Robtex

Up: 210.221.128.0/18
Can't show all results, try to descend to a more specific CIDR
Down left: 210.221.128.0/20
Down right: 210.221.144.0/20
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
210.221.130.0	PTR	noneptr.skline.co.kr
210.221.131.130	A	sniper.panstarline.com
210.221.131.131	PTR	mail.panstar.co.kr
210.221.131.132	A	han21.com
210.221.131.132	A	mail.han21.com
210.221.131.132	A	sanstar.co.jp
210.221.131.194	PTR	plus.hongwon.com
210.221.134.141	A	ns1.sparemap.com
210.221.134.141	A	sparemap.com
210.221.134.141	A	www.smepc.co.kr
210.221.135.0	PTR	noneptr.skline.co.kr
210.221.149.134	A	mailsrv.shimadzu.co.kr
210.221.154.72	A	mail.taegu.co.kr
210.221.154.72	A	mail.ohmycampus.com
210.221.154.122	A	mail.kumhomusul.com
210.221.154.122	A	mail.hsd.pe.kr
210.221.154.136	PTR	mail.b2bgate.co.kr
210.221.154.139	PTR	mail.twin-soft.co.kr
210.221.154.140	PTR	mail.puritech.kr
210.221.154.251	A+PTR	mail.dongbuam.com
210.221.154.251	A	mail.dongbuitm.com