Robtex

Up: 192.16.16.0/22
Can't show all results, try to descend to a more specific CIDR
Down left: 192.16.16.0/24
Down right: 192.16.17.0/24
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
192.16.16.5	PTR	ns1.edgecastdns.net
192.16.16.5	A	ns1.cedist.com
192.16.16.5	A	ns1.vanish.com
192.16.16.6	PTR	ns2.edgecastdns.net
192.16.16.6	A	ns2.mecalux.org
192.16.16.6	A	ns2.counterpersontraining.com