Robtex

Up: 72.5.80.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 72.5.84.0/23
Down right: 72.5.86.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
72.5.84.3	PTR	mx5.gtlaw.com
72.5.84.4	A+PTR	mx4.gtlaw.com
72.5.85.17	PTR	nanalp002.am.ansell.com
72.5.85.76	PTR	nanalp002.ansell.com
72.5.86.70	PTR	imsagentsite.com
72.5.86.70	A	mail.bishopscience.com
72.5.86.71	PTR	imsagentsite.com
72.5.86.72	PTR	imsagentsite.com
72.5.86.73	PTR	imsagentsite.com
72.5.86.74	PTR	imsagentsite.com
72.5.86.220	PTR	ndins.com
72.5.86.223	PTR	ndins.com
72.5.86.224	PTR	ndins.com
72.5.86.245	PTR	ultimategameserver.com
72.5.87.34	A	inmark.co.uk
72.5.87.34	A	inmarkeuropeltd.com
72.5.87.34	A	inmarkinc.us
72.5.87.38	A	ts.dyndns.dk