Robtex

Up: 64.16.64.0/20
Can't show all results, try to descend to a more specific CIDR
Down left: 64.16.72.0/22
Down right: 64.16.76.0/22
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
64.16.72.120	PTR	unused.spark-networks.com
64.16.72.168	PTR	unused.spark-networks.com
64.16.72.168	A	campingvr.ca
64.16.72.168	A	mail.campingvr.ca
64.16.72.208	PTR	unused.spark-networks.com
64.16.72.242	PTR	unused.spark-networks.com
64.16.73.33	PTR	unused.spark-networks.com
64.16.73.34	PTR	unused.spark-networks.com
64.16.73.50	PTR	unused.spark-networks.com
64.16.73.57	PTR	unused.spark-networks.com
64.16.73.80	PTR	unused.spark-networks.com
64.16.73.105	PTR	unused.spark-networks.com
64.16.73.112	PTR	unused.spark-networks.com
64.16.73.137	PTR	unused.spark-networks.com
64.16.73.163	PTR	unused.spark-networks.com
64.16.73.177	PTR	unused.spark-networks.com
64.16.73.187	PTR	unused.spark-networks.com
64.16.73.203	PTR	unused.spark-networks.com
64.16.74.129	PTR	unused.spark-networks.com
64.16.74.161	PTR	unused.spark-networks.com
64.16.74.186	PTR	unused.spark-networks.com
64.16.75.18	PTR	unused.spark-networks.com
64.16.75.35	PTR	unused.spark-networks.com
64.16.75.120	PTR	unused.spark-networks.com
64.16.75.187	PTR	unused.spark-networks.com
64.16.75.202	PTR	unused.spark-networks.com
64.16.76.177	PTR	unused.spark-networks.com
64.16.76.194	PTR	unused.spark-networks.com
64.16.78.40	PTR	unused.spark-networks.com
64.16.78.81	PTR	unused.spark-networks.com
64.16.78.91	PTR	unused.spark-networks.com
64.16.78.123	PTR	unused.spark-networks.com
64.16.78.129	PTR	unused.spark-networks.com
64.16.78.203	PTR	unused.spark-networks.com
64.16.78.217	PTR	unused.spark-networks.com
64.16.78.233	PTR	unused.spark-networks.com
64.16.78.243	PTR	unused.spark-networks.com
64.16.79.129	PTR	unused.spark-networks.com