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

Viktor Dukhovni ietf-dane at dukhovni.org
Fri Sep 8 04:48:59 UTC 2017

On Thu, Sep 07, 2017 at 09:27:14PM -0700, Jothan Frakes wrote:

> tl;dr :   I suggest this... Try xx--[whateverword] to avoid most/many
> future collisions       it takes advantage of the IDN blocking dashes at
> the third and fourth positions and allows for things like xx--vpn or
> xx--corp or xx--mshome etc which are human readable and won't trigger
> namespace collisions.

Who says that the reserved "xx--" prefix won't be allocated some

> deeper:
> The random gibberish TLDs that John suggested make sense, but could still
> cause a future collision, no matter how unlikely.

The prefixes John suggested, seem to me be less likely to suffer
an *accidental* collision than "xx--" is to be officially allocated.

However, if a name is not registered, and a competitor has a financial
incentive to hijack it, and it is not a trademark or similar protected
name, then all bets are off.

Therefore, IMHO the safest bet is to stick to subdomains of ".invalid",
if dot-envy is an issue, otherwise register a domain and put the names
in question under a 2ld or 3ld.

> If I can 'plus-up' Paul's great suggestion, and synthesize a few of the
> ideas from the genius on list here, there is a restricted space of null
> area that exists for IDN whereby names with dashes in the 3rd and 4th
> positions are restricted.  You could, if you avoided xn--, put any other
> two letters in front of a string then two dashes.

NO.  These prefixes are reserved, and more are likely to be allocated
in the future to carry some other semantics.  PHB is interested in
using "mm--" for his mathematical mesh.

Perhaps someone wants to publish and progress a draft that reserves
some particular "??--" prefix specifically for private use TLDs.
In *that* case squatting on names for that prefix might be ok.
How about "pr--" for "private" or "public relations", whichever
you prefer.


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