[ietf-dkim] Re: Issue 1365: drop "never send mail"?

[Frank Ellermann]

Arvel Hathcock wrote:

>> What mechanism is there for 'never send mail today'?

> Sender ID and NULL MX (draft-delany-nullmx-00.txt)

For the HELO and envelope sender add SPF.  The NULL MX
idea is a bit convoluted:  "Because I won't accept mail
for the relevant domain I'm also supposed to never use
it in an envelope sender address".  Based on RFC 2822
it's also clear that the domain can't be used in From,
Resent-From, or Reply-To addresses.

With a Sender ID "spf2.0/pra -all" it's IMHO less clear
what you get (unless you're in fact looking at the PRA).

An older idea is a RHSBL of domains never sending mail.

Frank