Robtex

Up: 81.16.156.0/23
Can't show all results, try to descend to a more specific CIDR
Down left: 81.16.157.0/25
Down right: 81.16.157.128/25
(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	digitale-plattform-austria.at
81.16.157.5	A+PTR	egov.rtr.at
81.16.157.6	A	tkk.rtr.at
81.16.157.7	PTR	www.fesa.eu
81.16.157.7	A	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