Re: [ietf-smtp] Curious, with this now being associated to emailcore, should list name change?

[Alessandro Vesely <[e-mail]>]

On Sun 19/Jul/2020 20:19:52 +0200 John C Klensin wrote:
> Would the suggestion that started this thread be consistent with an
> applicability statement, either in 2822bis or the separate document for
> which draft-klensin-email-core-as-00 is a placeholder, that said something
> like "Header field names starting in 'X-' or longer than NNN are prohibited
> unless they are legacy registrations in the IANA registry.  They MUST NOT
> be transmitted in messages and Submission Servers and other systems 
> encountering them MAY, and in most cases SHOULD, delete them"?

Such a drastic stance may make sense if we need to guard against some kind of 
violation.  For example, header fields which aim at capturing some traits of 
the body of a message which are considered relevant for tracking, profiling, or 
similar activities which might be considered intrusive.  Such fields can allow 
a mail system to link non-delivery notifications and DMARC/ DKIM/ SPF failure 
notices which contain text/rfc822-headers only to their missing bodies.  That 
way, they'd defeat the omission of the body due to privacy concerns.


Just ruminating...
Ale
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