----- Original Message -----
From: "Tony Finch" <dot(_at_)dotat(_dot_)at>
(2b) Having said that it's unimportant, I still wish to say that in my
experience, the terms "reject" or "SMTP-time reject" are used for 5xy
error replies, whereas "bounce" or "accept-and-bounce" are used for a
message that is accepted but subsequently results in an error message
being sent to the return path.
This relates to the discussion about failures and errors.
I would be nice to establish a consistent description as you outlined above.
Especially in this area since it is obviously becoming more important in the
area for new protocol level and/or administrator local policy "mail
I still come across operators who don't know they have a SMTP-LEVEL
rejection option for RCPT where it checks the user database. They are still
thinking Gateway mode where it use to be (as a old default) done and to
these people a rejection typically implies a bounce is an expected.
However, more and more today, they find out about a SMTP-level rejection
because they do want to reduce the bounce-attack form of malicious mail.
If anything, 2821bis, should have a section that discusses these two
important modes of operations - dynamic (SMTP Level) vs. post-smtp
(accept-bounce) rejections. This is clearly, in my view, as the world of
SMTP integration has evolved into the administrator whelm, a big factor in
the difference in philosophies in how thinks "should work" or is "expected
Hector Santos, Santronics Software, Inc.