Robtex

Up: 217.163.16.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 217.163.20.0/23
Down right: 217.163.22.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
217.163.20.0	PTR	unknown-217-163-20-x.yahoo.com
217.163.20.4	A+PTR	ge-3-1-7.msr1.ch1.yahoo.com
217.163.20.7	PTR	gi-1-8.bas-b2.ch1.yahoo.com
217.163.20.18	PTR	unknown.yahoo.com
217.163.20.37	PTR	eth-1-2-p207.tun1.ch1.yahoo.com
217.163.20.37	A	tun1.ch1.yahoo.com
217.163.20.40	A	c4948-z1.ch1.yahoo.com
217.163.20.65	A+PTR	ha1.vl-308.bas-c.ch1.yahoo.com
217.163.20.131	A+PTR	vl-309.bas-c1.ch1.yahoo.com
217.163.20.195	A+PTR	vl-307b.bas-c1.ch1.yahoo.com
217.163.20.198	A+PTR	c4948-c2.ch1.yahoo.com
217.163.20.202	PTR	unknown.yahoo.com
217.163.20.202	A	c4948-c6.ch1.yahoo.com
217.163.20.211	A+PTR	c4948-c103.ch1.yahoo.com
217.163.20.220	PTR	unknown.yahoo.com
217.163.20.220	A	c4948-c23.ch1.yahoo.com
217.163.20.224	A+PTR	c4948-c27.ch1.yahoo.com
217.163.20.225	A+PTR	c4948-c28.ch1.yahoo.com
217.163.20.227	A+PTR	c4948-c30.ch1.yahoo.com
217.163.21.3	PTR	unknown.yahoo.com
217.163.21.12	PTR	si-c5.vl320.ch1.yahoo.com
217.163.21.13	A+PTR	ve10.si-c3.ch1.yahoo.com
217.163.21.31	PTR	unknown.yahoo.com
217.163.21.31	A	bg0212.rm.ch1.yahoo.com
217.163.21.34	PTR	unknown.yahoo.com
217.163.21.34	A	ad.marschannels.com
217.163.21.34	A	fd-world.ngd.ysm.yahoodns.net
217.163.21.35	PTR	mpr2.ngd.vip.ch1.yahoo.com
217.163.21.35	A	ad.marschannels.com
217.163.21.35	A	fd-world.ngd.ysm.yahoodns.net
217.163.21.36	A+PTR	mpr3.ngd.vip.ch1.yahoo.com
217.163.21.37	A+PTR	mpr4.ngd.vip.ch1.yahoo.com
217.163.21.38	PTR	unknown.yahoo.com
217.163.21.38	A	mpr5.ngd.vip.ch1.yahoo.com
217.163.21.39	A+PTR	mpr6.ngd.vip.ch1.yahoo.com
217.163.21.40	PTR	unknown-217-163-21-x.yahoo.com
217.163.21.40	A	mpr7.ngd.vip.ch1.yahoo.com
217.163.21.41	A+PTR	mpr8.ngd.vip.ch1.yahoo.com
217.163.21.71	PTR	unknown-217-163-21-x.yahoo.com
217.163.21.78	PTR	unknown.yahoo.com
217.163.21.78	A	mpr0111.rm.ch1.yahoo.com
217.163.21.121	A	mpr0140.rm.ch1.yahoo.com
217.163.21.124	PTR	mpr0143.rm.ch1.yahoo.com
217.163.21.144	PTR	mpr0159.rm.ch1.yahoo.com
217.163.21.160	A+PTR	tpi0103.rm.ch1.yahoo.com
217.163.21.168	A	cms0001.rm.ch1.yahoo.com
217.163.21.181	A	tpi0116.rm.ch1.yahoo.com
217.163.21.206	A+PTR	tpi0132.rm.ch1.yahoo.com
217.163.21.211	PTR	unknown.yahoo.com
217.163.21.211	A	tpi0137.rm.ch1.yahoo.com
217.163.21.224	A	bap0013.rm.ch1.yahoo.com
217.163.21.255	PTR	unknown-217-163-21-x.yahoo.com
217.163.22.0	PTR	217-163-22-0.choopa.net
217.163.22.5	PTR	217-163-22-5.choopa.net
217.163.22.71	PTR	217-163-22-71.choopa.net
217.163.22.83	PTR	217-163-22-83.choopa.net
217.163.22.130	PTR	217-163-22-130.choopa.net
217.163.22.151	PTR	217-163-22-151.choopa.net
