The SpeedCurve testing agents run in Amazon EC2 datacenters and are standard WebPagetest instances.
URL's are loaded in real web browsers and detailed page performance metrics recorded. Each URL is loaded a minimum of 3 times in each web browser and the median result for each browser is collected and displayed on your dashboard.
User agent and IP range
SpeedCurve testing agents use the standard WebPagetest user agent and you can filter testing agents out of your analytics by search for the string "PTST" in the user agent string.
As the test agents run in Amazon datacenters they don't have static IP addresses that can be filtered on. You would have to filter out all traffic from Amazon AWS.