Re: [Exim] Invalid Sender: headers

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Author: Alan J. Flavell
Date:  
To: Phil Chambers
CC: Exim users list
Subject: Re: [Exim] Invalid Sender: headers
On Fri, 2 May 2003, Phil Chambers wrote:

> But the ChangeLog says that smtp_return_error_details says that is
> for address verification callouts. This failure is not the result
> of a callout, but a syntax check.


My apologies for the irregular email followups here, but I lost P.H's
actual reply, and only now I realise that it's in need of correction.
P.H wrote:

| Put your own message into the ACL:

|
|  deny  message = Your message contains invalid syntax: $acl_verify_message
|        verify = header_syntax


Just this very morning we had a complaint from a Prof. in another dept
who had included cc: to himself with an unqualified address, and
therefore had got his mail rejected by us - he complained that (a) it
wasn't causing problems for anyone else (hmmm, how could he determine
that? I reckon what he really meant was that his own mail system
wasn't catching the problem and reporting it to _him_, but was rather
passing the problem on to his correspondents...). However... (b) our
error report wasn't detailed enough to show him what the problem was.

I agreed that the latter was fair comment. This prompted me to
implement Phil's suggested fix, whereupon I realised that his verify
needed to be negated.

Also it _is_ necessary to assert smtp_return_error_details in the main
configuration, in spite of the discussion about it being for callouts.
Having done that, my test mail (with exim -bh ...) now gets rejected
with this:

550-Your message headers contain invalid syntax: Rejected after DATA:
550-unqualified address not permitted: failing address in "Cc" header is:
550-wibble
550-If your local mail support is unable to identify the problem,
550 please contact [...]

which is what we want, whereas, without asserting
smtp_return_error_details, it does this:

550-Your message headers contain invalid syntax:
550-If your local mail support is unable to identify the problem,
550 please contact [...]

even though our _log_ does contain the additional detail.

Our actual ACL snippet for this is

 deny    !verify = header_syntax
  message = Your message headers contain invalid syntax: $acl_verify_message\n\
            If your local mail support is unable to identify the problem,\n\
            please contact [...]
          hosts = *


Hope this helps.