RE: [Exim] Removing headers in ACLs

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Author: David Woodhouse
Date:  
To: exim-users
CC: Nigel Metheringham
Subject: RE: [Exim] Removing headers in ACLs
On Thu, 2004-01-15 at 00:49 +0000, Philip Hazel wrote:
> On Wed, 14 Jan 2004, Nigel Metheringham wrote:
>
> > You do need to watch this since routers are a per recipient item, and
> > acls may also be per recipient items, so the header set you are carrying
> > will also become per-recipient before it ever gets to the transports.
> > This could make life very interesting indeed :-
>
> Thanks for highlighting another perhaps non-obvious feature. Or perhaps
> "feature".


Bear in mind that if you implement immediate header mangling you may
also break existing configurations which rely on header changes not
being effectively immediately, such as...

  warn  condition = ${if !def:h_Message-ID: {1}}
        message = Message-ID: <E$message_id@$primary_hostname>


< ... other checks ... >

accept hosts = +relay_hosts

< ... more stringent tests, including ... >

  deny  condition = ${if !def:h_Message-ID: {1}}
        message = RFC2822 says you SHOULD have a Message-ID.\n\
                  Most messages without it are spam, so your mail has been rejected.



Not that this means I think you shouldn't _do_ it -- just that it's
something that needs documenting clearly in the release notes.

--
dwmw2