usefor-usepro-02 December 2004

6.  Control Messages

   The following sections document the control messages.  "Message" is
   used herein as a synonym for "article" unless context indicates
   otherwise.

   Each control message comprises a verb, which indicates the action to
   be taken, and argument(s), which supply the details. In some cases
   the body of the article may also supply details. The following
   sections contain syntactic definitions for the verb, arguments, and
   possibly the body, for each type of control message.

   The Newsgroups-header of each control message SHOULD include the
   newsgroup-name(s) for the group(s) affected (i.e. groups to be
   created, modified or removed, or containing articles to be canceled).
   This is to ensure that the message propagates to all sites which
   receive (or would receive) that group(s). It MAY include other
   newsgroup-names so as to improve propagation (but this practice may
   cause the control message to propagate also to places where it is
   unwanted, or even cause it not to propagate where it should, so it
   should not be used without good reason).

        NOTE: Propagation is controlled by relaying agents, and it may
        be necessary for relaying agents to take special steps to ensure
        that control messages such as newgroup messages for not-yet-
        existent newsgroups are propagated correctly (see 7.3).
[The first of those paragraphs was originally scheduled to be moved to
USEFOR (and it may yet be so moved). It has been reinstated here (at
least temporarily) to make sure that it does not get overlooked.]

   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 (even if no genuine Control
   header was present). Indeed, some implementations went further and
   added the implied Control header before injecting. Likewise, the
   presence of a newsgroup-name ending in ".ctl" in the Newsgroups
   header caused the Subject header content (not starting with "cmsg" in
   this case) to be interpreted as a <control-message>.

   All these practices are now declared to be Obsolete, and Subject
   headers MUST NOT now be interpreted as <control-message>s under any
   circumstances.

   The descriptions below set out REQUIREMENTS to be followed by sites
   that receive control messages and choose to honour them. However,
   nothing in these descriptions should be taken as overriding the right
   of any such site, in accordance with its local policy, to refuse to
   honour any particular control message, or to refer it to an
   administrator for approval (either as a class or on a case-by-case
   basis).

--- ../usefor-usepro-01/Control_Messages.out          September 2004
+++ ../usefor-usepro-02/Control_Messages.out          December 2004
@@ -4,6 +4,43 @@
    used herein as a synonym for "article" unless context indicates
    otherwise.
 
+   Each control message comprises a verb, which indicates the action to
+   be taken, and argument(s), which supply the details. In some cases
+   the body of the article may also supply details. The following
+   sections contain syntactic definitions for the verb, arguments, and
+   possibly the body, for each type of control message.
+
+   The Newsgroups-header of each control message SHOULD include the
+   newsgroup-name(s) for the group(s) affected (i.e. groups to be
+   created, modified or removed, or containing articles to be canceled).
+   This is to ensure that the message propagates to all sites which
+   receive (or would receive) that group(s). It MAY include other
+   newsgroup-names so as to improve propagation (but this practice may
+   cause the control message to propagate also to places where it is
+   unwanted, or even cause it not to propagate where it should, so it
+   should not be used without good reason).
+
+        NOTE: Propagation is controlled by relaying agents, and it may
+        be necessary for relaying agents to take special steps to ensure
+        that control messages such as newgroup messages for not-yet-
+        existent newsgroups are propagated correctly (see 7.3).
+[The first of those paragraphs was originally scheduled to be moved to
+USEFOR (and it may yet be so moved). It has been reinstated here (at
+least temporarily) to make sure that it does not get overlooked.]
+
+   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 (even if no genuine Control
+   header was present). Indeed, some implementations went further and
+   added the implied Control header before injecting. Likewise, the
+   presence of a newsgroup-name ending in ".ctl" in the Newsgroups
+   header caused the Subject header content (not starting with "cmsg" in
+   this case) to be interpreted as a <control-message>.
+
+   All these practices are now declared to be Obsolete, and Subject
+   headers MUST NOT now be interpreted as <control-message>s under any
+   circumstances.
+
    The descriptions below set out REQUIREMENTS to be followed by sites
    that receive control messages and choose to honour them. However,
    nothing in these descriptions should be taken as overriding the right
@@ -11,11 +48,4 @@
    honour any particular control message, or to refer it to an
    administrator for approval (either as a class or on a case-by-case
    basis).
-
-   Relaying Agents MUST propagate all control messages regardless of
-   whether or not they are recognized or processed locally.
-
-   In the following sections, each type of control message is defined
-   syntactically by defining its verb, its arguments, and possibly its
-   body.