ietf-nntp POST SHOULD return an accurate response

[Russ Allbery]

I'm currently reviewing -15 against my saved notes and will hopefully have
a new set of open issues available shortly, along with my promised but
much-delayed new text for HDR (which remains a right mess, and didn't get
any cleaner from looking at it with new eyes, unfortunately).

This bit was buried in other threads and doesn't seem to have made it into
-15, but I also didn't see any additional responses to it.  Given that,
I'm reproposing it; please let me know if there's some reason you object
to this text.

With IHAVE, generally the other server doesn't particularly care whether
or not the article was posted, but with POST, it's actually important to
let the client know that the article is invalid.  The exception is
generally only for dealing with spam, where the intention is to make the
server be deceptive to try to fool a spammer.

This sounds like a textbook example of a case where SHOULD is the
appropriate term, since there are reasons why a server may not want to
follow the constraint.  I propose adding to the end of the third
paragraph of 9.3.1 after:

    Note that response codes 340 and 440 are used in direct response to
    the POST command. Others are returned following the sending of the
    article.

the following new text (perhaps as a separate paragraph):

    A response of 240 SHOULD indicate that barring unforseen server errors
    the posted article will be made available on the server and/or
    transferred to other servers as appropriate.  In other words, articles
    not wanted by the server SHOULD be rejected with a 411 response and
    not accepted and silently discarded.

Intentionally deceptive spam filters can then be left as a conscious
decision to not abide by SHOULD, which is explicitly allowed in the
definition of SHOULD.

-- 
Russ Allbery (rra at stanford.edu)             <http://www.eyrie.org/~eagle/>