-$Cambridge: exim/doc/doc-misc/WishList,v 1.60 2006/02/28 10:03:06 ph10 Exp $
+$Cambridge: exim/doc/doc-misc/WishList,v 1.70 2007/02/27 11:51:27 ph10 Exp $
EXIM 4 WISH LIST
----------------
+This Wish List is now obsolete. The items it contains have been imported into
+the Exim Bugzilla, which is where all new wishes should be added. This file is
+no longer maintained. Some day it should be deleted.
+
+
+===============================================================================
Even when it was first released, Exim 4 had a Wish List because not all the
things suggested for it were implemented. The list has not stopped growing...
So several warnings could be generated as the mailbox got bigger and bigger.
------------------------------------------------------------------------------
-(146) 15-May-2000 M Allow SMTP error codes in retry rules
-
-This would allow special handling of certain errors from certain hosts. In
-particular, it would allow failing of certain 4xx codes.
-
-This is now available for 4xx responses to RCPT commands. Is anything more
-needed? Apparently, yes; there's been a request for a similar feature for MAIL
-commands.
-------------------------------------------------------------------------------
-
(148) 15-May-2000 S Warn recipient if message rejected for quota excession.
Heinz Ekker
different kinds of verify failure.
------------------------------------------------------------------------------
-(196) 30-Sep-03 S A way of detecting whether it was HELO or EHLO in the ACL
-
-$received_protocol isn't reset until after the command is accepted (which
-seems right), and $smtp_data shows only the arguments. Maybe $smtp_command?
-------------------------------------------------------------------------------
-
(197) 30-Sep-03 S MACROS_DROP_PRIVS and ALT_CONFIG_DROP_PRIVS
Now that alternative configurations can be restricted to certain directories,
that it can be used as a safety-net while testing configurations. Instead of a
local bounce, the message stays on the queue; instead of 5xx SMTP responses,
4xx ones are given.
-
-The ability to do the opposite - turn 4xx into 5xx under certain circumstances
-might also be useful (e.g. after a certain time). This might best be done by
-extending the retry logic to recognize 4xx as a special error. (This is now
-done.)
------------------------------------------------------------------------------
(202) 10-Oct-03 S -bvsomething to do a callout after the verify
------------------------------------------------------------------------------
(209) 31-Oct-03 S a way of making crashes in pipe commands temporary errors
-
------------------------------------------------------------------------------
(210) 31-Oct-03 S runtime option to change the daemon name used for tcprwappers
Unfortunately, this isn't quite as trivial as it seems.
------------------------------------------------------------------------------
-(215) 14-Nov-03 S A way of turning off message-submission fix-ups
-
-Globally, and perhaps also via an ACL control so that it can be done on a
-per-message basis. Is this still needed? Since this item was added to this
-list, default fixups for non-local messages have been removed, and control =
-submission has been added.
-------------------------------------------------------------------------------
-
(215) 26-Nov-03 M/L Conversion of IDNA domain names for logging
IDNA (RFCs 3490-3492) converts domains names containing non-ASCII characters
changed.)
------------------------------------------------------------------------------
-(216) 27-Nov-03 S Option to bounce if required TLS doesn't happen
-
-This is for the smtp transport with hosts_require_tls set. Currently, it
-defers. Possibly the best approach is to make the error one that can be seen by
-the retry logic.
-------------------------------------------------------------------------------
-
(217) 27-Nov-03 M A function to pass back variables from Perl
This is a function that can be called from Perl, to take a name and a value and
(236) 02-Feb-04 S String in local_scan that's added to the binary version string
------------------------------------------------------------------------------
-(237) 02-Feb-04 M Add_header in ACLs because "message" is overloaded
-
-This would be useful for verbs where "message" is an error message. See also
-333.
-------------------------------------------------------------------------------
-
(238) 05-Feb-04 S ${address to handle multiple addresses
At present, ${address expects to see just one address. An extension would let
both of them.
------------------------------------------------------------------------------
-(286) 21-Jul-04 M Distinguishing a larger number of errors
-
-For instance, detecting "connection reset by peer" (ENETRESET or ECONNRESET)
-might be useful.
-------------------------------------------------------------------------------
-
(288) 10-Aug-04 M Option for verify to require MX
e.g. verify=sender/require_mx
These are the main previous items:
Exim 3 Wish List: 41, 85, 149, 187.
-Exim 4 Wish List: 55, 62, 63, 160, 212, 237, 270, 314, 328.
+Exim 4 Wish List: 55, 62, 63, 160, 212, 270, 314, 328.
------------------------------------------------------------------------------
(334) 07-Jun-05 M Support for messages larger than 2G
(341) 15-Sep-05 S Add /return_path_retain to submission mode
-This would re-instate the behaviour prior to change 4.52/TF/02.
