Robtex

Up: 98.139.21.0/24
Can't show all results, try to descend to a more specific CIDR
Down left: 98.139.21.128/26
Down right: 98.139.21.192/26
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
98.139.21.134	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.135	A+PTR	console.vap.vip.bf1.yahoo.net
98.139.21.136	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.137	PTR	vporigin.vap.vip.bf1.yahoo.com
98.139.21.138	PTR	vporigin.yvap.vip.bf1.yahoo.com
98.139.21.139	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.140	A+PTR	sorryadx.adx.vip.bf1.yahoo.com
98.139.21.140	A	www6101.apt.apx.yahoodns.net
98.139.21.141	A+PTR	sorryadxauth.adx.vip.bf1.yahoo.com
98.139.21.142	PTR	sorryunified.adx.vip.bf1.yahoo.com
98.139.21.143	PTR	adminui.adx.vip.bf1.yahoo.com
98.139.21.144	A+PTR	iws.adx.vip.bf1.yahoo.com
98.139.21.145	A+PTR	bcpgeoapi1.adx.vip.bf1.yahoo.com
98.139.21.146	PTR	bcpiws.adx.vip.bf1.yahoo.com
98.139.21.147	A+PTR	bcpnetewsbcp1.adx.vip.bf1.yahoo.com
98.139.21.148	A+PTR	bcpsrchqrsbcp1.adx.vip.bf1.yahoo.com
98.139.21.149	A+PTR	cfi-zipline.adx.vip.bf1.yahoo.com
98.139.21.150	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.151	A+PTR	daxredir1.adx.vip.bf1.yahoo.com
98.139.21.151	A	dax-rd.apt.yahoo.com
98.139.21.151	A	dax-rd-yahoo.a00.yahoodns.net
98.139.21.152	A+PTR	bf1-daxsign.adx.vip.bf1.yahoo.com
98.139.21.153	PTR	daxredir2.adx.vip.bf1.yahoo.com
98.139.21.154	A+PTR	inxaptgw.adx.vip.bf1.yahoo.com
98.139.21.155	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.156	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.157	PTR	cmpui.adx.vip.bf1.yahoo.com
98.139.21.158	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.159	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.160	A+PTR	pricing.vip.bf1.yahoo.com
98.139.21.161	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.162	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.163	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.164	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.164	A	ufe1.cb.g01.yahoodns.net
98.139.21.165	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.166	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.167	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.168	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.169	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.169	A	edit.in.yahoo.com
98.139.21.169	A	login.korea.yahoo.com
98.139.21.170	A+PTR	ads1.cbs.vip.bf1.yahoo.com
98.139.21.170	A	sendmeacruise.net
98.139.21.171	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.171	A	notifybytext.net
98.139.21.171	A	atlanticvoyage.com
98.139.21.172	A+PTR	dpgwsadmin.ngd.vip.bf1.yahoo.com
98.139.21.173	A+PTR	dpgwsadminym.ngd.vip.bf1.yahoo.com
98.139.21.174	A+PTR	dpgws.ngd.vip.bf1.yahoo.com
98.139.21.175	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.176	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.177	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.178	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.179	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.180	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.181	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.182	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.183	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.184	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.185	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.186	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.187	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.188	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.189	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.190	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.191	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.192	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.193	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.194	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.195	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.196	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.197	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.198	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.199	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.200	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.201	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.202	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.203	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.204	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.205	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.206	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.207	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.208	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.209	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.210	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.211	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.212	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.213	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.214	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.215	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.216	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.217	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.218	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.219	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.220	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.221	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.222	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.223	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.224	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.225	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.226	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.227	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.228	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.229	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.230	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.231	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.232	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.233	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.234	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.235	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.236	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.237	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.238	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.239	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.240	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.241	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.242	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.243	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.244	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.245	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.246	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.247	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.248	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.249	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.250	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.251	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.252	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.253	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.254	PTR	unknown-98-139-21-x.yahoo.com
98.139.21.255	PTR	unknown-98-139-21-x.yahoo.com