Robtex

Up: 72.13.200.0/21
Can't show all results, try to descend to a more specific CIDR
Down left: 72.13.204.0/23
Down right: 72.13.206.0/23

IP	Type	Hostname
72.13.204.2	PTR	windows.plc.pcisys.net
72.13.204.11	A+PTR	calix-ghm.plc.pcisys.net
72.13.204.133	PTR	mathey-gw.133.204.13.72.plc.sta.pcisys.net
72.13.204.134	PTR	mathey-cust.133.204.13.72.plc.sta.pcisys.net
72.13.204.134	A	mail.qdserv.com
72.13.204.164	A	webmail.altnetworks.net
72.13.204.165	A	altnetworks.net
72.13.204.170	A	donutholesolutions.com
72.13.204.195	A	mail.altnetworks.net
72.13.204.213	A	mail.pmwm.org
72.13.204.214	PTR	214.192-26.204.13.72.in-addr.arpa
72.13.205.3	A	mail.goldhillmesa.com
72.13.205.18	A+PTR	a1369-18.205.13.72.sta.pcisys.net
72.13.205.20	A	mail.genesis-medspa.com
72.13.205.22	A+PTR	a1369-22.205.13.72.sta.pcisys.net
72.13.205.34	A+PTR	endeavor.fountaincolorado.org
72.13.205.34	A	fountaincolorado.org
72.13.205.34	A	ns1.fountaincolorado.org
72.13.205.36	A+PTR	wolf359.fountaincolorado.org
72.13.205.36	A	mail.fountaincolorado.org
72.13.205.37	A+PTR	gps-01.fountaincolorado.org
72.13.205.39	A+PTR	exchange.fountaincolorado.org
72.13.205.62	A+PTR	deltavega.fountaincolorado.org
72.13.206.40	PTR	fm01rtr01.dhcp.40.206.13.72.plc.dyn.pcisys.net
72.13.206.56	A	thebansbrewery.us
72.13.206.61	A	bdombrowski.us
72.13.206.61	A	brow.us
72.13.206.83	A	cruiseagainstcancer.org
72.13.206.83	A	evanrush.com
72.13.206.102	PTR	lc01rtr01.dhcp.102.206.13.72.dyn.pcisys.net
72.13.206.102	A	thebansbrewery.us
72.13.206.114	PTR	fm01rtr01.dhcp.114.206.13.72.plc.dyn.pcisys.net
72.13.206.114	A	midevia.com
72.13.206.118	PTR	fm01rtr01.dhcp.118.206.13.72.plc.dyn.pcisys.net
72.13.207.20	A+PTR	csn01rtr01.dhcp.20.207.13.72.plc.dyn.pcisys.net
72.13.207.20	A	ns2.dkbhosting.net
72.13.207.23	PTR	csn01rtr01.dhcp.23.207.13.72.plc.dyn.pcisys.net
72.13.207.25	PTR	csn01rtr01.dhcp.25.207.13.72.plc.dyn.pcisys.net
72.13.207.31	PTR	csn01rtr01.dhcp.31.207.13.72.plc.dyn.pcisys.net
72.13.207.62	PTR	static.dhcp.62.207.13.72.plc.sta.pcisys.net