Robtex

Up: 51.81.64.0/18
Can't show all results, try to descend to a more specific CIDR
Down left: 51.81.64.0/20
Down right: 51.81.80.0/20
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
51.81.64.213	PTR	hml01.besagonar.info
51.81.64.238	PTR	server.hostingnice.com
51.81.65.14	PTR	secure.explorahost.com
51.81.65.196	PTR	ip196.ip-51-81-65.us
51.81.66.39	PTR	ns1001513.ip-51-81-66.us
51.81.66.39	A	allinmedia.xyz
51.81.66.58	PTR	ns1001653.ip-51-81-66.us
51.81.66.153	A	rockets.my.id
51.81.66.195	PTR	ns1003177.ip-51-81-66.us
51.81.66.200	A	eachporn.com
51.81.67.15	PTR	ns1001948.ip-51-81-67.us
51.81.67.84	A	pix-us.revjet.com
51.81.68.27	A	justminiaturescale.com
51.81.68.219	PTR	wm1.servidor101.xyz
51.81.68.235	A	web.mexiserver.com
51.81.69.69	PTR	mail.vanttech.com
51.81.69.152	A	atrombetanews.com.br
51.81.70.4	A	constructoratextor.com
51.81.70.248	A	ftp.marketus.com
51.81.71.146	PTR	ip146.ip-51-81-71.us
51.81.71.155	PTR	ni2.integraeserver.com
51.81.71.155	A	grupogolan.com.ni
51.81.71.184	A	ns2.fastcpanelserver.com
51.81.71.184	A	ns1.fastcpanelserver.com
51.81.71.184	A	fastcpanelserver.com
51.81.71.187	A	fastdirectadminserver.com
51.81.71.222	PTR	ip222.ip-51-81-71.us
51.81.72.0	A	mail.spower.com.kw
51.81.72.15	A	ns80.webmasters.com
51.81.72.83	PTR	ns35.webmasters.com
51.81.72.83	A	p4mu.net
51.81.72.83	A	cchsnow.org
51.81.73.70	A	na.la
51.81.73.71	A	blog.tk
51.81.73.182	PTR	master.virtuati.com.br
51.81.73.182	A	ns3.virtuati.com.br
51.81.73.182	A	ns2.virtuati.com.br
51.81.73.219	A	stanproperty.com
51.81.73.219	A	sffireapp.org
51.81.74.131	A	mail.ekaleo.com
51.81.74.159	A	ns2.kaleotek.com
51.81.75.41	PTR	ip41.ip-51-81-75.us
51.81.75.61	A	blackline.cl
51.81.75.129	A	celestial.design
51.81.75.196	A	advt7.advertising-tech.com
51.81.80.14	A	best-blowjobs.com
51.81.80.14	A	hotteensxxx.com
51.81.80.16	A	khitzradio.com
51.81.80.55	PTR	vps-34dc5ebc.vps.ovh.us
51.81.80.57	A	ownserver.com.br
51.81.80.59	A	secretlab.pw
51.81.80.62	A	getresponse.co.il
51.81.80.62	A	yalaland.com
51.81.80.126	A	ssh-us1.serverip.co
51.81.80.126	A	ssh-us1.hostip.co
51.81.80.127	PTR	usa-v2ray.sshkit.net
51.81.80.129	PTR	vps-58273cbc.vps.ovh.us
51.81.80.163	PTR	fw.melatoninavix.com
51.81.80.176	PTR	us.pingvpn.net
51.81.80.233	PTR	vps-d10f8535.vps.ovh.us
51.81.81.60	PTR	vps-8156151b.vps.ovh.us
51.81.81.60	A	ns2.vexhost.com.br
51.81.81.60	A	ns1.iconeautomacao.com.br
51.81.81.67	A	api.aprendoencasa.pe.usain.tk
51.81.81.69	A	api.aprendoencasa.pe.usain.tk
51.81.81.114	A	meebox.com.mx
51.81.81.226	PTR	vps-6dc2a5e9.vps.ovh.us
51.81.81.242	PTR	vps-a4aee412.vps.ovh.us
51.81.81.251	PTR	sphinx.chicagopeoplez.org
51.81.81.251	A	kgarner.com
51.81.82.0	PTR	web04.collipsis.com
51.81.82.139	A	xxvidos.mobi
51.81.82.210	PTR	mail.konduit.live
51.81.82.224	A	tel-ergy.com
51.81.83.26	A	www.hosttechno.com
51.81.83.181	A	tntautobody.net
51.81.84.18	A	maxmax.com
51.81.84.108	PTR	vps-f6e1bc20.vps.ovh.us
51.81.84.176	A	xib.com
51.81.84.205	PTR	mailserver.softpointcloud.com
51.81.84.222	A	server-us1.sshkit.net
51.81.85.0	PTR	vps-bdb16b3a.vps.ovh.us
51.81.85.0	A	vps-b462556d.vps.ovh.us
51.81.85.6	PTR	server.hudhudit.xyz
51.81.85.38	PTR	clickerit.info
51.81.85.70	A	vps-a0f17d6a.vps.ovh.us
51.81.85.92	PTR	vps-de29e3f9.vps.ovh.us
51.81.85.129	PTR	host.gecs.com.br
51.81.85.232	A	www.thegamingcloud.com
51.81.85.242	A	ipst-sbsgxi.cdn.byteark.com
51.81.86.38	PTR	vps-2b1257f2.vps.ovh.us
51.81.86.58	PTR	mail.huenix.com
51.81.86.73	A	avahost.net
51.81.86.184	PTR	iespsanmarcos.peruteletrabajo.com
51.81.86.190	A	smartkids.com.br
51.81.87.50	PTR	vps-fb140769.vps.ovh.us
51.81.87.86	PTR	jarahaefo.com
51.81.87.181	PTR	vps-aa93bf34.vps.ovh.us
51.81.90.48	A	ns74.webmasters.com
51.81.90.52	A	nudebeachtube.com
51.81.90.52	A	fqu.com
51.81.90.52	A	www.gaysexchat.com
51.81.90.108	PTR	mail.gamwelltech.com
51.81.90.175	A	deixon.com
51.81.90.175	A	leansolutions.co
51.81.90.204	A	estadopb.com
51.81.91.196	A	ns5.8ssi.com
51.81.91.197	A	ns6.8ssi.com
51.81.91.199	A	corpohosting.com
51.81.93.23	A	hlc.ie
51.81.93.23	A	gkc.ca
51.81.93.23	A	tys.biz
51.81.93.63	PTR	dedicado.bitstorm.com.br
51.81.94.28	A	onthemapmarketing.com