Robtex

Up: 177.23.160.0/20
Can't show all results, try to descend to a more specific CIDR
Down left: 177.23.168.0/22
Down right: 177.23.172.0/22
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
177.23.168.0	PTR	mx5.planaltonet.net.br
177.23.168.7	PTR	ip-177.23.168.7.planaltonet.net.br
177.23.168.18	A+PTR	dns1.planaltonet.net.br
177.23.168.19	A+PTR	dns2.planaltonet.net.br
177.23.168.23	A+PTR	webmail.planaltonet.net.br
177.23.168.140	PTR	cache.google.com
177.23.168.140	A	r1.sn-2a5o5auvoxu-gxje.googlevideo.com
177.23.168.140	A	r1---sn-2a5o5auvoxu-gxje.googlevideo.com
177.23.168.141	PTR	cache.google.com
177.23.168.141	A	r2.sn-2a5o5auvoxu-gxje.googlevideo.com
177.23.168.142	PTR	cache.google.com
177.23.168.142	A	r3.sn-2a5o5auvoxu-gxje.googlevideo.com
177.23.168.150	PTR	ip-177.23.168.150.planaltonet.net.br
177.23.168.209	A+PTR	scontent.frec22-1.fna.fbcdn.net
177.23.168.209	PTR	external.frec22-1.fna.fbcdn.net
177.23.168.209	PTR	instagram.frec22-1.fna.fbcdn.net
177.23.168.210	A+PTR	video.frec22-1.fna.fbcdn.net
177.23.168.210	PTR	instagram.frec22-1.fna.fbcdn.net
177.23.168.210	PTR	external.frec22-1.fna.fbcdn.net
177.23.168.225	A+PTR	instagram.frec22-1.fna.fbcdn.net
177.23.168.225	PTR	video.frec22-1.fna.fbcdn.net
177.23.168.225	PTR	scontent.frec22-1.fna.fbcdn.net
177.23.168.232	PTR	ip-177.23.168.232.planaltonet.net.br
177.23.169.197	PTR	ip-177.23.169.197.planaltonet.net.br
177.23.170.0	PTR	ip-177.23.170.0.planaltonet.net.br
177.23.173.159	PTR	ip-177.23.173.159.planaltonet.net.br
177.23.175.155	PTR	ip-177.23.175.155.planaltonet.net.br
177.23.175.255	PTR	ip-177.23.175.255.planaltonet.net.br