X-Git-Url: https://git.exim.org/users/heiko/exim.git/blobdiff_plain/51a0ece14d610b73162eb330bef9c92fb5ce40aa..f3d11401d1cf97be77dbaa3246e06d07809f48b5:/doc/doc-txt/NewStuff?ds=inline diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff index 0496b39c5..76947300e 100644 --- a/doc/doc-txt/NewStuff +++ b/doc/doc-txt/NewStuff @@ -1,803 +1,993 @@ -$Cambridge: exim/doc/doc-txt/NewStuff,v 1.17 2004/11/24 16:36:19 ph10 Exp $ - New Features in Exim -------------------- -This file contains descriptions of new features that have been added to Exim, -but have not yet made it into the main manual (which is most conveniently -updated when there is a relatively large batch of changes). The doc/ChangeLog -file contains a listing of all changes, including bug fixes. +This file contains descriptions of new features that have been added to Exim. +Before a formal release, there may be quite a lot of detail so that people can +test from the snapshots or the CVS before the documentation is updated. Once +the documentation is updated, this file is reduced to a short list. + +Version 4.85 +------------ + + 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the + DANE smtp draft to assess a secure chain of trust of the certificate + used to establish the TLS connection based on a TLSA record in the + domain of the sender. + + 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT + and several new events have been created. The reason is because it has + been expanded beyond just firing events during the transport phase. Any + existing TPDA transport options will have to be rewritten to use a new + $event_name expansion variable in a condition. Refer to the + experimental-spec.txt for details and examples. + + 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that + server certs used for TLS match the result of the MX lookup. It does + not use the same mechanism as DANE. + + +Version 4.84 +------------ + + +Version 4.83 +------------ + + 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be + configured to expect an initial header from a proxy that will make the + actual external source IP:host be used in exim instead of the IP of the + proxy that is connecting to it. + + 2. New verify option header_names_ascii, which will check to make sure + there are no non-ASCII characters in header names. Exim itself handles + those non-ASCII characters, but downstream apps may not, so Exim can + detect and reject if those characters are present. + + 3. New expansion operator ${utf8clean:string} to replace malformed UTF8 + codepoints with valid ones. + + 4. New malware type "sock". Talks over a Unix or TCP socket, sending one + command line and matching a regex against the return data for trigger + and a second regex to extract malware_name. The mail spoolfile name can + be included in the command line. + + 5. The smtp transport now supports options "tls_verify_hosts" and + "tls_try_verify_hosts". If either is set the certificate verification + is split from the encryption operation. The default remains that a failed + verification cancels the encryption. + 6. New SERVERS override of default ldap server list. In the ACLs, an ldap + lookup can now set a list of servers to use that is different from the + default list. -Version 4.44 + 7. New command-line option -C for exiqgrep to specify alternate exim.conf + file when searching the queue. + + 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that. + + 9. Support for DNSSEC on outbound connections. + +10. New variables "tls_(in,out)_(our,peer)cert" and expansion item + "certextract" to extract fields from them. Hash operators md5 and sha1 + work over them for generating fingerprints, and a new sha256 operator + for them added. + +11. PRDR is now supported dy default. + +12. OCSP stapling is now supported by default. + +13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output + Delivery Status Notification messages in MIME format, and negociate + DSN features per RFC 3461. + + +Version 4.82 ------------ - 1. There is a new build-time option called CONFIGURE_GROUP which works like - CONFIGURE_OWNER. It specifies one additional group that is permitted for - the runtime configuration file when the group write permission is set. + 1. New command-line option -bI:sieve will list all supported sieve extensions + of this Exim build on standard output, one per line. + ManageSieve (RFC 5804) providers managing scripts for use by Exim should + query this to establish the correct list to include in the protocol's + SIEVE capability line. + + 2. If the -n option is combined with the -bP option, then the name of an + emitted option is not output, only the value (if visible to you). + For instance, "exim -n -bP pid_file_path" should just emit a pathname + followed by a newline, and no other text. + + 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now + has a "tls_dh_min_bits" option, to set the minimum acceptable number of + bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites) + acceptable for security. (Option accepted but ignored if using OpenSSL). + Defaults to 1024, the old value. May be lowered only to 512, or raised as + far as you like. Raising this may hinder TLS interoperability with other + sites and is not currently recommended. Lowering this will permit you to + establish a TLS session which is not as secure as you might like. + + Unless you really know what you are doing, leave it alone. + + 4. If not built with DISABLE_DNSSEC, Exim now has the main option + dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library + to send the DO flag to your recursive resolver. If you have a recursive + resolver, which can set the Authenticated Data (AD) flag in results, Exim + can now detect this. Exim does not perform validation itself, instead + relying upon a trusted path to the resolver. + + Current status: work-in-progress; $sender_host_dnssec variable added. + + 5. DSCP support for outbound connections: on a transport using the smtp driver, + set "dscp = ef", for instance, to cause the connections to have the relevant + DSCP (IPv4 TOS or IPv6 TCLASS) value in the header. + + Similarly for inbound connections, there is a new control modifier, dscp, + so "warn control = dscp/ef" in the connect ACL, or after authentication. + + Supported values depend upon system libraries. "exim -bI:dscp" to list the + ones Exim knows of. You can also set a raw number 0..0x3F. + + 6. The -G command-line flag is no longer ignored; it is now equivalent to an + ACL setting "control = suppress_local_fixups". The -L command-line flag + is now accepted and forces use of syslog, with the provided tag as the + process name. A few other flags used by Sendmail are now accepted and + ignored. + + 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery" + ACL modifier; works for single-recipient mails which are recieved on and + deliverable via SMTP. Using the connection made for a recipient verify, + if requested before the verify, or a new one made for the purpose while + the inbound connection is still active. The bulk of the mail item is copied + direct from the inbound socket to the outbound (as well as the spool file). + When the source notifies the end of data, the data acceptance by the destination + is negociated before the acceptance is sent to the source. If the destination + does not accept the mail item, for example due to content-scanning, the item + is not accepted from the source and therefore there is no need to generate + a bounce mail. This is of benefit when providing a secondary-MX service. + The downside is that delays are under the control of the ultimate destination + system not your own. + + The Recieved-by: header on items delivered by cutthrough is generated + early in reception rather than at the end; this will affect any timestamp + included. The log line showing delivery is recorded before that showing + reception; it uses a new ">>" tag instead of "=>". + + To support the feature, verify-callout connections can now use ESMTP and TLS. + The usual smtp transport options are honoured, plus a (new, default everything) + hosts_verify_avoid_tls. + + New variable families named tls_in_cipher, tls_out_cipher etc. are introduced + for specific access to the information for each connection. The old names + are present for now but deprecated. + + Not yet supported: IGNOREQUOTA, SIZE, PIPELINING. + + 8. New expansion operators ${listnamed:name} to get the content of a named list + and ${listcount:string} to count the items in a list. + + 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS + rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11 + modules. For some situations this is desirable, but we expect admin in + those situations to know they want the feature. More commonly, it means + that GUI user modules get loaded and are broken by the setuid Exim being + unable to access files specified in environment variables and passed + through, thus breakage. So we explicitly inhibit the PKCS11 initialisation + unless this new option is set. + + Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability, + so have also added a build option which can be used to build Exim with GnuTLS + but without trying to use any kind of PKCS11 support. Uncomment this in the + Local/Makefile: + + AVOID_GNUTLS_PKCS11=yes + +10. The "acl = name" condition on an ACL now supports optional arguments. + New expansion item "${acl {name}{arg}...}" and expansion condition + "acl {{name}{arg}...