Robtex

Up: 65.69.80.0/23
Can't show all results, try to descend to a more specific CIDR
Down left: 65.69.81.0/25
Down right: 65.69.81.128/25
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
65.69.81.2	A	gw.bcbsmo.com
65.69.81.8	A	gw3.bcbsmo.com
65.69.81.10	A	orthus.bcbsmo.com
65.69.81.22	A+PTR	terra.bcbsmo.com
65.69.81.22	A+PTR	terra.missouriblue.com
65.69.81.22	A+PTR	terra.myblueplan.com
65.69.81.25	A	mail.bcbsmo.com
65.69.81.26	A	mail2.bcbsmo.com
65.69.81.31	A	m9llazix01.wellpoint.com
65.69.81.32	A	mail2.wellpoint.com
65.69.81.32	A	m9llazix02.wellpoint.com
65.69.81.33	A+PTR	m9llazix03.wellpoint.com
65.69.81.33	A+PTR	mail3.wellpoint.com
65.69.81.34	A	mail4.wellpoint.com
65.69.81.34	A	m9llazix04.wellpoint.com
65.69.81.35	A	m9llazix05.wellpoint.com
65.69.81.35	A	mail5.wellpoint.com
65.69.81.36	A	mail6.wellpoint.com
65.69.81.36	A	m9llazix06.wellpoint.com
65.69.81.37	A	mail7.wellpoint.com
65.69.81.37	A	m9llazix07.wellpoint.com
65.69.81.41	A+PTR	smtp3.anthem.com
65.69.81.50	PTR	central.bcbsmo.com
65.69.81.50	A+PTR	vpn.bcbsmo.com
65.69.81.53	A	ns1.bcbsmo.com
65.69.81.54	A	ns2.bcbsmo.com
65.69.81.81	A+PTR	bcbsmo.biz
65.69.81.81	A+PTR	missouriblue.biz
65.69.81.81	A+PTR	myblueplan.biz
65.69.81.90	A	smtp2.wellpoint.com
65.69.81.100	A+PTR	smtp1.anthem.com
65.69.81.100	A	m9llalx001.wellpoint.com
65.69.81.105	A+PTR	www2.bcbsmo.com