Robtex

Up: 216.163.176.0/23
Can't show all results, try to descend to a more specific CIDR
Down left: 216.163.176.0/25
Down right: 216.163.176.128/25
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
216.163.176.31	A	dtcwsd.1.geo.ctmail.com
216.163.176.32	A	server.f-prot.com
216.163.176.32	A	fprot5.ctmail.com
216.163.176.32	A	avdl.5.geo.ctmail.com
216.163.176.33	A+PTR	ns5.ctmail.com
216.163.176.33	A	httpdns.1.geo.ctmail.com
216.163.176.33	A	ns3.ctmail.com
216.163.176.35	PTR	c2resolver.ctmail.com
216.163.176.35	A	resolver3.ast.ctmail.com
216.163.176.35	A	resolver3.altn.ctmail.com
216.163.176.36	PTR	c2iprep1.ctmail.com
216.163.176.36	A	ipres.3.geo.ctmail.com
216.163.176.36	A	ipres.8.geo.ctmail.com
216.163.176.37	A+PTR	c2webresolver1.ctmail.com
216.163.176.37	A	cloudurl1.netasq.com
216.163.176.37	A	webres3.zyxel.ctmail.com
216.163.176.38	A+PTR	publicms3.mail2world.com
216.163.176.38	A	mx1.mail.name.com
216.163.176.38	A	mx2.rpi.mail2world.com
216.163.176.39	PTR	eforwardct3.name-services.com
216.163.176.40	PTR	mx03.mx-server.net
216.163.176.40	A	uemxin.tjnic.com
216.163.176.40	A	mail.lmspecialties.com
216.163.176.41	A+PTR	c2bh.prontomail.net
216.163.176.42	A+PTR	p2.nsm.ctmail.com
216.163.176.42	A	p.nsm.ctmail.com
216.163.176.44	A	olympus.1.geo.ctmail.com
216.163.176.45	A	c1ctasd1.ctmail.com
216.163.176.47	A	auth.1.geo.ctmail.com
216.163.176.48	PTR	wn.cpsserv.com
216.163.176.48	A	wn.1.geo.ctmail.com
216.163.176.53	A	mail.commandcom.com
216.163.176.53	A	mail.avsubmit.com
216.163.176.53	A	mail.commandsoftware.com
216.163.176.57	A	server.f-prot.com
216.163.176.57	A	renewkey.f-prot.net
216.163.176.57	A	f-prot.com
216.163.176.198	A	directupdates.f-prot.net
216.163.176.200	A	c2outbound200.ctmail.com
216.163.176.201	A+PTR	c2outbound201.ctmail.com
216.163.176.202	A+PTR	c2outbound202.ctmail.com
216.163.176.203	A+PTR	c2outbound203.ctmail.com
216.163.176.204	A+PTR	c2outbound204.ctmail.com
216.163.176.205	A+PTR	c2outbound205.ctmail.com
216.163.176.206	A	c2outbound206.ctmail.com
216.163.176.207	A+PTR	c2outbound207.ctmail.com
216.163.176.208	A+PTR	c2outbound208.ctmail.com
216.163.176.209	A+PTR	c2outbound209.ctmail.com