Robtex

Up: 72.52.16.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 72.52.20.0/23
Down right: 72.52.22.0/23

IP	Type	Hostname
72.52.20.13	PTR	unknown.prolexic.com
72.52.20.41	PTR	unknown.prolexic.com
72.52.20.56	PTR	a72-52-20-56.deploy.static.akamaitechnologies.com
72.52.20.63	PTR	unknown.prolexic.com
72.52.20.144	PTR	unknown.prolexic.com
72.52.21.125	PTR	unknown.prolexic.com
72.52.21.140	PTR	unknown.prolexic.com
72.52.21.162	PTR	unknown.prolexic.com
72.52.21.169	PTR	unknown.prolexic.com
72.52.21.226	PTR	unknown.prolexic.com
72.52.21.231	PTR	unknown.prolexic.com
72.52.21.253	PTR	unknown.prolexic.com
72.52.22.1	PTR	unknown.prolexic.com
72.52.22.2	PTR	unknown.prolexic.com
72.52.22.24	PTR	unknown.prolexic.com
72.52.22.86	PTR	unknown.prolexic.com
72.52.22.103	PTR	unknown.prolexic.com
72.52.22.134	PTR	unknown.prolexic.com
72.52.22.190	PTR	unknown.prolexic.com
72.52.22.242	PTR	unknown.prolexic.com
72.52.23.211	PTR	unknown.prolexic.com
72.52.23.225	PTR	unknown.prolexic.com