Robtex

Up: 81.173.4.0/23
Can't show all results, try to descend to a more specific CIDR
Down left: 81.173.4.0/25
Down right: 81.173.4.128/25
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
81.173.4.66	PTR	mx.internetpiraten.com
81.173.4.66	A	www.etherpiraten.com
81.173.4.66	A	mail.internetpiraten.com
81.173.4.67	A	ns2.internetpiraten.com
81.173.4.68	A	babboe.dk
81.173.4.68	A	mail.babboe.dk
81.173.4.73	A	fairytalefestival.nl
81.173.4.73	A	mail.fairytalefestival.nl
81.173.4.73	A	ns1.websitefabriek.nl
81.173.4.74	A	ns2.websitefabriek.nl
81.173.4.82	PTR	www.redoptics.com
81.173.4.98	PTR	98.blueberry.nl
81.173.4.98	A	mail.promotielocaties.nl
81.173.4.98	A	vege.es
81.173.4.99	PTR	99.blueberry.nl
81.173.4.99	A	hoogstespaarrente.nl
81.173.4.99	A	www.kredietadviesnl.nl
81.173.4.100	PTR	mail.online-magazine.nl
81.173.4.100	A	skinnmagazine.com
81.173.4.100	A	magazine.parktheater.nl
81.173.4.102	PTR	102.blueberry.nl
81.173.4.102	A	reddemo.nl
81.173.4.102	A	digibordbij.nl
81.173.4.105	A+PTR	105.blueberry.nl