+This would re-instate the behaviour prior to change 4.52/PH/04.
------------------------------------------------------------------------------
(342) 26-Sep-05 T Log and maybe defer odd values for condition pre-condition
The natural syntax for this would be to use a regex, like this:
${lookup regex{/some/file regex}{found-string}{not-found-string}}
+However, it would be natural to want to use $1 etc in the found-string; this
+would be hard because of the lookup caching (if repeated, the lookup won't
+actually be done and therefore the numerical variables won't be set), and in
+any case, even without caching (and it could, I suppose, be disabled for this
+lookup) those variables are not in the right storage pool even if they were
+preserved after the lookup.
+
+An alternative approach might be to implement something like this:
+
+ ${scanfile{/some/file}{sub-expression}}
+
+where the sub-expression is expanded for every line in the file, with each line
+in turn being put into $value. This is like a conditional ${readfile, and in
+fact ${readfile could be written using ${scanfile. It would be nice to find a
+way of stopping the scan once something has happened. The only thing I can
+think of is to invent a variable that changes when scanning a line generates
+some non-null text, and then always to stop on a forced failure. That would
+allow expressions like this:
+
+ ${scanfile{/some/file}
+ {
+ ${if eq{$generated}{}{${if match{regex}{$value}{something}}} fail}
+ }}
+
+It's all rather clumsy. Once a line has matched and generated some text, the
+next iteration would stop the scan. Another thought: maybe use $scanline
+instead of $value (to save confusion) and have $scantext containing everything
+that's been generated so far. That sounds pretty flexible.
------------------------------------------------------------------------------
(344) 10-Oct-05 M Make debug_print work in authenticators
enwildlsearch.
------------------------------------------------------------------------------
-(348) 17-Nov-05 S Option to allow AUTH when not advertised.
+(351) 31-Mar-06 ? Allow some/all/a few internal variables to be set
+
+The original idea was to allow "set authenticated = x" to pretend a connection
+is authenticated after other conditions are true. This can, of course, be
+packaged up using macros in other ways. Setting other variables could cause
+problems.
+------------------------------------------------------------------------------
+
+(352) 04-Apr-06 S Add +accept_defer for host lists (and maybe others)
+
+At present, a defer causes a delivery defer. For non-critical ACLs there are
+times when it may be better to accept. See also 226 and 289.
+------------------------------------------------------------------------------
+
+(354) 30-Jun-06 ? Extensions to SMTP error codes
+
+A number of ideas arose following a discussion on the mailing list. I record
+them here so that they don't get lost. The motivations were to support the 551
+bounce code and enhanced status codes. Suggestions are to add a new ACL
+feature, possibly one of:
+
+ errorcode = 511
+ control = errorcode=551
+ message = 551 xxxx
-It seems that there are clients that send AUTH when it hasn't been advertised,
-some even after HELO, not even EHLO. Sigh. Possibly this should be an ACL
-control, to enable it to be restricted to certain hosts.
+where in the last case, it's recognized by being 3 digits. In all cases, the
+first digit must be "right" for the circumstance - ignore or fault if not?
+
+To handle ESC, perhaps a new variable called $smtp_errorcode, settable by an
+option in a router when it fails, would do the trick. It could be used in any
+of the above modifiers.
------------------------------------------------------------------------------
-(350) 28-Feb-06 S Additional errors for retry rules
+(355) 30-Jun-06 ? Facility to permit experiments with SMTP extensions
+
+This is what was suggested:
+
+- adding some expansion variables: $ehlo_extensions (which will
+ hold the remote server supported smtp extensions announced
+ in the ehlo) and $rcpt_arguments with any RCPT extra argument
+
+- a main configuration option for adding ehlo extensions to the
+ ehlo response, like:
+
+ extra_ehlo_extensions = XFOO : XBAR
+
+- a extra option for the smtp transport to add arguments to
+ the RCPT TO command, like:
+
+ rcpt_args = FOO=BAR (will make exim issue RCPT TO:<a@b.c> FOO=BAR
+ when delivering that message)
+
+- a new acl for unknown smtp commands
-(i) Unexpected connection close; (ii) mail_4xx.
+This should be very simple to implement and will allow to make
+some experiments and implement custom extensions, i.e. one to
+known if remote client will redirect on 551 or not. Also the acl
+for unknown smpt command could be used for other purposes, like
+to dectect and react to some kiddies that send things like
+http://... on the smtp port.
------------------------------------------------------------------------------
---- HWM 350 ------------------------------------------------------------------
+--- HWM 355 ------------------------------------------------------------------
---------------------------- End of WishList ---------------------------------
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