usefor-article-03 February 2000

8.2.2.  Procedure to be followed by Injecting Agents

   A injecting agent receives proto-articles from posting and followup
   agents. It verifies them, adds headers where required and then either
   forwards them to a moderator or injects them by passing them to
   serving or relaying agents.

   If an injecting agent receives an otherwise valid article that has
   already been injected it SHOULD either act as if it is a relaying
   agent or else pass the article on to a relaying agent completely
   unaltered. Exceptionally, it MAY reinject the article, perhaps as a
   part of some complex gatewaying process (in which case it will add a
   second '%' delimiter to the Path header).  It MUST NOT forward an
   already injected article to a moderator.

   An injecting agent processes articles as follows:

   1. It SHOULD verify that the article is from a trusted source.
      However, it MAY allow articles in which headers contain "forged"
      email addresses, that is, addresses which are not valid for the
      known and trusted source, especially if they end in ".invalid".

   2. It MUST reject any article whose Date header is more than 24 hours
      into the past or into the future (cf. 5.1).

   3. It MUST reject any article that does not have the correct
      mandatory headers for a proto-article (5 and 8.2.1) present, or
      which contains any header that does not have legal contents.

   4. If the article is rejected, or is otherwise incorrectly formatted
      or unacceptable due to site policy, the posting agent MUST be
      informed (such as via an NNTP 44x response code) that posting has
      failed and the article MUST NOT then be processed further.

   5. The Message-ID and Date headers (and their content) MUST be added
      when not already present.

   6. A Path header with a tail-entry (5.6.3) MUST be correctly added if
      not already present (except that it SHOULD NOT be added if the
      article is to be forwarded to a moderator).

   7. The path-identity of the injecting agent with a '%' delimiter
      (5.6.2) MUST be prepended to the Path header; moreover, that
      path-identity MUST be an FQDN mailable address (5.6.2).
[At this point, we should mention the Injector-Info header if/when we
invent it.]

   8. The injecting agent MAY add other headers not already provided by
      the poster, but SHOULD NOT alter, delete or reorder any headers
      already present in the article (except for headers intended for
      tracing purposes). The injecting agent MUST NOT alter the body of
      the article in any way.
[An Injector-Info header would be mentioned as an example of tracing.]

   9. If the Newsgroups line contains one or more moderated groups and
      the article does NOT contain an Approved header, then the
      injecting agent MUST forward it to the moderator of the first
      (leftmost) moderated group listed in the Newsgroups line via
      email. The complete article SHOULD be encapsulated (headers and
      all) within the email, preferably using the Content-Type
      "application/news-transmission" (6.17.6.1).

   10.Otherwise, the injecting agent forwards the article to one or more
      relaying or serving agents.