Robtex

Up: 113.197.64.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 113.197.64.0/23
Down right: 113.197.66.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
113.197.64.2	PTR	mx1.au.smxemail.com
113.197.64.2	A	mx1.fujitsu.au.smxemail.com
113.197.64.2	A	mx2.fujitsu.au.smxemail.com
113.197.66.2	A+PTR	mx2.au.smxemail.com
113.197.66.2	A	mx1.fujitsu.au.smxemail.com
113.197.66.2	A	mx2.fujitsu.au.smxemail.com