X-Git-Url: https://git.exim.org/users/jgh/exim.git/blobdiff_plain/48c7f9e2e3b50cd5548447de62c77c7ddfe21519..56f5d9bd6bb563f4f0eab011ed665da234d93e37:/doc/doc-txt/NewStuff diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff index 695acce86..9d0e93993 100644 --- a/doc/doc-txt/NewStuff +++ b/doc/doc-txt/NewStuff @@ -1,4 +1,4 @@ -$Cambridge: exim/doc/doc-txt/NewStuff,v 1.120 2006/11/06 15:50:12 ph10 Exp $ +$Cambridge: exim/doc/doc-txt/NewStuff,v 1.124 2006/12/05 11:35:28 ph10 Exp $ New Features in Exim -------------------- @@ -12,155 +12,234 @@ 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 : \ + 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 - 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. + 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.