Re: [exim] @example.net versus ""@example.net

On Fri, Mar 8, 2013 at 2:56 PM, Michael Fischer v. Mollard
<exim-users@???> wrote:
>
> Hello,


Hi!

>
>
> there is a strange difference in Exim's handling of empty local parts »@example.net« and »""@???«:
>
> mail from: <>
> 250 OK
> rcpt to:<@example.net>
> 501 <@example.net>: no local part
> rcpt to:<""@???>
> 250 Accepted
>
> I would have expected that the latter address gives an "501 no local part" as well. Is this intentional or a mistake?


It is standards compliant.

The local-part of an e-mail message (I'll stick to RFC 2821 now) must follow:

Local-part = Dot-string / Quoted-string

Whereas a Dot-string must have at least one character (Dot-string =
Atom *("." Atom)), the Quoted-string has other requirements:

Quoted-string = DQUOTE *qcontent DQUOTE

This means that the Quoted-string must consist of a double quote,
followed by zero or more qcontent expressions, followed by a double
quote.

If there are zero qcontent expressions, you end up with:

""@example
--
Jan