Robtex

Up: 203.122.0.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 203.122.0.0/23
Down right: 203.122.2.0/23

IP	Type	Hostname
203.122.0.0	PTR	203.122.0.0.reverse.spectranet.in
203.122.0.80	PTR	ca-mod80-a.spectranet.com
203.122.0.191	PTR	203.122.0.191.reverse.spectranet.in
203.122.1.13	PTR	203.122.1.13.reverse.spectranet.in
203.122.1.218	PTR	203.122.1.218.reverse.spectranet.in
203.122.1.224	PTR	ca-mod224-b.spectranet.com
203.122.1.249	PTR	203.122.1.249.reverse.spectranet.in
203.122.2.4	PTR	203.122.2.4.reverse.spectranet.in
203.122.3.57	A	mail.allahabad4u.com