Robtex

Up: 66.72.128.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 66.72.128.0/23
Down right: 66.72.130.0/23

IP	Type	Hostname
66.72.129.22	A+PTR	66-72-129-22.lightspeed.nsvltn.sbcglobal.net
66.72.129.145	A+PTR	66-72-129-145.lightspeed.nsvltn.sbcglobal.net
66.72.129.193	A+PTR	66-72-129-193.lightspeed.nsvltn.sbcglobal.net
66.72.129.249	A+PTR	66-72-129-249.lightspeed.nsvltn.sbcglobal.net
66.72.129.255	A+PTR	66-72-129-255.lightspeed.nsvltn.sbcglobal.net
66.72.130.1	A+PTR	adsl-66-72-130-1.dsl.dytnoh.ameritech.net
66.72.130.249	A+PTR	adsl-66-72-130-249.dsl.dytnoh.ameritech.net
66.72.131.149	A+PTR	66-72-131-149.lightspeed.nsvltn.sbcglobal.net
66.72.131.149	A	adsl-66-72-131-149.dsl.dytnoh.ameritech.net