doc/doc-txt/NewStuff

   1 $Cambridge: exim/doc/doc-txt/NewStuff,v 1.120 2006/11/06 15:50:12 ph10 Exp $
   2
   3 New Features in Exim
   4 --------------------
   5
   6 This file contains descriptions of new features that have been added to Exim.
   7 Before a formal release, there may be quite a lot of detail so that people can
   8 test from the snapshots or the CVS before the documentation is updated. Once
   9 the documentation is updated, this file is reduced to a short list.
  10
  11
  12 Version 4.64
  13 ------------
  14
  15 1. ACL variables can now be given arbitrary names, as long as they start with
  16    "acl_c" or "acl_m" (for connection variables and message variables), are
  17    at least six characters long, with the sixth character being either a digit
  18    or an underscore. The rest of the name can contain alphanumeric characters
  19    and underscores. This is a compatible change because the old set of
  20    variables such as acl_m12 are a subset of the allowed names. There may now
  21    be any number of ACL variables. For example:
  22
  23      set acl_c13   = value for original ACL variable
  24      set acl_c13b  = whatever
  25      set acl_m_foo = something
  26
  27    What happens if a syntactically valid but undefined ACL variable is
  28    referenced depends on the setting of the strict_acl_vars option. If it is
  29    false (the default), an empty string is substituted; if it is true, an error
  30    is generated. This affects all ACL variables, including the "old" ones such
  31    as acl_c4. (Previously there wasn't the concept of an undefined ACL
  32    variable.)
  33
  34    The implementation has been done in such a way that spool files containing
  35    ACL variable settings written by previous releases of Exim are compatible
  36    and can be read by the new release. If only the original numeric names are
  37    used, spool files written by the new release can be read by earlier
  38    releases.
  39
  40 2. There is a new ACL modifier called log_reject_target. It makes it possible
  41    to specify which logs are used for messages about ACL rejections. Its
  42    argument is a list of words which can be "main", "reject", or "panic". The
  43    default is "main:reject". The list may be empty, in which case a rejection
  44    is not logged at all. For example, this ACL fragment writes no logging
  45    information when access is denied:
  46
  47      deny <some conditions>
  48           log_reject_target =
  49
  50    The modifier can be used in SMTP and non-SMTP ACLs. It applies to both
  51    permanent and temporary rejections.
  52
  53 3. There is a new authenticator called "dovecot". This is an interface to the
  54    authentication facility of the Dovecot POP/IMAP server, which can support a
  55    number of authentication methods. If you are using Dovecot to authenticate
  56    POP/IMAP clients, it might be helpful to use the same mechanisms for SMTP
  57    authentication. This is a server authenticator only. The only option is
  58    server_socket, which must specify the socket which is the interface to
  59    Dovecot authentication. The public_name option must specify an
  60    authentication mechanism that Dovecot is configured to support. You can have
  61    several authenticators for different mechanisms. For example:
  62
  63      dovecot_plain:
  64        driver = dovecot
  65        public_name = PLAIN
  66        server_name = /var/run/dovecot/auth-client
  67        server_setid = $auth1
  68
  69      dovecot_ntlm:
  70        driver = dovecot
  71        public_name = NTLM
  72        server_name = /var/run/dovecot/auth-client
  73        server_setid = $auth1
  74
  75    If the SMTP connection is encrypted, or if $sender_host_address is equal to
  76    $interface_address (that is, the connection is local), the "secured" option
  77    is passed in the Dovecot authentication command. If, for a TLS connection, a
  78    client certificate has been verified, the "valid-client-cert" option is
  79    passed.
  80
  81 4. The variable $message_headers_raw provides a concatenation of all the
  82    messages's headers without any decoding. This is in contrast to
  83    $message_headers, which does RFC2047 decoding on the header contents.
