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********************************
* SHOULD YOU USE THIS PACKAGE? *
********************************

Since version 4.50, Exim has the content-scanning extension formerly
known as "exiscan" built-in. It has a number of advantages and
disadvantages compared to SA-Exim.

Advantages of built-in content-scanning interface:

 * One less configuration file to edit.
 * Spam control policy integrates better with Exim's ACL system.
 * It's possible to tell SA which user to scan for (the -u parameter of
   spamc). SA-Exim can't do that (yet).
 * Finer control over the mail header is possible, but not in a clean
   way (it involves putting all header fields you might possibly want
   to add in the report template, and using rather complicated
   expansion expressions to extract the wanted ones from
   $spam_report). At any rate, you can choose a prefix different from
   "X-Spam-".

Advantages of SA-Exim:

 * It is possible to use the report_safe feature, which turns mail
   deemed to be spam into a message/rfc822 attachment of a report
   message. (Note however that if you do, then any X-SA-* fields added
   to help the greylisting module can't be removed.)
 * All the add_header and rewrite_header options in 
   /etc/spamassassin/local.cf will be obeyed. In other words,
   everything will be *almost* as if you filtered the mail through 
   spamassassin on the command line.
 * So-called teergrubing ("tarpitting") is possible in a way that
   isn't possible with exiscan (I'm not in any way saying that it
   works as a counterattack against spammers).
 * You can simply add the sa-exim package to a standard exim4
   installation and it should, in principle, instantly work (except
   you have to uncomment one line in sa-exim.conf).

Both alternatives enable you to defer, greylist, reject, and blackhole
mail, optionally saving copies, at configurable score levels.

*****************
* CONFIGURATION *
*****************

This version of the sa-exim package defaults to placing a configuration
sniplet in /etc/exim4/conf.d/. Depending on what you have answered to the
DebConf questions while configuring Exim4, the module will be loaded
automatically, or human intervention is required.

To find out what configuration file Exim4 is using, issue:

  $ exim4 -bV | tail -1
  Configuration file is /path/to/configfile

If /path/to/configfile shows:

  - /etc/exim4/exim4.conf
    You are using the hand-crafted configuration file.
        See the 'HAND-CRAFTED' section below.
        
  - /var/lib/exim4/config.autogenerated 
    You are using the debianized configuration scheme - with either
    'split' or 'unsplit' configuration file.
        See the 'DEBIANIZED' section below.


HAND-CRAFTED
------------

Use 'grep "local_scan_path" /etc/exim4/exim4.conf" to see if the sa-exim
line is included in the configuration. If grep returns something, check
if it matches the following line. If grep returns nothing, you have to
manually add the following line to the exim4.conf file and restart exim4.

    local_scan_path = /usr/lib/exim4/local_scan/sa-exim.so

Change or add the line above and manually restart exim4 by issuing
'invoke-rc.d exim4 reload' or '/etc/init.d/exim4 reload' as root.


DEBIANIZED
----------

Use 'grep "local_scan_path" /var/lib/exim4/config.autogenerated' to
see if the sa-exim line is included in the configuration. If grep
returns something, you're set and already using the sa-exim module. If
grep returns nothing, we need to figure out a few things:

Issue:
        $ grep "use_split_config" /etc/exim4/update-exim4.conf.conf 
      dc_use_split_config='true'

If your result shows 'false' where mine shows 'true', then you're
using the unsplit configuration, generated from
/etc/exim4/exim4.conf.template.  If you haven't customized that file
you could edit /etc/exim4/update-exim4.conf.conf by hand, change the
'false' to 'true' and issue 'update-exim4.conf' as root. Then, check
again if the sa-exim module line is included. It should. If it still
isn't: mail me. If it is, restart exim4 by issuing 'invoke-rc.d exim4
restart' or '/etc/init.d/exim4 restart' as root. If you *have*
customized /etc/exim4/exim4.conf.template, then you'd better stick
with the unsplit configuration scheme and add the local_scan_path
setting by hand, like with the hand-crafted configuration file.

Next, read all about greylisting and sa-exim:

***************
* GREYLISTING *
***************
Notes on greylisting with sa-exim.

If you use SpamAssassin 3.0 or better, you do not need to patch it, you
can just use the Greylisting module shipped with sa-exim. 
The only thing you need to do to enable it, is to copy the 4 lines below
loadplugin in the greylisting README, and adjust the score if you wish (see
README.Greylisting for details)


If you use a version of SA older than 3.0 (if you are, you really,
really should upgrade!), you will need to patch spamassassin's sources
to support greylisting.

There are two versions of the patches: 
 - /usr/share/doc/sa-exim/patches/SA-greylisting-2.4x.diff 
   This patch can be applied to versions 2.4x of SpamAssassin. Note
   that this patch is not fully functional anymore, it is just left as
   a template should you want to backport the current 2.6x patch. 
   That said, you really ought to upgrade SA to 2.6x or 3.x

 - /usr/share/doc/sa-exim/patches/SA-greylisting-2.6.diff 
   This patch can be applied to versions 2.6x of SpamAssassin.

Please read README.Greylisting for more information on how to enable
this feature, and what further changes are needed.
Note that this configuration won't be supported in the future, and you
are encouraged to upgrade to SA 3.0 or better.

*************
* BE WARNED *
*************

By applying these patches, you change the sourcecode of SpamAssassin
(again, this is if you use a version of SpamAssassin earlier than 3.0)
This also means that when the SpamAssassin package gets upgraded, the
changes made by the patch are LOST. 
This *MIGHT* cause your mail setup to break. It might be best to put
SpamAssassin on hold:

  $ echo "spamassassin hold" | dpkg --set-selections

You can later set it to install again with:

  $ echo "spamassassin install" | dpkg --set-selections


**********************************
* NOTICE ABOUT SPAMC CONFIG FILE *
**********************************

Recent versions of spamc can read command-line parameters and switches
from a configuration file called /etc/spamassassin/spamc.conf. If that
file specifies conflicting options, it will prevent SA-Exim from 
working. For now, you'll have to make sure that it doesn't.