If you have the legacy free edition of G Suite, upgrade to Google Workspace to get this feature.
By default, Gmail lets users automatically forward incoming mail to another address. As an administrator, you can disable this option to prevent users from setting up automatic forwarding. When you disable the option, users don't see the forwarding option in their Gmail settings, and any existing forwarding rules or filters no longer forward messages.
After you configure an advanced Gmail setting, it may take up to 24 hours for that configuration to propagate to individual user accounts. You can track prior changes under Admin console audit log.
Disable automatic forwarding
In the Admin console, go to Menu AppsGoogle WorkspaceGmailEnd User Access.
Tip: To see End User Access, scroll to the bottom of the Gmail page.
- In the Organizations section, highlight your domain or the organizational unit for which you want to configure settings (see Configure email settings for an organizational unit for more details).
- In the Automatic Forwarding section, clear the check box Allow users to automatically forward email to another address.