Robtex

Up: 199.109.16.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 199.109.16.0/23
Down right: 199.109.18.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
199.109.17.7	A+PTR	lin-dns01.nysernet.org
199.109.17.7	A	dns01.nysernet.org
199.109.17.18	PTR	lin-web01.nysernet.org
199.109.17.18	A	nyscio.org
199.109.17.18	A	nysernet.org
199.109.17.130	A+PTR	lin-dns03.nysernet.org
199.109.17.130	A	dns03.nysernet.org
199.109.18.5	A+PTR	cookiemonster.nysernet.org
199.109.18.5	A	agjerome.com
199.109.18.26	A	billpi.nysernet.org