[exim] Re: [exim-dev] EXPN and :fail:

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Author: Philip Hazel
Date:  
To: exim-users
CC: exim-dev
Subject: [exim] Re: [exim-dev] EXPN and :fail:
On Thu, 27 Jan 2005, Philip Hazel wrote:

> > In exim4 (4.34) I observe that when I set a custom error message using
> > :fail: in /etc/aliases (or using the fail command in an exim filter),
> > I see the custom message in the result of a VRFY command, and in the
> > result of a RCPT command (if the relevant ACL doesn't override the
> > message, or incorporates $acl_verify_message into its override) but I
> > don't see it in the result of an EXPN command, and it looks like there's
> > currently no way of configuring EXPN to show it. Is that by design?
>
> Probably by accident. My natural instinct is to think that nobody
> permits the use of EXPN any more, so it is not in my consciousness.


> Thanks for pointing out this anomaly. I'll check them all out in the
> current source code, and fix the problem, as it seems reasonable that
> EXPN should show the error. Unless I find some buried comment in the
> code which explains why a change was made. If so, I'll document it.


On looking at the code, it seems to be quite deliberate. The data from
:fail: is shown only when the address verification is NOT from EXPN. I
suspect that the reasoning is to reduce the amount of information
leakage when EXPN is permitted, but there is no comment in the code
giving any reasoning. I will document the restriction.

Regards,
Philip

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