X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/87ba3f5f78da0d53bfb3bdef9db569c8da241eba..ea2c01d20f397fb6f7bbaba22ff82ea2ce815907:/doc/doc-txt/NewStuff diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff index 24993b5ac..9d0e93993 100644 --- a/doc/doc-txt/NewStuff +++ b/doc/doc-txt/NewStuff @@ -1,272 +1,355 @@ -$Cambridge: exim/doc/doc-txt/NewStuff,v 1.42 2005/05/17 15:00:04 ph10 Exp $ +$Cambridge: exim/doc/doc-txt/NewStuff,v 1.124 2006/12/05 11:35:28 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. - - -Exim version 4.52 ------------------ - -TF/01 Support for checking Client SMTP Authorization has been added. CSA is a - system which allows a site to advertise which machines are and are not - permitted to send email. This is done by placing special SRV records in - the DNS, which are looked up using the client's HELO domain. At this - time CSA is still an Internet-Draft. - - Client SMTP Authorization checks are performed by the ACL condition - verify=csa. This will fail if the client is not authorized. If there is - a DNS problem, or if no valid CSA SRV record is found, or if the client - is authorized, the condition succeeds. These three cases can be - distinguished using the expansion variable $csa_status, which can take - one of the values "fail", "defer", "unknown", or "ok". The condition - does not itself defer because that would be likely to cause problems - for legitimate email. - - The error messages produced by the CSA code include slightly more - detail. If $csa_status is "defer" this may be because of problems - looking up the CSA SRV record, or problems looking up the CSA target - address record. There are four reasons for $csa_status being "fail": - the client's host name is explicitly not authorized; the client's IP - address does not match any of the CSA target IP addresses; the client's - host name is authorized but it has no valid target IP addresses (e.g. - the target's addresses are IPv6 and the client is using IPv4); or the - client's host name has no CSA SRV record but a parent domain has - asserted that all subdomains must be explicitly authorized. - - The verify=csa condition can take an argument which is the domain to - use for the DNS query. The default is verify=csa/$sender_helo_name. - - This implementation includes an extension to CSA. If the query domain - is an address literal such as [192.0.2.95], or if it is a bare IP - address, Exim will search for CSA SRV records in the reverse DNS as if - the HELO domain was e.g. 95.2.0.192.in-addr.arpa. Therefore it is - meaningful to say, for example, verify=csa/$sender_host_address - in - fact, this is the check that Exim performs if the client does not say - HELO. This extension can be turned off by setting the main - configuration option dns_csa_use_reverse = false. - - If a CSA SRV record is not found for the domain itself, then a search - is performed through its parent domains for a record which might be - making assertions about subdomains. The maximum depth of this search is - limited using the main configuration option dns_csa_search_limit, which - takes the value 5 by default. Exim does not look for CSA SRV records in - a top level domain, so the default settings handle HELO domains as long - as seven (hostname.five.four.three.two.one.com) which encompasses the - vast majority of legitimate HELO domains. - - The dnsdb lookup also has support for CSA. Although dnsdb already - supports SRV lookups, this is not sufficient because of the extra - parent domain search behaviour of CSA, and (as with PTR lookups) - dnsdb also turns IP addresses into lookups in the reverse DNS space. - The result of ${lookup dnsdb {csa=$sender_helo_name} } has two - space-separated fields: an authorization code and a target host name. - The authorization code can be "Y" for yes, "N" for no, "X" for explicit - authorization required but absent, or "?" for unknown. - -PH/01 The amount of output produced by the "make" process has been reduced, - because the compile lines are often rather long, making it all pretty - unreadable. The new style is along the lines of the 2.6 Linux kernel: - just a short line for each module that is being compiled or linked. - However, it is still possible to get the full output, by calling "make" - like this: - - FULLECHO='' make -e - - The value of FULLECHO defaults to "@", the flag character that suppresses - command reflection in "make". When you ask for the full output, it is - given in addition to the the short output. - -PH/02 There have been two changes concerned with submission mode: - - (a) A new option, /name=value, makes it possible to supply a user name - to be inserted into any created Sender: header line. Typically, this - would be looked up from $authenticated_id. - - (b) The envelope sender address is forced to be the