Robtex

Up: 121.243.8.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 121.243.12.0/23
Down right: 121.243.14.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
121.243.12.216	PTR	121.243.12.216.static-kolkata.vsnl.net.in
121.243.13.203	PTR	121.243.13.203.static-kolkata.vsnl.net.in
121.243.13.203	A	shriramwealth.co
121.243.13.208	A	imail.shriraminsight.in
121.243.13.213	A+PTR	mail.shriraminsight.com
121.243.13.216	PTR	121.243.13.216.static-kolkata.vsnl.net.in
121.243.13.216	A	www.shriraminsight.com
121.243.13.216	A	shriraminsight.com
121.243.13.223	A	shriraminsight.in
121.243.13.223	A	www.shriraminsight.in
121.243.13.223	A	insight.shriram
121.243.13.227	PTR	121.243.13.227.static-kolkata.vsnl.net.in
121.243.13.227	A	swmail2.fifaindia.com
121.243.13.227	A	dhruvmehta.in
121.243.13.228	PTR	121.243.13.228.static-kolkata.vsnl.net.in
121.243.13.228	A	swm.malabarcapitaladvisors.com
121.243.13.229	A	sisbl.net
121.243.13.233	PTR	121.243.13.233.static-kolkata.vsnl.net.in
121.243.13.245	PTR	121.243.13.245.static-kolkata.vsnl.net.in
121.243.13.245	A	zmail.sisbl.in
121.243.13.247	PTR	121.243.13.247.static-kolkata.vsnl.net.in
121.243.13.247	A	peobrics.in
121.243.13.247	A	sisbl.in
121.243.14.2	PTR	121.243.14.2.static-kolkata.vsnl.net.in
121.243.14.10	PTR	121.243.14.10.static-kolkata.vsnl.net.in
121.243.14.58	PTR	121.243.14.58.static-kolkata.vsnl.net.in
121.243.14.218	PTR	121.243.14.218.static-kolkata.vsnl.net.in
121.243.14.245	PTR	121.243.14.245.static-kolkata.vsnl.net.in
121.243.14.254	PTR	gw.alumnux.com
121.243.15.80	PTR	121.243.15.80.static-kolkata.vsnl.net.in
121.243.15.147	PTR	121.243.15.147.static-kolkata.vsnl.net.in
121.243.15.158	PTR	121.243.15.158.static-kolkata.vsnl.net.in
121.243.15.173	PTR	121.243.15.173.static-kolkata.vsnl.net.in
121.243.15.210	PTR	121.243.15.210.static-kolkata.vsnl.net.in
121.243.15.246	PTR	121.243.15.246.static-kolkata.vsnl.net.in