[DNSOP] ANAME intro text

[Ray Bellis <[e-mail]>]

The introduction of draft-ietf-dnsop-aname-02 includes this text:

   If the web site is hosted by a third-party provider, the ideal way to
   provision its name in the DNS is using a CNAME record, so that the
   third party provider retains control over the mapping from names to
   IP address(es).

I have some issue with the use of the term "ideal" there.  At best it's
merely "expedient", but either way it'ws an abuse of the true original
semanatics of the CNAME record.

AIUI, various protocols have at times required that when a CNAME record
is encountered that the target of that record (the "canonical name") be
the one subsequently used in protocol exchanges.  [e.g. the apparently
obsolete text in §5.2.2 of RFC 1123].

This reinforced the semantic that the RHS of a CNAME is the "one true
name" and that the owner name is just an alias for it [RFC 2181].

Browsers, unfortunately, never did this.  Name-based virtual hosting
actually required the opposite - you have to put the original owner name
in the 'Host:' header.

If we've moved to a world where those original semantics really no
longer apply, I think that needs to be written down in a consensus
document somewhere.

Ray