Robtex

Up: 138.255.224.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 138.255.228.0/23
Down right: 138.255.230.0/23

IP	Type	Hostname
138.255.228.31	PTR	31.228.255.138.alinkbrasil.com.br
138.255.230.0	A	ns1.alinkbrasil.com.br
138.255.231.3	A	alinkbrasil.com.br
138.255.231.3	A	mx.alinkbrasil.com.br
138.255.231.4	A	ns2.alinkbrasil.com.br