Hi. A little additional perspective on this from someone who has (deliberately) not been active in the SIEVE effort. Cyrus has alluded to some of this, but the real constraint is with SMTP, not SIEVE, and should be addressed in the SMTP context. The issue of NDN blowback has come up repeatedly in discussions of SMTP. The bottom-line answer, despite complaints from zealous anti-blowback advocates and clever alternate readings of the spec, is that the SMTP model simply doesn't work without the possibility of non-delivery messages. While there are other issues, the most important and obvious of them is that SMTP permits and encourages multiple-recipient messages and has no in-protocol mechanism for returning per-recipient replies. In theory, that problem could be overcome with an SMTP extension for per-recipient replies. There is a long-expired I-D that discussed doing just that, but it never got an traction (and may or may not have been the best way to do it). However, while per-recipient responses have other advantages, there is no reason to assume that spammers would voluntarily make their lives more difficult by invoking such an extension. Conversely, the blowback problem could be solved in principle by authenticating message senders (probably beyond their authorization to send mail, which is more or less the problem to which DKIM and SPF are addressed). But there is again a deployment problem unless one assumes that legitimate deployed SMTP implementations can be changed in only a short period of time. See http://www.rhyolite.com/anti-spam/you-might-be.html#senior-IETF-member-5 and the surrounding context for further discussion on that issue. The bottom line is that a debate about prohibiting SIEVE from returning NDNs is meaningless without changes to SMTP. We don't have any proposals on the table for such SMTP changes and don't know how to get from "here" to "there" with any of the proposals that have been made. I guess that makes this I-D a more tempting target, but it still does not make it relevant. If the SIEVE WG somehow decided that it liked one of the proposals for suppressing the possibility of NDNs, we would then be having a discussion about whether or not that WG is permitted to write a spec that requires violations of SMTP. Fortunately, they did not present us with that choice. best, john --On Thursday, 11 September, 2008 10:38 -0400 Cyrus Daboo <cyrus@xxxxxxxxxx> wrote: > Hi Matthew, > > --On September 10, 2008 3:13:33 PM -0700 Matthew Elvey > <matthew@xxxxxxxxx> wrote: > >> Lisa D reported being told: "There is strong WG consensus >> behind [-07]". Lisa D specifically claimed the WG chairs >> indicated there was. CHAIRS: Can you each please confirm >> that you stated that there is strong WG consensus behind >> [-07]? > > Yes, I can confirm that and firmly believe that the overall > consensus of the WG is to publish the -07 draft. I don't > believe there is a need to re-poll the WG on this, but if the >... _______________________________________________ Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf