Newsgroups and  Message-ID are  keywords that  LISTSERV will  generate by
itself if missing  from the original message. There are  available in all
the  lists, but  they are  part  of the  subset  of tags  which has  been
declared  "boring for  human beings"  and is  not sent  unless explicitly
requested  by  "SET  listname   FULLHDR"  (or  FULLBSMTP),  or  similarly
defaulted ("Default-Options= FULLHDR").
 
  Eric