[1] [CITE@en[RFC 2606 - Reserved Top Level DNS Names]], [TIME[2021-03-28T07:19:55.000Z]], [TIME[2021-04-09T08:41:39.119Z]] <https://tools.ietf.org/html/rfc2606#section-2>

[2] [CITE@en[RFC 6761 - Special-Use Domain Names]]
( ([TIME[2013-06-27 22:35:13 +09:00]] 版))
<http://tools.ietf.org/html/rfc6761#section-6.5>