Robtex

Up: 27.123.192.0/20
Can't show all results, try to descend to a more specific CIDR
Down left: 27.123.200.0/22
Down right: 27.123.204.0/22
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
27.123.200.0	PTR	unknown.yahoo.com
27.123.200.34	A	r1.travel.vip.tw1.yahoo.com
27.123.200.40	A+PTR	category.nevec.vip.tw1.yahoo.com
27.123.200.56	PTR	b.sca1.nevec.vip.tw1.yahoo.com
27.123.200.56	A	tw-beapav.bc.gysm.yahoodns.net
27.123.200.56	A	tw1.af.beap.bc.yahoo.com
27.123.200.68	A	yts.l7.search.vip.tw1.yahoo.com
27.123.200.83	PTR	prod-hv2.usi.tw1.yahoo.com
27.123.200.83	A	bcp-apac401.zenfs.com
27.123.200.83	A	gops.apac401.mobstor.vip.tw1.yahoo.com
27.123.200.96	A+PTR	int.img.search.vip.tw1.yahoo.com
27.123.200.96	A	hk.image.search.ystg1.b.yahoo.com
27.123.200.96	A	tw.image.search.ystg1.b.yahoo.com
27.123.200.109	A	edmbc.mall.vip.tw1.yahoo.com
27.123.201.20	A	yts1.manhattan.csp.g03.yahoodns.net
27.123.201.20	A	yts1.man.csp.vip.tw1.yahoo.com
27.123.201.23	A	gd.ads.vip.tw1.yahoo.com
27.123.201.26	A	w1.yhsl.member.tw.fyap.b.yahoo.com
27.123.201.167	A	w101.ysm.tw.g00.yahoodns.net
27.123.201.167	A	w101.ysm.vip.tw1.yahoo.com
27.123.201.167	A	tw.emarketing.yahoo.com
27.123.201.170	PTR	unknown-27-123-201-x.yahoo.com
27.123.201.170	A	mw.bid.tw.g01.yahoodns.net
27.123.201.170	A	mstore.bid.tw.g03.yahoodns.net
27.123.201.194	A	tw.fashionsp.fashion.yahoo.com
27.123.201.194	A	w5.media.tw.g01.yahoodns.net
27.123.201.199	A	tw.sf.search.mall.yahoo.com
27.123.201.199	A	sf.srch.ect.tw.g01.yahoodns.net
27.123.201.208	PTR	w1.bigdeals.acs.vip.tw1.yahoo.com
27.123.201.208	A	tw.charity.yahoo.com
27.123.201.212	A	csc-beap.adx.vip.tw1.yahoo.com
27.123.201.221	A	media.groups.g03.yahoodns.net
27.123.201.221	A	tw-media.groups.g03.yahoodns.net
27.123.201.224	PTR	w102.ysm.vip.tw1.yahoo.com
27.123.201.224	A	tw.ysm.emarketing.yahoo.com
27.123.201.225	A+PTR	linkspot101.search.vip.tw1.yahoo.com
27.123.201.225	A	tw.linkspot.search.yahoo.com
27.123.201.226	A	w2.info.platform.vip.tw1.yahoo.com
27.123.201.236	A	sg.yimg.com
27.123.201.237	A	a1.apiproxy.house.vip.tw1.yahoo.com
27.123.201.240	A+PTR	w101.rd.vip.tw1.yahoo.com
27.123.201.252	A	r101.finance.vip.tw1.yahoo.com
27.123.201.252	A	r101.tw.finance.g03.yahoodns.net
27.123.201.253	A	m.tw.bigdeals.yahoo.com
27.123.202.0	PTR	unknown-27-123-202-x.yahoo.com
27.123.202.178	PTR	b-l401.ac.tw1.yahoo.com
27.123.202.178	A	b-oapi1.adp.tw1.yahoo.com
27.123.202.179	A+PTR	cst0.adp.tw1.yahoo.com
27.123.202.216	PTR	unknown-27-123-202-x.yahoo.com
