http://ya.maya.st/d/201103a.html#s20110303_2 http://ya.maya.st/d/201102c.html#s20110224_1 Reverse DNS in IPv6 for Internet Service Providers http://tools.ietf.org/html/draft-howard-isp-ip6rdns-04 v6 アドレスを配る ISP は逆引きをどうすれば…