Robtex

Up: 71.21.0.0/16
Can't show all results, try to descend to a more specific CIDR
Down left: 71.21.0.0/18
Down right: 71.21.64.0/18
(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
71.21.4.250	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
71.21.12.128	PTR	71-21-12-128.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
71.21.18.239	A	mail.rockotiger.net
71.21.18.239	A	rockotiger.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
71.21.25.207	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
71.21.46.96	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
71.21.62.130	PTR	71-21-62-130.los.clearwire-wmx.net
71.21.62.131	PTR	71-21-62-131.los.clearwire-wmx.net
71.21.65.0	PTR	71-21-65-0.hou.clearwire-wmx.net
71.21.67.71	PTR	71-21-67-71.hou.clearwire-wmx.net
71.21.68.167	PTR	71-21-68-167.hou.clearwire-wmx.net
71.21.71.128	PTR	71-21-71-128.hou.clearwire-wmx.net
71.21.71.129	PTR	71-21-71-129.hou.clearwire-wmx.net
71.21.71.131	PTR	71-21-71-131.hou.clearwire-wmx.net
71.21.72.3	PTR	71-21-72-3.hou.clearwire-wmx.net
71.21.74.0	PTR	71-21-74-0.hou.clearwire-wmx.net
71.21.74.3	PTR	71-21-74-3.hou.clearwire-wmx.net
71.21.78.0	PTR	71-21-78-0.hou.clearwire-wmx.net
71.21.80.0	PTR	71-21-80-0.hou.clearwire-wmx.net
71.21.80.101	PTR	71-21-80-101.hou.clearwire-wmx.net
71.21.80.101	A	mail.esitedna01.com
71.21.81.0	PTR	71-21-81-0.hou.clearwire-wmx.net
71.21.81.2	PTR	71-21-81-2.hou.clearwire-wmx.net
71.21.82.7	PTR	71-21-82-7.hou.clearwire-wmx.net
71.21.91.60	A	aabeseptic.com
71.21.92.75	PTR	71-21-92-75.hou.clearwire-wmx.net
71.21.93.1	PTR	71-21-93-1.hou.clearwire-wmx.net
71.21.95.0	PTR	71-21-95-0.hou.clearwire-wmx.net
71.21.95.113	A	mail.eclipseentertainment.net
71.21.95.130	PTR	71-21-95-130.hou.clearwire-wmx.net
71.21.95.131	PTR	71-21-95-131.hou.clearwire-wmx.net
71.21.98.196	PTR	71-21-98-196.hou.clearwire-wmx.net
71.21.102.83	A	nurbs.us
71.21.103.129	PTR	71-21-103-129.hou.clearwire-wmx.net
71.21.108.18	PTR	71-21-108-18.hou.clearwire-wmx.net
71.21.109.2	PTR	71-21-109-2.hou.clearwire-wmx.net
71.21.109.37	A	ruthstreet.com
71.21.110.59	A	hallsteadlaw.net
71.21.112.155	PTR	71-21-112-155.hou.clearwire-wmx.net
71.21.112.188	PTR	71-21-112-188.hou.clearwire-wmx.net
71.21.115.34	PTR	71-21-115-34.hou.clearwire-wmx.net
71.21.115.99	PTR	71-21-115-99.hou.clearwire-wmx.net
71.21.117.108	PTR	71-21-117-108.hou.clearwire-wmx.net
71.21.118.143	A	cansler.org
71.21.118.150	A	frobozz.smci.org
71.21.118.228	PTR	71-21-118-228.hou.clearwire-wmx.net
71.21.119.106	PTR	71-21-119-106.hou.clearwire-wmx.net
71.21.120.106	A	mail.revionicsportal.com
71.21.120.106	A	revionicsportal.com
71.21.120.131	PTR	71-21-120-131.hou.clearwire-wmx.net
71.21.126.14	PTR	71-21-126-14.hou.clearwire-wmx.net
71.21.126.76	PTR	71-21-126-76.hou.clearwire-wmx.net