In most enterprise environments, the development and testing is done in a DMZ within the corporate firewall. This means in order for the Sauce Labs client, which runs in the cloud to access the application under test, it must have a way to circumvent the firewall to get into the network.

Sauce Labs has a secure tunneling feature called SauceConnect that allows its cloud platform to talk to a corporation's development environment. It is fairly complex to set up, but once it is configured, it can be started and stopped before and after the test run, so it doesn't leave any tunnel openings into the network on an unlimited time basis.