[Dovecot] For the record: Postfix+Spamassassin+ClamAV+Dovecot

[James Butler]

Egbert Jan van den Bussche wrote:
>> -----Oorspronkelijk bericht-----
>> Van: dovecot-bounces+egbert=vandenbussche.nl at dovecot.org 
>> [mailto:dovecot-bounces+egbert=vandenbussche.nl at dovecot.org] 
>> Namens James Butler
>> Verzonden: vrijdag 17 april 2009 20:58
>> Aan: Dovecot Mailing List
>> Onderwerp: [Dovecot] For the record: 
>> Postfix+Spamassassin+ClamAV+Dovecot
>>
>>
>> Postfix 2.5.5
>> SpamAssassin 3.2.5 (under Perl 5.10.0)
>> ClamAV 0.95.1
>> Dovecot 1.2.rc2
>>
>> works fine on Fedora 10.
>>
>> Installed Dovecot and ClamAV from source and everything else 
>> using yum.
>>
>> I'm using the ClamAV plugin for Spamassassin:  
>> http://wiki.apache.org/spamassassin/ClamAVPlugin
>>
>> I'm calling Spamassassin with:
>>
>> /etc/postfix/main.cf:
>> mailbox_command = /usr/bin/spamc -f -e 
>> /usr/local/libexec/dovecot/deliver
>>
>> Postfix hands off to Spamassassin, which processes ALL mail (not just
>> attachments) through the ClamAV plugin before parsing for 
>> spam, and then hands the whole mess off to Dovecot for 
>> 'deliver' to handle.
>>
>> How simple is that?
>>
>> Since ClamAV scanns all mail, it might be too 
>> processor-intensive for really large mail systems, but it is 
>> working great for our 120+ user system with lots of spam 
>> coming in. If you're using Procmail or some other 
>> preprocessor that can hand off to a pipe, then you could skip 
>> the plugin and pipe messages over a certain size (i.e. >1024) 
>> to clamd, instead.
>>
>> Enjoy!
>>
>> James
> 
> Hi!
> 
> Apologies for digging an old thread from the bin. I was wondering how this
> relates to Amavisd? Should I regard the proposed plugin solution as a 'poor
> mans' solution when one does not want to install amavis?
> 
> Thanks!
> Egbert Jan (NL)
> 
> 

The plugin setup is required for my solution because of issues between
Procmail and Postfix when Postfix is running in a QMail-style Maildir
setup, which Procmail seems to have issues with, at least for me.
(I couldn't get Procmail to recognize environment variables correctly in
my Fedora 10 installation, so I just stopped using it in favor of
Dovecot's Sieve.)

Amavisd would *replace* Procmail, similar to what Sieve would do. You
would pipe your mail to Amavisd, test messages there, and then send
qualified messages to 'deliver' or to another program for further
processing/flagging. For example, under Amavisd, you would want to test
for messages >1024 bytes (1 MB) and pipe them through your anti-virus
app and then from there *back* to Amavisd to check for virus flags (into
the bit bucket or 'deliver' to the user's 'Possible Virus' directory)
and then on to 'deliver' for normal delivery if there were no flags.

I've never used Amavisd, but this seems to be its purpose. FYI, the
above setup is easy to administer and since additional apps are not
required, it keeps the overhead down a bit. It could be considered a
"poor man's replacement" for Amavisd in that it makes Amavisd
irrelevant, AFAIK ... but Amavisd probably does other stuff that I
simply haven't found the need for, so I really couldn't tell you.

James