  84
  85 5. In a DNS black list, when the facility for restricting the matching IP
  86    values is used, the text from the TXT record that is set in $dnslist_text
  87    may not reflect the true reason for rejection. This happens when lists are
  88    merged and the IP address in the A record is used to distinguish them;
  89    unfortunately there is only one TXT record. One way round this is not to use
  90    merged lists, but that can be inefficient because it requires multiple DNS
  91    lookups where one would do in the vast majority of cases when the host of
  92    interest is not on any of the lists.
  93
  94    A less inefficient way of solving this problem has now been implemented. If
  95    two domain names, comma-separated, are given, the second is used first to do
  96    an initial check, making use of any IP value restrictions that are set. If
  97    there is a match, the first domain is used, without any IP value
  98    restrictions, to get the TXT record. As a byproduct of this, there is also a
  99    check that the IP being tested is indeed on the first list. The first domain
 100    is the one that is put in $dnslist_domain. For example:
 101
 102      reject message  = rejected because $sender_ip_address is blacklisted \
 103                        at $dnslist_domain\n$dnslist_text
 104             dnslists = sbl.spamhaus.org,sbl-xbl.spamhaus.org=127.0.0.2 : \
 105                        dul.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.10
 106
 107    For the first blacklist item, this starts by doing a lookup in
 108    sbl-xbl.spamhaus.org and testing for a 127.0.0.2 return. If there is a
 109    match, it then looks in sbl.spamhaus.org, without checking the return value,
 110    and as long as something is found, it looks for the corresponding TXT
 111    record. If there is no match in sbl-xbl.spamhaus.org, nothing more is done.
 112    The second blacklist item is processed similarly.
 113
 114    If you are interested in more than one merged list, the same list must be
 115    given several times, but because the results of the DNS lookups are cached,
 116    the DNS calls themselves are not repeated. For example:
 117
 118      reject dnslists = http.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.2 : \
 119                       socks.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.3 : \
 120                        misc.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.4 : \
 121                         dul.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.10
 122
 123    In this case there is a lookup in dnsbl.sorbs.net, and if none of the IP
 124    values matches (or if no record is found), this is the only lookup that is
 125    done. Only if there is a match is one of the more specific lists consulted.
 126
 127 6. All authenticators now have a server_condition option. Previously, only
 128    plaintext had this, and this has not changed: it must be set to the
 129    authenticator as a server. For the others, if server_condition is set, it is
 130    expanded if authentication is successful, and treated exactly as it is in
 131    plaintext. This can serve as a means of adding authorization to an
 132    authenticator.
 133
 134 7. There is a new command-line option called -Mset. It is useful only in
 135    conjunction with -be (that is, when testing string expansions). It must be
 136    followed by a message id; Exim loads the given message from its spool before
 137    doing the expansions, thus setting message-specific variables such as
 138    $message_size and the header variables. The $recipients variable is
 139    available. This feature is provided to make it easier to test expansions
 140    that make use of these variables. However, Exim must be called by an admin
 141    user when -Mset is used.
 142
 143 8. Another similar new command-line option is called -bem. It operates like -be
 144    except that it must be followed by the name of a file. For example:
 145
 146      exim -bem /tmp/testmessage
 147
 148    The file is read as a message (as if receiving a locally-submitted non-SMTP
 149    message) before any of the test expansions are done. Thus, message-specific
 150    variables such as $message_size and $h_from: are available. However, no
 151    Received: header is added to the message. If the -t option is set,
 152    recipients are read from the headers in the normal way, and are shown in the
 153    $recipients variable. Note that recipients cannot be given on the command
 154    line, because further arguments are taken as strings to expand (just like
 155    -be).
 156
 157 9. When an address is delayed because of a 4xx response to a RCPT command, it
 158    is now the combination of sender and recipient that is delayed in subsequent
 159    queue runs until its retry time is reached. You can revert to the previous
 160    behavious, that is, delay the recipient independent of the sender, by
 161    setting address_retry_include_sender=false in the smtp transport. However,
 162    this can lead to problems with servers that regularly issue 4xx responses to
 163    RCPT commands.
 164
 165
 166
 167 Version 4.63
 168 ------------
 169
 170 1. There is a new Boolean option called filter_prepend_home for the redirect
 171    router.
