From: Russ Allbery (rra@stanford.edu)
Date: Wed Jul 07 2004 - 22:08:06 CDT
Charles Lindsey <chl@clerew.man.ac.uk> writes:
> 1. I note that son-of-1036 did include
> "For historical reasons, the subject MUST not begin with "cmsg " (note
> that this sequence ends with a blank)."
> followed by a NOTE explaining why and declaring the cmsg-hack as
> "obsolete". That is probably the reason why various agents currently
> reject such Subjects, as noted by Frank. It would be useful to know how
> many current agents actually do that. Does INN, for example?
I like that statement; it's nice and simple.
INN (nnrpd, to be precise) adds a Control header matching the contents of
the Subject header following "cmsg ", provided that no Control header is
already present. From what you mention later in your message, I'm
guessing that tactic was taken straight from C News.
That's obviously not the best behavior. I would be interested in what
this group would recommend instead; I'm happy to implement the suggestion
of the group in the next version. Should such messages simply be rejected
if no Control header is present? (Note that there is no way in the NNTP
protocol to issue a warning about a message but post it anyway.)
> 2. Our draft contained a similar sentence at one stage, but it got moved
> to USEAGE (and demoted to SHOULD) as part of the great split. Nobody
> commented on that at the time. Replacing that text in USEFOR is clearly
> one of the options open to us.
I think we should restore that statement. I'm ambivalent as to whether it
should say MUST NOT or SHOULD NOT.
> 3. Alternatively, we insert a warning as suggested above. Here is a
> possible text, to replace the present NOTE in 6.13
> The presence of a Subject-content starting with the string "cmsg "
> and followed by a control-message was construed under [RFC 1036] as a
> request to perform that control action (though no implementation
> actually did so if a genuine Control-header was present, and few
> current implementations still observe the practice).
I have no idea whether any implementation that has ever existed acted on
the Subject contents in preference to the Control message and doubt that
you do either, so I would be hesitant to make such a strong claim.
I also doubt that "few current implementations" is well-defended; so far
as I can tell, only one current implementation is represented on this
mailing list at all (namely INN), and I have not investigated what the
many other news servers in the world do. Do you know what Diablo does?
Exchange? D News? Cyrus IMAP? Typhoon? Breeze? leafnode? MyNews? In
the absence of more facts, I think we should be careful about what we
claim here.
> Likewise, the presence of "all.all.ctl" in the Newsgroups-content
> caused (in the absence of any genuine Control-header) the
> Subject-content (not starting with "cmsg" in this case) to be
> interpreted as a control-message.
I'm not sure where you got the "all.all" from. My understanding is that
only the ".ctl" part of that matters and can be appended to most any
newsgroup.
I'm moderately sure that no implementations after C News implemented "all"
as a wildcard or "ctl" as an indicator of a control message. I know INN
never did.
-- Russ Allbery (rra@stanford.edu) <http://www.eyrie.org/~eagle/>