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How can I prevent Outlook emails from being sent to external domains?

Sam Perrow 5 Reputation points
2023-04-19T18:13:28.0466667+00:00

I am trying to prevent users within my domain from being able to send emails with attachments or other potentially sensitive information to any external email domains. For example, I don't want anyone in my company (with an @example.com email address) to be able to send emails with a PDF attachment to an email address outside the organization. TIA!

Outlook
Outlook
A family of Microsoft email and calendar products.
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Outlook Management
Outlook Management
Outlook: A family of Microsoft email and calendar products.Management: The act or process of organizing, handling, directing or controlling something.
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  1. ChristyZhang-MSFT 26,111 Reputation points Microsoft External Staff
    2023-04-20T02:28:37.4766667+00:00

    Hi @Sam Perrow ,

    Welcome to our forum!

    Are you using Exchange online or Exchange on-premises?

    If so, it's suggested that you could try to use the EAC to create a mail flow rule:

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    Hope the above help!

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