From: Lionel Bouton (no email)
Date: Thu Mar 03 2005 - 05:27:23 EST
Greg A. Woods wrote the following on 03.03.2005 09:37 :
>[ On Tuesday, March 1, 2005 at 00:53:17 (+0100), Lionel Bouton wrote: ]
>
>
>>Subject: Re: Blocking mail from=<>
>>
>>Thanks for all of us poor stupid souls coding various greylisting policy
>>services...
>>
>>
>
>You're wasting other people's time to solve a problem that you have many
>other better alternatives to solve.
>
>
>
Has anyone said that greylisting is the holy grail? Personnaly I start
with the most safe Postfix UCE controls then hand it to greylisting,
then to RBLs and finally DSPAM does the delivery.
I don't think you have 'alternatives' for SPAM filtering, you have a set
of tools you can choose from but none of them is good enough to be used
alone.
>Either accept the mail when it's offered in as efficient a manner as
>possible (and then either deliver it as addressed or quarantine it); or
>reject it outright right away.
>
>
>
The problem is the amount of quarantine (or tagged messages) you
generate, the amount of CPU/disk space needed to filter the SPAM, the
time the users must spent searching for FP. Greylisting takes away a
good chunk of this, even after UCE controls. For admins using RBLs
before greylisting it either:
- stops the message
- delays it enough to allow the RBLs to kick in
often enough to make them happy with it.
>Anything else, especially what has been inappropriately called
>"greylisting",
>
Agreed, but the name is here :-/
> is an unnecessary abuse of the SMTP protocol and is a
>continual ongoing waste of everyone's time and resources.
>
>
Don't think so, the amount of time a server saves processing messages
that only greylisting can temporarily refuse far outweight the time
needed to process the occasional messages that have to be processed
twice. Sure this time is shared by the sender and the receiver and you
can argue that it is an "abuse" of the protocol.
But lets talk about what happens in reality. When I started SQLgrey one
of my goals was minimising this "waste of time" with auto-whitelisting.
For the 2 'efficiency' reports I already have :
- one has more than 99% (ie : less than 1 legit mail out of 100 is
delayed) after one month of SQLgrey learning,
- another is at 96% after one week.
So as far as I can tell this "waste of time" is marginal.
Best regards,
Lionel.
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