[Asrg] On assertions

[Steve Atkins]

On Jul 29, 2008, at 10:30 AM, der Mouse wrote:

>> There seems to be considerable interest in making assertions about
>> the mail behavior of domains.  The simplest useful assertion is
>> probably "we send no mail", but we've seen at least three different
>> variations on that, including SPF -all, the MX 0 . proposal, and
>> attempts to shoehorn it into SSP/ADSP.
>
> I thought "MX 0 ." asserted not "we send no mail" but rather "we
> receive no mail".  (Of course, as far as receivers are concerned,
> either one may lead to rejection of mail, but that doesn't make them
> the same thing.)

They're not the same thing. But if a domain can receive no email
then it's certainly not sending any email it cares about, as there's
no way for it to receive any bounces. So it's an assertion that the
sending domain doesn't have any problem with receivers rejecting
or discarding that mail, and the implication there is obvious.

Cheers,
   Steve