27.123.202.216	A	f0.adp.tw1.yahoo.com
27.123.202.220	A	b-f1.adp.tw1.yahoo.com
27.123.202.221	A	oapi0.adp.tw1.yahoo.com
27.123.203.29	A	rcv2.mall.tw1.yahoo.com
27.123.203.32	A	lbatch1.mall.tw1.yahoo.com
27.123.204.60	A	mg31a.mail.vip.tw1.yahoo.com
27.123.204.239	A	sendmailws110.mail.tw1.yahoo.com
27.123.204.240	PTR	f753.mail.vip.tw1.yahoo.com
27.123.204.240	A	imap-nokia.mail.global.gm0.yahoodns.net
27.123.205.0	PTR	unknown-27-123-205-x.yahoo.com
27.123.205.77	A	imap4.mail.tw.gm0.yahoodns.net
27.123.205.77	A	imap4-rr.mail.global.gm0.yahoodns.net
27.123.205.79	A	imap-star.mail.tw.gm0.yahoodns.net
27.123.206.31	A	imap-star.mail.tw.gm0.yahoodns.net
27.123.206.55	A	mta-v1.mail.vip.tw1.yahoo.com
27.123.206.59	A	omp1004.mail.tw1.yahoo.com
27.123.206.62	A	tw56294.ostk.bm2.prod.tw1.yahoo.com
27.123.206.84	A	n5.bullet.mail.tw1.yahoo.com
27.123.206.119	A	htc.imap.mail.yahoo.com
27.123.206.119	A	imap10.mail.vip.tw1.yahoo.com
27.123.206.119	A	imap-ssl.mail.yahoo.com
27.123.206.123	PTR	unknown-27-123-206-x.yahoo.com
27.123.206.123	A	htc.imap.mail.yahoo.com
27.123.206.123	A	imap-ssl.mail.yahoo.com
27.123.206.144	A	mta1016.mail.tw1.yahoo.com
27.123.206.180	A	mta1052.mail.tw1.yahoo.com
27.123.206.201	PTR	imap12.mail.vip.tw1.yahoo.com
27.123.206.201	A	htc.imap.mail.yahoo.com
27.123.206.201	A	imap-ssl.mail.yahoo.com
27.123.206.229	A	n4-vm2.bullet.mail.tw1.yahoo.com
27.123.207.1	A+PTR	n11-vm1.bullet.mail.tw1.yahoo.com
27.123.207.69	A	htc.imap.mail.yahoo.com
27.123.207.69	A	imap-ssl.mail.yahoo.com
27.123.207.69	A	android.imap.mail.yahoo.com
27.123.207.116	A	n10-vm8.bullet.mail.tw1.yahoo.com
27.123.207.149	A	htc.imap.mail.yahoo.com
27.123.207.149	A	imap-ssl.mail.yahoo.com
27.123.207.149	A	android.imap.mail.yahoo.com
27.123.207.157	A	htc.imap.mail.yahoo.com
27.123.207.157	A	imap-ssl.mail.yahoo.com
27.123.207.157	A	android.imap.mail.yahoo.com
27.123.207.165	A	htc.imap.mail.yahoo.com
27.123.207.165	A	imap-ssl.mail.yahoo.com
27.123.207.165	A	android.imap.mail.yahoo.com
27.123.207.173	A	htc.imap.mail.yahoo.com
27.123.207.173	A	imap-ssl.mail.yahoo.com
27.123.207.173	A	android.imap.mail.yahoo.com
27.123.207.217	PTR	unknown-27-123-207-x.yahoo.com
27.123.207.233	PTR	unknown-27-123-207-x.yahoo.com
27.123.207.234	PTR	unknown-27-123-207-x.yahoo.com
27.123.207.235	PTR	unknown-27-123-207-x.yahoo.com
27.123.207.242	PTR	unknown-27-123-207-x.yahoo.com
27.123.207.248	PTR	unknown-27-123-207-x.yahoo.com
27.123.207.251	PTR	unknown-27-123-207-x.yahoo.com