Robtex

Up: 165.21.20.0/23
Can't show all results, try to descend to a more specific CIDR
Down left: 165.21.21.0/25
Down right: 165.21.21.128/25
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
165.21.21.2	A+PTR	mail-gw.singnet.com.sg
165.21.21.38	A	pingcs.com
165.21.21.70	A+PTR	mail10.singtel.com
165.21.21.81	PTR	galaxy.singtel.com
165.21.21.151	A	orion.singtel.com
165.21.21.153	A+PTR	aries.singtel.com
165.21.21.153	A	aries.miostadium.com
165.21.21.153	A	aries.singtel.tv
165.21.21.155	A	mail.singtel.com.sg
165.21.21.162	A+PTR	mobimis.singtel.com
165.21.21.172	A	galaxy.singtel.com
165.21.21.178	A+PTR	ftp.singtel.com
165.21.21.179	A+PTR	slmsuat.singtel.com
165.21.21.180	A+PTR	mona.singtel.com
165.21.21.180	A	mail.optus.com.au
165.21.21.181	PTR	smtp1.singtel.com
165.21.21.188	A+PTR	lisa.singtel.com
165.21.21.188	A	mail.optus.com.au
165.21.21.189	A+PTR	atlantis.singtel.com
165.21.21.190	A	davinci.singtel.com
165.21.21.192	PTR	lisa.singtel.com
165.21.21.220	A	mail.mime.singtel.com