Robtex

Up: 204.216.0.0/15
Can't show all results, try to descend to a more specific CIDR
Down left: 204.217.0.0/17
Down right: 204.217.128.0/17

IP	Type	Hostname
204.217.5.11	PTR	exoc.com
204.217.6.2	PTR	princeton.com
204.217.15.221	A	mx.thars.org
204.217.28.5	PTR	mac5.hi-tech.com
204.217.48.50	PTR	irm.navcen.uscg.mil
204.217.48.100	PTR	www.navcen.uscg.mil
204.217.54.3	PTR	pegasus.widmeyer.com
204.217.54.129	PTR	www.cslr.org
204.217.60.1	PTR	www.avis.com
204.217.60.2	PTR	ftp.avis.com
204.217.72.158	A	avaa.cn
204.217.184.100	PTR	www.gerd.com
204.217.254.5	PTR	weightman.com