Set up your firewall
Use the information on the Network Access page under to configure your firewall.
Because the email hybrid service is a managed service, Forcepoint is responsible for managing system capacity. For this reason, the route of your email may occasionally alter within the service. To enable this to happen seamlessly without requiring you to make further changes, you must allow SMTP access requests from all the IP ranges listed on the Network Access page to port 25.
Click Next to continue with hybrid configuration on the page Configure your MX records.