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Hi there
In our organization, we need to mark email notifications from external SharePoint Online tenants as "External", and white list the ones sent from our own tenant.
How to detect if the email notification from no-reply@microsoft.com is from our SharePoint Online tenant or an external tenant?
Thank you.
You can create a transport rule in Exchange to flag them if they came from an external address outside of your tenant.
Hi Nick, what exactly will the Exchange transport-rule catch to flag? The from address is always "no-reply@microsoft.com".
Thanks.
To create a transport rule in Exchange Online that differentiates between internal and external emails from a specific "no-reply@microsoft.com" address, you can follow these steps:
In the Exchange admin center, go to the "Mail flow" section from the left-hand menu.
Click on "Rules" tab to view the existing transport rules.
Click on the "+" icon to create a new rule.
Provide a suitable name for the rule in the "Name" field.
Under "Apply this rule if..." section, select "The sender" > "Address matches any of these text patterns".
Enter the pattern "no-reply@microsoft.com" in the textbox.
Scroll down to the "Do the following..." section.
Click on "Add action" and select "Set the message header..." from the dropdown menu.
In the "Set the message header..." dialog, enter a suitable name for the header in the "Header name" field, such as "X-Internal-Sender".
In the "Value" field, enter a value to indicate that the email is internal, for example, "Yes".
Click "OK" to close the dialog.
Click on "Add action" again and select "Apply a disclaimer to the message..." from the dropdown menu.
In the "Apply a disclaimer to the message..." dialog, enter the desired disclaimer text, such as "External Email".
Customize the disclaimer settings as per your requirements.
Click "OK" to close the dialog.
Make sure the rule is enabled by checking the "Enable rule" checkbox.
Click "Save" to create the rule.
With these steps, you have created a transport rule in Exchange Online that will differentiate between internal and external emails from the "no-reply@microsoft.com" address. The rule adds a custom header ("X-Internal-Sender") with a value of "Yes" to internal emails, and applies a disclaimer to external emails indicating they are external. Both types of emails will be delivered to the recipients.
Also forgot to include you should mark the messages from other tenants first:
First get your Tenant ID
Mark different tenant header messages
Once the rule is in effect, any incoming email messages that have a different "X-MS-Exchange-CrossTenant-Id" than your own tenant will be marked with the custom header "X-Marked-From-Different-Tenant" and the value "Yes". This marking can be used to identify and differentiate these messages in further processing or filtering.
Please note that it may take some time for the rule to propagate and take effect, so be patient if you don't see the marking immediately. Also, make sure you have the necessary permissions to create mail flow rules in your Exchange Online environment.