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