}" are added. In all cases up to nine arguments + can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL. + Variable $acl_narg contains the number of arguments. If the ACL sets + a "message =" value this becomes the result of the expansion item, + or the value of $value for the expansion condition. If the ACL returns + accept the expansion condition is true; if reject, false. A defer + return results in a forced fail. + +11. Routers and transports can now have multiple headers_add and headers_remove + option lines. The concatenated list is used. + +12. New ACL modifier "remove_header" can remove headers before message gets + handled by routers/transports. + +13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured), + "aaaa" and "a" lookups is done and the full set of results returned. + +14. New expansion variable $headers_added with content from ACL add_header + modifier (but not yet added to messsage). - 2. The "control=submission" facility has a new option /sender_retain. This - has the effect of setting local_sender_retain true and local_from_check - false for the incoming message in which it is encountered. +15. New 8bitmime status logging option for received messages. Log field "M8S". - 3. $recipients is now available in the predata ACL (oversight). +16. New authenticated_sender logging option, adding to log field "A". - 4. The value of address_data from a sender verification is now available in - $sender_address_data in subsequent conditions in the ACL statement. Note: - this is just like $address_data. The value does not persist after the end - of the current ACL statement. If you want to preserve it, you can use one - of the ACL variables. +17. New expansion variables $router_name and $transport_name. Useful + particularly for debug_print as -bt commandline option does not + require privilege whereas -d does. - 5. The redirect router has two new options: forbid_sieve_filter and - forbid_exim_filter. When filtering is enabled by allow_filter, these - options control which type(s) of filtering are permitted. By default, both - Exim and Sieve filters are allowed. +18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a + proposed extension to SMTP from Eric Hall. - 6. A new option for callouts makes it possible to set a different (usually - smaller) timeout for making the SMTP connection. The keyword is "connect". - For example: +19. The pipe transport has gained the force_command option, to allow + decorating commands from user .forward pipe aliases with prefix + wrappers, for instance. + +20. Callout connections can now AUTH; the same controls as normal delivery + connections apply. - verify = sender/callout=5s,connect=1s +21. Support for DMARC, using opendmarc libs, can be enabled. It adds new + options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file. + It adds new expansion variables $dmarc_ar_header, $dmarc_status, + $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier + dmarc_status. It adds new control flags dmarc_disable_verify and + dmarc_enable_forensic. + +22. Add expansion variable $authenticated_fail_id, which is the username + provided to the authentication method which failed. It is available + for use in subsequent ACL processing (typically quit or notquit ACLs). - If not specified, it defaults to the general timeout value. +23. New ACL modifer "udpsend" can construct a UDP packet to send to a given + UDP host and port. - 7. The new variables $sender_verify_failure and $recipient_verify_failure - contain information about exactly what failed. In an ACL, after one of - these failures, the relevant variable contains one of the following words: +24. New ${hexquote:..string..} expansion operator converts non-printable + characters in the string to \xNN form. - qualify the address was unqualified (no domain), and the message - was neither local nor came from an exempted host; +25. Experimental TPDA (Transport Post Delivery Action) function added. + Patch provided by Axel Rau. - route routing failed; +26. Experimental Redis lookup added. Patch provided by Warren Baker. - mail routing succeeded, and a callout was attempted; rejection - occurred at or before the MAIL command (that is, on initial - connection, HELO, or MAIL); - recipient the RCPT command in a callout was rejected; +Version 4.80 +------------ - postmaster the postmaster check in a callout was rejected. + 1. New authenticator driver, "gsasl". Server-only (at present). + This is a SASL interface, licensed under GPL, which can be found at + http://www.gnu.org/software/gsasl/. + This system does not provide sources of data for authentication, so + careful use needs to be made of the conditions in Exim. - The main use of these variables is expected to be to distinguish between - rejections of MAIL and rejections of RCPT. + 2. New authenticator driver, "heimdal_gssapi". Server-only. + A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME + is no longer honoured for setuid programs by Heimdal. Use the + "server_keytab" option to point to the keytab. - 8. The command line option -dd behaves exactly like -d except when used on a - command that starts a daemon process. In that case, debugging is turned off - for the subprocesses that the daemon creates. Thus, it is useful for - monitoring the behaviour of the daemon without creating as much output as - full debugging. + 3. The "pkg-config" system can now be used when building Exim to reference + cflags and library information for lookups and authenticators, rather + than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and + "LOOKUP_LIBS" directly. Similarly for handling the TLS library support + without adjusting "TLS_INCLUDE" and "TLS_LIBS". - 9. $host_address is now set to the target address during the checking of - ignore_target_hosts. + In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to + find the headers and libraries for PCRE. -10. There are four new variables called $spool_space, $log_space, - $spool_inodes, and $log_inodes. The first two contain the amount of free - space in the disk partitions where Exim has its spool directory and log - directory, respectively. (When these are in the same partition, the values - will, of course, be the same.) The second two variables contain the numbers - of free inodes in the respective partitions. + 4. New expansion variable $tls_bits. - NOTE: Because disks can nowadays be very large, the values in the space - variables are in kilobytes rather than in bytes. Thus, for example, to - check in an ACL that there is at least 50M free on the spool, you would - write: + 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will + be joined together with ASCII NUL characters to construct the key to pass + into the DBM library. Can be used with gsasl to access sasldb2 files as + used by Cyrus SASL. - condition = ${if > {$spool_space}{50000}{yes}{no}} + 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1. - The values are recalculated whenever any of these variables is referenced. - If the relevant file system does not have the concept of inodes, the value - of those variables is -1. If the operating system does not have the ability - to find the amount of free space (only true for experimental systems), the - space value is -1. + Avoid release 1.0.1a if you can. Note that the default value of + "openssl_options" is no longer "+dont_insert_empty_fragments", as that + increased susceptibility to attack. This may still have interoperability + implications for very old clients (see version 4.31 change 37) but + administrators can choose to make the trade-off themselves and restore + compatibility at the cost of session security. -11. It is now permitted to omit both strings after an "if" condition; if the - condition is true, the result is the string "true". As before, when the - second string is omitted, a false condition yields an empty string. This - makes it less cumbersome to write custom ACL and router conditions. For - example, instead of + 7. Use of the new expansion variable $tls_sni in the main configuration option + tls_certificate will cause Exim to re-expand the option, if the client + sends the TLS Server Name Indication extension, to permit choosing a + different certificate; tls_privatekey will also be re-expanded. You must + still set these options to expand to valid files when $tls_sni is not set. - condition = ${if eq {$acl_m4}{1}{yes}{no}} + The SMTP Transport has gained the option tls_sni, which will set a hostname + for outbound TLS sessions, and set $tls_sni too. - or the shorter form + A new log_selector, +tls_sni, has been added, to log received SNI values + for Exim as a server. - condition = ${if eq {$acl_m4}{1}{yes}} + 8. The existing "accept_8bitmime" option now defaults to true. This means + that Exim is deliberately not strictly RFC compliant. We're following + Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default. + Those who disagree, or know that they are talking to mail servers that, + even today, are not 8-bit clean, need to turn off this option. - (because the second string has always defaulted to ""), you can now write + 9. Exim can now be started with -bw (with an optional timeout, given as + -bw). With this, stdin at startup is a socket that is + already listening for connections. This has a more modern name of + "socket activation", but forcing the activated socket to fd 0. We're + interested in adding more support for modern variants. - condition = ${if eq {$acl_m4}{1}} +10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix + for numbers indicates multiplication by 1024^3. - Previously this was a syntax error. +11. The GnuTLS support has been revamped; the three options gnutls_require_kx, + gnutls_require_mac & gnutls_require_protocols are no longer supported. + tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority + string, documentation for which is at: + http://www.gnutls.org/manual/html_node/Priority-Strings.html -12. There is a new "record type" that can be specified in dnsdb lookups. It - is "zns" (for "zone NS"). It performs a lookup for NS records on the given - domain, but if none are found, it removes the first component of the domain - name, and tries again. This process continues until NS records are found - or there are no more components left (or there's a DNS error). In other - words, it may return the name servers for a top-level domain, but it never - returns the root name servers. If there are no NS records for the top-level - domain, the lookup fails. + SNI support has been added to Exim's GnuTLS integration too. - For example, ${lookup dnsdb{zns=xxx.quercite.com}} returns the name - servers for quercite.com, whereas ${lookup dnsdb{zns=xxx.edu}} returns - the name servers for edu, assuming in each case that there are no NS - records for the full domain name. + For sufficiently recent GnuTLS libraries, ${randint:..