Robtex

Up: 187.104.144.0/20
Can't show all results, try to descend to a more specific CIDR
Down left: 187.104.152.0/22
Down right: 187.104.156.0/22

IP	Type	Hostname
187.104.152.224	PTR	bb6898e0.virtua.com.br
187.104.153.224	PTR	bb6899e0.virtua.com.br
187.104.154.49	PTR	bb689a31.virtua.com.br
187.104.158.147	PTR	bb689e93.virtua.com.br
187.104.159.96	PTR	bb689f60.virtua.com.br