On Mon, 22 Sep 2003, Larry Smith wrote:
You don't seem to understand how mail works. In both cases you get a
bounce. In neither case is a message sent.
Hmmm, again not totally true. In the first case (pre-Versign) the mail
"client" (user end of the equation - at least on all my servers) would get an
"invalid address" type error (whatever Microsoft dreams up) and hence the
message would never "leave" their machine. In the second case
(post-Verisign) the message is accepted by my server (since it cannot tell at
that stage) and it (my server) will then try to deliver. Depending upon the
error code, the server might bounce immediately, or it might try for "x"
amount of time before it bounces.
You missed the start of this discussion, I think. This is what Doug Boyer
said. However, the MUA should always hand the message to the MTA portion,
and the MTA should always return a bounce. We just went through why the
MUA shouldn't be performing these checks. You might want to go back
through the recent archives and look at this discussion.