Autor: ROGERS Richard Data: Para: exim-user Asunto: Re: [exim] Follow up to hole in bucket message
exim-users-bounces@??? wrote: > 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
Ditto here - it appears to apply to roughly 2% of all delivery attempts.
The only drawback is that a (very) few (legitimate) remote systems don't
seem able to cope and retry all recipients (whereupon the same problem
occurs again of course). Not enough of a problem to justify a change of
approach, though.
Richard
--
Richard Rogers
IT Development and Innovation Manager
Information Services, Staffordshire University
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