X-Git-Url: https://git.exim.org/users/jgh/exim.git/blobdiff_plain/f05da2e8b55f18554ebbcf97523fd54fb03d071e..af5614178a73fc5060e4c15064cc5855681fa02d:/doc/doc-txt/NewStuff

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-$Cambridge: exim/doc/doc-txt/NewStuff,v 1.18 2004/11/25 13:54:31 ph10 Exp $
+$Cambridge: exim/doc/doc-txt/NewStuff,v 1.121 2006/11/13 11:26:37 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 4.44
+Version 4.64
 ------------
 
- 1. There is a new build-time option called CONFIGURE_GROUP which works like
-    CONFIGURE_OWNER. It specifies one additional group that is permitted for
-    the runtime configuration file when the group write permission is set.
-
- 2. The "control=submission" facility has a new option /sender_retain. This
-    has the effect of setting local_sender_retain true and local_from_check
-    false for the incoming message in which it is encountered.
-
- 3. $recipients is now available in the predata ACL (oversight).
-
- 4. The value of address_data from a sender verification is now available in
-    $sender_address_data in subsequent conditions in the ACL statement. Note:
-    this is just like $address_data. The value does not persist after the end
-    of the current ACL statement. If you want to preserve it, you can use one
-    of the ACL variables.
-
- 5. The redirect router has two new options: forbid_sieve_filter and
-    forbid_exim_filter. When filtering is enabled by allow_filter, these
-    options control which type(s) of filtering are permitted. By default, both
-    Exim and Sieve filters are allowed.
-
- 6. A new option for callouts makes it possible to set a different (usually
-    smaller) timeout for making the SMTP connection. The keyword is "connect".
-    For example:
-
-       verify = sender/callout=5s,connect=1s
-
-    If not specified, it defaults to the general timeout value.
-
- 7. The new variables $sender_verify_failure and $recipient_verify_failure
-    contain information about exactly what failed. In an ACL, after one of
-    these failures, the relevant variable contains one of the following words:
-
-      qualify       the address was unqualified (no domain), and the message
-                    was neither local nor came from an exempted host;
-
-      route         routing failed;
-
-      mail          routing succeeded, and a callout was attempted; rejection
-                    occurred at or before the MAIL command (that is, on initial
-                    connection, HELO, or MAIL);
-
-      recipient     the RCPT command in a callout was rejected;
-
-      postmaster    the postmaster check in a callout was rejected.
-
-    The main use of these variables is expected to be to distinguish between
-    rejections of MAIL and rejections of RCPT.
-
- 8. The command line option -dd behaves exactly like -d except when used on a
-    command that starts a daemon process. In that case, debugging is turned off
-    for the subprocesses that the daemon creates. Thus, it is useful for
-    monitoring the behaviour of the daemon without creating as much output as
-    full debugging.
-
- 9. $host_address is now set to the target address during the checking of
-    ignore_target_hosts.
-
-10. There are four new variables called $spool_space, $log_space,
-    $spool_inodes, and $log_inodes. The first two contain the amount of free
-    space in the disk partitions where Exim has its spool directory and log
-    directory, respectively. (When these are in the same partition, the values
-    will, of course, be the same.) The second two variables contain the numbers
-    of free inodes in the respective partitions.
-
-    NOTE: Because disks can nowadays be very large, the values in the space
-    variables are in kilobytes rather than in bytes. Thus, for example, to
-    check in an ACL that there is at least 50M free on the spool, you would
-    write:
-
-       condition = ${if > {$spool_space}{50000}{yes}{no}}
-
-    The values are recalculated whenever any of these variables is referenced.
-    If the relevant file system does not have the concept of inodes, the value
-    of those variables is -1. If the operating system does not have the ability
-    to find the amount of free space (only true for experimental systems), the
-    space value is -1.
-
-11. It is now permitted to omit both strings after an "if" condition; if the
-    condition is true, the result is the string "true". As before, when the
-    second string is omitted, a false condition yields an empty string. This
-    makes it less cumbersome to write custom ACL and router conditions. For
-    example, instead of
-
-      condition = ${if eq {$acl_m4}{1}{yes}{no}}
-
