Re: [exim] Follow up to hole in bucket message

On 14/04/2008, Phil Chambers <P.A.Chambers@???> wrote:
> There is a spam-blocking scheme where you allow users to opt in or out of SMTP
> rejections. This is done by deferring at RCPT TO time any users who have opted
> differently from the first recipient. So, at DATA time you can to accept or
> reject all recipients which did not defer because they have all opted the same
> way. You expect the other recipients to arrive in a re-try later.
>
> Is this widely used? Are there any significant reasons for not doing it?

This technique is written up in the old 'Exiscan Examples' doc, which
is on the wiki. How widely used? Dunno, but I use it in exactly the
way your describe. I've never done any serious analysis of how many
receipients it actually defers, probably very few since the option
granularity here is per-domain not per-user, and the frequency of
multiple-recipient mail arriving across multiple domains must be very
low indeed.

But it's zero-maintenance, so it pays its way.

Bill describes the next level of sophistication, which assesses the
high and low watermarks of recipients' preferences - we're not that
clever!

Peter

--
Peter Bowyer
Email: peter@???
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