Unblocking IP of test server

I want to test the speed of my website which is in a test environment and only accessible for certain IP’s. Is there anywhere where I can find the IP’s of the test locations so that I can whitelist them?
Any help would be appreciated.

The IP addresses for all of the test locations is available here: http://www.webpagetest.org/getTesters.php?f=html

The Dulles ones will come from

What is the meaning of PRIVATE IP addresses 192.168.. in that list?