In some future version, I will add  code to let LISTSERV learn by itself about
this kind of things. It will record  the last N subjects coming from any given
address, along with the number of times they appeared, discard those which are
not  frequent enough  to warrant  being recorded,  and permanently  write down
anything which came  in more than M  times from a given address.  Then it will
know that this origin/subject combinations means a loop of some kind. The only
problem is  gateways which  don't include  a 'Subject:'  field in  their error
messages - I can't trap these, because if  I did I would also lock all the IBM
NOTE users (among others).
 
  Eric