Re: [Exim] exim4: acl_smtp_mail ?

> > Why is there no acl that runs after mail from?
>
> Because I discovered, in the early days of Exim, that there are MTAs out
> there that don't treat 5xx errors after MAIL commands as show stoppers.
> They just try to resend the message later. Exim 3 ended up with a
> complicated scheme of refusing after DATA the first time (so as to log
> the header), refusing after MAIL the second time (because that seemed
> the next best thing), and refusing each RCPT for the third attempt.
> These stages got added as we discovered actual MTA behaviour.
>
> For Exim 4, I didn't want to encourage refusals of MAIL commands,
> because it doesn't always work. The best known way to say "no" to an MTA
> is to refuse every RCPT. (Of course, there are some checks you can't do
> till after DATA, so I had to make that available, but you run the risk
> of getting repeated attempts.)
>
> > I would like to issue a 5xx right after MAIL FROM: under certain
> > conditions, yet I can't seem to find a way to do that..
>
> If you really want to do that, it is not a huge amount of work to add
> the code, but I would strongly advise you to think carefully about this.
>
> Philip

I had not noticed that Exim 4 would not be issuing 5xx after MAIL FROM. I will need
to see how that effects my setup. We have always had a small, but significant,
number of users who mis-type (or just get it wrong) their own e-mail address when
configuring their e-mail software. At present, when they try to send a message,
their software gets a rejection when it does the MAIL FROM and the error message
they get is distinctly different from what they get if it is the RCPT TO that fails.
Our helpdesk staff recognise these failures and can quickly tell the users what is
wrong. I can see it being confusing when the users are told that it is the
recipient addresses which are wrong. Any chance we could have a "fail_mail_from"
option?

Phil.
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Phil Chambers (postmaster@???)
University of Exeter