Robtex

Up: 177.21.0.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 177.21.4.0/23
Down right: 177.21.6.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
177.21.4.30	A+PTR	rta.univilas.teletalk.net.br
177.21.4.38	PTR	177-21-4-38.host.teletalk.net.br
177.21.4.38	A	rta.buscvida.teletalk.net.br
177.21.4.54	A+PTR	rta.bosquedaaldeia.teletalk.net.br
177.21.4.101	PTR	177-21-4-101.host.teletalk.net.br
177.21.4.103	PTR	177-21-4-103.host.teletalk.net.br
177.21.4.160	PTR	177-21-4-160.host.teletalk.net.br
177.21.4.200	PTR	200.4.21.177.teletalk.net.br
177.21.4.235	PTR	177-21-4-235.host.teletalk.net.br
177.21.5.5	PTR	5.5.21.177.teletalk.net.br
177.21.5.17	PTR	17.5.21.177.teletalk.net.br
177.21.5.17	A	afengenharia.com
177.21.5.17	A	packprojetos.com
177.21.5.88	PTR	88.5.21.177.teletalk.net.br
177.21.5.96	PTR	96.5.21.177.teletalk.net.br
177.21.5.103	PTR	103.5.21.177.teletalk.net.br
177.21.5.170	PTR	170.5.21.177.teletalk.net.br
177.21.5.176	PTR	176.5.21.177.teletalk.net.br
177.21.5.186	PTR	186.5.21.177.teletalk.net.br
177.21.6.53	PTR	177-21-6-53.host.teletalk.net.br
177.21.6.66	PTR	66.6.21.177.teletalk.net.br
177.21.6.145	PTR	145.6.21.177.teletalk.net.br
177.21.6.189	PTR	189.6.21.177.teletalk.net.br