same as the - submission mode sender address. - - -Version 4.51 +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 4.64 +------------ + + 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. The rest of the name can contain alphanumeric characters and + underscores. This is a compatible change because the old set of variables + such as acl_m12 are a subset of the allowed names. There may now be any + number of ACL variables. For example: + + set acl_c13 = value for original ACL variable + set acl_c13b = whatever + set acl_m_foo = something + + What happens if a syntactically valid but undefined ACL variable is + referenced depends on the setting of the strict_acl_vars option. If it is + false (the default), an empty string is substituted; if it is true, an + error is generated. This affects all ACL variables, including the "old" + ones such as acl_c4. (Previously there wasn't the concept of an undefined + ACL variable.) + + The implementation has been done in such a way that spool files containing + ACL variable settings written by previous releases of Exim are compatible + and can be read by the new release. If only the original numeric names are + used, spool files written by the new release can be read by earlier + releases. + + 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. Its + argument is a list of words which can be "main", "reject", or "panic". The + default is "main:reject". The list may be empty, in which case a rejection + is not logged at all. For example, this ACL fragment writes no logging + information when access is denied: + + deny + log_reject_target = + + The modifier can be used in SMTP and non-SMTP ACLs. It applies to both + permanent and temporary 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. If you are using Dovecot to authenticate + POP/IMAP clients, it might be helpful to use the same mechanisms for SMTP + authentication. This is a server authenticator only. The only option is + server_socket, which must specify the socket which is the interface to + Dovecot authentication. The public_name option must specify an + authentication mechanism that Dovecot is configured to support. You can + have several authenticators for different mechanisms. For example: + + dovecot_plain: + driver = dovecot + public_name = PLAIN + server_name = /var/run/dovecot/auth-client + server_setid = $auth1 + + dovecot_ntlm: + driver = dovecot + public_name = NTLM + server_name = /var/run/dovecot/auth-client + server_setid = $auth1 + + If the SMTP connection is encrypted, or if $sender_host_address is equal to + $interface_address (that is, the connection is local), the "secured" option + is passed in the Dovecot authentication command. If, for a TLS connection, + a client certificate has been verified, the "valid-client-cert" option is + passed. + + 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, when the facility for restricting the matching IP + values is used, the text from the TXT record that is set in $dnslist_text + may not reflect the true reason for rejection. This happens when lists are + merged and the IP address in the A record is used to distinguish them; + unfortunately there is only one TXT record. One way round this is not to + use merged lists, but that can be inefficient because it requires multiple + DNS lookups where one would do in the vast majority of cases when the host + of interest is not on any of the lists. + + A less inefficient way of solving this problem has now been implemented. 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. As a byproduct of this, there is also + a check that the IP being tested is indeed on the first list. The first + domain is the one that is put in $dnslist_domain. For example: + + reject message = rejected because $sender_ip_address is blacklisted \ + at $dnslist_domain\n$dnslist_text + dnslists = sbl.spamhaus.org,sbl-xbl.spamhaus.org=127.0.0.2 : \ + dul.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.10 + + For the first blacklist item, this starts by doing a lookup in + sbl-xbl.spamhaus.org and testing for a 127.0.0.2 return. If there is a + match, it then looks in sbl.spamhaus.org, without checking the return + value, and as long as something is found, it looks for the corresponding + TXT record. If there is no match in sbl-xbl.spamhaus.org, nothing more is + done. The second blacklist item is processed similarly. + + If you are interested in more than one merged list, the same list must be + given several times, but because the results of the DNS lookups are cached, + the DNS calls themselves are not repeated. For example: + + reject dnslists = http.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.2 : \ + socks.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.3 : \ + misc.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.4 : \ + dul.