Robtex

Up: 216.247.48.0/20
Can't show all results, try to descend to a more specific CIDR
Down left: 216.247.48.0/22
Down right: 216.247.52.0/22

IP	Type	Hostname
216.247.48.48	PTR	mail.frinz.com
216.247.48.219	PTR	mail.brentwoodappraisals.com
216.247.49.9	PTR	mail.spysite.com
216.247.49.94	PTR	mail.housearrest.com
216.247.49.95	A	mail.adusa.com
216.247.49.125	PTR	mail.kaagc.org
216.247.49.131	PTR	mail.hetzner.net
216.247.49.242	PTR	mail.tech2knet.com
216.247.49.242	PTR	mail.rccgatlanta.org
216.247.50.8	PTR	mail.visionsite.org
216.247.50.28	PTR	mail.website2morrow.com
216.247.50.28	PTR	mail.worldev.com
216.247.50.28	PTR	mail.xshapes.com
216.247.50.75	PTR	mail.wmrc.org
216.247.50.83	PTR	mail.natlfire.com
216.247.50.93	PTR	mail.cpafs.com
216.247.50.101	PTR	mail.techdrivers.com
216.247.50.101	PTR	mail.utilitygeek.com
216.247.50.189	PTR	mail.prints.com
216.247.50.190	PTR	mail.eslawrence.com
216.247.50.213	A	mail.bikesportworld.com
216.247.51.76	PTR	mail.americancampus.com
216.247.52.64	PTR	mail.fabricom.net
216.247.52.66	PTR	mail.intelliteam.com
216.247.52.123	A	mail.auntbessies.com
216.247.52.123	A	mail.krakusham.com
216.247.52.171	PTR	mail.radioytelevision.com
216.247.52.240	PTR	mail.rgruden.org
216.247.53.91	A	mail.isovox.net
216.247.53.91	A	mail.isovox.org
216.247.53.187	PTR	mail.topdrivers.com
216.247.53.194	PTR	mail.walleye.on.ca
216.247.54.59	PTR	mail.mapia.net
216.247.54.122	PTR	mail.handymanjack.com
216.247.54.189	PTR	mail.frickweb.com
216.247.54.238	PTR	mail.lyndhurstfoundation.org
216.247.54.239	PTR	mail.bahman.net
216.247.55.37	A	mail.computerxperts.net
216.247.55.192	PTR	mail.coolmenow.com