-    or the shorter form
-
-      condition = ${if eq {$acl_m4}{1}{yes}}
-
-    (because the second string has always defaulted to ""), you can now write
-
-      condition = ${if eq {$acl_m4}{1}}
-
-    Previously this was a syntax error.
-
-12. There is a new "record type" that can be specified in dnsdb lookups. It
-    is "zns" (for "zone NS"). It performs a lookup for NS records on the given
-    domain, but if none are found, it removes the first component of the domain
-    name, and tries again. This process continues until NS records are found
-    or there are no more components left (or there's a DNS error). In other
-    words, it may return the name servers for a top-level domain, but it never
-    returns the root name servers. If there are no NS records for the top-level
-    domain, the lookup fails.
-
-    For example, ${lookup dnsdb{zns=xxx.quercite.com}} returns the name
-    servers for quercite.com, whereas ${lookup dnsdb{zns=xxx.edu}} returns
-    the name servers for edu, assuming in each case that there are no NS
-    records for the full domain name.
-
-    You should be careful about how you use this lookup because, unless the
-    top-level domain does not exist, the lookup will always return some host
-    names. The sort of use to which this might be put is for seeing if the name
-    servers for a given domain are on a blacklist. You can probably assume that
-    the name servers for the high-level domains such as .com or .co.uk are not
-    going to be on such a list.
-
-13. Another new "record type" is "mxh"; this looks up MX records just as "mx"
-    does, but it returns only the names of the hosts, omitting the priority
-    values.
-
-14. It is now possible to specify a list of domains or IP addresses to be
-    looked up in a dnsdb lookup. The list is specified in the normal Exim way,
-    with colon as the default separator, but with the ability to change this.
+ 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 <some conditions>
+           log_reject_target =
+
+    The modifier can be used in SMTP and non-SMTP ACLs. It applies to both
+    permanent and temporary rejections.
+
+ 3. There is a new authenticator called "dovecot". This is an interface to the
+    authentication facility of the Dovecot POP/IMAP server, which can support a
+    number of authentication methods. If you are using Dovecot to authenticate
+    POP/IMAP clients, it might be helpful to use the same mechanisms for SMTP
+    authentication. This is a server authenticator only. The only option is
+    server_socket, which must specify the socket which is the interface to
+    Dovecot authentication. The public_name option must specify an
+    authentication mechanism that Dovecot is configured to support. You can
+    have several authenticators for different mechanisms. For example:
+
+      dovecot_plain:
+        driver = dovecot
+        public_name = PLAIN
+        server_name = /var/run/dovecot/auth-client
+        server_setid = $auth1
+
+      dovecot_ntlm:
+        driver = dovecot
+        public_name = NTLM
+        server_name = /var/run/dovecot/auth-client
+        server_setid = $auth1
+
+    If the SMTP connection is encrypted, or if $sender_host_address is equal to
+    $interface_address (that is, the connection is local), the "secured" option
+    is passed in the Dovecot authentication command. If, for a TLS connection,
+    a client certificate has been verified, the "valid-client-cert" option is
+    passed.
+
+ 4. The variable $message_headers_raw provides a concatenation of all the
+    messages's headers without any decoding. This is in contrast to
+    $message_headers, which does RFC2047 decoding on the header contents.
+
+ 5. In a DNS black list, when the facility for restricting the matching IP
+    values is used, the text from the TXT record that is set in $dnslist_text
+    may not reflect the true reason for rejection. This happens when lists are
+    merged and the IP address in the A record is used to distinguish them;
+    unfortunately there is only one TXT record. One way round this is not to
+    use merged lists, but that can be inefficient because it requires multiple
+    DNS lookups where one would do in the vast majority of cases when the host
+    of interest is not on any of the lists.
+
+    A less inefficient way of solving this problem has now been implemented. If
+    two domain names, comma-separated, are given, the second is used first to
+    do an initial check, making use of any IP value restrictions that are set.
+    If there is a match, the first domain is used, without any IP value
+    restrictions, to get the TXT record. As a byproduct of this, there is also
