referencing IDNA2008 (and IDNA2003?)

Andrew Sullivan ajs at
Fri Oct 22 16:20:03 CEST 2010

On Fri, Oct 22, 2010 at 03:30:45PM +0200, J-F C. Morfin wrote:

> better we stay in our respective areas. And Internet IETF RFCs stay  
> within the boundaries of lowercase A-Labels.

There is no guarantee that A-labels will never have capital letters in
them, is there?  RFC 5891 says this in section 3.1, number 2:
"A-labels MUST be compared as case-insensitive ASCII (as with all
comparisons of ASCII DNS labels)."

A-labels are, to an IDNA-ignorant application, just plain old DNS
labels that happen to conform to the LDH hostname convention.  They
can be in either case, AFAIK.


Andrew Sullivan
ajs at
Shinkuro, Inc.

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