The screenshots are generated server side by a farm of servers running the different combinations of browsers and operating systems to ensure the screenshots match up to what the user saw.
To give an overview of how the screenshots are generated:
- This HTML is sent to Saber’s server
- Saber then triggers an appropriate screenshot server to take a screenshot of that HTML being rendered on Saber’s server.
- The HTML is then deleted from Saber’s server
It is not possible to take the screenshot directly in the browser, due to browser security restrictions. There are a couple of common and easily fixable scenarios that can cause Saber Feedback’s screenshots to render incorrectly.
Range of IP addresses used by our servers
In some corporate environments, you might need to give our screenshot servers access to your site via a whitelist.
Our screenshot servers use the following range of IP addresses:
126.96.36.199/21 (this is equivalent to the range 188.8.131.52 – 184.108.40.206) and 220.127.116.11/21 (this is equivalent to the range 18.104.22.168 - 22.214.171.124)
HTTP Basic Authentication
Our remote screenshot servers are unable to set a cookie on a page with HTTP authentication. This is a limitation of the Selenium web driver used to control the screenshot servers, and currently there is no way around this.