X-Git-Url: https://git.exim.org/users/jgh/exim.git/blobdiff_plain/4c590bd11647b7440bd982a8c72ebcf5c66564b0..4aa45c318ef507a75ea0aa97e0241b866b966b24:/doc/doc-txt/NewStuff diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff index b05db458a..fa86b1e07 100644 --- a/doc/doc-txt/NewStuff +++ b/doc/doc-txt/NewStuff @@ -1,4 +1,4 @@ -$Cambridge: exim/doc/doc-txt/NewStuff,v 1.138 2007/02/06 12:19:27 ph10 Exp $ +$Cambridge: exim/doc/doc-txt/NewStuff,v 1.146 2007/04/17 13:06:10 ph10 Exp $ New Features in Exim -------------------- @@ -14,219 +14,32 @@ Version 4.67 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. + MAIL command. 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 + 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 defaule "any" matching. - 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 - - for the condition to be true. - - When ! is used to negate IP address matching, it inverts the result, giving - the precise opposite of the behaviour above. Thus: - - . If != or !& is used, the condition is true if none of the looked up IP - addresses matches one of the listed addresses. Consider: - - dnslists = a.b.c!&0.0.0.1 - - If the DNS lookup yields both 127.0.0.1 and 127.0.0.2, the condition is - false because 127.0.0.1 matches. - - . If !== or !=& is used, the condition is true there is at least one looked - up IP address that does not match. Consider: - - dnslists = a.b.c!=&0.0.0.1 - - If the DNS lookup yields both 127.0.0.1 and 127.0.0.2, the condition is - true, because 127.0.0.2 does not match. You would need to have + 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. - dnslists = a.b.c!=&0.0.0.1,0.0.0.2 + 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is + set, Exim compiles a runtime option called disable_fsync. - for the condition to be false. + 5. There is a new variable called $smtp_count_at_connection_start. - 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. + 6. There's a new control called no_pipelining. 7. There are two new variables called $sending_ip_address and $sending_port. - These are set whenever an SMTP connection to another host has been set up, - 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. + These are set whenever an SMTP connection to another host has been set up. 8. The expansion of the helo_data option in the smtp transport now happens - after the connection to the server has been made. 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. + after the connection to the server has been made. 9. There is a new expansion operator ${rfc2047d: that decodes strings that - are encoded as per RFC 2047. 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. + are encoded as per RFC 2047. 10. There is a new log selector called "pid", which causes the current process id to be added to every log line, in square brackets, immediately after the @@ -236,51 +49,37 @@ Version 4.67 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. + respectively, at some earlier stage of the connection. 12. There are two new expansion conditions that iterate over a list. They are - called forany and forall, and they are used like this: - - ${if forany{}{}{}{}} - ${if forall{}{}{}{}} + called forany and 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. +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). - 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. +14. The smtp transport has a new option called hosts_avoid_pipelining. - In this example, the list separator is changed to a comma: +15. By default, exigrep does case-insensitive matches. There is now a -I option + that makes it case-sensitive. - ${if forany{<, $recipients}{match{$item}{^user3@}}{yes}{no}} +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. - 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. +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. -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: +18. It is now possible to use newline and other control characters (those with + values less than 32, plus DEL) as separators in lists. - dsn_from = Mail Delivery System +19. The exigrep utility now has a -v option, which inverts the matching + condition. - The value is expanded every time it is needed. If the expansion fails, a - panic is logged, and the default setting is used. +20. The host_find_failed option in the manualroute router can now be set to + "ignore". Version 4.66