Robtex

Up: 201.151.48.0/20
Can't show all results, try to descend to a more specific CIDR
Down left: 201.151.56.0/22
Down right: 201.151.60.0/22
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
201.151.56.2	PTR	static-201-151-56-2.alestra.net.mx
201.151.56.4	PTR	static-201-151-56-4.alestra.net.mx
201.151.56.8	PTR	static-201-151-56-8.alestra.net.mx
201.151.56.9	PTR	static-201-151-56-9.alestra.net.mx
201.151.56.17	PTR	static-201-151-56-17.alestra.net.mx
201.151.56.18	PTR	static-201-151-56-18.alestra.net.mx
201.151.56.25	PTR	static-201-151-56-25.alestra.net.mx
201.151.56.40	PTR	static-201-151-56-40.alestra.net.mx
201.151.56.43	PTR	static-201-151-56-43.alestra.net.mx
201.151.56.56	PTR	static-201-151-56-56.alestra.net.mx
201.151.56.57	PTR	static-201-151-56-57.alestra.net.mx
201.151.56.74	PTR	static-201-151-56-74.alestra.net.mx
201.151.56.80	PTR	static-201-151-56-80.alestra.net.mx
201.151.56.81	PTR	static-201-151-56-81.alestra.net.mx
201.151.56.82	PTR	static-201-151-56-82.alestra.net.mx
201.151.56.83	PTR	static-201-151-56-83.alestra.net.mx
201.151.56.88	PTR	static-201-151-56-88.alestra.net.mx
201.151.56.105	PTR	static-201-151-56-105.alestra.net.mx
201.151.56.120	PTR	static-201-151-56-120.alestra.net.mx
201.151.56.121	PTR	static-201-151-56-121.alestra.net.mx
201.151.56.123	PTR	static-201-151-56-123.alestra.net.mx
201.151.56.130	PTR	static-201-151-56-130.alestra.net.mx
201.151.56.138	PTR	static-201-151-56-138.alestra.net.mx
201.151.56.144	PTR	static-201-151-56-144.alestra.net.mx
201.151.56.145	PTR	static-201-151-56-145.alestra.net.mx
201.151.56.147	PTR	static-201-151-56-147.alestra.net.mx
201.151.56.155	PTR	static-201-151-56-155.alestra.net.mx
201.151.56.162	PTR	static-201-151-56-162.alestra.net.mx
201.151.56.169	PTR	static-201-151-56-169.alestra.net.mx
201.151.56.176	PTR	static-201-151-56-176.alestra.net.mx
201.151.56.176	A	mail.intranet.unid.edu.mx
201.151.56.186	PTR	static-201-151-56-186.alestra.net.mx
201.151.56.194	PTR	static-201-151-56-194.alestra.net.mx
201.151.56.195	PTR	static-201-151-56-195.alestra.net.mx
201.151.56.216	PTR	static-201-151-56-216.alestra.net.mx
201.151.56.225	PTR	static-201-151-56-225.alestra.net.mx
201.151.56.226	PTR	static-201-151-56-226.alestra.net.mx
201.151.56.243	PTR	static-201-151-56-243.alestra.net.mx
201.151.57.1	PTR	static-201-151-57-1.alestra.net.mx
201.151.57.2	PTR	static-201-151-57-2.alestra.net.mx
201.151.57.9	PTR	static-201-151-57-9.alestra.net.mx
201.151.57.19	PTR	static-201-151-57-19.alestra.net.mx
201.151.57.24	PTR	static-201-151-57-24.alestra.net.mx
201.151.57.35	PTR	static-201-151-57-35.alestra.net.mx
201.151.57.56	PTR	static-201-151-57-56.alestra.net.mx
201.151.57.58	PTR	static-201-151-57-58.alestra.net.mx
201.151.57.59	PTR	static-201-151-57-59.alestra.net.mx
201.151.57.65	PTR	static-201-151-57-65.alestra.net.mx
