ptrhost Query PTR record from hostname Installation Requirement: Go % go get github.com/itochan/ptrhost Usage % ptrhost itochan.jp 2001:e42:102:1819:160:16:234:100 -> 160.16.234.100.v6.sakura.ne.jp. 160.16.234.100 -> hatsukoi.itochan.jp.