Injecting agents and From (was: Re: Protocol changes in draft-allbery-usefor-usepro-00)

[Russ Allbery <[e-mail]>]

Charles Lindsey <[e-mail]> writes:
> Russ Allbery <[e-mail]> writes:
>> Charles Lindsey <[e-mail]> writes:

>>> 3. [-1] (3.3.1,3.4,3.9.2) From not omittable in proto-article

>>> There is existing usage where the injecting agent fills in From header
>>> (not possible in NNTP, of course)

>> Intentional change.

>> What injecting agent supports this?

> INN apparently (see below).

> Newsreaders such as rn, trn, nn, and others of that generation had (and
> still have) the capability to interact directly with the newspool
> (either on the same host, or more likely NFS mounted from some server)
> rather than going via NNTP (which did not exist when they were first
> written). They injected articles by calling a program 'inews' which, in
> the absence of an explicit From:, assumed the poster was the user who
> had called 'inews'.

inews as distributed with INN or the common news readers is a (part of a)
posting agent, not an injecting agent.  You can see this by observing what
actions it takes and what agent it talks to.  It sends messages to an
injecting agent via POST and expects that agent to do the injection; it
doesn't perform those actions itself and then send messages directly to
relaying and serving agents the way that an injecting agent does.

Our agent distinctions are largely based on how INN and similar news
servers work.  C News, being a much earlier implementation, may not have
the same distinctions, or they may be much less clear.  Some
implementations written prior to our standard will combine different
agents into one program, so it's possible that in C News inews combines
functions of a posting agent and an injecting agent.  However, I believe
you'll find that treating creation of the From header field as a function
of the posting agent, which is possibly combined with an injecting agent,
will work correctly and not contradict the work flow of any existing
implementation.

INN's inews used to redundantly perform a few (although not all by any
means) of the functions of an injecting agent, such as mailing posts to
the moderators of moderated newsgroups.  This behavior was a bad idea,
causing various problems in practice, and has been removed from current
versions.

-- 
Russ Allbery ([e-mail])             <http://www.eyrie.org/~eagle/>