RFC2821 allows an empty local-part, provided that it is quoted:
""@???
Exim correctly removes the quoting leaving an empty local-part in its
$local_part variable.
But when I wish to restore the quoted form of the address using the
quote: operator as per the example in 17.12.1 "Quoting addresses" in the
Exim 4 book:
data = ${quote:$local_part}@???
Exim fails to quote the local-part so I end up with
@example.com
Which is illegal under RFC2821.
If the quote: operator is intended to produce legal RFC2821 local-parts,
as the example in the book suggests, then it needs to quote the empty
string.
(This may be obscure but we discovered this today on our mail server.
The offending message was being repeatedly deferred because our redirect
router had removed the quoted empty local-part as above.)
Regards
--
Paul Overell Development Manager, Client Software, Thus plc