Robtex

Up: 72.171.128.0/19
Can't show all results, try to descend to a more specific CIDR
Down left: 72.171.144.0/21
Down right: 72.171.152.0/21

IP	Type	Hostname
72.171.159.0	PTR	host72171000159.direcway.com
72.171.159.2	PTR	host72171002159.direcway.com
72.171.159.32	PTR	host721710032159.direcway.com
72.171.159.33	PTR	host721710033159.direcway.com
72.171.159.35	PTR	host721710035159.direcway.com
72.171.159.51	PTR	host721710051159.direcway.com
72.171.159.64	PTR	host721710064159.direcway.com
72.171.159.65	PTR	host721710065159.direcway.com
72.171.159.66	PTR	host721710066159.direcway.com
72.171.159.80	PTR	host721710080159.direcway.com
72.171.159.81	PTR	host721710081159.direcway.com
72.171.159.129	PTR	host7217100129159.direcway.com
72.171.159.144	PTR	host7217100144159.direcway.com
72.171.159.160	PTR	host7217100160159.direcway.com
72.171.159.161	PTR	host7217100161159.direcway.com
72.171.159.179	PTR	host7217100179159.direcway.com
72.171.159.243	PTR	host7217100243159.direcway.com