WatchGuard Endpoint Security products require access to multiple Internet-hosted resources. To install and operate Endpoint Security products when you have a firewall, proxy server, or other network restrictions, such as SSL/TLS inspection, you must have access to the required domains and URLs. For a complete list of the access requirements for WatchGuard Cloud and Endpoint Security, go to WatchGuard Cloud URLs and Network Access Requirements.
Endpoint Security Network Requirements
WatchGuard Endpoint Security Release Notes (external link)