RE: [idn] Unicode tagging

[Andrew Draper <ADRAPER@altera.com>]

Keith Moore wrote:
> no, IDN must not attempt to change this.  the format of I18N'ed email
> addresses is not within scope of this group.  email addresses 
> must remain as they are until the email folks figure out how to either
> change RFC 822 to accept some form of Unicode in message headers
> or (more likely) encode I18N'ed addreses as ASCII for transmission 
> in email messages.  the question of how to encode I18N'ed 
> email addresses
> in SOA records must wait until that work has been done.  presumably
> if email adopts an ascii encoding for use on the wire then 
> SOA records 
> (and other records) can use the same encoding as email adopts.

I am not saying that the IDN group should try to change the email system.

However, an internationalised DNS should be capable of encoding
internationalised email addressees ready for the time when email is able to
handle them.  If it can't then email people will have the same problem in
reverse when they design their I18N solution (although I would expect that
email addresses within SOA/RP etc. will be towards the bottom of their list
of problems).

I think we need to be careful to distinguish between Internationalised
Domain Names and internationalised DNS labels since the former will be much
more restricted than the latter.  The requirements document is somewhat
vague about this, sometimes it says DNS name and sometimes IDN, apparently
using the terms interchangeably.  

I think there are (at least) three options for DNS labels which are not part
of host or domain names, and I suggest a new requirement to clarify this
(probably best after number 16):

[16a] The protocol must specify the behaviour of the DNS as regards DNS
labels which are not part of host or domain names (for example the first
label of a DNS name which represents an email address).  These labels could
be restricted by the protocol to remain as ASCII only, they could be
internationalised with the same canonicalisation as IDNs or they could be
internationalised with different canonicalisation.

(Or we could decide now what the handling of these labels should be and just
put one option into the requirements document).

Regards,

    Andy