Robtex

Up: 50.0.0.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 50.0.4.0/23
Down right: 50.0.6.0/23

IP	Type	Hostname
50.0.4.0	PTR	50-0-4-0.dsl.dyn.son.sunset.net
50.0.4.31	PTR	50-0-4-31.dsl.dyn.son.sunset.net
50.0.4.32	PTR	50-0-4-32.adsl.dynamic.finestplanet.com
50.0.4.63	PTR	50-0-4-63.adsl.dynamic.finestplanet.com
50.0.4.64	PTR	50-0-4-64.dsl.redwoods.quik.com
50.0.4.127	PTR	50-0-4-127.adsl.dynamic.pacific.net
50.0.4.128	PTR	50-0-4-128.dynamic.sn.garlic.net
50.0.4.160	PTR	50-0-4-160.adsl-dynamic.nccn.net
50.0.4.191	PTR	50-0-4-191.adsl-dynamic.nccn.net
50.0.4.223	PTR	50-0-4-223.adsl-dhcp.cal.net
50.0.4.224	PTR	50-0-4-224.adsl.dynamic.exwire.com
50.0.4.255	PTR	50-0-4-255.adsl.dynamic.exwire.com
50.0.5.0	PTR	50-0-5-0.adsl-dhcp.cal.net
50.0.5.6	A+PTR	50-0-5-6.adsl-dhcp.cal.net
50.0.5.118	A	50-0-5-118.adsl-dhcp.cal.net
50.0.5.126	PTR	50-0-5-126.adsl-dhcp.cal.net
50.0.5.191	A	50-0-5-191.adsl-dhcp.cal.net
50.0.5.255	PTR	50-0-5-255.adsl-dhcp.cal.net
50.0.6.0	PTR	50-0-6-0.adsl-dhcp.cal.net
50.0.6.9	A+PTR	50-0-6-9.adsl-dhcp.cal.net
50.0.6.47	PTR	50-0-6-47.adsl-dhcp.cal.net
50.0.6.255	PTR	50-0-6-255.adsl-dhcp.cal.net
50.0.7.1	A+PTR	50-0-7-1.dsl.dynamic.omsoft.com
50.0.7.2	PTR	50-0-7-2.dsl.dynamic.omsoft.com
50.0.7.21	PTR	50-0-7-21.dsl.dynamic.omsoft.com
50.0.7.30	A+PTR	50-0-7-30.dsl.dynamic.omsoft.com
50.0.7.127	PTR	50-0-7-127.dsl.dynamic.omsoft.com
50.0.7.128	PTR	50-0-7-128.dsl.dynamic.omsoft.com
50.0.7.255	PTR	50-0-7-255.dsl.dynamic.omsoft.com