Re: [Exim] Amavis-perl and Exim 4.10, somebody get it to wor…

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Συντάκτης: Marc Haber
Ημερομηνία:  
Προς: exim-users
Αντικείμενο: Re: [Exim] Amavis-perl and Exim 4.10, somebody get it to work (or other solution to virus scanning)
On Thu, 16 Jan 2003 11:49:30 +0100, Alexander Koch <koch@???>
wrote:
>As a happy debian user I really like to have packages for
>things I do. At current there is no Exim4.deb at all. But
>things can be done.


there are preliminary exim4 packages available from
http://www.logic.univie.ac.at/~ametzler/debian/exim4manpages

The package should have been in Debian experimental before Christmas.
Guess we missed it this year.

>Do I understand it right that I could apply Exim various
>filters to specific routers/directors/whatever so I could
>in fact decide via the respective filters what is filtered
>and when?


amavis-ng can be used as an embedded perl function, and is usually
used from a system filter like this:

|  if
|  ${perl{amavis_filter_scan}{$message_id}{$sender_address}{$recipients}} is "drop"
|  then
|      seen finish
|  elif ${perl{amavis_filter_result}} is "fail"
|  then
|    fail "${perl{amavis_filter_text}}"
|  elif ${perl{amavis_filter_result}} is "freeze"
|  then
|    freeze "${perl{amavis_filter_text}}"
|  elif ${perl{amavis_filter_result}} is "accept"
|  then
|    headers add "X-Virus-Scanned-By: Amavis with ${perl{amavis_virus_scanner_list}} on ${primary_hostname}"
|  else
|    freeze "illegal output from amavis_filter_result: ${perl{amavis_filter_result}}"
|  endif


I guess that these functions can also be invoked from a router's
condition, but that has never been tried.

The general idea could possibly be that amavis-ng adds headers, and
the routers base their decision on these headers. The advantage of
that approach is that it is virtually guaranteed that the expensive
perl function is only run once per message.

>amavis-ng/amavis-perl therefore is able to do 'any'
>filtering, be it for virus and possible also for spam?


amavis-ng is a very modular design. While it was decided among the
developers that the "official" source code will only contain virus
scanner interfaces, it is as well possible to plug in modules that do
policy filtering (for example forbidding certain words or certain
kinds of attachment) or spam filtering. Hilko will at some time write
an amavis-ng module to interface with spamassassin, for example.

Everybody's free to contribute modules.

Greetings
Marc

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