 172
 173 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
 174    start of receiving a non-SMTP message, before any of the message has been
 175    read.
 176
 177 3. When an SMTP error message is specified in a "message" modifier in an ACL,
 178    or in a :fail: or :defer: message in a redirect router, Exim now checks the
 179    start of the message for an SMTP error code.
 180
 181 4. There is a new parameter for LDAP lookups called "referrals", which takes
 182    one of the settings "follow" (the default) or "nofollow".
 183
 184 5. Version 20070721.2 of exipick now included, offering these new options:
 185     --reverse
 186         After all other sorting options have bee processed, reverse order
 187         before displaying messages (-R is synonym).
 188     --random
 189         Randomize order of matching messages before displaying.
 190     --size
 191         Instead of displaying the matching messages, display the sum
 192         of their sizes.
 193     --sort <variable>[,<variable>...]
 194         Before displaying matching messages, sort the messages according to
 195         each messages value for each variable.
 196     --not
 197         Negate the value for every test (returns inverse output from the
 198         same criteria without --not).
 199
 200
 201 Version 4.62
 202 ------------
 203
 204 1. The ${readsocket expansion item now supports Internet domain sockets as well
 205    as Unix domain sockets. If the first argument begins "inet:", it must be of
 206    the form "inet:host:port". The port is mandatory; it may be a number or the
 207    name of a TCP port in /etc/services. The host may be a name, or it may be an
 208    IP address. An ip address may optionally be enclosed in square brackets.
 209    This is best for IPv6 addresses. For example:
 210
 211      ${readsocket{inet:[::1]:1234}{<request data>}...
 212
 213    Only a single host name may be given, but if looking it up yield more than
 214    one IP address, they are each tried in turn until a connection is made. Once
 215    a connection has been made, the behaviour is as for ${readsocket with a Unix
 216    domain socket.
 217
 218 2. If a redirect router sets up file or pipe deliveries for more than one
 219    incoming address, and the relevant transport has batch_max set greater than
 220    one, a batch delivery now occurs.
 221
 222 3. The appendfile transport has a new option called maildirfolder_create_regex.
 223    Its value is a regular expression. For a maildir delivery, this is matched
 224    against the maildir directory; if it matches, Exim ensures that a
 225    maildirfolder file is created alongside the new, cur, and tmp directories.
 226
 227
 228 Version 4.61
 229 ------------
 230
 231 The documentation is up-to-date for the 4.61 release. Major new features since
 232 the 4.60 release are:
 233
 234 . An option called disable_ipv6, to disable the use of IPv6 completely.
 235
 236 . An increase in the number of ACL variables to 20 of each type.
 237
 238 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
 239   $2, $3, (though those are still set) because the numeric variables get used
 240   for other things in complicated expansions.
 241
 242 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
 243
 244 . It is possible to use setclassresources() on some BSD OS to control the
 245   resources used in pipe deliveries.
 246
 247 . A new ACL modifier called add_header, which can be used with any verb.
 248
 249 . More errors are detectable in retry rules.
 250
 251 There are a number of other additions too.
 252
 253
 254 Version 4.60
 255 ------------
 256
 257 The documentation is up-to-date for the 4.60 release. Major new features since
 258 the 4.50 release are:
 259
 260 . Support for SQLite.
 261
 262 . Support for IGNOREQUOTA in LMTP.
 263
 264 . Extensions to the "submission mode" features.
 265
 266 . Support for Client SMTP Authorization (CSA).
 267
 268 . Support for ratelimiting hosts and users.
 269
 270 . New expansion items to help with the BATV "prvs" scheme.
 271
 272 . A "match_ip" condition, that matches an IP address against a list.
 273
 274 There are many more minor changes.
 275
 276 ****