Robtex

Up: 203.19.8.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 203.19.8.0/23
Down right: 203.19.10.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
203.19.9.4	PTR	rb-bne1-04.idx.com.au
203.19.9.13	PTR	rb-bne1-13.idx.com.au
203.19.9.14	PTR	rb-bne1-14.idx.com.au
203.19.9.15	PTR	rb-bne1-15.idx.com.au
203.19.9.16	PTR	rb-bne1-16.idx.com.au
203.19.9.21	PTR	rb-bne1-21.idx.com.au
203.19.9.24	PTR	rb-bne1-24.idx.com.au
203.19.9.28	PTR	rb-bne1-28.idx.com.au
203.19.9.31	PTR	rb-bne1-31.idx.com.au
203.19.9.33	PTR	rb-bne1-33.idx.com.au
203.19.9.34	PTR	rb-bne1-34.idx.com.au
203.19.9.36	PTR	rb-bne1-36.idx.com.au
203.19.9.47	PTR	rb-bne1-47.idx.com.au
203.19.9.49	PTR	rb-bne1-49.idx.com.au
203.19.9.55	PTR	rb-bne1-55.idx.com.au
203.19.9.56	PTR	rb-bne1-56.idx.com.au
203.19.9.62	PTR	rb-bne1-62.idx.com.au
203.19.9.65	PTR	rb-bne1-65.idx.com.au
203.19.9.67	PTR	rb-bne1-67.idx.com.au
203.19.9.73	PTR	rb-bne1-73.idx.com.au
203.19.9.74	PTR	rb-bne1-74.idx.com.au
203.19.9.79	PTR	rb-bne1-79.idx.com.au
203.19.9.86	PTR	rb-bne1-86.idx.com.au
203.19.9.87	PTR	rb-bne1-87.idx.com.au
203.19.9.90	PTR	rb-bne1-90.idx.com.au
203.19.9.91	PTR	rb-bne1-91.idx.com.au
203.19.9.92	PTR	rb-bne1-92.idx.com.au
203.19.9.96	PTR	rb-bne1-96.idx.com.au
203.19.9.98	PTR	rb-bne1-98.idx.com.au
203.19.9.101	PTR	rb-bne1-101.idx.com.au
203.19.9.107	PTR	rb-bne1-107.idx.com.au
203.19.9.117	PTR	rb-bne1-117.idx.com.au
203.19.9.119	PTR	rb-bne1-119.idx.com.au
203.19.9.120	PTR	rb-bne1-120.idx.com.au
203.19.9.129	PTR	rb-bne1-129.idx.com.au
203.19.9.131	PTR	rb-bne1-131.idx.com.au
203.19.9.136	PTR	rb-bne1-136.idx.com.au
203.19.9.137	PTR	rb-bne1-137.idx.com.au
203.19.9.141	PTR	rb-bne1-141.idx.com.au
203.19.9.145	PTR	rb-bne1-145.idx.com.au
203.19.9.149	PTR	rb-bne1-149.idx.com.au
203.19.9.151	PTR	rb-bne1-151.idx.com.au
203.19.9.153	PTR	rb-bne1-153.idx.com.au
203.19.9.156	PTR	rb-bne1-156.idx.com.au
203.19.9.164	PTR	rb-bne1-164.idx.com.au
203.19.9.165	PTR	rb-bne1-165.idx.com.au
203.19.9.166	PTR	rb-bne1-166.idx.com.au
203.19.9.170	PTR	rb-bne1-170.idx.com.au
203.19.9.171	PTR	rb-bne1-171.idx.com.au
203.19.9.172	PTR	rb-bne1-172.idx.com.au
203.19.9.177	PTR	rb-bne1-177.idx.com.au
203.19.9.178	PTR	rb-bne1-178.idx.com.au
203.19.9.179	PTR	rb-bne1-179.idx.com.au
203.19.9.180	PTR	rb-bne1-180.idx.com.au
203.19.9.183	PTR	rb-bne1-183.idx.com.au
203.19.9.188	PTR	rb-bne1-188.idx.com.au
203.19.9.192	PTR	rb-bne1-192.idx.com.au
