Robtex

Up: 168.72.0.0/15
Can't show all results, try to descend to a more specific CIDR
Down left: 168.73.0.0/17
Down right: 168.73.128.0/17

IP	Type	Hostname
168.73.226.1	A	7606a-ha.nol.nexteldata.net
168.73.240.30	A	nextelonline.nextel.com
168.73.240.78	A+PTR	www.nextel.com
168.73.240.78	A	nextelonline.com
168.73.240.78	A	nextel.com
168.73.245.110	PTR	mail.nextel.com
168.73.245.115	A+PTR	imail.nextel.com
168.73.245.116	A	imail.nextel.com
168.73.248.26	A	ans1.nextel.com
168.73.249.26	A+PTR	ans2.nextel.com