Re: [Exim] sender verification in 3.20

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Author: Philip Hazel
Date:  
To: John Holman
CC: exim-users
Subject: Re: [Exim] sender verification in 3.20
On Mon, 9 Apr 2001, John Holman wrote:

> However, with exim 3.20 there is a problem. Sender verification now follows
> up child addresses resulting from the expansion of local addresses
> (providing there is only one such address).


Oh dear. One man's bug is another man's facility. I should have known
that somebody would have been relying on the old behaviour.

The change was made to make things better for sites that have alias
files like this:

J.Bloggs:     jb
James.Bloggs: jb
Jim.Bloggs:   jb


and then want to add the line

jb: :fail: No longer works here

Before the change, this would fail only the local part "jb"; after the
change it fails all the synonyms. I am now reasonably convinced that
this is the "right" behaviour.

I'm not exactly sure I follow what you are doing, but ...

> 1. Create special directors used only for sender verification in place of
> the normal ones and use these to emulate the old sender verification
> behaviour.


That is what I would have suggested.

> 2. Reproduce the mapping process in the router that checks sender
> addresses. I think this would lead to the following sequence:


<details snipped>

3. Another possibility might be not to rewrite sender addresses on
arrival, but to rewrite them in outgoing transports, by setting the
return_path option in the transports.

> better approach? Failing that, might it be sensible to have a configuration
> option to restore the old sender verification behaviour?


I am not sure this would be a good idea because of the possibility of
confusion. Also, although this particular action isn't changing, the
whole scheme of incoming policy checking is changing for Exim 4. It may
be better to see how that turns out before contemplating changes.

You can, of course, defeat the new behaviour by a nasty kludge:

J.Bloggs: jb, /dev/null

Come to think of it, even

J.Bloggs: jb, jb

would do it (and would not cause duplicate deliveries).

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