On Sun, 21 Sep 2003 Valdis(_dot_)Kletnieks(_at_)vt(_dot_)edu wrote:
On Sun, 21 Sep 2003 16:00:47 EDT, Dean Anderson <dean(_at_)av8(_dot_)com>
It never sends the email in either case. In the first case, it will say no
such host, and return an error to the user. In the second case, it will
attempt to connect to 18.104.22.168 and will get an error, which will be
returned to the MUA.
So if a domain gets shelved by accident, as happened to one NANOG poster
this weekend, all their mail gets sucked up and handed a 5xx error by the
Verisign server and bounced, rather than getting hit with a 4xx and retried
for a few days.
As was pointed out, some servers will give up right away. In either case,
the user should get a bounce, and can follow the instructions as to
whether the delivery will be retried or not.