172.99.64.0/18

ip:	172.99.64.0 
loc:	United States, Windcrest (Texas)  
isp:	AS27357 Rackspace Hosting » Rackspace Hosting » Cloud Servers Cell 0001-0003 IAD3 131.331 ms
route:	172.99.64.0/18, RACKS-8 - Rackspace Hosting, US (Washington D.C.) ... 
reg:	172.99.64.0/18, US, ARIN, 2015-06-18
addr:	  1 Fanatical Place Windcrest TX 78218 US
online:	  1.595 » latency: 123 ms (119ms) 

see also:
   172.99.64.0/19   AS27357  RACKS-8-NET-18 Rackspace Hosting, US
   172.99.96.0/19   AS33070  RACKS-8-NET-18 Rackspace Hosting, US