217.163.22.157	PTR	217-163-22-157.choopa.net
217.163.22.169	PTR	217-163-22-169.choopa.net
217.163.22.221	PTR	217-163-22-221.choopa.net
217.163.22.225	PTR	217-163-22-225.choopa.net
217.163.22.231	PTR	217-163-22-231.choopa.net
217.163.22.250	PTR	217-163-22-250.choopa.net
217.163.22.254	PTR	217-163-22-254.choopa.net
217.163.23.14	PTR	217.163.23.14.vultr.com
217.163.23.16	PTR	217.163.23.16.vultr.com
217.163.23.16	A	kno781g.com
217.163.23.19	PTR	217.163.23.19.vultr.com
217.163.23.24	PTR	217.163.23.24.vultr.com
217.163.23.24	A	b.dayrek.com
217.163.23.32	PTR	217.163.23.32.vultr.com
217.163.23.32	A	yaligift.world
217.163.23.34	PTR	217.163.23.34.vultr.com
217.163.23.34	A	scampot.me
217.163.23.35	PTR	217.163.23.35.vultr.com
217.163.23.35	A	centos.alpdata.net
217.163.23.35	A	ns3.alpdata.net
217.163.23.39	PTR	217.163.23.39.vultr.com
217.163.23.62	A	mail.exubrify.com
217.163.23.66	PTR	specik.cloud
217.163.23.66	A	dc-b03af2925c94.specik.cloud
217.163.23.67	PTR	217.163.23.67.vultr.com
217.163.23.67	A	vivianland.com
217.163.23.67	A	nanocreem.com
217.163.23.68	PTR	217.163.23.68.vultr.com
217.163.23.75	A	uxpowered.com
217.163.23.98	A	davidesomaschini.com
217.163.23.98	A	cerati.it
217.163.23.110	PTR	217.163.23.110.vultr.com
217.163.23.110	A	days1and2.cf
217.163.23.110	A	getcelebaffair.info
217.163.23.115	PTR	217.163.23.115.vultr.com
217.163.23.115	A	autohaus-deutschland.de
217.163.23.118	PTR	217.163.23.118.vultr.com
217.163.23.118	A	jazads.com
217.163.23.123	PTR	217.163.23.123.vultr.com
217.163.23.123	A	www.casinoespanol.com.mx
217.163.23.124	PTR	217.163.23.124.vultr.com
217.163.23.124	A	profilesarte.com
217.163.23.124	A	dc-8043d0bb131c.artbianco.com
217.163.23.135	PTR	217.163.23.135.vultr.com
217.163.23.145	PTR	217.163.23.145.vultr.com
217.163.23.151	PTR	217.163.23.151.vultr.com
217.163.23.168	PTR	217.163.23.168.vultr.com
217.163.23.168	A	psarkfince.com
217.163.23.178	PTR	217.163.23.178.vultr.com
217.163.23.178	A	yazilimtestar.com
217.163.23.178	A	basvuruyapteb.com
217.163.23.195	PTR	217.163.23.195.vultr.com
217.163.23.200	PTR	217.163.23.200.vultr.com
217.163.23.200	A	columbusterminator.com
217.163.23.200	A	avoidantamend.com
217.163.23.206	PTR	217.163.23.206.vultr.com
217.163.23.206	A	masticatingjuicersguide.com
217.163.23.211	PTR	217.163.23.211.vultr.com
217.163.23.211	A	motionstud.com
217.163.23.217	PTR	217.163.23.217.vultr.com
217.163.23.217	A	master.sushipool.com
217.163.23.218	PTR	217.163.23.218.vultr.com
217.163.23.220	PTR	217.163.23.220.vultr.com
217.163.23.232	PTR	217.163.23.232.vultr.com
217.163.23.239	PTR	217.163.23.239.vultr.com
217.163.23.241	PTR	217.163.23.241.vultr.com
217.163.23.241	A	www.adnetwork.website