Re: [dnssd] UTF8 use in DNS populated by mDNS

[Andrew Sullivan <[e-mail]>]

Hi,

On Wed, Nov 19, 2014 at 04:50:39PM -0800, Douglas Otis wrote:
> If UTF-8 is to be permitted in DNS populated using mDNS inputs, a
> superset of rules directly and indirectly established to support
> safe use of IDNA labels are necessary, otherwise omitting such
> requirements would permit trivial spoofing.  The requirements should
> include IDNA2008 considerations that restrict permitted code points.

In which part of the DNS-SD name do you want these restrictions?  I
think there is considerable discussion of the different parts of those
names in the draft I discussed in Honolulu.

Note that there is _already_ a standard for putting "UTF-8 labels" in
the DNS (going back to STD 13 and reiterated by RFC 2181).  In effect,
they're not "UTF-8 labels" but rather series of octets.

> It seems some advocate use of spaces in a domain name label be
> permitted.  Even this minor change may confuse users about the
> specific domain when seen with respect to commandline based
> applications.

This is already permitted, of course, just like anything else in
labels.

But as I guess is plain from my work on the mdns-dns compatibility
I-D, I do think there is a long-term problem here, which is why I
recommend the minimal interoperable subset.

Best regards,

A

-- 
Andrew Sullivan
[e-mail]