Robtex

Up: 216.244.8.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 216.244.12.0/23
Down right: 216.244.14.0/23

IP	Type	Hostname
216.244.12.37	A+PTR	user-3cf8315.dsl.mindspring.com
216.244.12.96	PTR	user-3cf8330.dsl.mindspring.com
216.244.12.130	PTR	user-3cf8342.dsl.mindspring.com
216.244.13.63	A+PTR	user-3cf839v.dsl.mindspring.com
216.244.13.64	A+PTR	user-3cf83a0.dsl.mindspring.com
216.244.13.180	A+PTR	user-3cf83dk.dsl.mindspring.com
216.244.14.78	A+PTR	user-3cf83ie.dsl.mindspring.com
216.244.14.94	A	user-3cf83iu.dsl.mindspring.com
216.244.14.132	A+PTR	user-3cf83k4.dsl.mindspring.com
216.244.14.185	A+PTR	user-3cf83lp.dsl.mindspring.com
216.244.14.206	A+PTR	user-3cf83me.dsl.mindspring.com
216.244.14.234	A+PTR	user-3cf83na.dsl.mindspring.com
216.244.14.252	A+PTR	user-3cf83ns.dsl.mindspring.com
216.244.15.194	A+PTR	user-3cf83u2.dsl.mindspring.com