Robtex

Up: 81.16.152.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 81.16.156.0/23
Down right: 81.16.158.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
81.16.157.0	PTR	network.rtr.customers.nextlayer.at
81.16.157.2	A+PTR	mail.rtr.at
81.16.157.2	A	mail.rtr.gv.at
81.16.157.2	A	mail.signatur.rtr.at
81.16.157.3	PTR	ip3.rtr.customers.nextlayer.at
81.16.157.3	A	rtr.at
81.16.157.3	A	digitale-plattform-austria.at
81.16.157.4	PTR	www.rtr.at
81.16.157.4	A	rtr.at
81.16.157.4	A	digitalerrundfunk.at
81.16.157.5	PTR	egov.rtr.at
81.16.157.7	PTR	www.fesa.eu
81.16.157.19	A+PTR	ns1.rtr.at
81.16.157.19	A	ns1.rtr.gv.at
81.16.157.25	PTR	ip25.rtr.customers.nextlayer.at
81.16.157.36	PTR	ip36.rtr.customers.nextlayer.at
81.16.157.36	A	rtr.gv.at
81.16.157.59	PTR	ip59.rtr.customers.nextlayer.at
81.16.157.132	A+PTR	www.signatur.rtr.at
81.16.157.132	A	signatur.rtr.at
81.16.157.179	PTR	ip179.rtr.customers.nextlayer.at
81.16.158.12	A	mail4.descience.net
81.16.158.26	PTR	mail.i5invest.com
81.16.158.26	A	i5venture.com
81.16.158.26	A	i5incubate.com
81.16.158.34	A+PTR	mx1.paysafecard.com
81.16.158.39	PTR	sslvpn.paysafecard.com
81.16.158.42	A+PTR	mx3.paysafecard.com
81.16.158.72	PTR	mail.szero.at
81.16.158.72	A	szero.at
81.16.158.106	PTR	srvsql01-2.rebeat.nextlayer.at
81.16.158.106	A	artistcamp.com
81.16.158.106	A	rbworld.net
81.16.158.108	A	www.rebeatdigital.com
81.16.158.138	A+PTR	exchange.paradine.at
81.16.158.154	PTR	mail.phonecash.tv
81.16.158.154	A	*.phonecash.tv
81.16.158.154	A	telefonsex.cm
81.16.158.156	A+PTR	storage.phonecash.tv
81.16.158.156	A	telefonsexy.info
81.16.159.9	A	konzerthaus.or.at
81.16.159.29	PTR	ip29.funkinternet.customers.nextlayer.at
81.16.159.55	PTR	ip55.funkinternet.customers.nextlayer.at
81.16.159.70	A+PTR	mx.prosiebensat1puls4.com
81.16.159.70	A	mail2.puls4.com
81.16.159.70	A	mail2.prosiebensat1puls4.com
81.16.159.138	A	bifon.co.at
81.16.159.150	A	mail.musikfest.at
81.16.159.226	PTR	mail.oebv.at
81.16.159.226	A	mail.oewb.at
81.16.159.226	A	mail.oebvhpt.at
81.16.159.232	A	oebvinfo.at
81.16.159.232	A	mail.oebvinfo.at