We have a cloud-based infrastructure with thousands of IP addresses, which keep changing every day. However, our Local Testing feature makes whitelisting unnecessary. You do not need to open ports or whitelist IPs. It works out of the box even from behind firewalls and proxies. When you set up Local Testing, all hits to the restricted server come from your machine which is accessing BrowserStack. You only need to ensure that your machine has access to your restricted server.
Read more about Local Testing