usefor-article-13 May 2004

6.19.  Injection-Info

   The Injection-Info-header SHOULD be added to each article by the
   injecting agent in order to provide information as to how that
   article entered the Netnews system and to assist in tracing its true
   origin.

      header          =/ Injection-Info-header
      Injection-Info-header
            = "Injection-Info" ":" SP Injection-Info-content
                 *( ";" ( Injection-Info-parameter /
                          extension-parameter ) )
      Injection-Info-content
            = [CFWS] path-identity [CFWS]
      Injection-Info-parameter
            = posting-host-parameter /
              posting-account-parameter /
              posting-sender-parameter /
              posting-logging-parameter
              ; for {USENET}-parameters see 4.1
      posting-host-parameter
            = <a parameter with attribute "posting-host"
               and value some host-value>
      host-value      = dot-atom /
              [ dot-atom ":" ]
                ( IPv4address / IPv6address ); see [RFC 2373]
      posting-account-parameter
            = <a parameter with attribute "posting-account"
               and any value>

      posting-sender-parameter
            = <a parameter with attribute "sender"
               and value some sender-value>
      sender-value    = mailbox / "verified"
      posting-logging-parameter
            = <a parameter with attribute "logging-data"
               and any value>

   An Injection-Info-header MUST NOT be added to an article except by an
   injecting agent. Any Injection-Info-header present when an article
   arrives at an injecting agent MUST be removed. In particular if, for
   some exceptional reason, an article is being reinjected (8.2.2), the
   Injection-Info-header will always relate to the latest injection (to
   the extent that this happens, the Injection-Info-header can be
   regarded as a variant header).

   The path-identity MUST be the same as the path-identity prepended to
   the Path-header by that same injecting agent which, following section
   5.6.2, MUST therefore be a fully qualified domain name (FQDN)
   mailable address.

   Although comments and folding of white space are permitted throughout
   the Injection-Info-content specification, it is RECOMMENDED that
   folding is not used within any parameter (but only before or after
   the ";" separating those parameters), and that comments are only used
   following the last parameter. It is also RECOMMENDED that such
   parameters as are present are included in the order in which they
   have been defined in the syntax above.  An injecting agent SHOULD use
   a consistent form of this header for all articles emanating from the
   same or similar origins.

        NOTE: The effect of those recommendations is to facilitate the
        recognition of articles arising from certain designated origins
        (as in the so-called "killfiles" which are available in some
        reading agents). Observe that the order within the syntax has
        been chosen to place last those parameters which are most likely
        to change between successive articles posted from the same
        origin.

        NOTE:  To comply with the overall "attribute = value" syntax of
        parameters, any value containing an IPv6address, a date-time, a
        mailbox, or any CFWS MUST be quoted using <DQUOTE>s (the quoting
        is optional in other cases).

        NOTE: This header is intended to replace various currently-used
        but nowhere-documented headers such as "NNTP-Posting-Host" and
        "X-Trace". These headers are now deprecated, and any of them
        present when an article arrives at an injecting agent SHOULD
        also be removed as above.