Re: [ietf-smtp] Valid RFC5322 address

John C Klensin <> Sun, 03 May 2020 17:45 UTC

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Date: Sun, 03 May 2020 13:45:12 -0400
From: John C Klensin <>
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Subject: Re: [ietf-smtp] Valid RFC5322 address
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--On Sunday, May 3, 2020 12:07 -0400 Hector Santos
<> wrote:

> As Ned showed, I see now RFC5222 better defines the
> local-part. But with RFC5321, it wasn't quite clear.  It seems
> to stop with only one occurrence of atext, no BNF for it and
> no reference to atext being defined in RFC5322.
> I suppose this might be another clarification issue for
> RFC5321bis.

The first paragraph of Section 4.1.2 of RFC 5321 (and
rfc5321bis-03) concludes with

	"Terminals not defined in this document, such as ALPHA,
	DIGIT, SP, CR, LF, CRLF, are as defined in the "core"
	syntax in Appendix B of RFC 5234 [5] or in the message
	format syntax in RFC 5322 [11]."

So you can't say "no reference..."   However, it has been clear
to me for some time that turning that statement into a specific
list of productions defined in 5334 (not "such as" handwaving)
and a separate list of productions defined in 5322 and then
indexing both would be a considerable improvement.   If someone
wants to do the work of preparing those lists, I'd be happy to
fold them into 5321bis and provide an acknowledgment.

(An absence of volunteers might be interpreted by the editor,
who is known to be error-prone where ABNF is concerned, as
consensus that what is there is good enough and/or that no one
really cares.  :-) )