} will now use + gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness. - You should be careful about how you use this lookup because, unless the - top-level domain does not exist, the lookup will always return some host - names. The sort of use to which this might be put is for seeing if the name - servers for a given domain are on a blacklist. You can probably assume that - the name servers for the high-level domains such as .com or .co.uk are not - going to be on such a list. +12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file + is now available. If the contents of the file are valid, then Exim will + send that back in response to a TLS status request; this is OCSP Stapling. + Exim will not maintain the contents of the file in any way: administrators + are responsible for ensuring that it is up-to-date. -13. Another new "record type" is "mxh"; this looks up MX records just as "mx" - does, but it returns only the names of the hosts, omitting the priority - values. + See "experimental-spec.txt" for more details. -14. It is now possible to specify a list of domains or IP addresses to be - looked up in a dnsdb lookup. The list is specified in the normal Exim way, - with colon as the default separator, but with the ability to change this. - For example: +13. ${lookup dnsdb{ }} supports now SPF record types. They are handled + identically to TXT record lookups. - ${lookup dnsdb{one.domain.com:two.domain.com}} - ${lookup dnsdb{a=one.host.com:two.host.com}} - ${lookup dnsdb{ptr = <; 1.2.3.4 ; 4.5.6.8}} +14. New expansion variable $tod_epoch_l for higher-precision time. - In order to retain backwards compatibility, there is one special case: if - the lookup type is PTR and no change of separator is specified, Exim looks - to see if the rest of the string is precisely one IPv6 address. In this - case, it does not treat it as a list. +15. New global option tls_dh_max_bits, defaulting to current value of NSS + hard-coded limit of DH ephemeral bits, to fix interop problems caused by + GnuTLS 2.12 library recommending a bit count higher than NSS supports. - The data from each lookup is concatenated, with newline separators (by - default - see 14 below), in the same way that multiple DNS records for a - single item are handled. +16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier. + Option can now be a path or an identifier for a standard prime. + If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23". + Set to "historic" to get the old GnuTLS behaviour of auto-generated DH + primes. - The lookup fails only if all the DNS lookups fail. As long as at least one - of them yields some data, the lookup succeeds. However, if there is a - temporary DNS error for any of them, the lookup defers. +17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS). + Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL + install was not built with OPENSSL_NO_SSL2 ("no-ssl2"). -15. It is now possible to specify the character to be used as a separator when - a dnsdb lookup returns data from more than one DNS record. The default is a - newline. To specify a different character, put '>' followed by the new - character at the start of the query. For example: - ${lookup dnsdb{>: a=h1.test.ex:h2.test.ex}} - ${lookup dnsdb{>| mxh=<;m1.test.ex;m2.test.ex}} +Version 4.77 +------------ + + 1. New options for the ratelimit ACL condition: /count= and /unique=. + The /noupdate option has been replaced by a /readonly option. + + 2. The SMTP transport's protocol option may now be set to "smtps", to + use SSL-on-connect outbound. + + 3. New variable $av_failed, set true if the AV scanner deferred; ie, when + there is a problem talking to the AV scanner, or the AV scanner running. - It is permitted to specify a space as the separator character. Note that - more than one DNS record can be found for a single lookup item; this - feature is relevant even when you do not specify a list. + 4. New expansion conditions, "inlist" and "inlisti", which take simple lists + and check if the search item is a member of the list. This does not + support named lists, but does subject the list part to string expansion. - The same effect could be achieved by wrapping the lookup in ${tr...}; this - feature is just a syntactic simplification. + 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was + built, Exim no longer performs string expansion on the second string of + the match_* expansion conditions: "match_address", "match_domain", + "match_ip" & "match_local_part". Named lists can still be used. -16. It is now possible to supply a list of domains and/or IP addresses to be - lookup up in a DNS blacklist. Previously, only a single domain name could - be given, for example: - dnslists = black.list.tld/$sender_host_name +Version 4.76 +------------ + + 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on + or off in the resolver library. - What follows the slash can now be a list. As with all lists, the default - separator is a colon. However, because this is a sublist within the list of - DNS blacklist domains, it is necessary either to double the separators like - this: - dnslists = black.list.tld/name.1::name.2 +Version 4.75 +------------ + + 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there + is now LDAP/TLS support, given sufficiently modern OpenLDAP client + libraries. The following global options have been added in support of + this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key, + ldap_cipher_suite, ldap_require_cert, ldap_start_tls. - or to change the separator character, like this: + 2. The pipe transport now takes a boolean option, "freeze_signal", default + false. When true, if the external delivery command exits on a signal then + Exim will freeze the message in the queue, instead of generating a bounce. - dnslists = black.list.tld/<;name.1;name.2 + 3. Log filenames may now use %M as an escape, instead of %D (still available). + The %M pattern expands to yyyymm, providing month-level resolution. - If an item in the list is an IP address, it is inverted before the DNS - blacklist domain is appended. If it is not an IP address, no inversion - occurs. Consider this condition: + 4. The $message_linecount variable is now updated for the maildir_tag option, + in the same way as $message_size, to reflect the real number of lines, + including any header additions or removals from transport. - dnslists = black.list.tls/<;192.168.1.2;a.domain + 5. When contacting a pool of SpamAssassin servers configured in spamd_address, + Exim now selects entries randomly, to better scale in a cluster setup. - The DNS lookups that occur are for - 2.1.168.192.black.list.tld and a.domain.black.list.tld +Version 4.74 +------------ - Once a DNS record has been found (that matches a specific IP return - address, if specified), no further lookups are done. + 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux) + the flaw permitted the Exim run-time user to cause root to append to + arbitrary files of the attacker's choosing, with the content based + on content supplied by the attacker. -17. The log selector queue_time_overall causes Exim to output the time spent on - the queue as an addition to the "Completed" message. Like queue_time (which - puts the queue time on individual delivery lines), the time is tagged with - "QT=", and it is measured from the time that the message starts to be - received, so it includes the reception time. + 2. Exim now supports loading some lookup types at run-time, using your + platform's dlopen() functionality. This has limited platform support + and the intention is not to support every variant, it's limited to + dlopen(). This permits the main Exim binary to not be linked against + all the libraries needed for all the lookup types. -Version 4.43 +Version 4.73 ------------ - 1. There is a new Boolean global option called mua_wrapper, defaulting false. - This causes Exim to run an a restricted mode, in order to provide a very - specific service. - - Background: On a personal computer, it is a common requirement for all - email to be sent to a smarthost. There are plenty of MUAs that can be - configured to operate that way, for all the popular operating systems. - However, there are MUAs for Unix-like systems that cannot be so configured: - they submit messages using the command line interface of - /usr/sbin/sendmail. In addition, utility programs such as cron submit - messages this way. - - Requirement: The requirement is for something that can provide the - /usr/sbin/sendmail interface and deliver messages to a smarthost, but not - provide any queueing or retrying facilities. Furthermore, the delivery to - the smarthost should be synchronous, so that if it fails, the sending MUA - is immediately informed. In other words, we want something that in effect - converts a command-line MUA into a TCP/SMTP MUA. - - Solutions: There are a number of applications (for example, ssmtp) that do - this job. However, people have found them to be lacking in various ways. - For instance, some sites want to allow aliasing and forwarding before - sending to the smarthost. - - Using Exim: Exim already had the necessary infrastructure for doing this - job. Just a few tweaks were needed to make it behave as required, though it - is somewhat of an overkill to use a fully-featured MTA for this purpose. - - Setting mua_wrapper=true causes Exim to run in a special mode where it - assumes that it is being used to "wrap" a command-line MUA in the manner - just described. - - If you set mua_wrapper=true, you also need to provide a compatible router - and transport configuration. Typically there will be just one router and - one transport, sending