Robtex

Up: 202.51.192.0/23
Can't show all results, try to descend to a more specific CIDR
Down left: 202.51.192.0/25
Down right: 202.51.192.128/25
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
202.51.192.2	PTR	ip2.192.pb-snet.net.id
202.51.192.2	PTR	ip2.192.snet.net.id
202.51.192.22	PTR	ip22.192.snet.net.id
202.51.192.37	A	mail.imaxnet.net
202.51.192.37	A	smtp.sejahteragroup.net
202.51.192.37	A	smtp.snet.net.id