Robtex

Up: 173.1.64.0/19
Can't show all results, try to descend to a more specific CIDR
Down left: 173.1.80.0/21
Down right: 173.1.88.0/21
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
173.1.80.99	PTR	173.1.80.99.reverse.gogrid.com
173.1.80.130	PTR	lawyersoft.biz
173.1.80.130	PTR	mail.lawyersoft.biz
173.1.80.164	A	db2.trimtabs.com
173.1.81.2	PTR	173.1.81.2.reverse.gogrid.com
173.1.81.195	A	vidretal.com
173.1.82.0	PTR	173.1.82.0.reverse.gogrid.com
173.1.82.18	PTR	173.1.82.18.reverse.gogrid.com
173.1.82.50	PTR	173.1.82.50.reverse.gogrid.com
173.1.82.82	PTR	173.1.82.82.reverse.gogrid.com
173.1.82.156	A	ideatecnologia.com.br
173.1.83.0	PTR	173.1.83.0.reverse.gogrid.com
173.1.83.2	PTR	173.1.83.2.reverse.gogrid.com
173.1.83.64	PTR	173.1.83.64.reverse.gogrid.com
173.1.83.65	PTR	173.1.83.65.reverse.gogrid.com
173.1.83.67	PTR	173.1.83.67.reverse.gogrid.com
173.1.83.81	PTR	173.1.83.81.reverse.gogrid.com
173.1.83.82	PTR	173.1.83.82.reverse.gogrid.com
173.1.83.96	PTR	173.1.83.96.reverse.gogrid.com
173.1.83.98	PTR	173.1.83.98.reverse.gogrid.com
173.1.83.114	PTR	laguna.justnet.com
173.1.84.34	PTR	34.84.1.173.reverse.oncolocation.com
173.1.84.35	PTR	35.84.1.173.reverse.oncolocation.com
173.1.84.49	PTR	49.84.1.173.reverse.oncolocation.com
173.1.84.64	PTR	64.84.1.173.reverse.oncolocation.com
173.1.84.177	PTR	177.84.1.173.reverse.oncolocation.com
173.1.85.3	PTR	3.85.1.173.reverse.colocationreport.com
173.1.85.33	PTR	33.85.1.173.reverse.colocationreport.com
173.1.85.48	PTR	48.85.1.173.reverse.colocationreport.com
173.1.85.51	PTR	51.85.1.173.reverse.colocationreport.com
173.1.85.64	PTR	64.85.1.173.reverse.colocationreport.com
173.1.85.66	PTR	66.85.1.173.reverse.colocationreport.com
173.1.85.82	PTR	82.85.1.173.reverse.colocationreport.com
173.1.85.97	PTR	97.85.1.173.reverse.colocationreport.com
173.1.85.201	A	ns11.asatte.org
173.1.85.201	A	mail1.asatte.org
173.1.85.201	A	bepast.net
173.1.86.19	PTR	19.86.1.173.reverse.glorycolocation.com
173.1.86.48	PTR	48.86.1.173.reverse.glorycolocation.com
173.1.86.50	PTR	50.86.1.173.reverse.glorycolocation.com
173.1.86.66	PTR	66.86.1.173.reverse.glorycolocation.com
173.1.86.66	A	e-cubed.info
173.1.86.66	A	mail.ns2.e-cubed.com
173.1.86.82	PTR	82.86.1.173.reverse.glorycolocation.com
173.1.86.83	PTR	83.86.1.173.reverse.glorycolocation.com
173.1.86.98	PTR	98.86.1.173.reverse.glorycolocation.com
173.1.87.64	PTR	64.87.1.173.reverse.colocationsystems.com
173.1.88.3	PTR	173.1.88.3.reverse.gogrid.com
173.1.88.16	PTR	173.1.88.16.reverse.gogrid.com
173.1.88.67	PTR	173.1.88.67.reverse.gogrid.com
173.1.88.67	A	electricstory.com
173.1.88.67	A	retroleagues.com
173.1.88.83	PTR	173.1.88.83.reverse.gogrid.com
173.1.88.96	PTR	173.1.88.96.reverse.gogrid.com
173.1.89.3	PTR	173.1.89.3.reverse.gogrid.com
173.1.89.4	A	alphajax.com
173.1.89.4	A	smtp.alphajax.com
173.1.89.50	PTR	173.1.89.50.reverse.gogrid.com
173.1.89.83	PTR	173.1.89.83.reverse.gogrid.com
173.1.89.96	PTR	173.1.89.96.reverse.gogrid.com
173.1.89.130	PTR	173.1.89.130.reverse.gogrid.com
173.1.89.130	A	mwhowto.com
173.1.89.132	A	mail.virtualprom.com
173.1.89.132	A	live2.virtualprom.com
173.1.89.242	PTR	shared2-west.izoox.net
173.1.89.242	A	mail.ashhillcabinets.com
173.1.89.242	A	mail.transition-ourway.org
173.1.90.0	PTR	173.1.90.0.reverse.gogrid.com
173.1.90.1	PTR	173.1.90.1.reverse.gogrid.com
173.1.90.3	PTR	mail.apond.pt
173.1.90.19	PTR	173.1.90.19.reverse.gogrid.com
173.1.90.96	PTR	173.1.90.96.reverse.gogrid.com
173.1.90.180	A	mail3.eventioz.com
173.1.90.226	PTR	c5crm.dk
173.1.90.226	PTR	legisonline.dk
173.1.90.226	A+PTR	web-crm.dk
173.1.90.227	PTR	legis.dk
173.1.91.21	A	kobioshimaru.com
173.1.92.1	PTR	173.1.92.1.reverse.gogrid.com
173.1.92.2	PTR	173.1.92.2.reverse.gogrid.com
173.1.92.10	A	coupop.com
173.1.92.18	PTR	173.1.92.18.reverse.gogrid.com
173.1.92.19	PTR	173.1.92.19.reverse.gogrid.com
173.1.92.32	PTR	173.1.92.32.reverse.gogrid.com
173.1.92.35	PTR	173.1.92.35.reverse.gogrid.com
173.1.92.65	PTR	173.1.92.65.reverse.gogrid.com
173.1.92.67	PTR	173.1.92.67.reverse.gogrid.com
173.1.92.80	PTR	173.1.92.80.reverse.gogrid.com
173.1.93.2	PTR	173.1.93.2.reverse.gogrid.com
173.1.93.51	PTR	173.1.93.51.reverse.gogrid.com
173.1.93.82	A	safeandsoundprotection.com
173.1.93.82	A	signaturevsc.com
173.1.93.83	PTR	173.1.93.83.reverse.gogrid.com
173.1.93.83	A	protrainingcafe.net
173.1.93.83	A	touchpointsecureplan.com
173.1.93.99	PTR	173.1.93.99.reverse.gogrid.com
173.1.94.34	PTR	173.1.94.34.reverse.gogrid.com
173.1.94.35	PTR	173.1.94.35.reverse.gogrid.com
173.1.94.51	PTR	173.1.94.51.reverse.gogrid.com
173.1.94.180	A	*.healthperks.net
173.1.94.180	A	mail.healthperks.net
173.1.94.187	A	mail.mdor.co
173.1.94.187	A	supp.me
173.1.95.67	PTR	173.1.95.67.reverse.gogrid.com
173.1.95.80	PTR	173.1.95.80.reverse.gogrid.com
173.1.95.83	PTR	173.1.95.83.reverse.gogrid.com
173.1.95.96	PTR	173.1.95.96.reverse.gogrid.com
173.1.95.97	PTR	173.1.95.97.reverse.gogrid.com