Robtex

Up: 199.59.16.0/20
Can't show all results, try to descend to a more specific CIDR
Down left: 199.59.16.0/22
Down right: 199.59.20.0/22

IP	Type	Hostname
199.59.18.3	A	mail1.swmedicalcenter.com
199.59.18.3	A	mail1.swmedctr.com
199.59.18.4	A+PTR	mail2.swmedctr.com
199.59.18.4	A+PTR	mail2.swmedicalcenter.com
199.59.18.4	PTR	mail2.swmedicalcenter.org
199.59.18.5	PTR	webmail.swmedctr.com
199.59.18.5	PTR	webmail.swmedicalcenter.com
199.59.18.8	A+PTR	mail4.swmedctr.com
199.59.18.8	A+PTR	mail4.swmedicalcenter.com
199.59.18.8	PTR	mail4.swmedicalcenter.org
199.59.18.19	A	portal.swmedicalcenter.com