INTERNET-DRAFT                               Charles H. Lindsey
Usenet Format Working Group                  University of Manchester
                                             July 2001

7.4. The 'checkgroups' Control Message

7.4.  The 'checkgroups' Control Message
   The "checkgroups" control message contains a list of all the valid
   groups in a complete hierarchy.

      checkgroup-verb     = "checkgroups"
      checkgroup-arguments= [ chkscope ] [ chksernr ]
      chkscope            = 1*( CFWS ["!"] newsgroup-name )
      chksernr            = CFWS "#" 1*DIGIT

   The chkscope parameter(s) specifies the (sub)hierarchy(s) for which
   this "checkgroups" message applies. The chksernr parameter is a
   serial number, which can be any positive integer (e.g. just numbered
   or the date in YYYYMMDD).  It SHOULD increase by an arbitrary value
   with every change to the group list and MUST NOT ever decrease.

        NOTE: This was added to circumvent security problems in
        situations where the Date header cannot be authenticated.

   Example:

      Control: checkgroups de !de.alt #248



        NOTE: Some existing software does not support the "chkscope"
        parameter.  Thus a "checkgroups" message SHOULD also contain the
        groups of other subhierarchies the sender is not responsible
        for. "New" software MUST ignore groups which do not fall into
        the scope of the "checkgroups" message.

   If no scope for the checkgroups message is given, it applies to all
   hierarchies for which group statements appear in the message.

   The body of the message has the Content-Type "application/news-
   checkgroups".  It asserts that the newsgroups it lists are the only
   newsgroups in the specified hierarchies.

        NOTE: The checkgroups nessage is intended to synchronize the
        list of newsgroups stored by a serving agent, and their
        newsgroup-descriptions, with the lists stored by other serving
        agents throughout the network. However, it might be inadvisable
        for the serving agent actually to create or delete any
        newsgroups without first obtaining the approval of its
        administrators for such proposed actions.

Diffs to previous draft

--- {draft-04}	Wed Jul 11 21:56:05 2001
+++ {draft-05}	Wed Jul 11 21:56:05 2001
@@ -20,6 +20,8 @@
 
       Control: checkgroups de !de.alt #248
 
+
+
         NOTE: Some existing software does not support the "chkscope"
         parameter.  Thus a "checkgroups" message SHOULD also contain the
         groups of other subhierarchies the sender is not responsible