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We recommend testing all mail flow rules prior to setting them to Enforce.
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When you create the mail flow rule, you have the option to start using it immediately ( Enforce), or to test it first and logging the results. This ensures that the disclaimer is only added to the original message. To avoid multiple disclaimers being added in an email conversation, add an exception that looks for unique text in your disclaimer. By default, mail flow rules are applied to incoming and outgoing messages. If you want the information to be added only to outgoing messages, you need to add a corresponding condition (for example, recipients located outside the organization). For more information, see Create and add an email signature in Outlook on the web. Users can apply signatures to their own outgoing messages in Outlook or Outlook on the web (formerly known as Outlook Web App). To do this, you create a mail flow rule (also known as a transport rule) that adds the required information to messages. In Exchange Online organizations or standalone Exchange Online Protection (EOP) organizations without Exchange Online mailboxes, you can add an HTML or plain text legal disclaimer, disclosure statement, signature, or other information to the top or bottom of email messages that enter or leave your organization.
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