Robtex

Up: 81.0.228.0/22
Can't show all results, try to descend to a more specific CIDR
Down left: 81.0.230.0/24
Down right: 81.0.231.0/24
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
81.0.230.255	PTR	unassigned-81-0-230-0-255.casablanca.cz
81.0.231.0	PTR	net-81-0-231-0.casablanca.cz.cz
81.0.231.1	A	*.winemarket.cz
81.0.231.1	A	foodmarket.cz
81.0.231.1	A	*.buydirect.cz
81.0.231.2	PTR	unassigned-81-0-231-2.casablanca.cz.cz
81.0.231.2	A	awin-it.com
81.0.231.2	A	awin.cz
81.0.231.7	PTR	bcast-81-0-231-7.casablanca.cz.cz
81.0.231.11	A+PTR	perimeter.active24.cz
81.0.231.17	PTR	monnautic.com
81.0.231.17	A	mail.theprivatecollection.com
81.0.231.17	A	ipoj.cz
81.0.231.18	PTR	server.zlabek.com
81.0.231.18	A	tramuntana-experiences.com
81.0.231.18	A	autaproinvalidy.cz
81.0.231.19	PTR	unassigned-81-0-231-19.casablanca.cz
81.0.231.49	PTR	assigned-81-0-231-49.casablanca.cz
81.0.231.49	A	webcounter.cz
81.0.231.50	PTR	assigned-81-0-231-50.casablanca.cz
81.0.231.50	A	veritel.cz
81.0.231.50	A	*.ewords.cz
81.0.231.51	PTR	assigned-81-0-231-51.casablanca.cz
81.0.231.52	A	wwwzpravy.cz
81.0.231.52	A	wwwmesec.cz
81.0.231.52	A	www.wwwsprace.cz
81.0.231.53	PTR	assigned-81-0-231-53.casablanca.cz
81.0.231.71	PTR	unassigned-81-0-231-71.casablanca.cz
81.0.231.72	PTR	net-81-0-231-72.casablanca.cz
81.0.231.73	A	ezpprgdrp1.ezpada.com
81.0.231.79	PTR	bcast-81-0-231-79.casablanca.cz
81.0.231.80	PTR	net-81-0-231-080.casablanca.cz
81.0.231.82	PTR	unassigned-81-0-231-082.casablanca.cz
81.0.231.95	PTR	bcast-81-0-231-95.casablanca.cz
81.0.231.96	PTR	net-81-0-231-096.casablanca.cz
81.0.231.97	PTR	assigned-81-0-231-097.casablanca.cz
81.0.231.97	A	ns2.netcraft.cz
81.0.231.98	PTR	mail.houfek.cz
81.0.231.98	A	ns1.netcraft.cz
81.0.231.99	A+PTR	barracuda.omax.cz
81.0.231.99	A	barracuda.mail.atlas-as.sk
81.0.231.99	A	prask.cz
81.0.231.100	A+PTR	mail.omax.cz
81.0.231.100	A	relay.homecare.cz
81.0.231.101	PTR	assigned-81-0-231-101.casablanca.cz
81.0.231.101	A	www.odhaleno.cz
81.0.231.102	PTR	assigned-81-0-231-102.casablanca.cz
81.0.231.102	A	disneydvd.cz
81.0.231.103	PTR	assigned-81-0-231-103.casablanca.cz
81.0.231.103	A	www.bety.cz
81.0.231.103	A	www.prostreno.cz
81.0.231.104	PTR	assigned-81-0-231-104.casablanca.cz
81.0.231.104	A	dodane.sk
81.0.231.107	PTR	assigned-81-0-231-107.casablanca.cz
81.0.231.107	A	www.parlamentnilisty.cz
81.0.231.111	PTR	bcast-81-0-231-111.casablanca.cz
81.0.231.112	PTR	net-81-0-231-112.casablanca.cz
81.0.231.127	PTR	bcast-81-0-231-127.casablanca.cz
81.0.231.128	PTR	net-81-0-231-128.casablanca.cz
81.0.231.130	PTR	beta.cz99.cz
81.0.231.130	A	zetmarket.cz
81.0.231.130	A	biomaslo.cz
81.0.231.131	PTR	caligula.cz99.cz
81.0.231.132	PTR	alfa.cz99.cz
81.0.231.132	A	z-market.cz
81.0.231.132	A	z-market.eu
81.0.231.135	PTR	bcast-81-0-231-135.casablanca.cz
81.0.231.136	PTR	net-81-0-231-136.casablanca.cz
81.0.231.140	PTR	unassigned-81-0-231-140.casablanca.cz
81.0.231.140	A	esubagames.cz
81.0.231.157	A	sconto.netsecurity.cz
81.0.231.194	PTR	baracuda.tcx.cz
81.0.231.194	A	ns1.tcx.cz
81.0.231.194	A	ns1.email2sms.cz
81.0.231.195	PTR	vistaria.tcx.cz
81.0.231.196	A+PTR	octopoda.tcx.cz
81.0.231.196	A	*.tcx.cz
81.0.231.196	A	lefevre-chyne.cz
81.0.231.201	A+PTR	server.netplus.cz
81.0.231.201	A	ns.netplus.cz
81.0.231.203	PTR	unassigned-81-0-231-203.casablanca.cz.cz
81.0.231.203	A	www.cocker.cz
81.0.231.203	A	www.jonal.cz
81.0.231.204	A	mta1.netplus.cz
81.0.231.205	PTR	server.netplus.cz
81.0.231.209	PTR	praha.varicad.com
81.0.231.209	A	varicad.cz
81.0.231.209	A	varicad.ru
81.0.231.210	A+PTR	praha2.varicad.com
81.0.231.211	A+PTR	praha3.varicad.com
81.0.231.212	A+PTR	praha4.varicad.com
81.0.231.213	A+PTR	praha5.varicad.com
81.0.231.222	PTR	unassigned-81-0-231-222.casablanca.cz.cz
81.0.231.225	PTR	assigned-81-0-231-225.casablanca.cz.cz
81.0.231.225	A	www.mobilbonus.cz
81.0.231.225	A	pix.mobilbonus.cz
81.0.231.226	A+PTR	smaug.mobilbonus.cz
81.0.231.226	A	hrynamobil.cz
81.0.231.234	A	stratus.maincube.net
81.0.231.237	PTR	mx1.maincube.net
81.0.231.241	PTR	unassigned-81-0-231-242.casablanca.cz
81.0.231.241	A	mail.ergonomics.cz
81.0.231.248	PTR	net-81-0-231-248.casablanca.cz
81.0.231.250	PTR	www.casablanca.cz
81.0.231.251	PTR	assigned-81-0-231-251.casablanca.cz
81.0.231.255	PTR	bcast-81-0-231-255.casablanca.cz