Brian E Carpenter <brian(_dot_)e(_dot_)carpenter(_at_)gmail(_dot_)com> writes:
I am disturbed that the messy situation of X- headers,
created by RFC 2822's silence on the subject, has
not been fixed.
Me too.
I believe it would be appropriate to document that although
X- headers are widely used, they are not part of the standard
format and their treatment by Internet MTAs MUST NOT be relied on,
Agreed.
Further, one could discuss that using X- have caused interop problems
when standardizing the header field. Old applications only know about
the X- form and would not know the non-X- form, which makes it difficult
to standardize the X- header field. It may be preferable to avoid using
X- in experiment intended to be standardized later on. This point of
view may be more contentious than what you propose though. I'd be
interested to understand if others share this opinion.
unless registered under RFC 3864.
I'd prefer to avoid this escape mechanism. Can X-* headers really be
registered under RFC 3864? RFC 822 says:
Note: The prefatory string "X-" will never be used in the
names of Extension-fields. This provides user-defined
fields with a protected set of names.
...
extension-field =
<Any field which is defined in a document
published as a formal extension to this
specification; none will have names beginning
with the string "X-">
/Simon
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