Robtex

Up: 199.7.240.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 199.7.244.0/23
Down right: 199.7.246.0/23

IP	Type	Hostname
199.7.244.4	PTR	vpn.sentinel.com
199.7.244.20	A+PTR	ns1.sentinel.com
199.7.244.25	A+PTR	ks.sentinel.com
199.7.244.47	PTR	bscdmm5.bsc.sentinel.com
199.7.244.52	A+PTR	vtlab.sentinel.com
199.7.244.55	A	mail01.sentinelbsc.com
199.7.244.55	A	mail.its.sentinel.com
199.7.244.132	PTR	dgmsirp1.sentinel.com
199.7.244.197	A	vpn.sentinel.com
199.7.244.240	A+PTR	mail3.cloud.sentinel.com
199.7.245.4	PTR	vpn2.sentinel.com
199.7.245.6	A	dgex01.sentinel.com
199.7.245.20	A+PTR	ns2.sentinel.com
199.7.245.20	A	ns2bsc.sentinel.com
199.7.245.21	PTR	view.sentinel.com
199.7.245.22	A+PTR	mail2.sentinel.com
199.7.245.24	A+PTR	sms2.sentinel.com
199.7.245.28	A	monitoring.sentinel.com
199.7.245.28	A	monitoring2.sentinel.com
199.7.245.36	A	cl2ftp.sentinel.com
199.7.245.62	A+PTR	mail2.cloud.sentinel.com
199.7.246.7	A	350-ace-web-cluster.sentinel.com
199.7.246.7	A	sentinel.com
199.7.246.21	PTR	mail.sentinel.com
199.7.246.22	A	cl1ftp.sentinel.com
199.7.246.23	A+PTR	forums.sentinel.com
199.7.246.32	PTR	www.sentinel.com
199.7.246.33	PTR	service.sentinel.com
199.7.246.34	PTR	mpweb.sentinel.com
199.7.246.36	A	dgex01.sentinel.com
199.7.246.36	A	owa.sentinel.com
199.7.246.37	PTR	owa.sentinel.com
199.7.246.44	PTR	mms.sentinel.com
199.7.246.47	A+PTR	epmo.sentinel.com
199.7.246.52	PTR	vtlab.sentinel.com
199.7.246.54	A+PTR	mpwebconf.sentinel.com
199.7.246.86	A+PTR	monitoring.sentinel.com
199.7.246.86	A	monitoring1.sentinel.com
199.7.246.87	A	sms.sentinel.com
199.7.246.102	A	aademo.sentinel.com
199.7.246.106	A	view.sentinel.com
199.7.246.121	A	mail.sentinel.com
199.7.246.131	A	dgweb1.sentinel.com
199.7.246.131	A	service.sentinel.com
199.7.247.4	A	vpn.sentinel.com
199.7.247.4	A	vpn3.sentinel.com
199.7.247.4	A	vpn2.sentinel.com
199.7.247.69	A+PTR	mail2.doall.com
199.7.247.70	A	mail3.doall.com
199.7.247.84	A	myrubsteam.com
199.7.247.85	A	utilitysmart.com
199.7.247.86	A	owa.doall.cloud.sentinel.com
199.7.247.86	A	mail.doall.com
199.7.247.133	A+PTR	mail1.cloud.sentinel.com
199.7.247.134	A	mail3.cloud.sentinel.com
199.7.247.178	A	msp.sentinel.com
199.7.247.183	A+PTR	rdsdemobroker1.cloud.sentinel.com