Robtex

Up: 198.133.0.0/18
Can't show all results, try to descend to a more specific CIDR
Down left: 198.133.32.0/20
Down right: 198.133.48.0/20
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
198.133.36.1	PTR	198.133.36.1.tor.primus.ca
198.133.36.35	PTR	198.133.36.35.tor.primus.ca
198.133.37.5	A+PTR	user.firstclass.com
198.133.37.5	A	www.reg.firstclass.com
198.133.37.5	A	www.softarc.com
198.133.37.7	PTR	mail.firstclass.com
198.133.37.7	A	mail.softarc.com
198.133.37.33	PTR	standard.coolstuff.firstclass.com
198.133.37.33	A	mail.coolstuff.firstclass.com
198.133.37.33	A	screenreader.coolstuff.firstclass.com
198.133.37.39	A	scm.firstclass.com