everything to a smarthost. - - When run in MUA wrapping mode, the behaviour of Exim changes in the - following ways: - - (a) A daemon cannot be run, nor will Exim accept incoming messages from - inetd. In other words, the only way to submit messages is via the - command line. - - (b) Each message is synchonously delivered as soon as it is received (-odi - is assumed). All queueing options (queue_only, queue_smtp_domains, - control=queue, control=freeze in an ACL etc.) are quietly ignored. The - Exim reception process does not finish until the delivery attempt is - complete. If the delivery was successful, a zero return code is given. - - (c) Address redirection is permitted, but the final routing for all - addresses must be to the same remote transport, and to the same list of - hosts. Furthermore, the return_address must be the same for all - recipients, as must any added or deleted header lines. In other words, - it must be possible to deliver the message in a single SMTP - transaction, however many recipients there are. - - (d) If the conditions in (c) are not met, or if routing any address results - in a failure or defer status, or if Exim is unable to deliver all the - recipients successfully to one of the hosts immediately, delivery of - the entire message fails. - - (e) Because no queueing is allowed, all failures are treated as permanent; - there is no distinction between 4xx and 5xx SMTP response codes from - the smarthost. Furthermore, because only a single yes/no response can - be given to the caller, it is not possible to deliver to some - recipients and not others. If there is an error (temporary or - permanent) for any recipient, all are failed. - - (f) If more than one host is listed, Exim will try another host after a - connection failure or a timeout, in the normal way. However, if this - kind of failure happens for all the hosts, the delivery fails. - - (g) When delivery fails, an error message is written to the standard error - stream (as well as to Exim's log), and Exim exits to the caller with a - return code value 1. The message is expunged from Exim's spool files. - No bounce messages are ever generated. - - (h) No retry data is maintained, and any retry rules are ignored. - - (i) A number of Exim options are overridden: deliver_drop_privilege is - forced true, max_rcpt in the smtp transport is forced to "unlimited", - remote_max_parallel is forced to one, and fallback hosts are ignored. - - The overall effect is that Exim makes a single synchronous attempt to - deliver the message, failing if there is any kind of problem. Because no - local deliveries are done and no daemon can be run, Exim does not need root - privilege. It should be possible to run it setuid=exim instead of - setuid=root. See section 48.3 in the 4.40 manual for a general discussion - about the advantages and disadvantages of running without root privilege. - - 2. There have been problems with DNS servers when SRV records are looked up. - Some mis-behaving servers return a DNS error or timeout when a non-existent - SRV record is sought. Similar problems have in the past been reported for - MX records. The global dns_again_means_nonexist option can help with this - problem, but it is heavy-handed because it is a global option. There are - now two new options for the dnslookup router. They are called - srv_fail_domains and mx_fail_domains. In each case, the value is a domain - list. If an attempt to look up an SRV or MX record results in a DNS failure - or "try again" response, and the domain matches the relevant list, Exim - behaves as if the DNS had responded "no such record". In the case of an SRV - lookup, this means that the router proceeds to look for MX records; in the - case of an MX lookup, it proceeds to look for A or AAAA records, unless the - domain matches mx_domains. - - 3. The following functions are now available in the local_scan() API: - - (a) void header_remove(int occurrence, uschar *name) - - This function removes header lines. If "occurrence" is zero or negative, - all occurrences of the header are removed. If occurrence is greater - than zero, that particular instance of the header is removed. If no - header(s) can be found that match the specification, the function does - nothing. - - (b) BOOL header_testname(header_line *hdr, uschar *name, int length, - BOOL notdel) - - This function tests whether the given header has the given name. It - is not just a string comparison, because whitespace is permitted - between the name and the colon. If the "notdel" argument is TRUE, a - FALSE return is forced for all "deleted" headers; otherwise they are - not treated specially. For example: - - if (header_testname(h, US"X-Spam", 6, TRUE)) ... - - (c) void header_add_at_position(BOOL after, uschar *name, BOOL topnot, - int type, char *format, ...) - - This function adds a new header line at a specified point in the header - chain. If "name" is NULL, the new header is added at the end of the - chain if "after" is TRUE, or at the start if "after" is FALSE. If - "name" is not NULL, the headers are searched for the first non-deleted - header that matches the name. If one is found, the new header is added - before it if "after" is FALSE. If "after" is true, the new header is - added after the found header and any adjacent subsequent ones with the - same name (even if marked "deleted"). If no matching non-deleted header - is found, the "topnot" option controls where the header is added. If it - is TRUE, addition is at the top; otherwise at the bottom. Thus, to add - a header after all the Received: headers, or at the top if there are no - Received: headers, you could use - - header_add_at_position(TRUE, US"Received", TRUE, ' ', "X-xxx: ..."); - - Normally, there is always at least one non-deleted Received: header, - but there may not be if received_header_text expands to an empty - string. - - (d) BOOL receive_remove_recipient(uschar *recipient) - - This is a convenience function to remove a named recipient from the - list of recipients. It returns TRUE if a recipient was removed, and - FALSE if no matching recipient could be found. The argument must be a - complete email address. - - 4. When an ACL "warn" statement adds one or more header lines to a message, - they are added at the end of the existing header lines by default. It is - now possible to specify that any particular header line should be added - right at the start (before all the Received: lines) or immediately after - the first block of Received: lines in the message. This is done by - specifying :at_start: or :after_received: (or, for completeness, :at_end:) - before the text of the header line. (Header text cannot start with a colon, - as there has to be a header name first.) For example: - - warn message = :after_received:X-My-Header: something or other... - - If more than one header is supplied in a single warn statement, each one is - treated independently and can therefore be placed differently. If you add - more than one line at the start, or after the Received: block, they will - end up in reverse order. - - Warning: This facility currently applies only to header lines that are - added in an ACL. It does NOT work for header lines that are added in a - system filter or in a router or transport. - - 5. There is now a new error code that can be used in retry rules. Its name is - "rcpt_4xx", and there are three forms. A literal "rcpt_4xx" matches any 4xx - error received for an outgoing SMTP RCPT command; alternatively, either the - first or both of the x's can be given as digits, for example: "rcpt_45x" or - "rcpt_436". If you want (say) to recognize 452 errors given to RCPT - commands by a particular host, and have only a one-hour retry for them, you - can set up a retry rule of this form: - - the.host.name rcpt_452 F,1h,10m - - Naturally, this rule must come before any others that would match. - - These new errors apply to both outgoing SMTP (the smtp transport) and - outgoing LMTP (either the lmtp transport, or the smtp transport in LMTP - mode). Note, however, that they apply only to responses to RCPT commands. - - 6. The "postmaster" option of the callout feature of address verification has - been extended to make it possible to use a non-empty MAIL FROM address when - checking a postmaster address. The new suboption is called "postmaster_ - mailfrom", and you use it like this: - - require verify = sender/callout=postmaster_mailfrom=abc@x.y.z - - Providing this suboption causes the postmaster check to be done using the - given address. The original "postmaster" option is equivalent to - - require verify = sender/callout=postmaster_mailfrom= - - If both suboptions are present, the rightmost one overrides. - - Important notes: - - (1) If you use a non-empty sender address for postmaster checking, there is - the likelihood that the remote host will itself initiate a callout - check back to your host to check that address. As this is a "normal" - callout check, the sender will most probably be empty, thus avoiding - possible callout loops. However, to be on the safe side it would be - best to set up your own ACLs so that they do not do sender verification - checks when the recipient is the address you use for postmaster callout - checking. - - (2) The caching arrangements for postmaster checking do NOT take account of - the sender address. It is assumed that either the empty address, or a - fixed non-empty address will be used. All that Exim remembers is that - the postmaster check for the domain succeeded or failed. - - 7. When verifying addresses in header lines using the verify=header_sender - option, Exim behaves by default as if the addresses are envelope sender - addresses from a message. Callout verification therefore tests to see - whether a bounce message could be delivered, by using an empty address in - the MAIL FROM command. However, it is arguable that these addresses might - never be used as envelope senders, and could therefore justifiably reject - bounce messages (empty senders). There is now an additional callout option - for verify=header_sender that allows you to specify what address to use in - the MAIL FROM command. You use it as in this example: - - require verify = header_sender/callout=mailfrom=abcd@x.y.z - - Important notes: - - (1) As in the case of postmaster_mailfrom (see above), you should think - about possible loops. - - (2) In this case, as in the case of recipient callouts with non-empty - senders (the use_sender option), caching is done on the basis of a - recipient/sender pair. - - 8. If you build Exim with USE_READLINE=yes in Local/Makefile, it will try to - load libreadline dynamically whenever the -be (test expansion) option is - used without command line arguments. If successful, it will then use - readline() for reading the test data. A line history is supported. By the - time Exim does this, it is running as the calling user, so this should not - cause any security problems. Security is the reason why this is NOT - supported for -bt or -bv, when Exim is running as root or exim, - respectively. Note that this option adds to the size of the Exim binary, - because the dynamic loading library is not otherwise included. On my - desktop it adds about 2.5K. You may need to add -ldl to EXTRA_LIBS when you - set USE_READLINE=yes. - - 9. Added ${str2b64:} to the expansion operators. This operator - converts an arbitrary string into one that is base64 encoded. - -10. A new authenticator, called cyrus_sasl, has been added. This requires - the presence of the Cyrus SASL library; it authenticates by calling this - library, which supports a number of authentication mechanisms, including - PLAIN and LOGIN, but also several others that Exim does not support - directly. The code for this authenticator was provided by Matthew - Byng-Maddick of A L Digital Ltd (http://www.aldigital.co.uk). Here follows - draft documentation: - - xx. THE CYRUS_SASL AUTHENTICATOR - - The cyrus_sasl authenticator provides server support for the Cyrus library - Implementation of the RFC 2222 "Simple Authentication and Security Layer". - It provides a gatewaying mechanism directly to the Cyrus interface, so if - your Cyrus library can do, for example, CRAM-MD5, then so can the - cyrus_sasl authenticator. By default it uses the public name of the driver - to determine which mechanism to support. - - Where access to some kind of secret file is required, for example in GSSAPI - or CRAM-MD5, it is worth noting that the authenticator runs as the exim - user, and that the Cyrus SASL library has no way of escalating privileges - by default. You may also find you need to set environment variables, - depending on the driver you are using. - - xx.1 Using cyrus_sasl as a server - - The cyrus_sasl authenticator has four private options. It puts the username - (on a successful authentication) into $1. - - server_hostname Type: string* Default: $primary_hostname - - This option selects the hostname that is used when communicating with - the library. It is up to the underlying SASL plug-in what it does with - this data. - - server_mech Type: string Default: public_name - - This option selects the authentication mechanism this driver should - use. It allows you to use a different underlying mechanism from the - advertised name. For example: - - sasl: - driver = cyrus_sasl - public_name = X-ANYTHING - server_mech = CRAM-MD5 - server_set_id = $1 - - server_realm Type: string Default: unset - - This is the SASL realm that the server is claiming to be in. - - server_service Type: string Default: "smtp" - - This is the SASL service that the server claims to implement. - - For straigthforward cases, you do not need to set any of the - authenticator's private options. All you need to do is to specify an - appropriate mechanism as the public name. Thus, if you have a SASL library - that supports CRAM-MD5 and PLAIN, you might have two authenticators as - follows: - - sasl_cram_md5: - driver = cyrus_sasl - public_name = CRAM-MD5 - server_set_id = $1 - - sasl_plain: - driver = cyrus_sasl - public_name = PLAIN - server_set_id = $1 - -11. There is a new global option called tls_on_connect_ports. Its value must be - a list of port numbers; the most common use is expected to be - - tls_on_connect_ports = 465 - - Setting this option has the same effect as -tls-on-connect on the command - line, but only for the specified ports. It applies to all connections, both - via the daemon and via inetd. You still need to specify all the ports for - the daemon (using daemon_smtp_ports or local_interfaces or the -X command - line option) because this option does not add an extra port -- rather, it - specifies different behaviour on a port that is defined elsewhere. The - -tls-on-connect command line option overrides tls_on_connect_ports, and - forces tls-on-connect for all ports. - -12. There is a new ACL that is run when a DATA command is received, before the - data itself is received. The ACL is defined by acl_smtp_predata. (Compare - acl_smtp_data, which is run after the data has been received.) - This new ACL allows a negative response to be given to the DATA command - itself. Header lines added by MAIL or RCPT ACLs are not visible at this - time, but any that are defined here are visible when the acl_smtp_data ACL - is run. - -13. The "control=submission" ACL modifier has an option "/domain=xxx" which - specifies the domain to be used when creating From: or Sender: lines using - the authenticated id as a local part. If the option is supplied with an - empty domain, that is, just "/domain=", Exim assumes that the authenticated - id is a complete email address, and it uses it as is when creating From: - or Sender: lines. - -14. It is now possible to make retry rules that apply only when the failing - message has a specific sender. In particular, this can be used to define - retry rules that apply only to bounce messages. The syntax is to add a new - third item to a retry rule, of the form "senders=
". The retry - timings themselves then become the fourth item. For example: - - * * senders=: F,1h,30m - - would match all bounce messages. If the address list contains white space, - it must be enclosed in quotes. For example: - - a.domain timeout senders="x@b.dom : y@c.dom" G,8h,10m,1.5 - - When testing retry rules using -brt, you can supply a sender using the -f - command line option, like this: - - exim -f "" -brt user@dom.ain - - If you do not set -f with -brt, a retry rule that contains a senders list - will never be matched. - -15. Two new control modifiers have been added to ACLs: "control = enforce_sync" - and "control = no_enforce_sync". This makes it possible to be selective - about when SMTP synchronization is enforced. The global option - smtp_enforce_sync now specifies the default state of the switch. These - controls can appear in any ACL, but the most obvious place to put them is - in the ACL defined by acl_smtp_connect, which is run at the start of an - incoming SMTP connection, before the first synchronization check. - -16. Another two new control modifiers are "control = caseful_local_part" and - "control = caselower_local_part". These are permitted only in the ACL - specified by acl_smtp_rcpt (i.e. during RCPT processing). By default, the - contents of $local_part are lower cased before ACL processing. - After "control = caseful_local_part", any uppercase letters in the original - local part are restored in $local_part for the rest of the ACL, or until - "control = caselower_local_part" is encountered. However, this applies only - to local part handling that takes place directly in the ACL (for example, - as a key in lookups). If a "verify = recipient" test is obeyed, the - case-related handling of the local part during the verification is - controlled by the router configuration (see the caseful_local_part generic - router option). - - This facility could be used, for example, to add a spam score to local - parts containing upper case letters. For example, using $acl_m4 to - accumulate the spam score: - - warn control = caseful_local_part - set acl_m4 = ${eval:\ - $acl_m4 + \ - ${if match{$local_part}{[A-Z]}{1}{0}}\ - } - control = caselower_local_part - - Notice that we put back the lower cased version afterwards, assuming that - is what is wanted for subsequent tests. - -17. The option hosts_connection_nolog is provided so that certain hosts can be - excepted from logging when the +smtp_connection log selector is set. For - example, you might want not to log SMTP connections from local processes, - or from 127.0.0.1, or from your local LAN. The option is a host list with - an unset default. Because it is consulted in the main loop of the daemon, - you should strive to restrict its value to a short inline list of IP - addresses and networks. To disable logging SMTP connections from local - processes, you must create a host list with an empty item. For example: - - hosts_connection_nolog = : - - If the +smtp_connection log selector is not set, this option has no effect. - -18. There is now an acl called acl_smtp_quit, which is run for the QUIT - command. The outcome of the ACL does not affect the response code to QUIT, - which is always 221. Thus, the ACL does not in fact control any access. - For this reason, the only verbs that are permitted are "accept" and "warn". - - The ACL can be used for tasks such as custom logging at the end of an SMTP - session. For example, you can use ACL variables in other ACLs to count - messages, recipients, etc., and log the totals at QUIT time using one or - more "logwrite" modifiers on a "warn" command. - - You do not need to have a final "accept", but if you do, you can use a - "message" modifier to specify custom text that is sent as part of the 221 - response. - - This ACL is run only for a "normal" QUIT. For certain kinds of disastrous - failure (for example, failure to open a log file, or when Exim is bombing - out because it has detected an unrecoverable error), all SMTP commands - from the client are given temporary error responses until QUIT is received - or the connection is closed. In these special cases, the ACL is not run. - -19. The appendfile transport has two new options, mailbox_size and mailbox_ - filecount. If either these options are set, it is expanded, and the result - is taken as the current size of the mailbox or the number of files in the - mailbox, respectively. This makes it possible to use some external means of - maintaining the data about the size of a mailbox for enforcing quota - limits. The result of expanding these option values must be a decimal - number, optionally followed by "K" or "M". - -20. It seems that there are broken clients in use that cannot handle multiline - SMTP responses. Can't people who implement these braindead programs read? - RFC 821 mentions multiline responses, and it is over 20 years old. They - must handle multiline responses for EHLO, or do they still use HELO? - Anyway, here is YAWFAB (yet another workaround for asinine brokenness). - There's a new ACL switch that can be set by - - control = no_multiline_responses - - If this is set, it suppresses multiline SMTP responses from ACL rejections. - One way of doing this would have been just to put out these responses as - one long line. However, RFC 2821 specifies a maximum of 512 bytes per - response ("use multiline responses for more" it says), and some of the - responses might get close to that. So I have implemented this by doing two - very easy things: - - (1) Extra information that is normally output as part of a rejection - caused by sender verification failure is omitted. Only the final line - (typically "sender verification failed") is now sent. - - (2) If a "message" modifier supplies a multiline response, only the first - line is output. - - The setting of the switch can, of course, be made conditional on the - calling host. - -21. There is now support for the libradius library that comes with FreeBSD. - This is an alternative to the radiusclient library that Exim already - supports. To use the FreeBSD library, you need to set - - RADIUS_LIB_TYPE=RADLIB - - in Local/Makefile, in addition to RADIUS_CONFIGURE_FILE, and you probably - also need -libradius in EXTRALIBS. - - -Version 4.42 + NOTE: this version is not guaranteed backwards-compatible, please read the + items below carefully + + 1. A new main configuration option, "openssl_options", is available if Exim + is built with SSL support provided by OpenSSL. The option allows + administrators to specify OpenSSL options to be used on connections; + typically this is to set bug compatibility features which the OpenSSL + developers have not enabled by default. There may be security + consequences for certain options, so these should not be changed + frivolously. + + 2. A new pipe transport option, "permit_coredumps", may help with problem + diagnosis in some scenarios. Note that Exim is typically installed as + a setuid binary, which on most OSes will inhibit coredumps by default, + so that safety mechanism would have to be overridden for this option to + be able to take effect. + + 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless + Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes + Note that this switches Exim to use a new API ("INSTREAM") and a future + release of ClamAV will remove support for the old API ("STREAM"). + + The av_scanner option, when set to "clamd", now takes an optional third + part, "local", which causes Exim to pass a filename to ClamAV instead of + the file content. This is the same behaviour as when clamd is pointed at + a Unix-domain socket. For example: + + av_scanner = clamd:192.0.2.3 1234:local + + ClamAV's ExtendedDetectionInfo response format is now handled. + + 4. There is now a -bmalware option, restricted to admin users. This option + takes one parameter, a filename, and scans that file with Exim's + malware-scanning framework. This is intended purely as a debugging aid + to ensure that Exim's scanning is working, not to replace other tools. + Note that the ACL framework is not invoked, so if av_scanner references + ACL variables without a fallback then this will fail. + + 5. There is a new expansion operator, "reverse_ip", which will reverse IP + addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples: + + ${reverse_ip:192.0.2.4} + -> 4.2.0.192 + ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3} + -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2 + + 6. There is a new ACL control called "debug", to enable debug logging. + This allows selective logging of certain incoming transactions within + production environments, with some care. It takes two options, "tag" + and "opts"; "tag" is included in the filename of the log and "opts" + is used as per the -d command-line option. Examples, which + don't all make sense in all contexts: + + control = debug + control = debug/tag=.$sender_host_address + control = debug/opts=+expand+acl + control = debug/tag=.$message_exim_id/opts=+expand + + 7. It has always been implicit in the design and the documentation that + "the Exim user" is not root. src/EDITME said that using root was + "very strongly discouraged". This is not enough to keep people from + shooting themselves in the foot in days when many don't configure Exim + themselves but via package build managers. The security consequences of + running various bits of network code are severe if there should be bugs in + them. As such, the Exim user may no longer be root. If configured + statically, Exim will refuse to build. If configured as ref:user then Exim + will exit shortly after start-up. If you must shoot yourself in the foot, + then henceforth you will have to maintain your own local patches to strip + the safeties off. + + 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL + condition logic to determine truth/failure and will fail to expand many + strings, bool_lax{} uses the router condition logic, where most strings + do evaluate true. + Note: bool{00} is false, bool_lax{00} is true. + + 9. Routers now support multiple "condition" tests. + +10. There is now a runtime configuration option "tcp_wrappers_daemon_name". + Setting this allows an admin to define which entry in the tcpwrappers + config file will be used to control access to the daemon. This option + is only available when Exim is built with USE_TCP_WRAPPERS. The + default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME + build option. + +11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now + the Exim run-time user, instead of root. + +12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and + is forced on. This is mitigated by the new build option + TRUSTED_CONFIG_LIST which defines a list of configuration files which + are trusted; one per line. If a config file is owned by root and matches + a pathname in the list, then it may be invoked by the Exim build-time + user without Exim relinquishing root privileges. + +13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically + trusted to supply -D overrides on the command-line. Going + forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that + include the main config. As a transition mechanism, we are temporarily + providing a work-around: the new build option WHITELIST_D_MACROS provides + a colon-separated list of macro names which may be overridden by the Exim + run-time user. The values of these macros are constrained to the regex + ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values). + + +Version 4.72 ------------ - 1. The "personal" filter test is brought up-to-date with recommendations from - the Sieve specification: (a) The list of non-personal From: addresses now - includes "listserv", "majordomo", and "*-request"; (b) If the message - contains any header line starting with "List=-" it is treated as - non-personal. + 1. TWO SECURITY FIXES: one relating to mail-spools which are globally + writable, the other to locking of MBX folders (not mbox). + + 2. MySQL stored procedures are now supported. + + 3. The dkim_domain transport option is now a list, not a single string, and + messages will be signed for each element in the list (discarding + duplicates). + + 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups + in the presence of multiple character strings within the RR. Prior to 4.70, + only the first string would be returned. The dnsdb lookup now, by default, + preserves the pre-4.70 semantics, but also now takes an extended output + separator specification. The separator can be followed by a semicolon, to + concatenate the individual text strings together with no join character, + or by a comma and a second separator character, in which case the text + strings within a TXT record are joined on that second character. + Administrators are reminded that DNS provides no ordering guarantees + between multiple records in an RRset. For example: + + foo.example. IN TXT "a" "b" "c" + foo.example. IN TXT "d" "e" "f" + + ${lookup dnsdb{>/ txt=foo.example}} -> "a/d" + ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc" + ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f" + + +Version 4.70 / 4.71 +------------------- + + 1. Native DKIM support without an external library. + (Note that if no action to prevent it is taken, a straight upgrade will + result in DKIM verification of all signed incoming emails. See spec + for details on conditionally disabling) - 2. The Sieve functionality has been extended to support the "copy" and - "vacation" extensions, and comparison tests. + 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha). - 3. There is now an overall timeout for performing a callout verification. It - defaults to 4 times the callout timeout, which applies to individual SMTP - commands during the callout. The overall timeout applies when there is more - than one host that can be tried. The timeout is checked before trying the - next host. This prevents very long delays if there are a large number of - hosts and all are timing out (e.g. when the network connections are timing - out). The value of the overall timeout can be changed by specifying an - additional sub-option for "callout", called "maxwait". For example: + 3. There is now a bool{} expansion condition which maps certain strings to + true/false condition values (most likely of use in conjunction with the + and{} expansion operator). - verify = sender/callout=5s,maxwait=20s + 4. The $spam_score, $spam_bar and $spam_report variables are now available + at delivery time. - 4. Changes to the "personal" filter test: + 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as + options, provided that Exim is invoked by an admin_user. - (1) The list of non-personal local parts in From: addresses has been - extended to include "listserv", "majordomo", "*-request", and "owner-*", - taken from the Sieve specification recommendations. + 6. There is a new option gnutls_compat_mode, when linked against GnuTLS, + which increases compatibility with older clients at the cost of decreased + security. Don't set this unless you need to support such clients. - (2) If the message contains any header line starting with "List-" it is - treated as non-personal. + 7. There is a new expansion operator, ${randint:...