Robtex

Up: 186.237.40.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 186.237.40.0/23
Down right: 186.237.42.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
186.237.41.113	PTR	186.237.41.113
186.237.41.114	PTR	186.237.41.114
186.237.41.118	PTR	118.41.237.186.in-addr.arpa
186.237.43.7	PTR	186.237.43.7.west.com.br
186.237.43.7	A	speedtest0.cbf.west.net.br
186.237.43.22	PTR	186.237.43.22.west.com.br
186.237.43.22	A	speedtestbzs0.cbf.west.net.br
186.237.43.24	PTR	186.237.43.24.west.com.br
186.237.43.24	A	ns1.west.net.br
186.237.43.37	A+PTR	leibniz.cbf.west.net.br
186.237.43.39	A+PTR	abel.cbf.west.net.br
186.237.43.41	A+PTR	lagrange.cbf.west.net.br
186.237.43.42	A+PTR	hilbert.cbf.west.net.br
186.237.43.43	A+PTR	pitagoras.cbf.west.net.br
186.237.43.45	PTR	186.237.43.45.west.com.br
186.237.43.86	PTR	186.237.43.86.west.com.br
186.237.43.86	A	occ-0-1864-1123.1.nflxso.net
186.237.43.86	A	occ-0-1864-1567.1.nflxso.net