X-Git-Url: https://git.exim.org/users/jgh/exim.git/blobdiff_plain/495ae4b01f36d0d8bb0e34a1d7263c2b8224aa4a..b2d5182ba3c9c24a92edc47d9e4f8bae41c6ca0a:/doc/doc-txt/NewStuff?ds=sidebyside diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff index dfcc5e711..37368ac4d 100644 --- a/doc/doc-txt/NewStuff +++ b/doc/doc-txt/NewStuff @@ -1,605 +1,570 @@ -$Cambridge: exim/doc/doc-txt/NewStuff,v 1.1 2004/10/07 15:04:35 ph10 Exp $ +$Cambridge: exim/doc/doc-txt/NewStuff,v 1.144 2007/03/13 11:06:48 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 4.43 +Version 4.67 ------------ - 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. + 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. This includes both the case when the connection is dropped, + and the case when QUIT is used. Note that it does not include cases where + the connection is rejected right at the start (by an ACL, or because there + are too many connections, or whatever). These cases already have their own + log lines. + + The log line that is written contains the identity of the client in the + usual way, followed by D= and a time, which records the duration of the + connection. If the connection was authenticated, this fact is logged + exactly as it is for an incoming message, with an A= item. If the + connection was encrypted, CV=, DN=, and X= items may appear as they do for + an incoming message, controlled by the same logging options. + + Finally, if any SMTP commands were issued during the connection, a C= item + is added to the line, listing the commands that were used. For example, + + C=EHLO,QUIT + + shows that the client issued QUIT straight after EHLO. If there were fewer + than 20 commands, they are all listed. If there were more than 20 commands, + the last 20 are listed, preceded by "...". However, with the default + setting of 10 for smtp_accep_max_nonmail, the connection will in any case + be aborted before 20 non-mail commands are processed. + + 2. When an item in a dnslists list is followed by = and & and a list of IP + addresses, in order to restrict the match to specific results from the DNS + lookup, the behaviour was not clear when the lookup returned more than one + IP address. For example, consider the condition + + dnslists = a.b.c=127.0.0.1 + + What happens if the DNS lookup for the incoming IP address yields both + 127.0.0.1 and 127.0.0.2 by means of two separate DNS records? Is the + condition true because at least one given value was found, or is it false + because at least one of the found values was not listed? And how does this + affect negated conditions? + + The behaviour of = and & has not been changed; however, the text below + documents it more clearly. In addition, two new additional conditions (== + and =&) have been added, to permit the "other" behaviour to be configured. + + A DNS lookup may yield more than one record. Thus, the result of the lookup + for a dnslists check may yield more than one IP address. The question then + arises as to whether all the looked up addresses must be listed, or whether + just one is good enough. Both possibilities are provided for: + + . If = or & is used, the condition is true if any one of the looked up + IP addresses matches one of the listed addresses. Consider: + + dnslists = a.b.c=127.0.0.1 + + If the DNS lookup yields both 127.0.0.1 and 127.0.0.2, the condition is + true because 127.0.0.1 matches. + + . If == or =& is used, the condition is true only if every one of the + looked up IP addresses matches one of the listed addresses. Consider: + + dnslists = a.b.c==127.0.0.1 + + If the DNS lookup yields both 127.0.0.1 and 127.0.0.2, the condition is + false because 127.0.0.2 is not listed. You would need to have + + dnslists = a.b.c==127.0.0.1,127.0.0.2 - 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: + for the condition to be true. - 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. + When ! is used to negate IP address matching, it inverts the result, giving + the precise opposite of the behaviour above. Thus: - 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. + . If != or !& is used, the condition is true if none of the looked up IP + addresses matches one of the listed addresses. Consider: - xx.1 Using cyrus_sasl as a server + dnslists = a.b.c!&0.0.0.1 - The cyrus_sasl authenticator has four private options. It puts the username - (on a successful authentication) into $1. + If the DNS lookup yields both 127.0.0.1 and 127.0.0.2, the condition is + false because 127.0.0.1 matches. - server_hostname Type: string* Default: $primary_hostname + . If !== or !=& is used, the condition is true there is at least one looked + up IP address that does not match. Consider: - 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. + dnslists = a.b.c!=&0.0.0.1 - server_mech Type: string Default: public_name + If the DNS lookup yields both 127.0.0.1 and 127.0.0.2, the condition is + true, because 127.0.0.2 does not match. You would need to have - 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: + dnslists = a.b.c!=&0.0.0.1,0.0.0.2 - 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 + for the condition to be false. + + When the DNS lookup yields only a single IP address, there is no difference + between = and == and between & and =&. + + 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. Here is complete documentation for the + available features: + + GnuTLS allows the caller to specify separate lists of permitted key + exchange methods, main cipher algorithms, and MAC algorithms. These may be + used in any combination to form a specific cipher suite. This is unlike + OpenSSL, where complete cipher names can be passed to its control function. + GnuTLS also allows a list of acceptable protocols to be supplied. + + For compatibility with OpenSSL, the tls_require_ciphers option can be set + to complete cipher suite names such as RSA_ARCFOUR_SHA, but for GnuTLS this + option controls only the cipher algorithms. Exim searches each item in the + list for the name of an available algorithm. For example, if the list + contains RSA_AES_SHA, then AES is recognized, and the behaviour is exactly + the same as if just AES were given. + + There are additional options called gnutls_require_kx, gnutls_require_mac, + and gnutls_require_protocols that can be used to restrict the key exchange + methods, MAC algorithms, and protocols, respectively. These options are + ignored if OpenSSL is in use. + + All four options are available as global options, controlling how Exim + behaves as a server, and also as options of the smtp transport, controlling + how Exim behaves as a client. All the values are string expanded. After + expansion, the values must be colon-separated lists, though the separator + can be changed in the usual way. + + Each of the four lists starts out with a default set of algorithms. If the + first item in one of the "require" options does _not_ start with an + exclamation mark, all the default items are deleted. In this case, only + those that are explicitly specified can be used. If the first item in one + of the "require" items _does_ start with an exclamation mark, the defaults + are left on the list. + + Then, any item that starts with an exclamation mark causes the relevant + entry to be removed from the list, and any item that does not start with an + exclamation mark causes a new entry to be added to the list. Unrecognized + items in the list are ignored. Thus: + + tls_require_ciphers = !ARCFOUR + + allows all the defaults except ARCFOUR, whereas + + tls_require_ciphers = AES : 3DES + + allows only cipher suites that use AES or 3DES. For tls_require_ciphers + the recognized names are AES_256, AES_128, AES (both of the preceding), + 3DES, ARCFOUR_128, ARCFOUR_40, and ARCFOUR (both of the preceding). The + default list does not contain all of these; it just has AES_256, AES_128, + 3DES, and ARCFOUR_128. + + For gnutls_require_kx, the recognized names are DHE_RSA, RSA (which + includes DHE_RSA), DHE_DSS, and DHE (which includes both DHE_RSA and + DHE_DSS). The default list contains RSA, DHE_DSS, DHE_RSA. + + For gnutls_require_mac, the recognized names are SHA (synonym SHA1), and + MD5. The default list contains SHA, MD5. + + For gnutls_require_protocols, the recognized names are TLS1 and SSL3. + The default list contains TLS1, SSL3. + + In a server, the order of items in these lists is unimportant. The server + will advertise the availability of all the relevant cipher suites. However, + in a client, the order in the tls_require_ciphers list specifies a + preference order for the cipher algorithms. The first one in the client's + list that is also advertised by the server is tried first. + + 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. You must + not set this option unless you really, really, really understand what you + are doing. No pre-compiled distributions of Exim should ever set this + option. When it is set, Exim compiles a runtime option called + disable_fsync. If this is set true, Exim no longer calls fsync() to force + updated files' data to be written to disc. Unexpected events such as + crashes and power outages may cause data to be lost or scrambled. Beware. + + When ENABLE_DISABLE_FSYNC is not set, a reference to disable_fsync in a + runtime configuration generates an "unknown option" error. + + 5. There is a new variable called $smtp_count_at_connection_start. The name + is deliberately long, in order to emphasize what the contents are. This + variable is set greater than zero only in processes spawned by the Exim + daemon for handling incoming SMTP connections. When the daemon accepts a + new connection, it increments this variable. A copy of the variable is + passed to the child process that handles the connection, but its value is + fixed, and never changes. It is only an approximation of how many incoming + connections there actually are, because many other connections may come and + go while a single connection is being processed. When a child process + terminates, the daemon decrements the variable. + + 6. There's a new control called no_pipelining, which does what its name + suggests. It turns off the advertising of the PIPELINING extension to SMTP. + To be useful, this control must be obeyed before Exim sends its response to + an EHLO command. Therefore, it should normally appear in an ACL controlled + by acl_smtp_connect or acl_smtp_helo. + + 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, + and they contain the IP address and port of the local interface that is + being used. They are of interest only on hosts that have more than on IP + address that want to take on different personalities depending on which one + is being used. + + 8. The expansion of the helo_data option in the smtp transport now happens + after the connection to the server has been made. This means that it can + use the value of $sending_ip_address (see 7 above) to vary the text of the + message. For example, if you want the string that is used for helo_data to + be obtained by a DNS lookup of the interface address, you could use this: + + helo_data = ${lookup dnsdb{ptr=$sending_ip_address}{$value}\ + {$primary_hostname}} + + The use of helo_data applies both to sending messages and when doing + callouts. + + 9. There is a new expansion operator ${rfc2047d: that decodes strings that + are encoded as per RFC 2047. Binary zero bytes are replaced by question + marks. Characters are converted into the character set defined by + headers_charset. Overlong RFC 2047 "words" are not recognized unless + check_rfc2047_length is set false. + +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. The effect of the + new default behaviour is to disable the PIPELINING optimization in these + situations, in order to avoid unexpected timeouts in clients. + +12. There are two new expansion conditions that iterate over a list. They are + called forany and forall, and they are used like this: + + ${if forany{}{}{}{}} + ${if forall{}{}{}{}} + + The first argument is expanded, and the result is treated as a list. By + default, the list separator is a colon, but it can be changed by the normal + method. The second argument is interpreted as a condition that is to be + applied to each item in the list in turn. During the interpretation of the + condition, the current list item is placed in a variable called $item. + + - For forany, interpretation stops if the condition is true for any item, + and the yes-string is then expanded. If the condition is false for all + items in the list, the no-string is expanded. + + - For forall, interpration stops if the condition is false for any item, + and the no-string is then expanded. If the condition is true for all + items in the list, the yes-string is expanded. + + Note that negation of forany means that the condition must be false for all + items for the overall condition to succeed, and negation of forall means + that the condition must be false for at least one item. + + In this example, the list separator is changed to a comma: + + ${if forany{<, $recipients}{match{$item}{^user3@}}{yes}{no}} + + Outside a forany/forall condition, the value of $item is an empty string. + Its value is saved and restored while forany/forall is being processed, to + enable these expansion items to be nested. + +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). + The default setting is: + + dsn_from = Mail Delivery System + + The value is expanded every time it is needed. If the expansion fails, a + panic is logged, and the default setting is used. + +14. The smtp transport has a new option called hosts_avoid_pipelining. It can + be used to suppress the use of PIPELINING to certain hosts, while still + supporting the other SMTP extensions (cf hosts_avoid_tls). + +15. By default, exigrep does case-insensitive matches. There is now a -I option + that makes it case-sensitive. This may give a performance improvement when + searching large log files. Without -I, the Perl pattern matches use the /i + option; with -I they don't. In both cases it is possible to change the case + sensitivity within the pattern using (?i) or (?-i). + +16. A number of new features have been added to string expansions to make it + easier to process lists of items, typically addresses. These are 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 + * ${addresses:} + + The string (after expansion) is interpreted as a list of addresses in RFC + 2822 format, such as can be found in a To: or Cc: header line. The + operative address (local-part@domain) is extracted from each item, and the + result of the expansion is a colon-separated list, with appropriate + doubling of colons should any happen to be present in the email addresses. + Syntactically invalid RFC2822 address items are omitted from the output. + + It is possible to specify a character other than colon for the output + separator by starting the string with > followed by the new separator + character. For example: + + ${addresses:>& The Boss , sec@base.ment (dogsbody)} + + expands to "ceo@up.stairs&sec@base.ment". Compare ${address (singular), + which extracts the working address from a single RFC2822 address. + + * ${map{}{}} + + After expansion, is interpreted as a list, colon-separated by + default, but the separator can be changed in the usual way. For each item + in this list, its value is place in $item, and then is expanded + and added to the output as an item in a new list. The separator used for + the output list is the same as the one used for the input, but is not + included in the output. For example: + + ${map{a:b:c}{[$item]}} ${map{<- x-y-z}{($item)}} + + expands to "[a]:[b]:[c] (x)-(y)-(z)". At the end of the expansion, the + value of $item is restored to what it was before. + + * ${filter{}{}} + + After expansion, is interpreted as a list, colon-separated by + default, but the separator can be changed in the usual way. For each item + in this list, its value is place in $item, and then the condition is + evaluated. If the condition is true, $item is added to the output as an + item in a new list; if the condition is false, the item is discarded. The + separator used for the output list is the same as the one used for the + input, but is not included in the output. For example: + + ${filter{a:b:c}{!eq{$item}{b}} + + yields "a:c". At the end of the expansion, the value of $item is restored + to what it was before. + + * ${reduce{}{}{}} + + The ${reduce expansion operation reduces a list to a single, scalar string. + After expansion, is interpreted as a list, colon-separated by + default, but the separator can be changed in the usual way. Then + is expanded and assigned to the $value variable. After this, each item in + the list is assigned to $item in turn, and is expanded + for each of them. The result of that expansion is assigned to $value before + the next iteration. When the end of the list is reached, the final value of + $value is added to the expansion string. The ${reduce expansion item can be + used in a number of ways. For example, to add up a list of numbers: + + ${reduce {<, 1,2,3}{0}{${eval:$value+$item}}} + + The result of that expansion would be "6". The maximum of a list of numbers + can be found: + + ${reduce {3:0:9:4:6}{0}{${if >{$item}{$value}{$item}{$value}}}} + + At the end of a ${reduce expansion, the values of $item and $value is + restored to what they were before. + +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. Typically this would be for updating a database. It is really + just a syntactic tidiness, because the following two lines have the same + effect: + + continue = + condition = ${if eq{0}{}{true}{true}} + +18. It is now possible to use newline and other control characters (those with + values less than 32, plus DEL) as separators in lists. Such separators must + be provided literally at the time the list is processed, but the string + expansion that happens first means that you can write them using normal + escape sequences. For example, if a new-line separated list of domains is + generated by a lookup, you can now process it directly by a line such as + this: + + domains = <\n ${lookup mysql{.....}} + + This avoids having to change the list separator in such data. Unlike + printing character separators, which can be included in list items by + doubling, it is not possible to include a control character as data when it + is set as the separator. Two such characters in succession are interpreted + as enclosing an empty list item. + +19. The exigrep utility now has a -v option, which inverts the matching + condition. + + +Version 4.66 ------------ - 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. +No new features were added to 4.66. - 2. The Sieve functionality has been extended to support the "copy" and - "vacation" extensions, and comparison tests. - 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: +Version 4.65 +------------ + +No new features were added to 4.65. - verify = sender/callout=5s,maxwait=20s - 4. Changes to the "personal" filter test: +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. - (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. + 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. - (2) If the message contains any header line starting with "List-" it is - treated as non-personal. + 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. - (3) The test for "circular" in the Subject: header line has been removed - because it now seems ill-conceived. + 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. 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. + 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. -Version 4.40 + 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 ------------ -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. 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. - 1. log_incoming_interface affects more log lines. +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. - 2. New ACL modifier "control = submission". - 3. CONFIGURE_OWNER can be set at build time to define an alternative owner for - the configuration file, in addition to root and exim. +Version 4.61 +------------ + +The documentation is up-to-date for the 4.61 release. Major new features since +the 4.60 release are: - 4. Added expansion variables $body_zerocount, $recipient_data, and - $sender_data. +. An option called disable_ipv6, to disable the use of IPv6 completely. - 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. +. An increase in the number of ACL variables to 20 of each type. - 6. The special item "+ignore_unknown" may now appear in host lists. +. 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. - 7. The special domain-matching patterns @mx_any, @mx_primary, and - @mx_secondary can now be followed by "/ignore=". +. The default for rfc1413_query_timeout has been changed from 30s to 5s. - 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. +. It is possible to use setclassresources() on some BSD OS to control the + resources used in pipe deliveries. - 9. New lookup type called "iplsearch". +. A new ACL modifier called add_header, which can be used with any verb. -10. New log selectors ident_timeout, tls_certificate_verified, queue_time, - deliver_time, outgoing_port, return_path_on_delivery. +. More errors are detectable in retry rules. -11. New global options smtp_active_hostname and tls_require_ciphers. +There are a number of other additions too. -12. Exinext has -C and -D options. -13. "domainlist_cache" forces caching of an apparently variable list. +Version 4.60 +------------ + +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. ****