203.19.9.204	PTR	rb-bne1-204.idx.com.au
203.19.9.206	PTR	rb-bne1-206.idx.com.au
203.19.9.208	PTR	rb-bne1-208.idx.com.au
203.19.9.211	PTR	rb-bne1-211.idx.com.au
203.19.9.214	PTR	rb-bne1-214.idx.com.au
203.19.9.220	PTR	rb-bne1-220.idx.com.au
203.19.9.221	PTR	rb-bne1-221.idx.com.au
203.19.9.224	PTR	rb-bne1-224.idx.com.au
203.19.9.225	PTR	rb-bne1-225.idx.com.au
203.19.9.227	PTR	rb-bne1-227.idx.com.au
203.19.9.228	PTR	rb-bne1-228.idx.com.au
203.19.9.232	PTR	rb-bne1-232.idx.com.au
203.19.9.234	PTR	rb-bne1-234.idx.com.au
203.19.9.246	PTR	rb-bne1-246.idx.com.au
203.19.10.21	A+PTR	smtp.idx.com.au
203.19.10.25	PTR	maxb25.idx.com.au
203.19.10.25	A	mail.sefar.co.nz
203.19.11.1	PTR	tpg.lns-efm.idx.com.au
203.19.11.9	PTR	cp.idxhosting2.com.au
203.19.11.10	PTR	idxgs-10.static.idx.com.au
203.19.11.12	PTR	idxgs-12.static.idx.com.au
203.19.11.18	PTR	idxgs-18.static.idx.com.au
203.19.11.18	A	broadbandcity.com.au
203.19.11.22	PTR	idxgs-22.static.idx.com.au
203.19.11.22	A	flipbykes.com
203.19.11.23	A	dc-ed4392b3-mail.suertresresults.com
203.19.11.33	A+PTR	ns1.idxhosting.com.au
203.19.11.34	A	ns2.idxhosting.com.au
203.19.11.35	PTR	mail.idxhosting.com.au
203.19.11.35	A	mail.braganzaonline.com
203.19.11.36	PTR	colo-cp36.static.idx.com.au
203.19.11.37	PTR	mail2.idx.com.au
203.19.11.39	A+PTR	mail2.idx.com.au
203.19.11.44	PTR	idxgs-44.static.idx.com.au
203.19.11.47	PTR	idxgs-47.static.idx.com.au
203.19.11.47	A	ns1.broadbandcity.com.au
203.19.11.48	PTR	idxgs-48.static.idx.com.au
203.19.11.48	A	ns2.broadbandcity.com.au
203.19.11.49	PTR	idxgs-49.static.idx.com.au
203.19.11.49	A	mail.braganzaonline.com
203.19.11.49	A	mail.pscaudio.com
203.19.11.57	A+PTR	mail.idx.com.au
203.19.11.57	A	annoplan.idx.com.au
203.19.11.57	A	pop.idx.com.au
203.19.11.58	PTR	cp.idxhosting.com.au
203.19.11.58	A	mail.idxhosting.com.au
203.19.11.59	PTR	idxgs-59.static.idx.com.au
203.19.11.66	PTR	idxgs-66.static.idx.com.au
203.19.11.69	PTR	idxgs-69.static.idx.com.au
203.19.11.85	PTR	idxgs-85.static.idx.com.au
203.19.11.88	PTR	idxgs-88.static.idx.com.au
203.19.11.91	PTR	idxgs-91.static.idx.com.au
203.19.11.93	PTR	idxgs-93.static.idx.com.au
203.19.11.99	PTR	idxgs-99.static.idx.com.au
203.19.11.133	PTR	idxgs-133.static.idx.com.au
203.19.11.145	PTR	idxgs-145.static.idx.com.au
203.19.11.178	PTR	idxgs-178.static.idx.com.au
203.19.11.204	PTR	idxgs-204.static.idx.com.au
203.19.11.206	PTR	idxgs-206.static.idx.com.au