Robtex

Up: 170.72.16.0/20
Can't show all results, try to descend to a more specific CIDR
Down left: 170.72.16.0/22
Down right: 170.72.20.0/22
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
170.72.16.2	A+PTR	170-72-16-2.ut.vivintwireless.net
170.72.16.35	A+PTR	170-72-16-35.ut.vivintwireless.net
170.72.18.137	A+PTR	170-72-18-137.ut.vivintwireless.net
170.72.18.137	A	duadua.org
170.72.18.137	A	speedruntimer.com
170.72.19.2	A+PTR	170-72-19-2.ut.vivintwireless.net
170.72.19.168	A+PTR	170-72-19-168.ut.vivintwireless.net
170.72.19.168	A	thor.battleforce.com
170.72.19.168	A	mail.battleforce.com
170.72.19.249	A+PTR	170-72-19-249.ut.vivintwireless.net
170.72.20.89	A+PTR	170-72-20-89.ut.vivintwireless.net
170.72.20.89	A	geoffreyblotter.me
170.72.20.98	A+PTR	170-72-20-98.ut.vivintwireless.net
170.72.20.98	A	geoffreyblotter.me
170.72.22.162	A	djdaverocks.com
170.72.22.162	A	cleanrequests.com
170.72.22.162	A	davidwariner.com
170.72.22.232	A	nateastle.no-ip.biz
170.72.23.2	A+PTR	170-72-23-2.ut.vivintwireless.net