http://zetawiki.com/wiki/IP로_도메인_이름_알아내기
ipcalc
명령어 소스
https://gitlab.com/ipcalc/ipcalc
https://github.com/nmav/ipcalc/blob/master/ipcalc.c
$ ipcalc -h 10.101.52.128 HOSTNAME=jongpak.host