Robtex

Up: 166.111.204.0/23
Can't show all results, try to descend to a more specific CIDR
Down left: 166.111.204.0/25
Down right: 166.111.204.128/25
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
166.111.204.8	A+PTR	mail.tsinghua.edu.cn
166.111.204.8	PTR	sea.net.edu.cn
166.111.204.8	PTR	cernet.edu.cn
166.111.204.9	A+PTR	mails.tsinghua.edu.cn
166.111.204.9	A	tu204009.ip.tsinghua.edu.cn
166.111.204.9	A	mails.thu.edu.cn
166.111.204.26	A+PTR	smtp02.tsinghua.edu.cn
166.111.204.50	A	smtp26.tsinghua.edu.cn
166.111.204.51	A	smtp27.tsinghua.edu.cn
166.111.204.52	A	smtp28.tsinghua.edu.cn
166.111.204.53	PTR	smtp29.tsinghua.edu.cn
166.111.204.54	A+PTR	smtp30.tsinghua.edu.cn
166.111.204.55	A+PTR	smtp31.tsinghua.edu.cn
166.111.204.100	A+PTR	smtp76.tsinghua.edu.cn
166.111.204.120	A+PTR	smtp96.tsinghua.edu.cn
166.111.204.120	A	net.tsinghua.edu.cn