Re: [Exim] Sender verification...

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Author: Dave C.
Date:  
To: Michael Scott Shappe
CC: exim-users
Subject: Re: [Exim] Sender verification...
On Mon, 23 Sep 2002, Michael Scott Shappe wrote:

> Quoting Toralf Lund <toralf@???>:
>
> > It does, however, seem a bit drastic to plainly reject all messages
> > that can't be verified.
>
> There are, I would say, two schools of thought on that:
>
> The first is an Internet classic: "Be liberal in what you accept, and
> conservative in what you generate". Fair advice, I suppose, except that in
> our spam-laden network, where many spammers are trying their damnedest to
> obscure their trail, it doesn't really work.
>
> Given the existence of clear, readable standards, of dozens of books on the
> subject of configuring one's system to behave well on the Internet, and of
> hundreds if not thousands of individuals with clues willing to help the
> clueless...there is simply no good reason why Exim's sender verification
> should ever fail for a truly legitimate address.
>
> "But what if someone makes a mistake?" I hear you wondering. A legitimate
> question. One of my colleagues actually had this happen to him shortly after
> I switched our main server over to Exim4. Mail he was sending to us kept
> bouncing because his relay host had a misconfigured DNS.
>
> My answer is: if you don't generate errors when people misconfigure their
> systems, the systems never, ever get fixed.


Rejecting a message at SMTP time *is* generating an error. The only
difference is that the remote server is responsible for returing the
bounce, instead of your server being stuck with it.

As long as your server says something like

5xx rejected - sender address cannot be verified

This text *SHOULD* be included in the bounce that the sending server
generates. Theres your error.

>
> --
> Michael Scott Shappe <mikey@???>
> Addicting the Unsuspecting to the Internet since 1987
> Visit Radio Free Tomorrow at <http://www.radiofreetomorrow.org/>
>
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