Robtex

Up: 81.4.112.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 81.4.112.0/23
Down right: 81.4.114.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
81.4.112.0	PTR	ip-space.by.proserve.nl
81.4.112.2	A	ns2.spheranameserver.nl
81.4.112.3	A+PTR	mail.hollandduurzaam.nl
81.4.112.3	A	mail.zonenzo.nl
81.4.112.3	A	holland-duurzaam.nl
81.4.112.4	PTR	ftp.vandrveen.nl
81.4.112.4	A	mail.ledenled.com
81.4.112.4	A	mail.led-and-sun.com
81.4.112.5	PTR	ip-space.by.proserve.nl
81.4.112.34	A	mail1.alklima.nl
81.4.112.43	PTR	ip-space.by.proserve.nl
81.4.112.44	PTR	ip-space.by.proserve.nl
81.4.112.44	A	mail.go4promotions.nl
81.4.112.44	A	mail.heerenvanslydregt.nl
81.4.112.51	PTR	ip-space.by.proserve.nl
81.4.112.60	PTR	ip-space.by.proserve.nl
81.4.112.60	A	mail.marquip.eu
81.4.112.60	A	marquip.nl
81.4.112.70	PTR	ip-space.by.proserve.nl
81.4.112.119	A+PTR	filter.garciajeans.com
81.4.112.119	A	spamkiller.eurobrooks.nl
81.4.112.146	A+PTR	mail.mgb.nl
81.4.112.195	A+PTR	spamfilter.jeanscentre.nl
81.4.112.195	A	spamfilter.jeanscenter.nl
81.4.112.195	A	spamfilter.jeanscentre.com
81.4.112.196	PTR	ip-space.by.proserve.nl
81.4.112.196	A	mail.jeanscentre.nl
81.4.112.196	A	mail.ensignblue.com
81.4.112.250	PTR	ip-space.by.proserve.nl
81.4.113.4	A	mail.valkwelding.fr
81.4.113.34	PTR	ip-space.by.proserve.nl
81.4.113.34	A	mail.merinox.eu
81.4.113.103	PTR	ip-space.by.proserve.nl
81.4.113.104	PTR	ip-space.by.proserve.nl
81.4.114.19	PTR	ip-space.by.proserve.nl
81.4.114.19	A	mail.verklizan.com
81.4.114.19	A	mail.verklizan.fr
81.4.114.34	A	mail.vageri.nl
81.4.114.34	A	mail.webeasy.nl
81.4.114.42	PTR	ip-space.by.proserve.nl
81.4.114.43	PTR	ip-space.by.proserve.nl
81.4.114.43	A	mx01.cloudsecured.nl
81.4.114.45	A	meuksoftware.nl
81.4.114.45	A	mail.meuksoftware.nl
81.4.114.50	PTR	mail.securelink.nl
81.4.114.54	A+PTR	mail.securelink.nl
81.4.114.54	A	mail.securelabs.nl
81.4.114.77	PTR	webmail.breejen.com
81.4.114.86	A	mx2.pro-at.nl
81.4.114.101	A	email.alert-group.nl
81.4.114.106	A+PTR	mail.pipeline-control.com
81.4.114.106	A	mail.pipelinecontrol.nl
81.4.115.1	PTR	ip-space.by.proserve.nl
81.4.115.53	PTR	ip-space.by.proserve.nl
81.4.115.228	A	lm2.gcoeurope.com
81.4.115.233	PTR	ip-space.by.proserve.nl
81.4.115.233	A	mx03a-sl.gcoeurope.com
81.4.115.233	A	mx03-sl.gcoeurope.com
81.4.115.234	PTR	ip-space.by.proserve.nl
81.4.115.236	A	mx06a-sl.gcoeurope.com
81.4.115.240	PTR	ip-space.by.proserve.nl
81.4.115.240	A	mx01-dc.gcoglobal.com
81.4.115.240	A	mx01.gcoglobal.com