Robtex

Up: 168.121.176.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 168.121.180.0/23
Down right: 168.121.182.0/23

IP	Type	Hostname
168.121.180.0	A	0.180.121.168.rslnet.com.br
168.121.180.10	A+PTR	10.180.121.168.rslnet.com.br
168.121.180.10	A	rslnet.com.br
168.121.180.11	A+PTR	11.180.121.168.rslnet.com.br
168.121.180.11	A	rev1.rslnet.com.br
168.121.180.12	A+PTR	12.180.121.168.rslnet.com.br
168.121.180.12	A	ns2.rslnet.com.br
168.121.180.12	A	rev2.rslnet.com.br
168.121.181.0	PTR	168-121-181-0.rslnet.com.br
168.121.181.0	A	0.181.121.168.rslnet.com.br
168.121.182.0	A	0.182.121.168.rslnet.com.br
168.121.183.0	A	0.183.121.168.rslnet.com.br