Richard, 'Message-ID' is part of the set of 'junk' header keywords which are normally removed (remember the 30+ lines headers of Ricky's LISTSERV?). You might argue that 'Message-ID' is such an important tag that you cannot understand how I can call it 'junk', but my definition of 'junk' is 'not understood by the end user and not needed for delivery'. Anyway, you can get the 'Message-ID' back into your header by means of a 'SET listname FULLHDR' (or 'FULLBSMTP' if you prefer the BSMTP-style headers); to make it the default for the list, you can put a "Default-Options= FULLHDR<,etc>" in the list header. Eric