How to block user from sending emails


How can you prevent that users send emails to external contacts, and only allow sending emails to internal users?


  • Gmail
  • Admin console


You must create a Routing Rule in the Admin console by following these steps:
  1. Go to the Admin console.
  2. Go to Apps > Google Workspace > Gmail > Routing > Routing.
  3. Click Add another rule and then Configure.
  4. In the rule add a description.
  5. Check Outbount.
  6. Switch from Modify Message to Reject message.
  7. Click Show options.
  8. Check Use address lists to bypass or control application of this setting.
  9. Select Bypass this setting for specific addresses / domains.
  10. Add a list.
  11. Then check Only affect specific envelope senders and add the email address that's not allowed to send emails
  12. Save.


These steps are to prevent that a user sends emails to external users and only allow internal