+    a check that the IP being tested is indeed on the first list. The first
+    domain is the one that is put in $dnslist_domain. For example:
+
+      reject message  = rejected because $sender_ip_address is blacklisted \
+                        at $dnslist_domain\n$dnslist_text
+             dnslists = sbl.spamhaus.org,sbl-xbl.spamhaus.org=127.0.0.2 : \
+                        dul.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.10
+
+    For the first blacklist item, this starts by doing a lookup in
+    sbl-xbl.spamhaus.org and testing for a 127.0.0.2 return. If there is a
+    match, it then looks in sbl.spamhaus.org, without checking the return
+    value, and as long as something is found, it looks for the corresponding
+    TXT record. If there is no match in sbl-xbl.spamhaus.org, nothing more is
+    done. The second blacklist item is processed similarly.
+
+    If you are interested in more than one merged list, the same list must be
+    given several times, but because the results of the DNS lookups are cached,
+    the DNS calls themselves are not repeated. For example:
+
+      reject dnslists = http.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.2 : \
+                       socks.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.3 : \
+                        misc.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.4 : \
+                         dul.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.10
+
+    In this case there is a lookup in dnsbl.sorbs.net, and if none of the IP
+    values matches (or if no record is found), this is the only lookup that is
+    done. Only if there is a match is one of the more specific lists consulted.
+
+ 6. All authenticators now have a server_condition option. Previously, only
+    plaintext had this, and this has not changed: it must be set to the
+    authenticator as a server. For the others, if server_condition is set, it
+    is expanded if authentication is successful, and treated exactly as it is
+    in plaintext. This can serve as a means of adding authorization to an
+    authenticator.
+
+ 7. There is a new command-line option called -Mset. It is useful only in
+    conjunction with -be (that is, when testing string expansions). It must be
+    followed by a message id; Exim loads the given message from its spool
+    before doing the expansions, thus setting message-specific variables such
+    as $message_size and the header variables. The $recipients variable is
+    available. This feature is provided to make it easier to test expansions
+    that make use of these variables. However, Exim must be called by an admin
+    user when -Mset is used.
+
+ 8. Another similar new command-line option is called -bem. It operates like
+    -be except that it must be followed by the name of a file. For example:
+
+      exim -bem /tmp/testmessage
+
+    The file is read as a message (as if receiving a locally-submitted non-SMTP
+    message) before any of the test expansions are done. Thus, message-specific
+    variables such as $message_size and $h_from: are available. However, no
+    Received: header is added to the message. If the -t option is set,
+    recipients are read from the headers in the normal way, and are shown in
+    the $recipients variable. Note that recipients cannot be given on the
+    command line, because further arguments are taken as strings to expand
+    (just like -be).
+
+ 9. When an address is delayed because of a 4xx response to a RCPT command, it
+    is now the combination of sender and recipient that is delayed in
+    subsequent queue runs until its retry time is reached. You can revert to
+    the previous behavious, that is, delay the recipient independent of the
+    sender, by setting address_retry_include_sender=false in the smtp
+    transport. However, this can lead to problems with servers that regularly
+    issue 4xx responses to RCPT commands.
+
+10. Unary negation and the bitwise logical operators and, or, xor, not, and
+    shift, have been added to the eval: and eval10: expansion items. These
+    items may now contain arithmetic operators (plus, minus, times, divide,
+    remainder, negate), bitwise operators (and, or, xor, not, shift), and
+    parentheses. All operations are carried out using signed integer
+    arithmetic. Operator priorities are as in C, namely:
+
+      (highest) not, negate
+                times, divide, remainder
+                plus, minus
+                shift-left, shift-right
+                and
+                xor
+      (lowest)  or
+
+    Binary operators with the same priority are evaluated from left to right.
     For example:
 
