Dan Oscarsson <[EMAIL PROTECTED]> wrote: > Why is it that IETF can change the definition on for example what > characters are allowed in host names without an identifer of some > kind,
That's not what we're doing. In data intended for machine consumption (protocol messages, function arguments, machine-readable file formats, etc) we are insisting that domain names continue to be ASCII-only; non-ASCII domain names may appear only where they are explicitly invited by new protocols/interfaces/formats (or new versions of old ones). In data intended for human consumption (like email message bodies and user interfaces) we (IDNA) are being more lax, and encouraging domain names to use the same charset that is used for all text in that context. The rationale is that compared to machines, humans are better able to cope with change, and much less tolerant of unintelligible garbage. (There is a case to be made against this laxity, and Eric has made it.) > For example, the URI definition have changed making those applications > following the original specification reject what later revisions see > as valid URIs. That's fine. If the only difference between the old standard and the new standard is that old software rejects things that new software accepts, that's the best you can hope for. What's bad is if old software and new software both accept the same things, but behave differently. That's the situation we're afraid of with 8-bit domain names in DNS. Existing DNS servers already accept 8-bit names in queries. If we were to declare that such queries must now be handled differently, we'd create interoperability problems. AMC
