[Dovecot] Antispam only when LMTP delivers some specific messages
Hello, we're setting up a weird platform where every incoming email is passed from the MTA directly to a tool that then uses dovecot LMTP to deliver the message into the user mailbox.
We are legally *not* allowed to run antispam on all the incoming messages, but only on some of them, as they are recognized by the aforementioned tool; but given that tool directly uses LMTP to delivers the mail we need to find a way to parse the messages passing thru LMTP and run spamassassin only on those matching some regex on subject and mail body.
Is is possible to do that with some dovecot LMTP feature?
i've read a lot of documentation about how to possibly implement it and it *seems* there would be a way using pigeonhole sieve and extprograms - what do you think?
The idea I have in mind is something like:
- identify the mails we want to scan with spamassassin (using regex or whatever else to precisely pin-point them)
- run SA on those
- in case it's spam, rewrite the subject (or similar)
Do you think it's something doable with dovecot?
Thanks in advance,
Sandro Tosi Product Engineer Shared Hosting Products R&D | Dada.pro eml sandro.tosi@register.it
Am 03.08.2012 14:03, schrieb Sandro Tosi:
We are legally *not* allowed to run antispam on all the incoming messages
you ARE allowed if you are doing it right
right in this context means you have to run the filter pre-queue and REJECT blocked messages, so the sending server knows that you did NOT accept the message and can send a bounce to his user
wrong in this context means you accept the message, filter it after that and throw it away while the sender has a confirmed delivery - this is a legal problem in the first front and technically wrong because you risk to become a backscatter by starting active bounes on your server if you are not 100% sure how all the pieces work togehter and how the whole system acts in each situation
bringing LMTP and Dovecot in the context of spam-filtering is automatically doing it completly wrong
Hello, thanks for you reply.
On 08/03/2012 02:09 PM, Reindl Harald wrote:
Am 03.08.2012 14:03, schrieb Sandro Tosi:
We are legally *not* allowed to run antispam on all the incoming messages
you ARE allowed if you are doing it right
please.. don't consider everyone that writes a junior with no experience, I know what i'm doing :) In a classic mail setup, i'd have done as you described, but the introduction of my email makes it clear this is a particular situation.
as I said, we *cannot* do it the "standard way"! we are forced to accept messages if they come in a particular format (yes even spam ones), and we can only run SA on a subset if the incoming mails, as decided by the tool we're passing all the messages to.
Now, getting back on topic, is it possible to do what I have in mind? is there some other solutions to achieve my goal?
Regards,
Sandro Tosi Product Engineer Shared Hosting Products R&D | Dada.pro eml sandro.tosi@register.it
Am 03.08.2012 14:03, schrieb Sandro Tosi:
Hello, we're setting up a weird platform where every incoming email is passed from the MTA directly to a tool that then uses dovecot LMTP to deliver the message into the user mailbox.
We are legally *not* allowed to run antispam on all the incoming messages, but only on some of them, as they are recognized by the aforementioned tool; but given that tool directly uses LMTP to delivers the mail we need to find a way to parse the messages passing thru LMTP and run spamassassin only on those matching some regex on subject and mail body.
Is is possible to do that with some dovecot LMTP feature?
i've read a lot of documentation about how to possibly implement it and it *seems* there would be a way using pigeonhole sieve and extprograms - what do you think?
The idea I have in mind is something like:
- identify the mails we want to scan with spamassassin (using regex or whatever else to precisely pin-point them)
- run SA on those
- in case it's spam, rewrite the subject (or similar)
Do you think it's something doable with dovecot?
Thanks in advance,
you may use global sieve rules perhaps look here for ideas
http://wiki2.dovecot.org/Pigeonhole/Sieve/Examples#Spam.2BAC8-Virus_rules
-- Best Regards MfG Robert Schetterer
participants (3)
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Reindl Harald
-
Robert Schetterer
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Sandro Tosi