usefor-article-08 August 2002

7.3.  Cancel

   The cancel message requests that a target article be "canceled" i.e.
   be withdrawn from circulation or access. A cancel message may be
   issued in the following circumstances.

   1. The poster of an article (or, more specifically, any entity
      mentioned in the From-header or the Sender-header, whether or not
      that entity was the actual poster) is always entitled to issue a
      cancel message for that article, and serving agents SHOULD honour
      such requests. Posting agents SHOULD facilitate the issuing of
      cancel messages by posters fulfilling these criteria.

   2. The agent which injected the article onto the network (more
      specifically, the entity identified by the path-identity in front
      of the leftmost '%' delimiter in the Path-header (5.6) or in the
      Injector-Info-header (6.19) and, where appropriate, the moderator
      (more specifically, any entity mentioned in the Approved-header)
      is always entitled to issue a cancel message for that article, and
      serving agents SHOULD honour such requests.

   3. Other entities MAY be entitled to issue a cancel message for that
      article, in circumstances where established policy for any
      hierarchy or group in the Newsgroup-header, or established custom
      within Usenet, so allows (such policies and customs are not
      defined by this standard). Such cancel messages MUST include an
      Approved-header identifying the responsible entity. Serving agents
      MAY honour such requests, but SHOULD first take steps to verify
      their appropriateness.


      control-message     =/ Cancel-message
      Cancel-message      = "cancel" Cancel-arguments
      Cancel-arguments    = CFWS msg-id [CFWS]

   The argument identifies the article to be cancelled by its message
   identifier.  The body SHOULD contain an indication of why the
   cancellation was requested. The cancel message SHOULD be posted to
   the same newsgroup, with the same distribution, as the article it is
   attempting to cancel.

   A serving agent that elects to honour a cancel message SHOULD make
   the article unavailable for relaying or serving (perhaps by deleting
   it completely). If the target article is unavailable, and the
   acceptability of the cancel message cannot be established without it,
   activation of the cancel message SHOULD be delayed until the target
   article has been seen.  See also sections 8.3 and 8.4.

        NOTE: It is expected that the security extension envisaged in
        section 7.1 will make more detailed provisions for establishing
        whether honouring a particular cancel message is in order. In
        particular, it is likely that there will be provision for the
        digital signature of 3rd party cancels.

        NOTE: The former requirement [RFC 1036] that the From and/or
        Sender-headers of the cancel message should match those of the
        original article has been removed from this standard, since it
        only encouraged cancel issuers to conceal their true identity,
        and it was not usually checked or enforced by canceling
        software.  Therefore, both the From and/or Sender-headers and
        any Approved-header should now relate to the entity responsible
        for issuing the cancel message.

--- ../usefor-article-07/Cancel.out          May 2002
+++ ../usefor-article-08/Cancel.out          August 2002
@@ -31,7 +31,7 @@
 
       control-message     =/ Cancel-message
       Cancel-message      = "cancel" Cancel-arguments
-      Cancel-arguments    = CFWS msg-id
+      Cancel-arguments    = CFWS msg-id [CFWS]
 
    The argument identifies the article to be cancelled by its message
    identifier.  The body SHOULD contain an indication of why the