Robtex

Up: 72.131.128.0/18
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Down left: 72.131.128.0/20
Down right: 72.131.144.0/20

IP	Type	Hostname
72.131.136.1	PTR	mta-72-131-136-1.wi.rr.com
72.131.136.64	PTR	mta-72-131-136-64.wi.rr.com
72.131.136.98	PTR	mta-72-131-136-98.wi.rr.com
72.131.136.130	PTR	mta-72-131-136-130.wi.rr.com
72.131.136.161	PTR	mta-72-131-136-161.wi.rr.com
72.131.136.193	PTR	mta-72-131-136-193.wi.rr.com
72.131.155.2	PTR	mta-72-131-155-2.wi.rr.com
72.131.155.3	PTR	mta-72-131-155-3.wi.rr.com
72.131.155.34	PTR	mta-72-131-155-34.wi.rr.com
72.131.155.96	PTR	mta-72-131-155-96.wi.rr.com
72.131.155.192	PTR	mta-72-131-155-192.wi.rr.com
72.131.155.193	PTR	mta-72-131-155-193.wi.rr.com