Robtex

Up: 217.12.8.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 217.12.8.0/23
Down right: 217.12.10.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
217.12.8.2	PTR	ha2.vl-33.bas-a.ukl.yahoo.com
217.12.8.11	PTR	unknown-217-12-8-x.yahoo.com
217.12.8.16	PTR	unknown-217-12-8-x.yahoo.com
217.12.8.24	PTR	unknown-217-12-8-x.yahoo.com
217.12.8.30	PTR	unknown-217-12-8-x.yahoo.com
217.12.8.31	PTR	unknown-217-12-8-x.yahoo.com
217.12.8.51	PTR	node02-nfsforce4503.mail.ir2.yahoo.com
217.12.8.51	A	mobile1.login.vip.ukl.yahoo.com
217.12.8.59	A	mix450203.mail.ir2.yahoo.com
217.12.8.76	A+PTR	ir2-01355.ostk.bm2.prod.ir2.yahoo.com
217.12.8.76	A	1stepfromsomewhere.com
217.12.8.76	A	onestepfromsomewhere.com
217.12.8.79	PTR	unknown.yahoo.com
217.12.8.102	A	hsl10003.mail.ir2.yahoo.com
217.12.8.115	PTR	unknown-217-12-8-x.yahoo.com
217.12.8.115	A	web450204.mail.ir2.yahoo.com
217.12.8.117	PTR	unknown-217-12-8-x.yahoo.com
217.12.8.117	A	monsitemedical.com
217.12.8.120	A	120.8.12.217.aprez.ostk.prod.ir2.yahoo.com
217.12.8.169	A	169.8.12.217.aprez.ostk.prod.ir2.yahoo.com
217.12.8.173	A+PTR	e4.member.vip.ukl.yahoo.com
217.12.8.217	A+PTR	antares-vm1.ese.ukl.yahoo.com
217.12.8.244	PTR	3000596.ostk.bm2.prod.ir2.yahoo.com
217.12.8.244	A	sendmailws109.mail.ir2.yahoo.com
217.12.8.245	A+PTR	sendmailws110.mail.ir2.yahoo.com
217.12.8.250	A+PTR	bs10204.mail.ir2.yahoo.com
217.12.9.8	A+PTR	sendmailws101.mail.ir2.yahoo.com
217.12.9.9	PTR	sendmailws102.mail.ir2.yahoo.com
217.12.9.10	PTR	sendmailws103.mail.ir2.yahoo.com
217.12.9.11	A+PTR	sendmailws104.mail.ir2.yahoo.com
217.12.9.12	A+PTR	sendmailws105.mail.ir2.yahoo.com
217.12.9.13	A+PTR	sendmailws106.mail.ir2.yahoo.com
217.12.9.14	A+PTR	sendmailws107.mail.ir2.yahoo.com
217.12.9.15	PTR	sendmailws108.mail.ir2.yahoo.com
217.12.9.41	A	zt42252.ostk.bm2.prod.ir2.yahoo.com
217.12.9.75	PTR	address1.pim.vip.ir2.yahoo.com
217.12.9.75	A	address.yahoo.com
217.12.9.75	A	br.address.yahoo.com
217.12.9.78	PTR	unknown-217-12-9-x.yahoo.com
217.12.9.78	A	nfsbulk10201.mail.ir2.yahoo.com
217.12.10.37	PTR	ios-api93.finance.ir2.yahoo.com
217.12.10.39	A	nm21-vm9.bullet.mail.ukl.yahoo.com
217.12.10.62	PTR	pop-es.mail.vip.ukl.yahoo.com
217.12.10.63	PTR	unknown-217-12-10-x.yahoo.com
217.12.10.64	PTR	unknown-217-12-10-x.yahoo.com
217.12.10.65	PTR	unknown-217-12-10-x.yahoo.com
217.12.10.100	PTR	ios-api15.finance.ir2.yahoo.com
217.12.10.216	PTR	ios-api9.finance.ir2.yahoo.com
217.12.11.0	PTR	unknown-217-12-11-x.yahoo.com
217.12.11.31	PTR	unknown-217-12-11-x.yahoo.com
217.12.11.31	A	rx-28.reserved.dns.ukl.yahoo.com