Robtex

Up: 64.52.12.0/22
Can't show all results, try to descend to a more specific CIDR
Down left: 64.52.12.0/24
Down right: 64.52.13.0/24
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
64.52.12.1	PTR	64-52-12-1.client.cypresscom.net
64.52.12.2	PTR	64.52.12.2
64.52.12.3	PTR	64-52-12-3.client.cypresscom.net
64.52.12.4	PTR	64-52-12-4.client.cypresscom.net
64.52.12.6	PTR	64-52-12-6.client.cypresscom.net
64.52.12.9	PTR	64-52-12-9.client.cypresscom.net
64.52.12.22	PTR	64-52-12-22.client.cypresscom.net
64.52.12.22	A	mail.tahititourisme-usa.com
64.52.12.22	A	mail.tahiti-tourisme.ca
64.52.12.28	PTR	64-52-12-28.client.cypresscom.net
64.52.12.39	PTR	64-52-12-39.client.cypresscom.net
64.52.12.57	PTR	64-52-12-57.client.cypresscom.net
64.52.12.61	PTR	64-52-12-61.client.cypresscom.net
64.52.12.63	PTR	64-52-12-63.client.cypresscom.net
64.52.12.73	PTR	64-52-12-73.client.cypresscom.net
64.52.12.84	PTR	64-52-12-84.client.cypresscom.net
64.52.12.85	PTR	64-52-12-85.client.cypresscom.net
64.52.12.92	PTR	64-52-12-92.client.cypresscom.net
64.52.13.6	PTR	64-52-13-6.client.cypresscom.net
64.52.13.8	PTR	8.13.52.64.in-addr.arpa