Robtex

Up: 203.116.12.0/22
Can't show all results, try to descend to a more specific CIDR
Down left: 203.116.12.0/24
Down right: 203.116.13.0/24
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
203.116.12.21	PTR	atmail1.serialsystem.com
203.116.12.21	A	mail.serialsys.com.hk
203.116.12.21	A	webmail.achieva.co.id
203.116.12.22	PTR	atmail2.serialsystem.com
203.116.12.22	A	mail.globaltronics-intl.com
203.116.12.22	A	mail.css-medical.com
203.116.12.26	PTR	6h.serialsystem.com
203.116.12.26	A	mail.achievaglobal.com
203.116.12.26	A	mail.serialnetcom.com
203.116.12.90	A	infopub.sgx.com
203.116.12.133	A	mail.bludot.net
203.116.12.133	A	ntdns.bludot.net
203.116.12.133	A	smtp.bludot.net
203.116.12.135	A	voiddeck.com
203.116.12.141	A	thetraveldossier.com
203.116.12.160	PTR	patsnap.com
203.116.12.194	A+PTR	vgate1.tpasia.sg
203.116.12.228	A+PTR	demo.parkroyalhotels.com
203.116.12.228	A+PTR	intranet.parkroyalhotels.com
203.116.13.66	A	pridns.eximfr.com.sg
203.116.13.132	PTR	mail.scape.com.sg
203.116.13.132	A	email.scape.sg
203.116.13.195	A	mail.sgd688.com
203.116.13.196	A	sgd3333.com
203.116.13.197	A	mail.sgd789.com
203.116.13.197	A	www.sgd168.com
203.116.13.197	A	sgd168.com
203.116.13.201	A	sgd333.com
203.116.13.202	A	sgd999.com
203.116.13.202	A	sgd939.com
203.116.13.229	A	mail.creditbureau.com.sg