On Fri, Apr 12, 2013 at 03:18:09PM -0600, Peter Saint-Andre wrote:
>
> 3. This text is a bit confusing:
>
> One of the most useful case of delimiter mapping is when FULL STOP
> character (U+002E) is a delimiter as well as domain name.
>
> I am not a DNS expert, but my understanding is that FULL STOP is not
> part of the domain name but is a delimiter between the labels of a
> domain name. I think the sentence quoted above means that in certain
> protocols FULL STOP is used as a delimiter within protocol strings (such
> as identifiers) in addition to being used as a delimiter between domain
> name labels.
I think this feedback is right, but just so that we're clear, it's
much worse than the above in DNS names.
The dot in a DNS name is not part of the protocol _at all_. In the
wire format, labels are delimited conceptually as follows:
3www7example3com0NULL
It is only in the presentation format that we use dots as separators.
Moreover, we usually but not always leave off the final dot for
presentation purposes. So you _can't_ internationalize the protocol
separator in the DNS, because it isn't there in the protocol. It's
only there when humans look at it. (Schroedinger's separator?)
This set of issues, which is quite unusual (perhaps unique to DNS), is
also why DNS and IDNA are only a weak model for what should be done
in other cases.
Best,
A
--
Andrew Sullivan
[email protected]
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