-      ${lookup dnsdb{one.domain.com:two.domain.com}}
-      ${lookup dnsdb{a=one.host.com:two.host.com}}
-      ${lookup dnsdb{ptr = <; 1.2.3.4 ; 4.5.6.8}}
-
-    In order to retain backwards compatibility, there is one special case: if
-    the lookup type is PTR and no change of separator is specified, Exim looks
-    to see if the rest of the string is precisely one IPv6 address. In this
-    case, it does not treat it as a list.
-
-    The data from each lookup is concatenated, with newline separators (by
-    default - see 14 below), in the same way that multiple DNS records for a
-    single item are handled.
+      ${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
 
-    The lookup fails only if all the DNS lookups fail. As long as at least one
-    of them yields some data, the lookup succeeds. However, if there is a
-    temporary DNS error for any of them, the lookup defers.
 
-15. It is now possible to specify the character to be used as a separator when
-    a dnsdb lookup returns data from more than one DNS record. The default is a
-    newline. To specify a different character, put '>' followed by the new
-    character at the start of the query. For example:
-
-      ${lookup dnsdb{>: a=h1.test.ex:h2.test.ex}}
-      ${lookup dnsdb{>| mxh=<;m1.test.ex;m2.test.ex}}
-
-    It is permitted to specify a space as the separator character. Note that
-    more than one DNS record can be found for a single lookup item; this
-    feature is relevant even when you do not specify a list.
-
-    The same effect could be achieved by wrapping the lookup in ${tr...}; this
-    feature is just a syntactic simplification.
-
-16. It is now possible to supply a list of domains and/or IP addresses to be
-    lookup up in a DNS blacklist. Previously, only a single domain name could
-    be given, for example:
-
-      dnslists = black.list.tld/$sender_host_name
-
-    What follows the slash can now be a list. As with all lists, the default
-    separator is a colon. However, because this is a sublist within the list of
-    DNS blacklist domains, it is necessary either to double the separators like
-    this:
-
-      dnslists = black.list.tld/name.1::name.2
-
-    or to change the separator character, like this:
-
-      dnslists = black.list.tld/<;name.1;name.2
-
-    If an item in the list is an IP address, it is inverted before the DNS
-    blacklist domain is appended. If it is not an IP address, no inversion
-    occurs. Consider this condition:
-
-       dnslists = black.list.tls/<;192.168.1.2;a.domain
-
-    The DNS lookups that occur are for
-
-       2.1.168.192.black.list.tld  and  a.domain.black.list.tld
-
-    Once a DNS record has been found (that matches a specific IP return
-    address, if specified), no further lookups are done.
-
-17. The log selector queue_time_overall causes Exim to output the time spent on
-    the queue as an addition to the "Completed" message. Like queue_time (which
-    puts the queue time on individual delivery lines), the time is tagged with
-    "QT=", and it is measured from the time that the message starts to be
-    received, so it includes the reception time.
-
-18. It is now possible to use both -bF and -bf on the same command, in order to
-    test a system filter and a user filter in the same run. For example:
-
-      exim -bF /system/filter -bf /user/filter </test/message
-
-    This is helpful when the system filter adds header lines or sets filter
-    variables that are used by the user filter.
-
-
-Version 4.43
+Version 4.63
 ------------
 
- 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.
-
- 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:<string>} 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:
-
-                    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.
-
-    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.
-
-    xx.1 Using cyrus_sasl as a server
-
-    The cyrus_sasl authenticator has four private options. It puts the username
-    (on a successful authentication) into $1.
-
-    server_hostname         Type: string*         Default: $primary_hostname
-
-        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.
-
-    server_mech             Type: string                Default: public_name
-
-        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:
-
-        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
-    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=<address list>". 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
+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 <variable>[,<variable>...]
+        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
 ------------
 
- 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.
-
- 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:
-
-      verify = sender/callout=5s,maxwait=20s
+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:
 
- 4. Changes to the "personal" filter test:
+     ${readsocket{inet:[::1]:1234}{<request data>}...
 
-    (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.
+   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 the message contains any header line starting with "List-" it is
-    treated as non-personal.
+2. If a redirect router sets up file or pipe deliveries for more than one
+   incoming address, and the relevant transport has batch_max set greater than
+   one, a batch delivery now occurs.
 
-    (3) The test for "circular" in the Subject: header line has been removed
-    because it now seems ill-conceived.
+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.
 
- 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.
 
-
-Version 4.40
+Version 4.61
 ------------
 
-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. log_incoming_interface affects more log lines.
+The documentation is up-to-date for the 4.61 release. Major new features since
+the 4.60 release are:
 
- 2. New ACL modifier "control = submission".
+. An option called disable_ipv6, to disable the use of IPv6 completely.
 
- 3. CONFIGURE_OWNER can be set at build time to define an alternative owner for
-    the configuration file, in addition to root and exim.
+. An increase in the number of ACL variables to 20 of each type.
 
- 4. Added expansion variables $body_zerocount, $recipient_data, and
-    $sender_data.
+. 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.
 
- 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.
+. The default for rfc1413_query_timeout has been changed from 30s to 5s.
 
- 6. The special item "+ignore_unknown" may now appear in host lists.
+. It is possible to use setclassresources() on some BSD OS to control the
+  resources used in pipe deliveries.
 
- 7. The special domain-matching patterns @mx_any, @mx_primary, and
-    @mx_secondary can now be followed by "/ignore=<ip list>".
+. A new ACL modifier called add_header, which can be used with any verb.
 
- 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.
+. More errors are detectable in retry rules.
 
- 9. New lookup type called "iplsearch".
+There are a number of other additions too.
 
-10. New log selectors ident_timeout, tls_certificate_verified, queue_time,
-    deliver_time, outgoing_port, return_path_on_delivery.
 
-11. New global options smtp_active_hostname and tls_require_ciphers.
-
-12. Exinext has -C and -D options.
+Version 4.60
+------------
 
-13. "domainlist_cache" forces caching of an apparently variable list.
+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.
 
 ****