On 9/12/2014 8:35 AM, MH Michael Hammer (5304) wrote: >> From: ietf [mailto:ietf-bounces@xxxxxxxx] On Behalf Of Christian Huitema ... >> The big change with DMARC is a deprecation of the Sender/From >> differentiation, effectively requiring that these two will be the same. It >> seems that big systems have voted that the differentiation causes more >> harm (spam, phish) than good (remailers). > > This is actually not quite true. If the Sender and the From are in the same domain then there is no problem. It becomes an issue when the Sender and the From are different domains. DMARC does not care about the LHS of the email address (whether it is DKIM signing or SPF validation). In semantic terms, Christian's analysis is exactly correct. The fact that there might be some scenarios where things are not operationally problematic is a distraction, rather than meaningful to the analysis. By definition, p=reject enforces a semantic that requires the owner of the rfc5322.From domain to have a relatively tight relationship with the operator sending the message. IMO, it's quite reasonable to characterize this as conflating From: and Sender:. What tends to be missed, throughout all of the discussions about dealing with the effect on intermediaries such as mailing lists, is that most or all of the mechanisms being discussed for intermediaries will work equally well for bad actors... d/ -- Dave Crocker Brandenburg InternetWorking bbiw.net