Robtex

Up: 1.6.0.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 1.6.0.0/23
Down right: 1.6.2.0/23
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
1.6.0.1	PTR	segment-1.6.sify.net
1.6.0.2	PTR	segment-1.6.sify.net
1.6.0.3	PTR	segment-1.6.sify.net
1.6.0.4	A	126.0.4-static.reverse.softlayer.com
1.6.0.5	PTR	segment-1.6.sify.net
1.6.0.6	A	126.0.6-static.reverse.softlayer.com
1.6.0.7	PTR	segment-1.6.sify.net
1.6.0.8	PTR	1-6-0-0.lan.sify.net
1.6.0.9	PTR	segment-1.6.sify.net
1.6.0.11	PTR	segment-1.6.sify.net
1.6.0.17	PTR	segment-1.6.sify.net
1.6.0.25	PTR	ex01.taaltech.com
1.6.0.27	PTR	segment-1.6.sify.net
1.6.0.28	PTR	segment-1.6.sify.net
1.6.0.35	PTR	segment-1.6.sify.net
1.6.0.36	PTR	1-6-0-0.lan.sify.net
1.6.0.43	PTR	segment-1.6.sify.net
1.6.0.45	PTR	segment-1.6.sify.net
1.6.0.53	PTR	segment-1.6.sify.net
1.6.0.55	PTR	segment-1.6.sify.net
1.6.0.59	PTR	segment-1.6.sify.net
1.6.0.60	PTR	segment-1.6.sify.net
1.6.0.61	PTR	1-6-0-0.lan.sify.net
1.6.0.62	PTR	segment-1.6.sify.net
1.6.0.65	PTR	segment-1.6.sify.net
1.6.0.66	PTR	segment-1.6.sify.net
1.6.0.67	PTR	segment-1.6.sify.net
1.6.0.68	PTR	segment-1.6.sify.net
1.6.0.72	PTR	segment-1.6.sify.net
1.6.0.73	PTR	segment-1.6.sify.net
1.6.0.74	PTR	segment-1.6.sify.net
1.6.0.75	PTR	segment-1.6.sify.net
1.6.0.78	PTR	segment-1.6.sify.net
1.6.0.85	PTR	segment-1.6.sify.net
1.6.0.91	PTR	segment-1.6.sify.net
1.6.0.93	PTR	segment-1.6.sify.net
1.6.0.95	PTR	segment-1.6.sify.net
1.6.0.96	PTR	segment-1.6.sify.net
1.6.0.97	PTR	segment-1.6.sify.net
1.6.0.98	PTR	segment-1.6.sify.net
1.6.0.99	PTR	segment-1.6.sify.net
1.6.0.116	PTR	segment-1.6.sify.net
1.6.0.125	PTR	segment-1.6.sify.net
1.6.0.131	PTR	segment-1.6.sify.net
1.6.0.139	PTR	segment-1.6.sify.net
1.6.0.158	PTR	segment-1.6.sify.net
1.6.0.163	PTR	segment-1.6.sify.net
1.6.0.171	PTR	segment-1.6.sify.net
1.6.0.188	PTR	segment-1.6.sify.net
1.6.0.190	PTR	segment-1.6.sify.net
1.6.0.194	PTR	segment-1.6.sify.net
1.6.0.195	PTR	segment-1.6.sify.net
1.6.0.203	PTR	segment-1.6.sify.net
1.6.0.205	PTR	segment-1.6.sify.net
1.6.0.207	PTR	segment-1.6.sify.net
1.6.0.210	PTR	segment-1.6.sify.net
1.6.0.226	PTR	segment-1.6.sify.net
1.6.0.235	PTR	segment-1.6.sify.net
1.6.0.239	PTR	segment-1.6.sify.net
1.6.0.254	PTR	segment-1.6.sify.net
1.6.1.0	A	196.150-static.reverse.softlayer.com
1.6.1.0	A	126.130-static.reverse.softlayer.com
1.6.1.0	A	156.180-static.reverse.softlayer.com
1.6.1.4	A	136.174-static.reverse.softlayer.com
1.6.1.4	A	166.124-static.reverse.softlayer.com
1.6.1.4	A	166.174-static.reverse.softlayer.com
1.6.1.8	A	186.168-static.reverse.softlayer.com
1.6.1.8	A	146.128-static.reverse.softlayer.com
1.6.1.8	A	136.108-static.reverse.softlayer.com
1.6.1.80	A	smiles.happiestminds.com
1.6.1.80	A	smilescentral.happiestminds.com
1.6.2.0	A	136.230-static.reverse.softlayer.com
1.6.2.0	A	146.220-static.reverse.softlayer.com
1.6.2.0	A	146.230-static.reverse.softlayer.com
1.6.2.1	A	186.211-static.reverse.softlayer.com
1.6.2.4	A	186.244-static.reverse.softlayer.com
1.6.2.4	A	176.204-static.reverse.softlayer.com
1.6.2.4	A	176.244-static.reverse.softlayer.com
1.6.2.5	A	146.235-static.reverse.softlayer.com
1.6.2.8	A	176.228-static.reverse.softlayer.com
1.6.2.8	A	146.218-static.reverse.softlayer.com
1.6.2.9	A	126.229-static.reverse.softlayer.com
1.6.2.74	A	126.2.74-static.reverse.softlayer.com
1.6.3.180	A	jyl-y.com
1.6.3.195	A	joyalukkasdigital.in