[ietf-822] draft-crocker-inreply-react-- header field approach
John C Klensin <john-ietf@jck.com> Fri, 23 October 2020 17:08 UTC
Return-Path: <john-ietf@jck.com>
X-Original-To: ietf-822@ietfa.amsl.com
Delivered-To: ietf-822@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 4B3C63A084D for <ietf-822@ietfa.amsl.com>; Fri, 23 Oct 2020 10:08:09 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.898
X-Spam-Level:
X-Spam-Status: No, score=-1.898 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_NONE=0.001] autolearn=ham autolearn_force=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ALUsHXRyWS2C for <ietf-822@ietfa.amsl.com>; Fri, 23 Oct 2020 10:08:07 -0700 (PDT)
Received: from bsa2.jck.com (bsa2.jck.com [70.88.254.51]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id A152E3A083F for <ietf-822@ietf.org>; Fri, 23 Oct 2020 10:08:07 -0700 (PDT)
Received: from [198.252.137.10] (helo=PSB) by bsa2.jck.com with esmtp (Exim 4.82 (FreeBSD)) (envelope-from <john-ietf@jck.com>) id 1kW0Xu-000F2R-A7 for ietf-822@ietf.org; Fri, 23 Oct 2020 13:08:06 -0400
Date: Fri, 23 Oct 2020 13:07:59 -0400
From: John C Klensin <john-ietf@jck.com>
To: ietf-822@ietf.org
Message-ID: <B22C9047AFA80CCBCDED0FF6@PSB>
X-Mailer: Mulberry/4.0.8 (Win32)
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
X-SA-Exim-Connect-IP: 198.252.137.10
X-SA-Exim-Mail-From: john-ietf@jck.com
X-SA-Exim-Scanned: No (on bsa2.jck.com); SAEximRunCond expanded to false
Archived-At: <https://mailarchive.ietf.org/arch/msg/ietf-822/hiuC3SbGvGhS0j_vAaEXAk3Hiu8>
Subject: [ietf-822] draft-crocker-inreply-react-- header field approach
X-BeenThere: ietf-822@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "Discussion of issues related to Internet Message Format \[RFC 822, RFC 2822, RFC 5322\]" <ietf-822.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/ietf-822>, <mailto:ietf-822-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/ietf-822/>
List-Post: <mailto:ietf-822@ietf.org>
List-Help: <mailto:ietf-822-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/ietf-822>, <mailto:ietf-822-request@ietf.org?subject=subscribe>
X-List-Received-Date: Fri, 23 Oct 2020 17:08:09 -0000
Several comments about the proposal and evolving discussion rather than any particular note. I have read many, but not all, of the comments leading up to this point so, if some of what follows is redundant, my apologies. (1) I haven't tried to do a careful study of MUAs in years and the one I use most often is even older, but what I keep seeing when looking over the shoulders of others is that MUAs display the headers they recognize and think are important. If some header field is not on that (typically very) short list, the only way that a user will see it involves knowing where to find the "show all headers" option (most end users I see, work with, or am related to don't) and then, due in no small part to DKIM and assorted other things related to authentication, spam filtering, or list expansion, get buried in noise. Not a good way to deliver what is supposed to be a quick reaction. (2) Some (at one time many, but I gather fewer recently) MUAs will allow users to add their header fields of their own choosing and a subset of them will allow adding header field values on a per-message basis. Like the above, I don't think expecting casual users to do that is likely to be successful. (3) Several of the systems I've looked at (including both assorted filters and MUAs) don't deal kindly with messages with empty bodies. Even when they are delivered, they may be presented with obnoxious warnings. (4) Whatever emoji may or may not be, they are not ASCII characters. That takes us into i18n space. Unless SMTPUTF8 is in use, if they appear in a header field in UTF-8, a plausible reading of 5322 would call for that field to be rejected, ignored, or treated with great skepticism, possibly along with the whole message of which they are a part. Using encoded words should be fine except that the potential new header field is not called out as a place where encoded words are to be accepted and decoded. Presumably we could amend those specs but the other problem, connected to (1) above, is that many MUAs that support a "show all headers" feature consider it a debugging option and hence will display encoded words without decoding them -- not what the user is likely to want to see. As a consequence of the issues above, I recommend against adding a header field for this function unless there is clear evidence that the implementers and maintainers of the vast majority [1] of MUAs are prepared to implement specific support for this and feature the header as something that can be set (on the sending side) or seen (on the receiving side) without going to more extraordinary means than setting/looking at, e.g., a subject line. Of course, a different way to look at that is that a few MUA developers and/or MSPs are anxious to offer this feature in a way that would give them a market advantage and put those who don't implement it quickly at a disadvantage. Were that to be any part of the argument or our thinking, it would be appropriate to ask for disclosures about who is being paid by whom to do what. But I hope that is not happening. best, john p.s. Another note will follow (soon but not immediately) about the use of Content-disposition, about which I'm also concerned, but not nearly as much. [1] By count of implementations, not of numbers of users.
- [ietf-822] draft-crocker-inreply-react-- header f… John C Klensin
- Re: [ietf-822] draft-crocker-inreply-react-- head… John Levine
- Re: [ietf-822] draft-crocker-inreply-react-- head… Keith Moore