Robtex

Up: 170.51.32.0/20
Can't show all results, try to descend to a more specific CIDR
Down left: 170.51.32.0/22
Down right: 170.51.36.0/22

IP	Type	Hostname
170.51.32.35	PTR	host35.170-51-32.static.telmex.net.ar
170.51.32.81	PTR	host81.170-51-32.static.telmex.net.ar
170.51.32.168	PTR	host168.170-51-32.static.telmex.net.ar
170.51.33.34	PTR	host34.170-51-33.static.telmex.net.ar
170.51.33.66	PTR	host66.170-51-33.static.telmex.net.ar
170.51.33.80	PTR	host80.170-51-33.static.telmex.net.ar
170.51.33.98	PTR	host98.170-51-33.static.telmex.net.ar
170.51.33.177	PTR	host177.170-51-33.static.telmex.net.ar
170.51.33.185	PTR	host185.170-51-33.static.telmex.net.ar
170.51.34.2	PTR	host2.170-51-34.static.telmex.net.ar
170.51.34.21	PTR	host21.170-51-34.static.telmex.net.ar
170.51.34.71	PTR	host71.170-51-34.claro.com.py
170.51.34.119	PTR	host119.170-51-34.claro.com.py
170.51.34.162	PTR	host162.170-51-34.static.telmex.net.ar
170.51.35.7	PTR	host7.170-51-35.static.telmex.net.ar
170.51.35.17	PTR	host17.170-51-35.static.telmex.net.ar
170.51.35.38	PTR	host38.170-51-35.static.telmex.net.ar
170.51.35.66	PTR	host66.170-51-35.static.telmex.net.ar
170.51.35.96	PTR	host96.170-51-35.static.telmex.net.ar
170.51.35.139	PTR	host139.170-51-35.static.telmex.net.ar
170.51.35.154	PTR	host154.170-51-35.static.telmex.net.ar
170.51.35.162	PTR	host162.170-51-35.static.telmex.net.ar
170.51.35.175	PTR	host175.170-51-35.static.telmex.net.ar
170.51.35.182	PTR	host182.170-51-35.static.telmex.net.ar
170.51.36.1	PTR	host1.170-51-36.static.telmex.net.ar
170.51.36.9	PTR	host9.170-51-36.claro.com.py
170.51.36.11	PTR	host11.170-51-36.claro.com.py
170.51.36.18	PTR	host18.170-51-36.static.telmex.net.ar
170.51.36.34	PTR	host34.170-51-36.static.telmex.net.ar
170.51.36.41	PTR	host41.170-51-36.static.telmex.net.ar
170.51.36.43	PTR	host43.170-51-36.static.telmex.net.ar
170.51.36.49	PTR	host49.170-51-36.static.telmex.net.ar
170.51.36.67	PTR	host67.170-51-36.claro.com.py
170.51.36.81	PTR	host81.170-51-36.static.telmex.net.ar
170.51.36.82	PTR	host82.170-51-36.static.telmex.net.ar
170.51.36.83	PTR	host83.170-51-36.claro.com.py
170.51.36.98	PTR	host98.170-51-36.claro.com.py
170.51.36.120	PTR	host120.170-51-36.static.telmex.net.ar
170.51.36.123	PTR	host123.170-51-36.static.telmex.net.ar
170.51.36.137	PTR	host137.170-51-36.static.telmex.net.ar
170.51.36.144	PTR	host144.170-51-36.static.telmex.net.ar
170.51.36.146	PTR	host146.170-51-36.static.telmex.net.ar
170.51.36.147	PTR	host147.170-51-36.static.telmex.net.ar
170.51.36.152	PTR	host152.170-51-36.static.telmex.net.ar
170.51.36.161	PTR	host161.170-51-36.claro.com.py
170.51.36.162	PTR	host162.170-51-36.static.telmex.net.ar
170.51.36.178	PTR	host178.170-51-36.static.telmex.net.ar
170.51.36.185	PTR	host185.170-51-36.static.telmex.net.ar
170.51.36.193	PTR	host193.170-51-36.static.telmex.net.ar
170.51.36.194	PTR	host194.170-51-36.static.telmex.net.ar
170.51.36.210	PTR	host210.170-51-36.static.telmex.net.ar
170.51.36.211	PTR	host211.170-51-36.static.telmex.net.ar
170.51.36.217	PTR	host217.170-51-36.static.telmex.net.ar
170.51.36.240	PTR	host240.170-51-36.static.telmex.net.ar
170.51.36.249	PTR	host249.170-51-36.static.telmex.net.ar
170.51.36.250	PTR	host250.170-51-36.claro.com.py