[Mimedefang] easy stream_by_recipient question

Michiel Brandenburg apex at xepa.nl
Tue Sep 29 14:31:03 EDT 2009

Jason Bertoch wrote:
>> When stream_by_recipient is in use, is the message copied for each
>> recipient before or after all the spam testing is done?
> I believe this is done prior to spam testing as each user may have different
> preferences.

This is indeed the reason for sending the each recipient of the email a 
seperate copy of the email and thus, like David pointed out it should be 
done before spam scanning the email.

One user might find it spam and the other might love Russian images.  A 
smarter approach would be, if at all possible in your situation, to 
"look" at the recipient's spam rules and send one message only per 
unique combination of these rules.  If you use per user bayes scanning 
this of course will not work.  I don't use this approach as there is 
only one bayes table all scanners work off.

What can be done is stream like this.
1. generate a hash for each user's spam rules (in the order the spam 
scanner looks at)
2. sort all destinations based on the hash
3. send only one email per unique hash (might have more than one recipient.

As most of our uses don't bother with making their own spam rules this 
saves us some scanning work.

PS: my android sends html mail, just found out this list does not like 
it this message or something like it might appear twice, as the response 
from the Listbot told me my original message was changed.
Michiel Brandenburg

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