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.10 + + In this case there is a lookup in dnsbl.sorbs.net, and if none of the IP + values matches (or if no record is found), this is the only lookup that is + done. Only if there is a match is one of the more specific lists consulted. + + 6. All authenticators now have a server_condition option. Previously, only + plaintext had this, and this has not changed: it must be set to the + authenticator as a server. For the others, if server_condition is set, it + is expanded if authentication is successful, and treated exactly as it is + in plaintext. This can serve as a means of adding authorization to an + authenticator. + + 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, thus setting message-specific variables such + as $message_size and the header variables. The $recipients variable is + available. This feature is provided to make it easier to test expansions + that make use of these variables. However, Exim must be called by an admin + user when -Mset is used. + + 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. For example: + + exim -bem /tmp/testmessage + + The file is read as a message (as if receiving a locally-submitted non-SMTP + message) before any of the test expansions are done. Thus, message-specific + variables such as $message_size and $h_from: are available. However, no + Received: header is added to the message. If the -t option is set, + recipients are read from the headers in the normal way, and are shown in + the $recipients variable. Note that recipients cannot be given on the + command line, because further arguments are taken as strings to expand + (just like -be). + + 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. You can revert to + the previous behavious, that is, delay the recipient independent of the + sender, by setting address_retry_include_sender=false in the smtp + transport. However, this can lead to problems with servers that regularly + issue 4xx responses to RCPT commands. + +10. Unary negation and the bitwise logical operators and, or, xor, not, and + shift, have been added to the eval: and eval10: expansion items. These + items may now contain arithmetic operators (plus, minus, times, divide, + remainder, negate), bitwise operators (and, or, xor, not, shift), and + parentheses. All operations are carried out using signed integer + arithmetic. Operator priorities are as in C, namely: + + (highest) not, negate + times, divide, remainder + plus, minus + shift-left, shift-right + and + xor + (lowest) or + + Binary operators with the same priority are evaluated from left to right. + For example: + + ${eval:1+1} yields 2 + ${eval:1+2*3} yields 7 + ${eval:(1+2)*3} yields 9 + ${eval:2+42%5} yields 4 + ${eval:0xc&5} yields 4 + ${eval:0xc|5} yields 13 + ${eval:0xc^5} yields 9 + ${eval:0xc>>1} yields 6 + ${eval:0xc<<1} yields 24 + ${eval:~255&0x1234} yields 4608 + ${eval:-(~255&0x1234)} yields -4608 + +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 acl verbs to vary the message + that is sent when an SMTP command is accepted. For example, in a RCPT ACL + you could have: + + accept + message = OK, I'll allow you through today + + Previously, this message modifier would have had no effect whatsoever. + + IMPORTANT: The new behaviour applies to "accept" (and "discard") only if + there is no occurrence of "endpass" in the statement. If "endpass" is + present, the behaviour reverts to the old case, where "message" applies to + rejection. This is for backwards compatibility. + + It is always possible to rewrite ACL statements so that "endpass" is not + needed (and indeed it is no longer used in the default configuration, and + is somewhat not recommended nowadays because it causes confusion.) + + It is now generally true that the "message" modifier sets up a text string + that is expanded and used as a response message if the current statement + terminates the ACL. The expansion happens at the time Exim decides that the + ACL is to end, not at the time it processes "message". If the expansion + fails, or generates an empty string, the modifier is ignored. + + For ACLs that are triggered by SMTP commands, the message is returned as + part of the SMTP response. In this situation, the message may begin with an + overriding SMTP response code, optionally followed by an "extended response + code". However, the first digit of the supplied response code must be the + same as would be sent by default. A panic occurs if it is not. For the + predata ACL, note that the default success code is 354, not 2xx. + + However, notwithstanding the previous paragraph, for the QUIT ACL, unlike + the others, the message modifier cannot override the 221 response code. + + In the case of the "connect" ACL, accepting with a message modifier + overrides the value