[dns-operations] TLD(s) for private use

Suzanne Woolf suzworldwide at gmail.com
Mon Sep 11 13:52:17 UTC 2017

On Sep 9, 2017, at 2:29 PM, "John Levine" <johnl at taugh.com> wrote:

> In article <97ad36f6-4b83-8db9-1bab-e88466988e77 at jrcs.co.uk> you write:
>> I've not yet seen any response as to why a prefix that includes one or 
>> more UNDERSCORE wouldn't be a viable solution - e.g. "zz__" - or even 
>> all "[LETTER][LETTER]__" - where "XN__" could be IDN?
> Because you can't use underscores in hostnames.  Even if it's not on
> the public Internet, you will run into too much software that
> correctly refuses hostnames that aren't ldh.

Indeed, I'd regard LDH compliance as essential. See also https://www.icann.org/resources/pages/universal-acceptance-2012-02-25-en; the "universal acceptance" problem, as stated, is rather wider than the requirement here, because we were talking about locally scoped names-- but assuming "lowest common denominator" software and operational practice is pretty important if you're trying to draft a solution that works for even most of the people, most of the time.


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