Re: [Exim] Sender verification via callout

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Author: Thomas Fini Hansen
Date:  
To: Exim users list
Old-Topics: Re: [Exim] Sender verification via callout
Subject: Re: [Exim] Sender verification via callout
On Mon, Mar 01, 2004 at 01:55:01PM +0000, Alan J. Flavell wrote:
> Indeed. I'd recommend using callout selectively, however, because
> there's sure to be irresistible pressure (i.e from someone
> sufficiently high enough in manglement to make the technical arguments
> irrelevant) on the mail admin to accept mail from a few of those
> broken MTAs.


Well, we're just providing email service to small cutomers, and out of
a about 100 domains there was just *one* that complained when we moved
him to the new Exim 4 setup..

So now the virtual users table in MySQL got one extra enum field
called 'ben_dover', and an 'accept' very high in the rcpt_acl.

So far, he's been the only one. I've been plesantly surprised at how
many customers actually accept it when you explain the basics and that
these rules saves them a great deal of spam (which they noticed when
they got moved over).

> What we do is to have a list (partially wildcarded) of domains where
> callout *is* used. Having an exception list where callout is *not*
> used would be another possible approach, obviously - note, however,
> that there are vast numbers of MTAs out there which swallow just any
> preposterous local-part at RCPT time, and only reject later (too late
> for callouts to work), and it would be a waste of effort doing
> callouts to them.


Yes, but isn't the random option for those?

( http://www.exim.org/exim-html-4.30/doc/html/spec_38.html#SECT38.21 )

--
Thomas
beast@???