variable is a colon-separated +list, defining a position in the tree of possible events; it may be used as +a list or just matched on as a whole. There will be no whitespace. + +New event types may be added in the future. + + +There is an auxilary variable, $event_data, for which the content is event_dependent: msg:delivery smtp confirmation mssage + msg:rcpt:host:defer error string + msg:rcpt:defer error string msg:host:defer error string tls:cert verification chain depth smtp:connect smtp banner -The msg:host:defer event populates one extra variable, $tpda_defer_errno. +The :defer events populate one extra variable, $event_defer_errno. The following variables are likely to be useful depending on the event type: @@ -815,12 +836,12 @@ The following variables are likely to be useful depending on the event type: tls_out_peercert lookup_dnssec_authenticated, tls_out_dane sending_ip_address, sending_port - message_exim_id + message_exim_id, verify_mode An example might look like: -tpda_event_action = ${if = {msg:delivery}{$tpda_event} \ +event_action = ${if eq {msg:delivery}{$event_name} \ {${lookup pgsql {SELECT * FROM record_Delivery( \ '${quote_pgsql:$sender_address_domain}',\ '${quote_pgsql:${lc:$sender_address_local_part}}', \ @@ -831,12 +852,19 @@ tpda_event_action = ${if = {msg:delivery}{$tpda_event} \ '${quote_pgsql:$message_exim_id}')}} \ } {}} -The string is expanded for each of the supported events and any -side-effects will happen. The result is then discarded. -Note that for complex operations an ACL expansion can be used. +The string is expanded when each of the supported events occur +and any side-effects of the expansion will happen. + +Note that for complex operations an ACL expansion can be used, +however due to the multiple contexts the Exim operates in +a) variables set in events raised from transports will not + be visible outside that transport call. +b) acl_m variables in a server context are lost on a new connection, + and after helo/ehlo/mail/starttls/rset commands -The expansion of the tpda_event_action option should normally + +The expansion of the event_action option should normally return an empty string. Should it return anything else the following will be forced: @@ -848,8 +876,13 @@ following will be forced: tls:cert refuse verification smtp:connect close connection +No other use is made of the result string. +Known issues: +- the tls:cert event is only called for the cert chain elements + received over the wire, with GnuTLS. OpenSSL gives the entire + chain including those loaded locally. Redis Lookup @@ -1078,82 +1111,39 @@ QUIT 221 mail.example.net closing connection -DSN Support --------------------------------------------------------------- - -DSN Support tries to add RFC 3461 support to Exim. It adds support for -*) the additional parameters for MAIL FROM and RCPT TO -*) RFC complient MIME DSN messages for all of - success, failure and delay notifications -*) dsn_advertise_hosts main option to select which hosts are able - to use the extension -*) dsn_lasthop router switch to end DSN processing - -In case of failure reports this means that the last three parts, the message body -intro, size info and final text, of the defined template are ignored since there is no -logical place to put them in the MIME message. -All the other changes are made without changing any defaults -Building exim: --------------- - -Define -EXPERIMENTAL_DSN=YES -in your Local/Makefile. - -Configuration: --------------- -All DSNs are sent in MIME format if you built exim with EXPERIMENTAL_DSN=YES -No option needed to activate it, and no way to turn it off. - -Failure and delay DSNs are triggered as usual except a sender used NOTIFY=... -to prevent them. - -Support for Success DSNs is added and activated by NOTIFY=SUCCESS by clients. - -Add -dsn_advertise_hosts = * -or a more restrictive host_list to announce DSN in EHLO answers - -Those hosts can then use NOTIFY,ENVID,RET,ORCPT options. - -If a message is relayed to a DSN aware host without changing the envelope -recipient the options are passed along and no success DSN is generated. - -A redirect router will always trigger a success DSN if requested and the DSN -options are not passed any further. - -A success DSN always contains the recipient address as submitted by the -client as required by RFC. Rewritten addresses are never exposed. +SOCKS +------------------------------------------------------------ +Support for proxying outbound SMTP via a Socks 5 proxy +(RFC 1928) is included if Exim is compiled with +EXPERIMENTAL_SOCKS defined. -If you used DSN patch up to 1.3 before remove all "dsn_process" switches from -your routers since you don't need them anymore. There is no way to "gag" -success DSNs anymore. Announcing DSN means answering as requested. +If an smtp transport has a nonempty socks_proxy option +defined, this is active. The option is expanded and +should be a list (colon-separated by default) of +proxy specifiers. Each proxy specifier is a list +(space-separated by default) where the initial element +is an IP address and any subsequent elements are options. -You can prevent Exim from passing DSN options along to other DSN aware hosts by defining -dsn_lasthop -in a router. Exim will then send the success DSN himself if requested as if -the next hop does not support DSN. -Adding it to a redirect router makes no difference. +Options are a string =. +These options are currently defined: +- "auth", with possible values "none" and "name". + Using "name" selects username/password authentication + per RFC 1929. Default is "none". +- "name" sets the authentication username. Default is empty. +- "pass" sets the authentication password. Default is empty. +- "port" sets the tcp port number for the proxy. Default is 1080. +- "tmo" sets a connection timeout in seconds for this proxy. Default is 5. +Proxies from the list are tried in order until +one responds. The timeout for the overall connection +applies to the set of proxied attempts. -Certificate name checking --------------------------------------------------------------- -The X509 certificates used for TLS are supposed be verified -that they are owned by the expected host. The coding of TLS -support to date has not made these checks. +If events are used, the remote IP/port during a +tcp:connect event will be that of the proxy. -If built with EXPERIMENTAL_CERTNAMES defined, code is -included to do so, and a new smtp transport option -"tls_verify_cert_hostname" supported which takes a list of -names for which the checks must be made. The host must -also be in "tls_verify_hosts". -Both Subject and Subject-Alternate-Name certificate fields -are supported, as are wildcard certificates (limited to -a single wildcard being the initial component of a 3-or-more -component FQDN). DANE @@ -1277,12 +1267,13 @@ MX, A and TLSA records. A TLSA lookup will be done if either of the above options match and the host-lookup succeded using dnssec. -If the TLSA lookup succeeds, a TLS connection will be required -for the host. +If a TLSA lookup is done and succeeds, a DANE-verified TLS connection +will be required for the host. (TODO: specify when fallback happens vs. when the host is not used) -If dane is in use the following transport options are ignored: +If DANE is requested and useable (see above) the following transport +options are ignored: hosts_require_tls tls_verify_hosts tls_try_verify_hosts @@ -1290,6 +1281,10 @@ If dane is in use the following transport options are ignored: tls_crl tls_verify_cert_hostnames +If DANE is not usable, whether requested or not, and CA-anchored +verification evaluation is wanted, the above variables should be set +appropriately. + Currently dnssec_request_domains must be active (need to think about that) and dnssec_require_domains is ignored. @@ -1298,10 +1293,151 @@ in the delivery log line will show as "CV=dane". There is a new variable $tls_out_dane which will have "yes" if verification succeeded using DANE and "no" otherwise (only useful -in combination with EXPERIMENTAL_TPDA), and a new variable +in combination with EXPERIMENTAL_EVENT), and a new variable $tls_out_tlsa_usage (detailed above). + +INTERNATIONAL +------------------------------------------------------------ +SMTPUTF8 +Internationalised mail name handling. +RFCs 6530, 6533, 5890 + +Compile with EXPERIMENTAL_INTERNATIONAL and libidn. + +New main config option smtputf8_advertise_hosts, default '*', +a host list. If this matches the sending host and +accept_8bitmime is true (the default) then the ESMTP option +SMTPUTF8 will be advertised. + +If the sender specifies the SMTPUTF8 option on a MAIL command +international handling for the message is enabled and +the expansion variable $message_smtputf8 will have value TRUE. + +The option