Robtex

Up: 190.136.16.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 190.136.16.0/23
Down right: 190.136.18.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
190.136.18.2	A+PTR	host2.190-136-18.telecom.net.ar
190.136.18.6	A+PTR	host6.190-136-18.telecom.net.ar
190.136.19.0	PTR	host0.190-136-19.telecom.net.ar
190.136.19.198	A+PTR	host198.190-136-19.telecom.net.ar
190.136.19.253	PTR	host253.190-136-19.telecom.net.ar
190.136.19.253	A	estudiobarile.com.ar
190.136.19.253	A	lacesira.com.ar