📋FTAPI Gateway: Configuring O365 Send and Receive Connectors

Adding an inbound O365 connector

To forward emails from the gateway to O365, add a new mail flow connector:

1. Log in to the Exchange Admin Center.
2. Under Mail flow -> Connectors -> Add a connector, create a new connector.
3. In the "From" field, select: Your organization's email server.
4. In the "To" field, select: Office 365. Click Next.
5. Enter a name (e.g., FTAPI S/MIME Inbound Connector) and an optional description.
6. Under "What should happen after the connector is saved?", select Turn it on and Retain internal Exchange email headers.
7. Click Next.
8. Under "How should Office 365 identify email from your email server?", select By verifying that the subject name on the certificate... and enter the domain name of the gateway's TLS certificate.
9. Click Create connector.

Adding an outbound O365 connector

To forward emails from O365 to the FTAPI gateway, add a new mail flow connector:

1. Log in to the Exchange Admin Center.
2. Under Mail flow -> Connectors -> Add a connector, create a new connector.
3. In the "From" field, select: Office 365.
4. In the "To" field, select: Your organization's email server. Click Next.
5. Enter a name (e.g., FTAPI S/MIME Outbound Connector) and an optional description.
6. Under "What should happen after the connector is saved?", select Turn it on and Retain internal Exchange email headers.
7. Click Next.
8. Select Only when I have a transport rule set up that redirects messages to this connector. Click Next.
9. Add a new smart host by clicking the + icon.
10. Enter the fully qualified domain name (FQDN) of the FTAPI gateway (e.g., ftapi-smime.example.com).
11. Click Save and then Next.
12. Ensure that Always use Transport Layer Security (TLS) to secure the connection and Issued by a trusted certificate authority (CA) are selected. For additional security, you can optionally enable domain name validation. Click Next.
13. In the next step, the connector is validated by sending an email from Office 365 through the connector. Enter a valid email address to receive a test email and click Validate.
14. After successful validation, click Save.

Configuring forced TLS

To ensure that the connection from the FTAPI gateway to O365 is secured using TLS, proceed as follows:

1. Open the MTA assignments page: MTA -> Maps.
2. Click tls-policy.
3. Add the following line: [<your-o365-domain>.mail.protection.outlook.com]:25 verify match=mail.protection.outlook.com
4. Click Save.

Creating and assigning transport rules

Inbound

Create a new rule via Add a rule:

• Name: e.g., S/MIME inbound
• Apply this rule if:
  • The sender is: external/internal -> Outside this Organisation
  • AND
  • The recipient is: external/internal -> Inside this Organisation
• Do the following:
  • Redirect the message to -> the following connector -> FTAPI S/MIME Inbound Connector
• Except if:
  • The message headers include any of these words:
    • Header name: Received
    • Words: <FQDN of the FTAPI S/MIME server>

Outbound

Create a new rule via Add a rule:

• Name: e.g., S/MIME outbound
• Apply this rule if:
  • The sender is: external/internal -> Inside this Organisation
  • AND
  • The recipient is: external/internal -> Outside this Organisation
• Do the following:
  • Redirect the message to -> the following connector -> FTAPI S/MIME Outbound Connector
• Except if:
  • The message headers include any of these words:
    • Header name: Received
    • Words: <FQDN of the FTAPI server>