allow_utf8_domains is set to true for this +message. All DNS lookups are converted to a-label form +whatever the setting of allow_utf8_domains. + +Both localparts and domain are maintained as the original +utf8 form internally; any matching or regex use will +require appropriate care. Filenames created, eg. by +the appendfile transport, will have utf8 name. + +Helo names sent by the smtp transport will have any utf8 +components expanded to a-label form. + +Any certificate name checks will be done using the a-label +form of the name. + +Log lines and Received-by: header lines will aquire a "utf8" +prefix on the protocol element, eg. utf8esmtp. + +New expansion operators: + ${utf8_domain_to_alabel:str} + ${utf8_domain_from_alabel:str} + ${utf8_localpart_to_alabel:str} + ${utf8_localpart_from_alabel:str} + +New "control = utf8_downconvert" ACL modifier, +sets a flag requiring that addresses are converted to +a-label form before smtp delivery, for use in a +Message Submission Agent context. Can also be +phrased as "control = utf8_downconvert/1" and is +mandatory. The flag defaults to zero and can be cleared +by "control = utf8_downconvert/0". The value "-1" +may also be used, to use a-label for only if the +destination host does not support SMTPUTF8. + +If mua_wrapper is set, the utf8_downconvert control +defaults to -1 (convert if needed). + + +There is no explicit support for VRFY and EXPN. +Configurations supporting these should inspect +$smtp_command_argument for an SMTPUTF8 argument. + +There is no support for LMTP on Unix sockets. +Using the "lmtp" protocol option on an smtp transport, +for LMTP over TCP, should work as expected. + +Known issues: + - DSN unitext handling is not present + - no provision for converting logging from or to UTF-8 + +---- +IMAP folder names + +New expansion operator: + +${imapfolder {} {} {}} + +The string is converted from the charset specified by the headers charset +command (in a filter file) or headers_charset global option, to the +modified UTF-7 encoding specified by RFC 2060, with the following +exception: All occurences of (which has to be a single character) +are replaced with periods ("."), and all periods and slashes that aren't + and are not in the string are BASE64 encoded. + +The third argument can be omitted, defaulting to an empty string. +The second argument can be omitted, defaulting to "/". + +This is the encoding used by Courier for Maildir names on disk, and followed +by many other IMAP servers. + + Example 1: ${imapfolder {Foo/Bar}} yields "Foo.Bar". + Example 2: ${imapfolder {Foo/Bar}{.}{/}} yields "Foo&AC8-Bar". + Example 3: ${imapfolder {Räksmörgås}} yields "R&AOQ-ksm&APY-rg&AOU-s". + +Note that the source charset setting is vital, and also that characters +must be representable in UTF-16. + + + +DSN extra information +--------------------- +If compiled with EXPERIMENTAL_DSN_INFO extra information will be added +to DSN fail messages ("bounces"), when available. The intent is to aid +tracing of specific failing messages, when presented with a "bounce" +complaint and needing to search logs. + + +The remote MTA IP address, with port number if nonstandard. +Example: + Remote-MTA: X-ip; [127.0.0.1]:587 +Rationale: + Several addresses may correspond to the (already available) + dns name for the remote MTA. + +The remote MTA connect-time greeting. +Example: + X-Remote-MTA-smtp-greeting: X-str; 220 the.local.host.name ESMTP Exim x.yz Tue, 2 Mar 1999 09:44:33 +0000 +Rationale: + This string sometimes presents the remote MTA's idea of its + own name, and sometimes identifies the MTA software. + +The remote MTA response to HELO or EHLO. +Example: + X-Remote-MTA-helo-response: X-str; 250-the.local.host.name Hello localhost [127.0.0.1] +Limitations: + Only the first line of a multiline response is recorded. +Rationale: + This string sometimes presents the remote MTA's view of + the peer IP connecting to it. + +The reporting MTA detailed diagnostic. +Example: + X-Exim-Diagnostic: X-str; SMTP error from remote mail server after RCPT TO:: 550 hard error +Rationale: + This string somtimes give extra information over the + existing (already available) Diagnostic-Code field. + + +Note that non-RFC-documented field names and data types are used. + + + + -------------------------------------------------------------- End of file --------------------------------------------------------------