Prepending a Warning Message to Emails Originating from Outside of Organization

This article describes how to set up a mail flow rule that prepends a message that warns users that an email originated from outside your organization.

1. Navigate to the following URL https://outlook.office365.com/ecp.
2. Log in with global admin credentials.
3. On the left navigation click 'mail flow'.
4. On the top navigation select 'rules'.
5. Click the '+' icon and select 'Create a new rule' from the dropdown menu.
6. Near the bottom of the popup window click 'More options...'.
7. In the 'Name:' field type a name for the rule.
8. Under 'Apply this rule if' click the dropdown, click 'The sender...' and select 'is external/internal'.
9. In the popup window under 'select sender location' select 'Outside the organization' and click 'OK'.
10. Under 'Do the following' click the dropdown, click 'Apply a disclaimer to the message...' and select 'prepend a disclaimer'.
11. Click the 'Enter text' link.
12. In the popup copy and paste the HTML code from below into the text box and click 'OK'.
13. Click on the link that says 'Select one' and select 'Wrap' from the dropdown.
14. Under 'Properties of this rule:' keep the defaults selected.
15. Under 'Choose a mode for this rule:' select 'Enforce'.
16. Click 'Save'

HTML Code: