X-Git-Url: https://vcs.fsf.org/?a=blobdiff_plain;f=doc%2Fdoc-txt%2FNewStuff;h=7e0c472ec1de1003cd538a817f64d012d10d1538;hb=6c512171a8449f14cc284e13aabc0153d9977c43;hp=ae6c48991bf07a2bee3df9396b699088c557a4c6;hpb=047bdd8ce4bf9cc9fd22fb22a2ebaf190d492343;p=exim.git diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff index ae6c48991..7e0c472ec 100644 --- a/doc/doc-txt/NewStuff +++ b/doc/doc-txt/NewStuff @@ -1,4 +1,4 @@ -$Cambridge: exim/doc/doc-txt/NewStuff,v 1.135 2007/02/05 12:35:46 ph10 Exp $ +$Cambridge: exim/doc/doc-txt/NewStuff,v 1.149 2007/06/18 13:57:49 ph10 Exp $ New Features in Exim -------------------- @@ -8,233 +8,114 @@ 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 4.67 +Version 4.68 ------------ - 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 + 1. The body_linecount and body_zerocount C variables are now exported in the + local_scan API. - dnslists = a.b.c=127.0.0.1 + 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: - 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? + deny dnslists = spamhaus.example - 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. + 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: - 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: + deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|... - . If = or & is used, the condition is true if any one of the looked up - IP addresses matches one of the listed addresses. Consider: + If this condition succeeds, the value in $dnslist_matched might be + 192.168.6.7 (for example). - dnslists = a.b.c=127.0.0.1 + 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: - 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. + client_condition = ${if !eq{$tls_cipher}{}} - . 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: + 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. - 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 +Version 4.67 +------------ - dnslists = a.b.c==127.0.0.1,127.0.0.2 + 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. - for the condition to be true. + 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. - When ! is used to negate IP address matching, it inverts the result, giving - the precise opposite of the behaviour above. Thus: + 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. - . If != or !& is used, the condition is true if none of the looked up IP - addresses matches one of the listed addresses. Consider: + 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is + set, Exim compiles a runtime option called disable_fsync. - dnslists = a.b.c!&0.0.0.1 + 5. There is a new variable called $smtp_count_at_connection_start. - 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. + 6. There's a new control called no_pipelining. - . If !== or !=& is used, the condition is true there is at least one looked - up IP address that does not match. Consider: + 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. - dnslists = a.b.c!=&0.0.0.1 + 8. The expansion of the helo_data option in the smtp transport now happens + after the connection to the server has been made. - 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 + 9. There is a new expansion operator ${rfc2047d: that decodes strings that + are encoded as per RFC 2047. - dnslists = a.b.c!=&0.0.0.1,0.0.0.2 +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. - for the condition to be false. +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. - When the DNS lookup yields only a single IP address, there is no difference - between = and == and between & and =&. +12. There are two new expansion conditions that iterate over a list. They are + called forany and forall. - 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. +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). - 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. +14. The smtp transport has a new option called hosts_avoid_pipelining. - 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: +15. By default, exigrep does case-insensitive matches. There is now a -I option + that makes it case-sensitive. - helo_data = ${lookup dnsdb{ptr=$sending_ip_address}{$value}\ - {$primary_hostname}} +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. - The use of helo_data applies both to sending messages and when doing - callouts. +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. - 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. +18. It is now possible to use newline and other control characters (those with + values less than 32, plus DEL) as separators in lists. -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. +19. The exigrep utility now has a -v option, which inverts the matching + condition. -11. Exim has been modified so that it flushes SMTP output before implementing - a delay in an ACL. This behaviour can be disabled by obeying control = - no_delay_flush at some earlier point. +20. The host_find_failed option in the manualroute router can now be set to + "ignore". Version 4.66