Re: [Exim] Wish list (I think) regarding sender verify callo…

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Author: Dave C.
Date:  
To: exim-users
CC: Tom Marazita
Subject: Re: [Exim] Wish list (I think) regarding sender verify callout.
On Wed, 2 Oct 2002, Philip Hazel wrote:

> On Tue, 1 Oct 2002, Tom Marazita wrote:
>
> > 2) The MAIL FROM:<> can itself fail, which indicates the host at the
> > other end has a poorly configured mailer; or at least
> > that's what it seems to have indicated with the hosts I've
> > come up against recently. The sender might still
> > actually be valid though, and in that case I might still want
> > to accept the message even if I can't verify it due to their not
> > accepting the bounce.
>
> I personally take the hard line on this issue. We should make life
> difficult for the users of MTAs that are unable to accept bounce
> messages. That way, those users might put enough pressure on their
> sysadmins to fix their MTAs.
>
> Nevertheless, I realise that some people come under political pressure
> to break the rules. I am prepared to contemplate some kind of scheme
> (details as yet unknown because I haven't thought about it) by which you
> can say "if callout fails because MAIL was rejected, still accept the
> message". What I do not think is a good idea is using something other
> than <> in the MAIL command.
>
> > I've come up against about half dozen of these in the past
> > six months; in all cases the sender would have been a valid
> > address but we rejected the message. Naturally I have contacted
> > their postmasters, but with very little response.
>
> Did you contact the senders to tell them they are using a system that
> doesn't accept bounces?


While this is ideal, the problem is its a technical issue that they dont
understand, and they 'dont have problems mailing anywhere else', so it
must be our problem. Often if its a business with their own server, they
either have no admin, or the admin they have isnt really qualified to
even understand the issue, let alone fix it. And in some cases some
source they trust has told them it heps block spam. In the meantime,
your customer that cant get mail from this party is pressuring you to
'fix the problem'...

Callbacks as an antispam measure can be fantastic, but until a large
enough percentage of sites use them to begin pressuring non "<>"
accepting MTA's to start doing so, they cant get in the way of otherwise
legitimate mail, even if its from a domain whose server is broken that
way.

>
> --
> Philip Hazel            University of Cambridge Computing Service,
> ph10@???      Cambridge, England. Phone: +44 1223 334714.

>
>
> --
>
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