In response to Philip Hazel:
> That is all fine, except when considering how to handle multiple
> addresses in a single message that differ only in the case of their
> letters. The problem is in defining exactly what is a "duplicate
> address".
>
> I've been trying to find a clean way of doing this, and as far as I can
> see, the really only clean way is:
>
> * Two addresses are the same only if they match casefully.
>
> * If there are two addresses that differ only in case in one message,
> two deliveries will take place.
>
> * This does not prevent the routing of each address from proceeding in
> a caseless manner in those routers that are so configured.
> Does anybody have any objections? Other ideas?
I can see some problems with final delivery to local addresses. As
far as I can see, if I send to PH10@??? (upper-case as in
the days of Phoenix 8-) _and_ to ph10@???, then the message
will get delivered, once, to your lower-case address
ph10@???, and this needs to keep working. I suggest that
there needs to be a way to force addresses to lower-case at some
stage, ie not just to ignore case when matching, but actually to
rewrite them to lower-case (not in the headers of course, just in the
envelope address that Exim is looking at), and then to discard
duplicates.
Another option perhaps?
Gyan.