Peter J. Holzer writes:
On 2007-05-01 14:03:58 -0400, John C Klensin wrote:
--On Tuesday, May 01, 2007 6:52 PM +0200 Frank Ellermann
<nobody(_at_)xyzzy(_dot_)claranet(_dot_)de> wrote:
>Actually it should verify jones(_at_)xyz at the time when it decides
>to accept the mail, but at this time xyz is down, and so that's
>not possible.
that verification can be done even if xyz is down if foo has the
necessary information.
An example, easily done with postfix: A set of good addresses are
(ir/)regularly copied from the primary mx, and the secondary replies
4xx for other addresses. Done.
Arnt