Subject: [Emailcore] Ticket #7: trace header fields - lone Return-Path case

From: Alexey Melnikov <[email-masked]>
Date: Fri, 9 Jul 2021 13:49:33 +0100

Hi all,

Following up on the discussion at IETF 110: I think we settled on the 
text (what is currently in draft-ietf-emailcore-rfc5322bis-01), but 
there are still a couple of issues about ABNF that we need to resolve. 
One of them is whether the current ABNF for trace header fields is correct:

    trace           =   [return]
                        1*received

In particular, this disallows the lone Return-Path case.

I would like to poll the WG about whether messages with lone 
Return-Paths are generated in the wild. If they are, the ABNF should 
probably be relaxed.

Best Regards,

Alexey

---

From: "John Levine" <[email-masked]>
Date: 9 Jul 2021 22:14:42 -0400

>Return-Paths are generated in the wild. If they are, the ABNF should 

Sometimes if they are generated and delivered on the same system.  Of course,
then they haven't used SMTP.

R's,
John

---

From: Dave Crocker <[email-masked]>
Date: Fri, 9 Jul 2021 19:43:51 -0700

> then they haven't used SMTP.

but then, the email object doesn't require SMTP (and, really, never has...)

d/

-- 
Dave Crocker
Brandenburg InternetWorking
bbiw.net

---

From: "John R Levine" <[email-masked]>
Date: 9 Jul 2021 23:03:15 -0400

>> Sometimes if they are generated and delivered on the same system.  Of 
>> course, then they haven't used SMTP.
>

Sure, but the messages are still in RFC 5322(bis) form and it would be 
nice if the MUAs that handle messages that arrived via SMTP can also 
handle ones that were sent locally.

Regards,
John Levine, [email-masked], Taughannock Networks, Trumansburg NY
"I dropped the toothpaste", said Tom, crestfallenly.

---

From: Dave Crocker <[email-masked]>
Date: Fri, 9 Jul 2021 20:25:39 -0700

> handle ones that were sent locally.

I think that that was my point.

d/

---

From: Viktor Dukhovni <[email-masked]>
Date: Sat, 10 Jul 2021 00:45:00 -0400

> then they haven't used SMTP.

Also, some MSAs are configured to suppress addition of a local
"Received: " header for privacy or other reasons.  If the message is
then delivered locally (even if submitted via SMTP, i.e. SUBMIT) it
may then have just a lone "Return-Path:", with no other trace headers.

One would however typically expect some of "From:", "Date:",
"Message-ID:" to be present, but these are not trace headers.

Also, FWIW, "Return-Path" is not typically sent in SMTP messages, it is
typically instead added on final delivery to a mailbox, recording
whatever the envelope sender appeared to be at that time.  So while
"in transit" such a message has no trace headers at all.

-- 
    Viktor.

---

From: Alexey Melnikov <[email-masked]>
Date: Sat, 10 Jul 2021 11:32:20 +0100

> On 10 Jul 2021, at 03:44, Dave Crocker <[email-masked]> wrote:
> 

+1. Email format document has wider applicability than just SMTP.
> Emailcore mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/emailcore