Robtex

Up: 179.233.16.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 179.233.16.0/23
Down right: 179.233.18.0/23

IP	Type	Hostname
179.233.17.2	PTR	b3e91102.virtua.com.br
179.233.18.2	PTR	b3e91202.virtua.com.br
179.233.18.8	PTR	b3e91208.virtua.com.br
179.233.18.59	PTR	b3e9123b.virtua.com.br
179.233.18.174	PTR	b3e912ae.virtua.com.br
179.233.18.194	PTR	b3e912c2.virtua.com.br
179.233.19.180	PTR	b3e913b4.virtua.com.br