Robtex

Up: 203.123.160.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 203.123.160.0/23
Down right: 203.123.162.0/23

IP	Type	Hostname
203.123.160.249	A+PTR	punsw01.pacific.net.in
203.123.162.90	PTR	mail90.pune-162.pacific.net.in
203.123.162.91	PTR	mail91.pune-162.pacific.net.in
203.123.162.92	PTR	dns15.parkpage.foundationapi.com
203.123.162.103	PTR	dns15.parkpage.foundationapi.com
203.123.162.106	PTR	dns15.parkpage.foundationapi.com
203.123.162.236	A	mail.qualexsystems.com
203.123.162.249	PTR	mail.colayer.com
203.123.163.35	PTR	mail35.pune-163.pacific.net.in
203.123.163.85	PTR	mail85.pune-163.pacific.net.in
203.123.163.126	PTR	mail126.pune-163.pacific.net.in
203.123.163.182	PTR	mail182.pune-163.pacific.net.in
203.123.163.206	PTR	dns15.parkpage.foundationapi.com
203.123.163.223	PTR	dns15.parkpage.foundationapi.com
203.123.163.224	PTR	dns15.parkpage.foundationapi.com