Robtex

Up: 192.72.128.0/19
Can't show all results, try to descend to a more specific CIDR
Down left: 192.72.128.0/21
Down right: 192.72.136.0/21

IP	Type	Hostname
192.72.129.0	PTR	h0-192-72-129.seed.net.tw
192.72.129.66	PTR	h66-192-72-129.seed.net.tw
192.72.129.67	PTR	h67-192-72-129.seed.net.tw
192.72.129.80	PTR	h80-192-72-129.seed.net.tw
192.72.129.82	PTR	h82-192-72-129.seed.net.tw
192.72.129.98	PTR	h98-192-72-129.seed.net.tw
192.72.129.112	PTR	h112-192-72-129.seed.net.tw
192.72.129.114	PTR	h114-192-72-129.seed.net.tw
192.72.129.129	PTR	h129-192-72-129.seed.net.tw
192.72.129.145	PTR	h145-192-72-129.seed.net.tw
192.72.129.160	PTR	h160-192-72-129.seed.net.tw
192.72.129.162	PTR	h162-192-72-129.seed.net.tw
192.72.129.209	PTR	h209-192-72-129.seed.net.tw
192.72.135.30	PTR	h30-192-72-135.seed.net.tw
192.72.136.1	A	maila.opto.com.tw
192.72.136.4	A+PTR	spama.opto.com.tw
192.72.136.4	A	mx1.opto.com.tw
192.72.136.4	A	spam.opto.com.tw
192.72.136.253	A+PTR	lns1.opto.com.tw
192.72.136.253	A	lns1.spam.opto.com.tw
192.72.136.253	A	lns1.www.opto.com.tw
192.72.139.0	PTR	h0-192-72-139.seed.net.tw
192.72.139.33	PTR	h33-192-72-139.seed.net.tw
192.72.139.34	PTR	h34-192-72-139.seed.net.tw
192.72.139.35	PTR	h35-192-72-139.seed.net.tw
192.72.139.48	PTR	h48-192-72-139.seed.net.tw
192.72.139.81	PTR	h81-192-72-139.seed.net.tw
192.72.139.113	PTR	h113-192-72-139.seed.net.tw
192.72.139.128	PTR	h128-192-72-139.seed.net.tw
192.72.139.131	PTR	h131-192-72-139.seed.net.tw
192.72.139.145	PTR	h145-192-72-139.seed.net.tw
192.72.139.179	PTR	h179-192-72-139.seed.net.tw
192.72.139.208	PTR	h208-192-72-139.seed.net.tw
192.72.139.211	PTR	h211-192-72-139.seed.net.tw
192.72.139.242	PTR	h242-192-72-139.seed.net.tw