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Office 365 / Exchange Setup

This section includes information on how to configure your Office 365 or Exchange inbound environment for use with Mesh:

Create a connector for Mesh in Microsoft 365 / Exchange (inbound)

To ensure that only email filtered by Mesh is delivered to your Microsoft 365 / Exchange tenant, create a connector for Mesh in Microsoft 365 / Exchange.

We recommend reviewing Microsoft’s official documentation for managing mail flow with a third-party cloud service to ensure that the configuration is suitable for your environment.

Note

Complete this procedure only after pointing your MX records to Mesh. Wait 24 hours to allow for DNS propagation.

Note

If you are moving from another Secure Email Gateway, you may have an existing connector that rejects email not sent from a specific IP range.

Remove the existing connector before changing your MX records to prevent clean email filtered by Mesh from being rejected.

This guide covers the following scenario:

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  1. Open the Connectors page

    In the Exchange admin center, go to the Connectors page.

  2. Add a connector

    Select Add a connector.

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  3. Specify the mail flow

    Select Partner organization. Office 365 is selected automatically in the Connection to field.

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  4. Configure the connector name

    Enter a name for the connector and, optionally, a description. Select Turn it on.

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  5. Configure connector usage

    Enter the * wildcard to always use the connector when receiving inbound email.

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  6. Configure security restrictions

    Select Reject email messages if they aren't sent over TLS and Reject email messages if they aren't sent from within this IP range.

    Add the Mesh IP ranges for your region. This setting prevents email from bypassing filtering and being delivered directly to your Microsoft 365 environment.

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    Note

    The IP address shown in the example belongs to Microsoft. Enter the Mesh IP ranges for your region.

  7. Review and save the connector

    Review the details, and then select Save. The connector list is updated to reflect the change.

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    Tip

    You’re all set.

Create a mail flow rule for Mesh in Microsoft 365 / Exchange (inbound)

To allow email filtered by Mesh to be delivered safely without additional filtering from Microsoft, create a mail flow rule in Microsoft 365 / Exchange for the Mesh IP ranges.

We recommend reviewing Microsoft’s official documentation for managing mail flow with a third-party cloud service to ensure that the configuration is suitable for your environment.

This guide covers the following scenario:

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  1. Open the Mail flow section

    In the Exchange admin center, go to Mail flow > Rules.

  2. Add a rule

    Select Add a rule > Create a new rule.

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  3. Configure the rule conditions

    Enter a name for the rule, and then configure the following conditions:

    • The sender > is external/internal > Outside the organization.

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    AND   

    Note

    Use the IP range applicable to your region. Using an incorrect range may result in email loss.

  4. Configure the action

    Under Do the following, select Modify the message properties > Set the spam confidence level (SCL) > Bypass spam filtering.

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  5. Review the completed rule

    Verify that the completed rule conditions match the following example:

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  6. Review the rule settings

    Keep the default rule settings, and then select Next.

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  7. Enable the rule

    After saving the rule, verify that it appears in the rule list and is enabled.

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    Tip

    You’re all set.

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