Re: [exim] DynaStop - I like it!

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Autor: Chris Lightfoot
Data:  
Dla: Peter Bowyer
CC: Exim, Users
Temat: Re: [exim] DynaStop - I like it!
On Thu, Nov 02, 2006 at 11:44:45PM +0000, Peter Bowyer wrote:
> On 02/11/06, Chris Lightfoot <chris@???> wrote:

    [...]

> > no. I asked, is there any evidence for the implicit theory
> > of things like Dynastop (i.e., that anybody with whom you
> > might want to exchange mail is rich enough to pay for some
> > sort of connectivity that doesn't appear in such a list).
> > You offered none, but instead offered evidence for a
> > completely different theory, presumably in the hope that
> > dimmer readers would mistake it for what I asked for.
> > (This is the bit of your message which I elided with
> > [...], above, because it was not relevant to the
> > discussion.)

    [...]

> My argument was that the 'implicit theory' you're trying to find
> evidence for doesn't exist. The bit about '...afford a leased line'
> was something you made up - nobody implied it.


I believe that the people who advocate the use of these
`black lists' and expend time and effort in composing them
do so based on the claim that they are generally useful
for some purpose or other. That must mean that there is a
feature which separates mail which is sent through mail
servers on IPs which appear on a `black list' from mail
which is through mail servers which are not on a `black
list'. This distinction obviously is not anything directly
to do with spam, because the definition of whether a mail
is spam or not is up to the recipient of the mail, and is
independent of the IPs through which the mail passes (and
the opinions of the people running any mail servers which
might consult `black lists', much as -- as discussion here
shows -- such administrators may believe otherwise).

Therefore there must be, in the opinion of the people
responsible, some feature of dynamic IPs which makes it
impossible that mail originating from them is desirable to
receive.

The widespread use of these `black lists' indicates that a
very large number of people (or at least of mail server
administrators) believe in this theory. However, history
shows that a theory can be believed in by a very large
number of people without being true, and as yet I have
heard no evidence for this theory; and when asking about
it, what is presented is evidence for other theories which
are easier to advocate. Hence my interest.

> Instead, there's a theory that [...]

    [ I didn't ask about, I've heard before, and anyway
      isn't interesting ]


> If the false positive rate were high enough to cause business issues,
> people wouldn't use them.


As I say, I understand that the promoters of these `black
lists' believe them to be of general usefulness. They are
rarely advertised on the basis that they simply encode
your employers' prejudices!

--
``In these troubled times, perhaps we all need reminding that when we all
work together and really put our minds to something, we still can't achieve
the impossible.'' (from Need To Know)