201.151.57.74	PTR	static-201-151-57-74.alestra.net.mx
201.151.57.83	PTR	static-201-151-57-83.alestra.net.mx
201.151.57.88	PTR	static-201-151-57-88.alestra.net.mx
201.151.57.96	PTR	static-201-151-57-96.alestra.net.mx
201.151.57.97	PTR	static-201-151-57-97.alestra.net.mx
201.151.57.105	PTR	static-201-151-57-105.alestra.net.mx
201.151.57.107	PTR	static-201-151-57-107.alestra.net.mx
201.151.57.122	PTR	static-201-151-57-122.alestra.net.mx
201.151.57.123	PTR	static-201-151-57-123.alestra.net.mx
201.151.57.129	PTR	static-201-151-57-129.alestra.net.mx
201.151.57.146	PTR	static-201-151-57-146.alestra.net.mx
201.151.57.152	PTR	static-201-151-57-152.alestra.net.mx
201.151.57.168	PTR	static-201-151-57-168.alestra.net.mx
201.151.57.169	PTR	static-201-151-57-169.alestra.net.mx
201.151.57.171	PTR	static-201-151-57-171.alestra.net.mx
201.151.57.184	PTR	static-201-151-57-184.alestra.net.mx
201.151.57.193	PTR	static-201-151-57-193.alestra.net.mx
201.151.57.194	PTR	static-201-151-57-194.alestra.net.mx
201.151.57.195	PTR	static-201-151-57-195.alestra.net.mx
201.151.57.200	PTR	static-201-151-57-200.alestra.net.mx
201.151.57.211	PTR	static-201-151-57-211.alestra.net.mx
201.151.57.248	PTR	static-201-151-57-248.alestra.net.mx
201.151.58.88	PTR	static-201-151-58-88.alestra.net.mx
201.151.58.201	PTR	static-201-151-58-201.alestra.net.mx
201.151.59.9	PTR	rugo.com.mx
201.151.59.34	A+PTR	correo.holidayinnmatamoros.com
201.151.59.34	A	ns1.holidayinnmatamoros.com
201.151.59.34	A	holidayinnmatamoros.com
201.151.59.35	PTR	ns1.himatamoros.com
201.151.59.35	A	mail.himatamoros.com
201.151.59.40	PTR	static-201-151-59-40.alestra.net.mx
201.151.59.81	PTR	static-201-151-59-81.alestra.net.mx
201.151.59.115	PTR	static-201-151-59-115.alestra.net.mx
201.151.59.128	PTR	static-201-151-59-128.alestra.net.mx
201.151.59.137	PTR	static-201-151-59-137.alestra.net.mx
201.151.60.2	PTR	static-201-151-60-2.alestra.net.mx
201.151.62.1	A+PTR	mail.telinet.com.mx
201.151.62.1	A	ns.telinet.com.mx
201.151.62.1	A	telinet.com.mx
201.151.62.3	PTR	static-201-151-62-3.alestra.net.mx
201.151.62.35	A	am3pri.aduanetm3.net
201.151.62.37	A	www.saviaduanet.net
201.151.62.38	A	aduanetcfd.net
201.151.62.38	A	www.aduanetcfd.net
201.151.62.44	A	www.tnl.com.mx
201.151.62.45	A	mail.tnl.com.mx
201.151.62.47	A	ns2.aduanet.net
201.151.62.49	PTR	static-201-151-62-49.alestra.net.mx
201.151.62.49	A	mail.aduanetm3.net
201.151.62.49	A	mail3.gpofm.com
201.151.62.61	A	ttforwarding.com
201.151.62.61	A	mail.ttforwarding.com
201.151.62.101	A	villatours.net
201.151.62.115	A+PTR	mail.cosmocel.com
201.151.62.115	A	sendmail.cosmocel.com
201.151.62.115	A	mail.cosmocel.biz
201.151.62.125	A	servicios.cosmocel.com
201.151.62.130	PTR	static-201-151-62-130.alestra.net.mx
201.151.62.130	A	evaa.com.mx
201.151.62.138	PTR	static-201-151-62-138.alestra.net.mx