Re: XMPP Compatibility

[Eric Rescorla <ekr@rtfm.com>]

ned.freed@mrochek.com writes:
> What's being claimed here is that implementation of critical features as
> message level metadata is going to be rare. But that's precisely what we've
> seen happen with RFC 822: While tons of random dreck is routinely added to RFC
> 822 message headers, practically none of it is used to implement anything
> resembling a critical feature.
I'm not sure what you mean by "critical feature". Are you attempting
to draw a distinction between things that need security and things
that don't? 

If so, I'm not really comfortable with that. Sure, there's tons
of stuff that applications stuff in the 822 header, 
(virus filtering stuff, spam attestations, loop detection),
and we may not think that's important. But the person who shoved
it in there did and so we ought to provide security for it.

> I also note in passing that MIME doesn't really fall into this
> category: It standardizes content labelling and content metadata,
> which ended up being conflated with RFC 822 fields only as a result
> of certain concerns about the installed base, concerns that should
> never apply to any other format.
I'm not quite sure I understand this either. MIME fields are in
the header, no? They contain information that the MUA needs
in order to process the message (like, what the media type is).

-Ekr

-- 
[Eric Rescorla                                   ekr@rtfm.com]
                http://www.rtfm.com/