Robtex

Up: 220.255.0.0/20
Can't show all results, try to descend to a more specific CIDR
Down left: 220.255.8.0/22
Down right: 220.255.12.0/22
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
220.255.10.1	PTR	bb220-255-10-1.singnet.com.sg
220.255.10.17	PTR	bb220-255-10-17.singnet.com.sg
220.255.10.25	PTR	bb220-255-10-25.singnet.com.sg
220.255.10.32	PTR	bb220-255-10-32.singnet.com.sg
220.255.10.34	PTR	socomecsicon.socomecsicon.com.sg
220.255.10.40	PTR	bb220-255-10-40.singnet.com.sg
220.255.10.41	PTR	bb220-255-10-41.singnet.com.sg
220.255.10.56	PTR	bb220-255-10-56.singnet.com.sg
220.255.10.59	PTR	bb220-255-10-59.singnet.com.sg
220.255.10.67	PTR	bb220-255-10-67.singnet.com.sg
220.255.10.73	PTR	bb220-255-10-73.singnet.com.sg
220.255.10.74	PTR	bb220-255-10-74.singnet.com.sg
220.255.10.75	PTR	bb220-255-10-75.singnet.com.sg
220.255.10.88	PTR	bb220-255-10-88.singnet.com.sg
220.255.10.96	PTR	bb220-255-10-96.singnet.com.sg
220.255.10.98	PTR	bb220-255-10-98.singnet.com.sg
220.255.10.104	PTR	bb220-255-10-104.singnet.com.sg
220.255.10.105	PTR	bb220-255-10-105.singnet.com.sg
220.255.10.113	PTR	bb220-255-10-113.singnet.com.sg
220.255.10.120	PTR	bb220-255-10-120.singnet.com.sg
220.255.10.122	PTR	bb220-255-10-122.singnet.com.sg
220.255.10.129	PTR	bb220-255-10-129.singnet.com.sg
220.255.10.138	PTR	bb220-255-10-138.singnet.com.sg
220.255.10.153	PTR	bb220-255-10-153.singnet.com.sg
220.255.10.161	PTR	bb220-255-10-161.singnet.com.sg
220.255.10.168	PTR	bb220-255-10-168.singnet.com.sg
220.255.10.176	PTR	bb220-255-10-176.singnet.com.sg
220.255.10.177	PTR	bb220-255-10-177.singnet.com.sg
220.255.10.185	PTR	bb220-255-10-185.singnet.com.sg
220.255.10.208	PTR	bb220-255-10-208.singnet.com.sg
220.255.10.211	PTR	bb220-255-10-211.singnet.com.sg
220.255.10.218	PTR	bb220-255-10-218.singnet.com.sg
220.255.10.226	PTR	bb220-255-10-226.singnet.com.sg
220.255.10.251	PTR	bb220-255-10-251.singnet.com.sg
220.255.11.54	PTR	bb220-255-11-54.singnet.com.sg
220.255.11.60	PTR	bb220-255-11-60.singnet.com.sg
220.255.11.76	PTR	bb220-255-11-76.singnet.com.sg
220.255.11.90	PTR	bb220-255-11-90.singnet.com.sg
220.255.11.138	A+PTR	sgtnt01.sankogosei.com.sg
220.255.11.138	A	mail.sankogosei.com.sg
220.255.11.139	PTR	bb220-255-11-139.singnet.com.sg
220.255.11.197	PTR	bb220-255-11-197.singnet.com.sg
220.255.11.202	PTR	bb220-255-11-202.singnet.com.sg
220.255.11.216	PTR	bb220-255-11-216.singnet.com.sg
220.255.11.217	PTR	bb220-255-11-217.singnet.com.sg
220.255.11.230	PTR	bb220-255-11-230.singnet.com.sg
220.255.12.68	A+PTR	smtp.hongthai.com.sg
220.255.12.117	A+PTR	ifsap.com
220.255.12.117	A	mail.ifsap.com
220.255.12.180	PTR	singdc1.argusmediagroup.com.sg
220.255.12.180	A	mailsvr.argusmediagroup.com.sg
220.255.12.180	A	mail.argusmediagroup.com.sg
220.255.12.226	PTR	mail.sinhengchan.com.sg
220.255.12.227	A	www.sinhengchan.com.sg
220.255.12.227	A	sinhengchan.com.sg
220.255.12.227	A	nestatamami.com
220.255.12.228	PTR	mail.sinhengchan.com.sg
220.255.12.243	PTR	pncgmail.ncgrp.com
220.255.12.245	PTR	zncgmail.ncgrp.com
220.255.13.51	A+PTR	webmail.rigel-group.com
220.255.13.91	A	ns3.sterling-intl.com
220.255.13.126	A	fortim.com.sg
220.255.13.162	A+PTR	mail.halifa-bobo.com
220.255.13.162	A	angkee.com
220.255.13.162	A	mail.bobo.sg
220.255.13.195	A	relay.dynamicsource.com
220.255.13.195	A	samba.dynamicsource.com
220.255.13.197	A+PTR	mta.dynamicsource.com
220.255.13.197	PTR	relay2.mta.dynamicsource.com
220.255.13.197	A	imap.dynamicsource.com
220.255.13.205	A	smtp0.anbros.com.sg
220.255.14.106	A+PTR	webmail.aaalliance.com.sg
220.255.14.106	A	mail.aaalliance.com.sg
220.255.14.129	A+PTR	mail.imes.com.sg
220.255.14.250	PTR	mail.eastbay.com.sg
220.255.14.250	A	eastbay.com.sg
220.255.15.18	PTR	mail.detpak.com.sg
220.255.15.68	A	marshallcavendish.us
220.255.15.69	PTR	mailhost2.brel.com
220.255.15.69	A	mailhost.brel.com
220.255.15.69	A	mail.atnt.com.sg
220.255.15.155	A	ns1.sitetectonix.com
220.255.15.155	A	mail.sitetectonix.com
220.255.15.163	A+PTR	smtp.fish-co.com
220.255.15.165	A+PTR	relay.fish-co.com
220.255.15.165	A	smtp.oceanaseafood.com