On Wed, Aug 02, 2006 at 09:33:17PM +0100, John Horne wrote:
> On Wed, 2006-08-02 at 17:45 +0100, Jeremy Harris wrote:
> > Chris Lightfoot wrote:
> >
> > > No valid bounce will have >1 recipient
> >
> > I think there are cases (mailinglists?) where that isn't so.
> >
> Yes. The RFC actual states that more than one recipient is possible (and
> hence allowed). I can't remember which RFC it was, I would have to dig
> it out again (possibly 2821), but I was reading about this very problem
> a week or two ago.
hmm -- what's the circumstance in which this occurs? RFC
2821 says (3.7),
If an SMTP server has accepted the task of relaying the mail and
later finds that the destination is incorrect or that the mail cannot
be delivered for some other reason, then it MUST construct an
"undeliverable mail" notification message and send it to the
originator of the undeliverable mail (as indicated by the reverse-
path). Formats specified for non-delivery reports by other standards
(see, for example, [24, 25]) SHOULD be used if possible.
[...]
One way
to prevent loops in error reporting is to specify a null reverse-path
in the MAIL command of a notification message. When such a message
is transmitted the reverse-path MUST be set to null (see section
4.5.5 for additional discussion). A MAIL command with a null
reverse-path appears as follows:
MAIL FROM:<>
which implies that bounce messages ought to have a single
recipient (but doesn't require it). Similarly RFC 3461 on
DSNs talks about (6.1) ``the'' DSN recipient address,
implying only one.
--
`I would write a book entitled ``Everything I Know I Learned At A Very
Expensive University'', but I doubt it would sell.'
(Daniel Davies)
