<http://links.ease.lsoft.com/trk/click?ref=znwrbbrs9_0-3b1x3960x3676>Understanding How LISTSERV®<http://links.ease.lsoft.com/trk/click?ref=znwrbbrs9_0-3b1x3960x3676> Handles Bounces (PDF) a five page PDF last updated 21 Sep 2004 complete with five RFC references. /Pete