of smtp_banner. + + The ACL test specified by acl_smtp_helo happens when the client issues the + HELO or EHLO commands, after the tests specified by helo_accept_junk_hosts, + helo_allow_chars and helo(_try)_verify_hosts. An acceptance message + modifier for EHLO/HELO may not contain more than one line (it will be + truncated at the first newline and a panic logged), and it cannot affect + the EHLO options. + + + +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 ------------ -PH/01 The format in which GnuTLS parameters are written to the gnutls-param - file in the spool directory has been changed. This change has been made - to alleviate problems that some people had with the generation of the - parameters by Exim when /dev/random was exhausted. In this situation, - Exim would hang until /dev/random acquired some more entropy. +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: - The new code exports and imports the DH and RSA parameters in PEM - format. This means that the parameters can be generated externally using - the certtool command that is part of GnuTLS. + ${readsocket{inet:[::1]:1234}{}... - To replace the parameters with new ones, instead of deleting the file - and letting Exim re-create it, you can generate new parameters using - certtool and, when this has been done, replace Exim's cache file by - renaming. The relevant commands are something like this: + 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 +------------ - # rm -f new.params - # touch new.params - # chown exim:exim new.params - # chmod 0400 new.params - # certtool --generate-privkey --bits 512 >new.params - # echo "" >>new.params - # certtool --generate-dh-params --bits 1024 >> new.params - # mv new.params params +The documentation is up-to-date for the 4.61 release. Major new features since +the 4.60 release are: - If Exim never has to generate the parameters itself, the possibility of - stalling is removed. +. An option called disable_ipv6, to disable the use of IPv6 completely. -PH/02 A new expansion item for dynamically loading and calling a locally- - written C function is now provided, if Exim is compiled with +. An increase in the number of ACL variables to 20 of each type. - EXPAND_DLFUNC=yes +. 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. - set in Local/Makefile. The facility is not included by default (a - suitable error is given if you try to use it when it is not there.) +. The default for rfc1413_query_timeout has been changed from 30s to 5s. - If you enable EXPAND_DLFUNC, you should also be aware of the new redirect - router option forbid_filter_dlfunc. If you have unprivileged users on - your system who are permitted to create filter files, you might want to - set forbid_filter_dlfunc=true in the appropriate router, to stop them - using ${dlfunc to run code within Exim. +. It is possible to use setclassresources() on some BSD OS to control the + resources used in pipe deliveries. - You load and call an external function like this: - - ${dlfunc{/some/file}{function}{arg1}{arg2}...} - - Once loaded, Exim remembers the dynamically loaded object so that it - doesn't reload the same object file in the same Exim process (but of - course Exim does start new processes frequently). - - There may be from zero to eight arguments to the function. When compiling - a local function that is to be called in this way, local_scan.h should be - included. The Exim variables and functions that are defined by that API - are also available for dynamically loaded functions. The function itself - must have the following type: - - int dlfunction(uschar **yield, int argc, uschar *argv[]) - - Where "uschar" is a typedef for "unsigned char" in local_scan.h. The - function should return one of the following values: - - OK Success. The string that is placed in "yield" is put into - the expanded string that is being built. - - FAIL A non-forced expansion failure occurs, with the error - message taken from "yield", if it is set. - - FAIL_FORCED A forced expansion failure occurs, with the error message - taken from "yield" if it is set. - - ERROR Same as FAIL, except that a panic log entry is written. - - When compiling a function that is to be used in this way with gcc, - you need to add -shared to the gcc command. Also, in the Exim build-time - configuration, you must add -export-dynamic to EXTRALIBS. - -TF/01 $received_time is a new expansion variable containing the time and date - as a number of seconds since the start of the Unix epoch when the - current message was received. - -PH/03 There is a new value for RADIUS_LIB_TYPE that can be set in - Local/Makefile. It is RADIUSCLIENTNEW, and it requests that the new API, - in use from radiusclient 0.4.0 onwards, be used. It does not appear to be - possible to detect the different versions automatically. - -PH/04 There is a new option called acl_not_smtp_mime that allows you to scan - MIME parts in non-SMTP messages. It operates in exactly the same way as - acl_smtp_mime - -PH/05 It is now possible to redefine a macro within the configuration file. - The macro must have been previously defined within the configuration (or - an included file). A definition on the command line using the -D option - causes all definitions and redefinitions within the file to be ignored. - In other words, -D overrides any values that are set in the file. - Redefinition is specified by using '==' instead of '='. For example: - - MAC1 = initial value - ... - MAC1 == updated value - - Redefinition does not alter the order in which the macros are applied to - the subsequent lines of the configuration file. It is still the same - order in which the macros were originally defined. All that changes is - the macro's value. Redefinition makes it possible to accumulate values. - For example: - - MAC1 = initial value - ... - MAC1 == MAC1 and something added - - This can be helpful in situations where the configuration file is built - from a number of other files. - -PH/06 Macros may now be defined or redefined between router, transport, - authenticator, or ACL definitions, as well as in the main part of the - configuration. They may not, however, be changed within an individual - driver or ACL, or in the local_scan, retry, or rewrite sections of the - configuration. - -PH/07 $acl_verify_message is now set immediately after the failure of a - verification in an ACL, and so is available in subsequent modifiers. In - particular, the message can be preserved by coding like this: +. A new ACL modifier called add_header, which can be used with any verb. - warn !verify = sender - set acl_m0 = $acl_verify_message +. More errors are detectable in retry rules. - Previously, $acl_verify_message was set only while expanding "message" - and "log_message" when a very denied access. - -PH/08 The redirect router has two new options, sieve_useraddress and - sieve_subaddress. These are passed to a Sieve filter to specify the :user - and :subaddress parts of an address. Both options are unset by default. - However, when a Sieve filter is run, if sieve_useraddress is unset, the - entire original local part (including any prefix or suffix) is used for - :user. An unset subaddress is treated as an empty subaddress. - -PH/09 Quota values can be followed by G as well as K and M. - -PH/10 $message_linecount is a new variable that contains the total number of - lines in the header and body of the message. Compare $body_linecount, - which is the count for the body only. During the DATA and - content-scanning ACLs, $message_linecount contains the number of lines - received. Before delivery happens (that is, before filters, routers, and - transports run) the count is increased to include the Received: header - line that Exim standardly adds, and also any other header lines that are - added by ACLs. The blank line that separates the message header from the - body is not counted. Here is an example of the use of this variable in a - DATA ACL: - - deny message = Too many lines in message header - condition = \ - ${if <{250}{${eval: $message_linecount - $body_linecount}}} - - In the MAIL and RCPT ACLs, the value is zero because at that stage the - message has not yet been received. - -PH/11 In a ${run expansion, the variable $value (which contains the standard - output) is now also usable in the "else" string. - -PH/12 In a pipe transport, although a timeout while waiting for the pipe - process to complete was treated as a delivery failure, a timeout while - writing the message to the pipe was logged, but erroneously treated as a - successful delivery. Such timeouts include transport filter timeouts. For - consistency with the overall process timeout, these timeouts are now - treated as errors, giving rise to delivery failures by default. However, - there is now a new Boolean option for the pipe transport called - timeout_defer, which, if set TRUE, converts the failures into defers for - both kinds of timeout. A transport filter timeout is now identified in - the log output. - - -Version 4.50 +There are a number of other additions too. + + +Version 4.60 ------------ -The documentation is up-to-date for the 4.50 release. +The documentation is up-to-date for the 4.60 release. Major new features since +the 4.50 release are: + +. Support for SQLite. + +. Support for IGNOREQUOTA in LMTP. + +. Extensions to the "submission mode" features. + +. Support for Client SMTP Authorization (CSA). + +. Support for ratelimiting hosts and users. + +. New expansion items to help with the BATV "prvs" scheme. + +. A "match_ip" condition, that matches an IP address against a list. + +There are many more minor changes. ****