Robtex

Up: 64.94.24.0/24
Can't show all results, try to descend to a more specific CIDR
Down left: 64.94.24.0/26
Down right: 64.94.24.64/26
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
64.94.24.20	A+PTR	mail4.activeapp.email.active.com
64.94.24.20	A	mail4.activeapp.psmessage.com
64.94.24.20	A	activeapp.psmessage.com
64.94.24.25	A+PTR	4.eteamz.email.active.com
64.94.24.26	A+PTR	5.eteamz.email.active.com