Robtex

Up: 121.236.248.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 121.236.252.0/23
Down right: 121.236.254.0/23

IP	Type	Hostname
121.236.253.101	PTR	101.253.236.121.broad.sz.js.dynamic.163data.com.cn
121.236.253.187	PTR	187.253.236.121.broad.sz.js.dynamic.163data.com.cn
121.236.254.155	PTR	155.254.236.121.broad.sz.js.dynamic.163data.com.cn
121.236.254.176	PTR	176.254.236.121.broad.sz.js.dynamic.163data.com.cn
121.236.255.62	PTR	62.255.236.121.broad.sz.js.dynamic.163data.com.cn