<div style="font-family: arial, helvetica, sans-serif; font-size: 10pt">mark is correct. No label with "--" should be allowed except (for the present) "xn--"<div><br></div><div>"putative" means that the "--" appears in 3rd and 4th position of the string - it means the label purports to be the prefix of a U-label.</div>
<div><br></div><div>vint</div><div><br><br><div class="gmail_quote">On Tue, Nov 6, 2012 at 12:01 PM, Mark Davis ☕ <span dir="ltr"><<a href="mailto:mark@macchiato.com" target="_blank">mark@macchiato.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><font face="times new roman,serif">Thanks for bringing this up.</font><div><font face="times new roman,serif"><br></font></div>
<div><font face="times new roman,serif">My understanding of the spec was that the intention is to permanently reserve anything of the form "xy--..." (where x and y are in [a-z0-9]. If that is not a requirement, we'd be glad to change our implementation.<br clear="all">
</font><font face="'times new roman', serif"><div style="background-color:transparent;margin-top:0px;margin-left:0px;margin-bottom:0px;margin-right:0px"><div></div></div><div style="background-color:transparent;margin-top:0px;margin-left:0px;margin-bottom:0px;margin-right:0px">
<br></div><div style="background-color:transparent;margin-top:0px;margin-left:0px;margin-bottom:0px;margin-right:0px"><a href="https://plus.google.com/114199149796022210033" target="_blank">Mark</a></div><div style="background-color:transparent;margin-top:0px;margin-left:0px;margin-bottom:0px;margin-right:0px">
<i><br></i></div><div style="background-color:transparent;margin-top:0px;margin-left:0px;margin-bottom:0px;margin-right:0px"><i>— Il meglio è l’inimico del bene —</i></div></font><div><div class="h5"><div><div><font face="'times new roman', serif"><i><span style="font-style:normal"><i></i></span><i></i></i></font></div>
</div><br>
<br><br><div class="gmail_quote">On Tue, Nov 6, 2012 at 7:43 AM, Marcos Sanz <span dir="ltr"><<a href="mailto:sanz@denic.de" target="_blank">sanz@denic.de</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Dear all,<br>
<br>
I had this small discussion with Mark and Markus and, despite our treefold<br>
homonymy, we couldn't get to common ground, so I've decided to get a<br>
reading of the standard directly from the IDNA2008 editors.<br>
<br>
According to my interpretation (cf. RFC 5891, Section 5) the lookup<br>
protocol relies on the assumption that names that are already present in<br>
the DNS are valid. And, in fact, I have a bunch of domains in my database<br>
with hyphens in the third and fourth position, so-called reserved LDH<br>
labels that are not XN-labels (s. nomenclature in RFC 5890, Section<br>
2.3.2.1). Take for instance "<a href="http://ad--acta.de" target="_blank">ad--acta.de</a>". My expectation would be that<br>
the protocol doesn't fail on those*. Mark however reminded me of the<br>
restrictions in RFC 5891, Section 4.2.3.1. But those are for the<br>
registration, which I am not interested in at the moment. If at all<br>
relevant, we'd have Section 5.4:<br>
<br>
"Putative U-labels with any of the following characteristics MUST be<br>
rejected prior to DNS lookup:<br>
[·..]<br>
o Labels containing '--' (two consecutive hyphens) in the third and<br>
fourth character positions."<br>
<br>
On my side, I claim that that restriction simply does not apply because<br>
"<a href="http://ad--acta.de" target="_blank">ad--acta.de</a>" is not a "putative U-label", in fact it is no U-label at all<br>
(cf. U-Label definition in RFC 5890, Section 2.3.2.1).<br>
<br>
Thus, the protocol should never fail on lookup for "<a href="http://ad--acta.de" target="_blank">ad--acta.de</a>". Is that<br>
correct?<br>
<br>
Best regards,<br>
Marcos<br>
<br>
* FWIW idnkit-2.2 works according to my expectations, ICU does not.<br>
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