Re: [dmarc-ietf] Definition of "value" in RFC8601

John R Levine <johnl@taugh.com> Mon, 30 March 2020 23:21 UTC

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Date: 30 Mar 2020 19:21:18 -0400
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From: "John R Levine" <johnl@taugh.com>
To: "Murray S. Kucherawy" <superuser@gmail.com>
Cc: "IETF DMARC WG" <dmarc@ietf.org>
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Subject: Re: [dmarc-ietf] Definition of "value" in RFC8601
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> Does someone have a fix in mind that could be submitted as an erratum?  The
> intent was indeed to make the authserv-id either a plain old ASCII domain
> name or an A-label which doesn't need quoting.  I missed that RFC 6532
> didn't update "value", unfortunately.

Unfortunately, 8601's defintion is a mess.  At the bottom of page 15 it 
says this about authserv-id, which contradicts the ABNF:

    Note that in an EAI-formatted message, this identifier may be
    expressed in UTF-8.

If you want it to be a domain, the ABNF should say:

      authserv-id = domain-name

The text below says domain-name is imported from RFC 6376, which I presume 
includes the updates from RFC 8616 that encourage U-labels in EAI 
messages.

This is not strictly backward compatible with the current text, but I 
don't think I've ever seen an authserv-id which wasn't syntactically a 
domain name.

Regards,
John Levine, johnl@taugh.com, Taughannock Networks, Trumansburg NY
Please consider the environment before reading this e-mail. https://jl.ly