} which will produce a + "random" number less than the supplied integer. This randomness is + not guaranteed to be cryptographically strong, but depending upon how + Exim was built may be better than the most naive schemes. - (3) The test for "circular" in the Subject: header line has been removed - because it now seems ill-conceived. + 8. Exim now explicitly ensures that SHA256 is available when linked against + OpenSSL. - 5. The autoreply transport has a new option called never_mail. This is an - address list. If any run of the transport creates a message with a - recipient that matches any item in the list, that recipient is quietly - discarded. If all recipients are discarded, no message is created. + 9. The transport_filter_timeout option now applies to SMTP transports too. -Version 4.40 +Version 4.69 ------------ -The documentation is up-to-date for the 4.40 release. What follows here is a -brief list of the new features that have been added since 4.30. + 1. Preliminary DKIM support in Experimental. + + +Version 4.68 +------------ + + 1. The body_linecount and body_zerocount C variables are now exported in the + local_scan API. + + 2. When a dnslists lookup succeeds, the key that was looked up is now placed + in $dnslist_matched. When the key is an IP address, it is not reversed in + this variable (though it is, of course, in the actual lookup). In simple + cases, for example: + + deny dnslists = spamhaus.example + + the key is also available in another variable (in this case, + $sender_host_address). In more complicated cases, however, this is not + true. For example, using a data lookup might generate a dnslists lookup + like this: + + deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|... + + If this condition succeeds, the value in $dnslist_matched might be + 192.168.6.7 (for example). + + 3. Authenticators now have a client_condition option. When Exim is running as + a client, it skips an authenticator whose client_condition expansion yields + "0", "no", or "false". This can be used, for example, to skip plain text + authenticators when the connection is not encrypted by a setting such as: + + client_condition = ${if !eq{$tls_cipher}{}} + + Note that the 4.67 documentation states that $tls_cipher contains the + cipher used for incoming messages. In fact, during SMTP delivery, it + contains the cipher used for the delivery. The same is true for + $tls_peerdn. + + 4. There is now a -Mvc option, which outputs a copy of the + message to the standard output, in RFC 2822 format. The option can be used + only by an admin user. + + 5. There is now a /noupdate option for the ratelimit ACL condition. It + computes the rate and checks the limit as normal, but it does not update + the saved data. This means that, in relevant ACLs, it is possible to lookup + the existence of a specified (or auto-generated) ratelimit key without + incrementing the ratelimit counter for that key. + + In order for this to be useful, another ACL entry must set the rate + for the same key somewhere (otherwise it will always be zero). + + Example: - 1. log_incoming_interface affects more log lines. + acl_check_connect: + # Read the rate; if it doesn't exist or is below the maximum + # we update it below + deny ratelimit = 100 / 5m / strict / noupdate + log_message = RATE: $sender_rate / $sender_rate_period \ + (max $sender_rate_limit) - 2. New ACL modifier "control = submission". + [... some other logic and tests...] - 3. CONFIGURE_OWNER can be set at build time to define an alternative owner for - the configuration file, in addition to root and exim. + warn ratelimit = 100 / 5m / strict / per_cmd + log_message = RATE UPDATE: $sender_rate / $sender_rate_period \ + (max $sender_rate_limit) + condition = ${if le{$sender_rate}{$sender_rate_limit}} - 4. Added expansion variables $body_zerocount, $recipient_data, and - $sender_data. + accept - 5. The time of last modification of the "new" subdirectory is now used as the - "mailbox time last read" when there is a quota error for a maildir - delivery. + 6. The variable $max_received_linelength contains the number of bytes in the + longest line that was received as part of the message, not counting the + line termination character(s). - 6. The special item "+ignore_unknown" may now appear in host lists. + 7. Host lists can now include +ignore_defer and +include_defer, analagous to + +ignore_unknown and +include_unknown. These options should be used with + care, probably only in non-critical host lists such as whitelists. - 7. The special domain-matching patterns @mx_any, @mx_primary, and - @mx_secondary can now be followed by "/ignore=". + 8. There's a new option called queue_only_load_latch, which defaults true. + If set false when queue_only_load is greater than zero, Exim re-evaluates + the load for each incoming message in an SMTP session. Otherwise, once one + message is queued, the remainder are also. - 8. New expansion conditions: match_domain, match_address, match_local_part, - lt, lti, le, lei, gt, gti, ge, and new expansion operators time_interval, - eval10, and base62d. + 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most + cases when an SMTP session ends without sending QUIT. However, when Exim + itself is is bad trouble, such as being unable to write to its log files, + this ACL is not run, because it might try to do things (such as write to + log files) that make the situation even worse. - 9. New lookup type called "iplsearch". + Like the QUIT ACL, this new ACL is provided to make it possible to gather + statistics. Whatever it returns (accept or deny) is immaterial. The "delay" + modifier is forbidden in this ACL. -10. New log selectors ident_timeout, tls_certificate_verified, queue_time, - deliver_time, outgoing_port, return_path_on_delivery. + When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set + to a string that indicates the reason for the termination of the SMTP + connection. The possible values are: -11. New global options smtp_active_hostname and tls_require_ciphers. + acl-drop Another ACL issued a "drop" command + bad-commands Too many unknown or non-mail commands + command-timeout Timeout while reading SMTP commands + connection-lost The SMTP connection has been lost + data-timeout Timeout while reading message data + local-scan-error The local_scan() function crashed + local-scan-timeout The local_scan() function timed out + signal-exit SIGTERM or SIGINT + synchronization-error SMTP synchronization error + tls-failed TLS failed to start + + In most cases when an SMTP connection is closed without having received + QUIT, Exim sends an SMTP response message before actually closing the + connection. With the exception of acl-drop, the default message can be + overridden by the "message" modifier in the NOTQUIT ACL. In the case of a + "drop" verb in another ACL, it is the message from the other ACL that is + used. + +10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of + servers with individual queries. This is done by starting the query with + "servers=x:y:z;", where each item in the list may take one of two forms: + + (1) If it is just a host name, the appropriate global option (mysql_servers + or pgsql_servers) is searched for a host of the same name, and the + remaining parameters (database, user, password) are taken from there. + + (2) If it contains any slashes, it is taken as a complete parameter set. + + The list of servers is used in exactly the same was as the global list. + Once a connection to a server has happened and a query has been + successfully executed, processing of the lookup ceases. + + This feature is intended for use in master/slave situations where updates + are occurring, and one wants to update a master rather than a slave. If the + masters are in the list for reading, you might have: + + mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw + + In an updating lookup, you could then write + + ${lookup mysql{servers=master; UPDATE ...} + + If, on the other hand, the master is not to be used for reading lookups: + + pgsql_servers = slave1/db/name/pw:slave2/db/name/pw + + you can still update the master by + + ${lookup pgsql{servers=master/db/name/pw; UPDATE ...} + +11. The message_body_newlines option (default FALSE, for backwards + compatibility) can be used to control whether newlines are present in + $message_body and $message_body_end. If it is FALSE, they are replaced by + spaces. + + +Version 4.67 +------------ -12. Exinext has -C and -D options. + 1. There is a new log selector called smtp_no_mail, which is not included in + the default setting. When it is set, a line is written to the main log + whenever an accepted SMTP connection terminates without having issued a + MAIL command. + + 2. When an item in a dnslists list is followed by = and & and a list of IP + addresses, the behaviour was not clear when the lookup returned more than + one IP address. This has been solved by the addition of == and =& for "all" + rather than the default "any" matching. + + 3. Up till now, the only control over which cipher suites GnuTLS uses has been + for the cipher algorithms. New options have been added to allow some of the + other parameters to be varied. + + 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is + set, Exim compiles a runtime option called disable_fsync. + + 5. There is a new variable called $smtp_count_at_connection_start. + + 6. There's a new control called no_pipelining. + + 7. There are two new variables called $sending_ip_address and $sending_port. + These are set whenever an SMTP connection to another host has been set up. + + 8. The expansion of the helo_data option in the smtp transport now happens + after the connection to the server has been made. + + 9. There is a new expansion operator ${rfc2047d: that decodes strings that + are encoded as per RFC 2047. + +10. There is a new log selector called "pid", which causes the current process + id to be added to every log line, in square brackets, immediately after the + time and date. + +11. Exim has been modified so that it flushes SMTP output before implementing + a delay in an ACL. It also flushes the output before performing a callout, + as this can take a substantial time. These behaviours can be disabled by + obeying control = no_delay_flush or control = no_callout_flush, + respectively, at some earlier stage of the connection. + +12. There are two new expansion conditions that iterate over a list. They are + called forany and forall. + +13. There's a new global option called dsn_from that can be used to vary the + contents of From: lines in bounces and other automatically generated + messages ("delivery status notifications" - hence the name of the option). + +14. The smtp transport has a new option called hosts_avoid_pipelining. + +15. By default, exigrep does case-insensitive matches. There is now a -I option + that makes it case-sensitive. + +16. A number of new features ("addresses", "map", "filter", and "reduce") have + been added to string expansions to make it easier to process lists of + items, typically addresses. + +17. There's a new ACL modifier called "continue". It does nothing of itself, + and processing of the ACL always continues with the next condition or + modifier. It is provided so that the side effects of expanding its argument + can be used. + +18. It is now possible to use newline and other control characters (those with + values less than 32, plus DEL) as separators in lists. + +19. The exigrep utility now has a -v option, which inverts the matching + condition. + +20. The host_find_failed option in the manualroute router can now be set to + "ignore". + + +Version 4.66 +------------ + +No new features were added to 4.66. + + +Version 4.65 +------------ + +No new features were added to 4.65. + + +Version 4.64 +------------ + + 1. ACL variables can now be given arbitrary names, as long as they start with + "acl_c" or "acl_m" (for connection variables and message variables), are at + least six characters long, with the sixth character being either a digit or + an underscore. + + 2. There is a new ACL modifier called log_reject_target. It makes it possible + to specify which logs are used for messages about ACL rejections. + + 3. There is a new authenticator called "dovecot". This is an interface to the + authentication facility of the Dovecot POP/IMAP server, which can support a + number of authentication methods. + + 4. The variable $message_headers_raw provides a concatenation of all the + messages's headers without any decoding. This is in contrast to + $message_headers, which does RFC2047 decoding on the header contents. + + 5. In a DNS black list, if two domain names, comma-separated, are given, the + second is used first to do an initial check, making use of any IP value + restrictions that are set. If there is a match, the first domain is used, + without any IP value restrictions, to get the TXT record. + + 6. All authenticators now have a server_condition option. + + 7. There is a new command-line option called -Mset. It is useful only in + conjunction with -be (that is, when testing string expansions). It must be + followed by a message id; Exim loads the given message from its spool + before doing the expansions. + + 8. Another similar new command-line option is called -bem. It operates like + -be except that it must be followed by the name of a file that contains a + message. + + 9. When an address is delayed because of a 4xx response to a RCPT command, it + is now the combination of sender and recipient that is delayed in + subsequent queue runs until its retry time is reached. + +10. Unary negation and the bitwise logical operators and, or, xor, not, and + shift, have been added to the eval: and eval10: expansion items. + +11. The variables $interface_address and $interface_port have been renamed + as $received_ip_address and $received_port, to make it clear that they + relate to message reception rather than delivery. (The old names remain + available for compatibility.) + +12. The "message" modifier can now be used on "accept" and "discard" acl verbs + to vary the message that is sent when an SMTP command is accepted. + + +Version 4.63 +------------ + +1. There is a new Boolean option called filter_prepend_home for the redirect + router. + +2. There is a new acl, set by acl_not_smtp_start, which is run right at the + start of receiving a non-SMTP message, before any of the message has been + read. + +3. When an SMTP error message is specified in a "message" modifier in an ACL, + or in a :fail: or :defer: message in a redirect router, Exim now checks the + start of the message for an SMTP error code. + +4. There is a new parameter for LDAP lookups called "referrals", which takes + one of the settings "follow" (the default) or "nofollow". + +5. Version 20070721.2 of exipick now included, offering these new options: + --reverse + After all other sorting options have bee processed, reverse order + before displaying messages (-R is synonym). + --random + Randomize order of matching messages before displaying. + --size + Instead of displaying the matching messages, display the sum + of their sizes. + --sort [,...] + Before displaying matching messages, sort the messages according to + each messages value for each variable. + --not + Negate the value for every test (returns inverse output from the + same criteria without --not). + + +Version 4.62 +------------ + +1. The ${readsocket expansion item now supports Internet domain sockets as well + as Unix domain sockets. If the first argument begins "inet:", it must be of + the form "inet:host:port". The port is mandatory; it may be a number or the + name of a TCP port in /etc/services. The host may be a name, or it may be an + IP address. An ip address may optionally be enclosed in square brackets. + This is best for IPv6 addresses. For example: + + ${readsocket{inet:[::1]:1234}{}... + + Only a single host name may be given, but if looking it up yield more than + one IP address, they are each tried in turn until a connection is made. Once + a connection has been made, the behaviour is as for ${readsocket with a Unix + domain socket. + +2. If a redirect router sets up file or pipe deliveries for more than one + incoming address, and the relevant transport has batch_max set greater than + one, a batch delivery now occurs. + +3. The appendfile transport has a new option called maildirfolder_create_regex. + Its value is a regular expression. For a maildir delivery, this is matched + against the maildir directory; if it matches, Exim ensures that a + maildirfolder file is created alongside the new, cur, and tmp directories. + + +Version 4.61 +------------ + +The documentation is up-to-date for the 4.61 release. Major new features since +the 4.60 release are: + +. An option called disable_ipv6, to disable the use of IPv6 completely. + +. An increase in the number of ACL variables to 20 of each type. + +. A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1, + $2, $3, (though those are still set) because the numeric variables get used + for other things in complicated expansions. + +. The default for rfc1413_query_timeout has been changed from 30s to 5s. + +. It is possible to use setclassresources() on some BSD OS to control the + resources used in pipe deliveries. + +. A new ACL modifier called add_header, which can be used with any verb. + +. More errors are detectable in retry rules. + +There are a number of other additions too. + + +Version 4.60 +------------ -13. "domainlist_cache" forces caching of an apparently variable list. +The documentation is up-to-date for the 4.60 release. Major new features since +the 4.50 release are: -14. For compatibility with Sendmail, the command line option -prval:sval - is equivalent to -oMr rval -oMs sval. +. Support for SQLite. -15. New callout options use_sender and use_postmaster for use when verifying - recipients. +. Support for IGNOREQUOTA in LMTP. -16. John Jetmore's "exipick" utility has been added to the distribution. +. Extensions to the "submission mode" features. -17. The TLS code now supports CRLs. +. Support for Client SMTP Authorization (CSA). -18. The dnslookup router and the dnsdb lookup type now support the use of SRV - records. +. Support for ratelimiting hosts and users. -19. The redirect router has a new option called qualify_domain. +. New expansion items to help with the BATV "prvs" scheme. -20. exigrep's output now also includes lines that are not related to any - particular message, but which do match the pattern. +. A "match_ip" condition, that matches an IP address against a list. -21. New global option write_rejectlog. If it is set false, Exim no longer - writes anything to the reject log. +There are many more minor changes. ****