Robtex

Up: 171.255.192.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 171.255.196.0/23
Down right: 171.255.198.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
171.255.196.65	PTR	dynamic-ip-adsl.viettel.vn
171.255.196.65	A	cdn.ereka.vn
171.255.196.69	PTR	dynamic-ip-adsl.viettel.vn
171.255.196.69	A	ns1.ereka.vn
171.255.196.70	PTR	dynamic-ip-adsl.viettel.vn
171.255.196.70	A	ns2.ereka.vn
171.255.196.169	A	itrithuc.vn
171.255.196.177	PTR	dynamic-ip-adsl.viettel.vn
171.255.196.177	A	cdn.ereka.vn
171.255.196.180	A	biendaovietnam.org.vn
171.255.196.180	A	logging.api.ereka.vn
171.255.196.180	A	ssr.ereka.vn
171.255.196.217	A	mail.viettel.io
171.255.197.1	PTR	dynamic-ip-adsl.viettel.vn
171.255.197.89	A	vtt.viettel.svpgate.com
171.255.197.89	A	videoipcc4g.viettel.vn
171.255.197.123	A	myclip.viettel.vn
171.255.197.123	A	beta.myclip.vn
171.255.197.123	A	myclip.vn
171.255.198.17	A	scontent.fhan5-3.fna.fbcdn.net
171.255.198.18	PTR	dynamic-adsl.viettel.vn
171.255.198.18	A	video.fhan5-3.fna.fbcdn.net
171.255.198.30	A	sonar.fhan5-3.fna.fbcdn.net
171.255.198.30	A	z-m-scontent.fhan5-3.fna.fbcdn.net
171.255.198.32	A	z-p3-scontent.fhan5-3.fna.fbcdn.net
171.255.198.33	A	instagram.fhan5-3.fna.fbcdn.net
171.255.198.34	PTR	dynamic-ip-adsl.viettel.vn
171.255.198.34	A	media.fhan5-3.fna.whatsapp.net
171.255.198.81	A	scontent.fhan5-4.fna.fbcdn.net
171.255.198.82	PTR	dynamic-ip-adsl.viettel.vn
171.255.198.82	A	video.fhan5-4.fna.fbcdn.net
171.255.198.94	A	sonar.fhan5-4.fna.fbcdn.net
171.255.198.94	A	z-m-scontent.fhan5-4.fna.fbcdn.net
171.255.198.96	A	z-p3-scontent.fhan5-4.fna.fbcdn.net
171.255.198.97	A	instagram.fhan5-4.fna.fbcdn.net
171.255.198.98	PTR	dynamic-ip-adsl.viettel.vn
171.255.198.98	A	media.fhan5-4.fna.whatsapp.net
171.255.198.145	PTR	dynamic-ip-adsl.viettel.vn
171.255.198.145	A	scontent.fsgn5-3.fna.fbcdn.net
171.255.198.146	A	video.fsgn5-3.fna.fbcdn.net
171.255.198.158	A	z-m-scontent.fsgn5-3.fna.fbcdn.net
171.255.198.158	A	sonar.fsgn5-3.fna.fbcdn.net
171.255.198.160	A	z-p3-scontent.fsgn5-3.fna.fbcdn.net
171.255.198.161	A	instagram.fsgn5-3.fna.fbcdn.net
171.255.198.162	PTR	dynamic-ip-adsl.viettel.vn
171.255.198.162	A	media.fsgn5-3.fna.whatsapp.net
171.255.198.209	A	scontent.fsgn5-4.fna.fbcdn.net
171.255.198.210	A	video.fsgn5-4.fna.fbcdn.net
171.255.198.222	A	sonar.fsgn5-4.fna.fbcdn.net
171.255.198.222	A	z-m-scontent.fsgn5-4.fna.fbcdn.net
171.255.198.224	A	z-p3-scontent.fsgn5-4.fna.fbcdn.net
171.255.198.225	A	instagram.fsgn5-4.fna.fbcdn.net
171.255.198.226	PTR	dynamic-ip-adsl.viettel.vn
171.255.198.226	A	media.fsgn5-4.fna.whatsapp.net
171.255.199.15	A	sfive.vn
171.255.199.19	PTR	dynamic-ip-adsl.viettel.vn
171.255.199.19	A	vtupdate.sfive.vn
171.255.199.40	PTR	dynamic-ip-adsl.viettel.vn
171.255.199.40	A	news.sfive.vn
171.255.199.68	A	lathuoc.com
171.255.199.140	PTR	dynamic-ip-adsl.viettel.vn
171.255.199.140	A	cdn.ereka.vn