Is it possible to mark external emails as internal by sender IP address?

Steven Couture 61 Reputation points

For the purpose of email delivery to distribution groups, is it possible to mark emails from an external sender as an internal email by sender IP address? We'd like distribution groups to receive emails from specific senders without setting the group to accept email from all senders. It looks like the X-MS-Exchange-Organization-AuthAs header cannot be modified so is there another method we could use?

Microsoft Exchange Online Management
Microsoft Exchange Online Management
Microsoft Exchange Online: A Microsoft email and calendaring hosted service.Management: The act or process of organizing, handling, directing or controlling something.
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  1. Andy David - MVP 142.7K Reputation points MVP

    Use a transport rule to drop messages from all external senders except the allowed ones. Set the Group to accept mal from all senders in including external, use the transport rule to protect it


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