From: mouss (moussnetoyen.net)
Date: Mon May 26 2008 - 20:18:46 CDT

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Anders wrote:
> Hi.
>
> We are currently running SQLgrey with good results, but sometimes delayed
> mails can be an annoyance.

do not greylist all mail. greylisting should be done selectively. also,
a client that successfully retries should be whitelisted forever.

when I see abusive greylisting, I "bounce" the message and whitelist the
client and domain. my server has better things to do.

and with:

$ host 77.75.163.100
100.163.75.77.in-addr.arpa domain name pointer
77.75.163.100.customers.telelet.dk.
$ host 77.75.163.100.customers.telelet.dk
Host 77.75.163.100.customers.telelet.dk not found: 3(NXDOMAIN)

you get a REJECT here (generic rDNS gets a reject_unknown_client among
other things).

> Also, there is some concern about us not being
> able to recover affected mails.
>
> For these reasons, I would like to greylist only after DATA. This way, we
> could have the rejected mails in a quarantine area. Also, we could
> greylist only above some SpamAssassin threshold.
>
> I know that this could be done with a before-queue content filter, but I
> have not been able to find any. Is there some recommended tool for this
> setup (Postfix friendly, obviously)?
>
> Before I go writing my own, is the lack of such a tool due to it being a
> really bad idea? We have sufficient bandwidth, CPU and disk resources for
> this setup, but I read that there might also be some compatibility
> problems with tempfail after DATA. I have, however, not been able to find
> any real data on the size of this problem.
>
>

what's the point? did you do measures that show how much spam you'll block?

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