DNS/RFC/4074について、ここに記述してください。

https://tools.ietf.org/html/rfc4074

Common Misbehavior Against DNS Queries for IPv6 Addresses

Status of This Memo
   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice
   Copyright (C) The Internet Society (2005).

Abstract
   There is some known misbehavior of DNS authoritative servers when
   they are queried for AAAA resource records.  Such behavior can block
   IPv4 communication that should actually be available, cause a
   significant delay in name resolution, or even make a denial of
   service attack.  This memo describes details of known cases and
   discusses their effects.