The following network ports must be open to ensure proper communication of components in the Veeam Backup for Google Cloud architecture.
Workstation web browser
Required to access the Web UI component from a user workstation.
Required to communicate with the REST API service running on the backup appliance.
Required to access the File-Level Restore browser running on a worker instance during the file-level recovery process.
Ubuntu Security Update Repository (security.ubuntu.com)
Required to get OS security updates.
Veeam Update Notification Server (repository.veeam.com)
Required to download the necessary 3rd party software upon the installation, and further to download information on available product updates.
Required to send email notifications.
Note: You cannot use the TCP port 25 that is most commonly used by SMTP servers — the port is always blocked by Google Compute Engine. For more information, see Google Cloud documentation.