Keith Moore <moore@cs.utk.edu> writes: > Note that the ones that don't add return-path are in violation of > over 20+ years of mail specificatons. See RFC 821 (top of page 22), > RFC 1123 (section 5.3.3 among others), and RFC 2821 (section 4.4). > > However there's no guarantee that Return-Path is either consistent > for all messages sent to a list, nor that it is uniquely associated > with a list. In practice, however, both are true, almost 100% of the time. Even when various bounce schemes are used, simple regexps almost always catch them. -- Perry E. Metzger perry@piermont.com