Robtex

Up: 76.13.24.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 76.13.24.0/23
Down right: 76.13.26.0/23

IP	Type	Hostname
76.13.24.33	PTR	unknown-76-13-24-x.yahoo.com
76.13.24.99	PTR	unknown-76-13-24-x.yahoo.com
76.13.26.6	PTR	ha6.ge-0-8.bas-g.ac4.yahoo.com
76.13.26.13	PTR	nfshs103-sm.mail.bf1.yahoo.com
76.13.26.39	PTR	unknown-76-13-26-x.yahoo.com
76.13.26.64	PTR	sendmailws141.mail.bf1.yahoo.com
76.13.26.65	PTR	hs10420.mail.bf1.yahoo.com
76.13.26.66	PTR	hs10418.mail.bf1.yahoo.com
76.13.26.71	PTR	mc162a.mail.vip.bf1.yahoo.com
76.13.26.79	PTR	sendmailws112.mail.bf1.yahoo.com
76.13.26.108	PTR	hs10137.mail.bf1.yahoo.com
76.13.26.109	PTR	hs10135.mail.bf1.yahoo.com
76.13.26.127	A+PTR	sendmailws115.mail.bf1.yahoo.com
76.13.26.136	A+PTR	sendmailws131.mail.bf1.yahoo.com
76.13.26.137	PTR	hs10404.mail.bf1.yahoo.com
76.13.26.138	PTR	hs10402.mail.bf1.yahoo.com
76.13.26.159	PTR	hs10439.mail.bf1.yahoo.com
76.13.26.172	A+PTR	mg1013.mail.bf1.yahoo.com
76.13.26.198	PTR	hs10140.mail.bf1.yahoo.com
76.13.26.226	PTR	unknown-76-13-26-x.yahoo.com
76.13.26.237	A+PTR	mg1046.mail.bf1.yahoo.com
76.13.26.240	PTR	mg1049.mail.bf1.yahoo.com
76.13.27.5	PTR	hs10436.mail.bf1.yahoo.com
76.13.27.6	A+PTR	sendmailws120.mail.bf1.yahoo.com
76.13.27.34	A+PTR	sendmailws127.mail.bf1.yahoo.com
76.13.27.35	A+PTR	sendmailws128.mail.bf1.yahoo.com
76.13.27.48	A+PTR	sendmailws133.mail.bf1.yahoo.com
76.13.27.49	A+PTR	sendmailws134.mail.bf1.yahoo.com
76.13.27.50	PTR	sendmailws121.mail.bf1.yahoo.com
76.13.27.54	A+PTR	sendmailws135.mail.bf1.yahoo.com
76.13.27.69	A+PTR	sendmailws122.mail.bf1.yahoo.com
76.13.27.113	PTR	unknown-76-13-27-x.yahoo.com
76.13.27.114	PTR	unknown-76-13-27-x.yahoo.com
76.13.27.132	A+PTR	sendmailws137.mail.bf1.yahoo.com
76.13.27.133	PTR	hs10428.mail.bf1.yahoo.com
76.13.27.134	PTR	sendmailws124.mail.bf1.yahoo.com
76.13.27.147	PTR	unknown-76-13-27-x.yahoo.com
76.13.27.196	PTR	sendmailws139.mail.bf1.yahoo.com
76.13.27.197	A+PTR	sendmailws140.mail.bf1.yahoo.com