Robtex

Up: 123.243.0.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 123.243.4.0/23
Down right: 123.243.6.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
123.243.4.19	PTR	123-243-4-19.static.tpgi.com.au
123.243.4.38	A	123-243-4-38.static.tpgi.com.au
123.243.4.65	A	123-243-4-65.static.tpgi.com.au
123.243.4.203	PTR	123-243-4-203.static.tpgi.com.au
123.243.4.238	PTR	123-243-4-238.static.tpgi.com.au
123.243.5.11	PTR	123-243-5-11.static.tpgi.com.au
123.243.5.11	A	mail.pepr.com.au
123.243.5.30	A	nsw.harcourts.com.au
123.243.5.31	PTR	123-243-5-31.static.tpgi.com.au
123.243.5.31	A	mail.enr.com.au
123.243.5.34	A+PTR	123-243-5-34.static.tpgi.com.au
123.243.5.162	A	keywayreport.com
123.243.5.181	PTR	123-243-5-181.static.tpgi.com.au
123.243.6.34	A	russellbarnard.net
123.243.6.111	A	mail.ashfieldrsl.com.au
123.243.6.146	PTR	123-243-6-146.static.tpgi.com.au
123.243.6.146	A	mail.gmarchitects.com.au
123.243.6.226	PTR	123-243-6-226.tpgi.com.au
123.243.6.226	A	adsl.booksandcollectibles.com.au
123.243.6.226	A	www.globalvillagebooks.com
123.243.6.228	A	123-243-6-228.static.tpgi.com.au
123.243.6.246	A+PTR	123-243-6-246.static.tpgi.com.au
123.243.6.246	A	ns4.corphosts.com
123.243.7.17	PTR	123-243-7-17.static.tpgi.com.au
123.243.7.38	A+PTR	123-243-7-38.static.tpgi.com.au
123.243.7.48	PTR	mail.electromaster.com.au
123.243.7.53	PTR	123-243-7-53.static.tpgi.com.au
123.243.7.53	A	mail.metrorehab.com.au
123.243.7.62	PTR	123-243-7-62.static.tpgi.com.au
123.243.7.62	A	mail.sydneycomedyfest.com.au
123.243.7.88	PTR	123-243-7-88.static.tpgi.com.au
123.243.7.89	PTR	woodwind-group.com.au
123.243.7.89	A	kolab.woodwind-group.com.au
123.243.7.89	A	poulenc.woodwind-group.com.au
123.243.7.214	PTR	123-243-7-214.static.tpgi.com.au
123.243.7.214	A	mail.product-checkout.com
123.243.7.214	A	mail.vinavisas.com