Robtex

Up: 165.166.4.0/23
Can't show all results, try to descend to a more specific CIDR
Down left: 165.166.4.0/25
Down right: 165.166.4.128/25
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
165.166.4.1	A	firewall.iaregistry.com
165.166.4.2	A+PTR	switch.iaregistry.com
165.166.4.10	A	iar.iaregistry.com
165.166.4.13	A+PTR	iar2.iaregistry.com
165.166.4.66	A+PTR	switch2.iaregistry.com
165.166.4.70	A+PTR	iaregistry.com
165.166.4.70	A+PTR	iaregistry.net
165.166.4.70	A	secure.iaregistry.com
165.166.4.100	A+PTR	dns1.iaregistry.com
165.166.4.100	A+PTR	iardns1.iaregistry.com
165.166.4.101	A+PTR	dns2.iaregistry.com
165.166.4.235	A+PTR	iardns01.iaregistry.com