Robtex

Up: 194.121.8.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 194.121.12.0/23
Down right: 194.121.14.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
194.121.12.50	PTR	static.kpn.net
194.121.12.50	A	mail.joswillems.nl
194.121.13.152	PTR	static.kpn.net
194.121.14.218	PTR	mail.sms-tb.nl
194.121.14.218	A	mail.artooling.nl
194.121.14.218	A	mail.artooling.com
194.121.14.223	PTR	static.kpn.net
194.121.14.224	PTR	static.kpn.net
194.121.14.231	PTR	static.kpn.net
194.121.14.232	PTR	static.kpn.net
194.121.15.0	PTR	static.kpn.net
194.121.15.141	PTR	static.kpn.net
194.121.15.141	A	next-solutions.nl
194.121.15.142	PTR	static.kpn.net
194.121.15.142	A	nextconsultancy.nl
194.121.15.250	A	mail.hotelamsterdamwest.nl