Robtex

Up: 71.21.0.0/17
Can't show all results, try to descend to a more specific CIDR
Down left: 71.21.0.0/19
Down right: 71.21.32.0/19
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
71.21.0.0	PTR	71-21-0-0.los.clearwire-wmx.net
71.21.0.168	PTR	71-21-0-168.los.clearwire-wmx.net
71.21.3.1	PTR	71-21-3-1.los.clearwire-wmx.net
71.21.3.192	PTR	71-21-3-192.los.clearwire-wmx.net
71.21.4.250	PTR	71-21-4-250.los.clearwire-wmx.net
71.21.4.250	A	cyderbox.com
71.21.5.253	PTR	71-21-5-253.los.clearwire-wmx.net
71.21.8.246	PTR	71-21-8-246.los.clearwire-wmx.net
71.21.9.36	PTR	71-21-9-36.los.clearwire-wmx.net
71.21.9.233	PTR	71-21-9-233.los.clearwire-wmx.net
71.21.10.2	PTR	71-21-10-2.los.clearwire-wmx.net
71.21.10.72	A	remote.worldgemologicalservices.com
71.21.12.1	PTR	71-21-12-1.los.clearwire-wmx.net
71.21.12.2	PTR	71-21-12-2.los.clearwire-wmx.net
71.21.12.65	PTR	71-21-12-65.los.clearwire-wmx.net
71.21.12.128	PTR	71-21-12-128.los.clearwire-wmx.net
71.21.12.192	PTR	71-21-12-192.los.clearwire-wmx.net
71.21.12.193	PTR	71-21-12-193.los.clearwire-wmx.net
71.21.12.194	PTR	71-21-12-194.los.clearwire-wmx.net
71.21.13.65	PTR	71-21-13-65.los.clearwire-wmx.net
71.21.13.194	PTR	71-21-13-194.los.clearwire-wmx.net
71.21.14.190	PTR	71-21-14-190.los.clearwire-wmx.net
71.21.14.190	A	aaronurbina.com
71.21.15.177	PTR	71-21-15-177.los.clearwire-wmx.net
71.21.16.2	PTR	71-21-16-2.los.clearwire-wmx.net
71.21.17.195	PTR	71-21-17-195.los.clearwire-wmx.net
71.21.18.239	A	mail.rockotiger.net
71.21.18.239	A	rockotiger.net
71.21.20.66	PTR	71-21-20-66.los.clearwire-wmx.net
71.21.21.21	A	671558.com
71.21.21.21	A	gf8999.com
71.21.21.21	A	*.626599.com
71.21.24.2	PTR	71-21-24-2.los.clearwire-wmx.net
71.21.24.3	PTR	71-21-24-3.los.clearwire-wmx.net
71.21.24.64	PTR	71-21-24-64.los.clearwire-wmx.net
71.21.24.65	PTR	71-21-24-65.los.clearwire-wmx.net
71.21.24.66	PTR	71-21-24-66.los.clearwire-wmx.net
71.21.24.194	PTR	71-21-24-194.los.clearwire-wmx.net
71.21.25.207	PTR	71-21-25-207.los.clearwire-wmx.net
71.21.26.224	PTR	71-21-26-224.los.clearwire-wmx.net
71.21.32.134	A	mail.iuseelite.us
71.21.35.129	PTR	71-21-35-129.los.clearwire-wmx.net
71.21.36.2	PTR	71-21-36-2.los.clearwire-wmx.net
71.21.36.169	PTR	71-21-36-169.los.clearwire-wmx.net
71.21.36.169	A	remotevirtualcloud.com
71.21.36.170	PTR	71-21-36-170.los.clearwire-wmx.net
71.21.36.170	A	findmyit.com
71.21.39.2	PTR	71-21-39-2.los.clearwire-wmx.net
71.21.39.37	PTR	71-21-39-37.los.clearwire-wmx.net
71.21.39.218	A	ns1.luminousstudio.com
71.21.42.66	PTR	71-21-42-66.los.clearwire-wmx.net
71.21.42.192	PTR	71-21-42-192.los.clearwire-wmx.net
71.21.42.193	PTR	71-21-42-193.los.clearwire-wmx.net
71.21.46.96	PTR	71-21-46-96.los.clearwire-wmx.net
71.21.46.116	PTR	71-21-46-116.los.clearwire-wmx.net
71.21.49.201	PTR	71-21-49-201.los.clearwire-wmx.net
71.21.50.3	PTR	71-21-50-3.los.clearwire-wmx.net
71.21.52.12	PTR	71-21-52-12.los.clearwire-wmx.net
71.21.52.122	A	elrodeoridingclub.net
71.21.55.0	PTR	71-21-55-0.los.clearwire-wmx.net
71.21.55.129	PTR	71-21-55-129.los.clearwire-wmx.net
71.21.62.1	PTR	71-21-62-1.los.clearwire-wmx.net
71.21.62.64	PTR	71-21-62-64.los.clearwire-wmx.net
71.21.62.65	PTR	71-21-62-65.los.clearwire-wmx.net
71.21.62.130	PTR	71-21-62-130.los.clearwire-wmx.net
71.21.62.131	PTR	71-21-62-131.los.clearwire-wmx.net