Robtex

Up: 156.154.130.0/23
Can't show all results, try to descend to a more specific CIDR
Down left: 156.154.131.0/25
Down right: 156.154.131.128/25
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
156.154.131.4	A+PTR	nsr1e1.f.root-servers.org
156.154.131.100	PTR	ns2.ascio.net
156.154.131.100	PTR	ns4.ascio.net
156.154.131.100	PTR	pdns2.cscdns.net
156.154.131.200	A+PTR	pdns2.registrar-servers.com