Joan may well be correct that these were error messages rather than duplicate postings and the subcribers didn't know the difference. However, Mauri described them as duplicate postings, not errors. We've had problems on MEDLAB-L with such in the past. If they were error messages, and they were sent to the list and the list distributed them again the header perhaps needs to be reconfigured. And maybe put in a filter for the address. If they were error messages mistakenly sent to the individuals who posted the original messages there is little you can do about it other than deleting the offending subscription, gripe at them, and tell your subscribers to ignore the garbage (if they must gripe, do so to you and/or the offending site, not to your list, please ;-) ). More detais are needed (are *all* subscribers getting them? are they truly repostings or are they error messages? etc.) Whatever the case, the first step would surely be to block the offending site. If that means getting rid of usenet or whatever gateways, well, it's your list; if the gateways cause problems you would rather not deal with just get rid of them. Douglas Douglas Winship Hays County, Texas [log in to unmask] Secondary AUTOCAT Listowner MEDLAB-L