How to Receive Incoming E-mail from Exchange Online to SharePoint On-Prem

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Problem Summary

Your company decided to use Exchange Online for e-mail, but leave the SharePoint Servers on-prem. After doing this you may have noticed that Exchange Online will not be able to deliver e-mail to the Drop folder, were SharePoint processes email for delivery. At this point the incoming e-mail feature in SharePoint is totally non-functional.

There is no need to panic, there is simple solution!

Solution

Since Exchange Online is “Online”, it will need access to an On-Prem SMTP Server to deliver e-mail to a DROP folder. This is where SharePoint process email for delivery to list and libraries. Most of this is or was in place before moving to Exchange Online, but opening ports on the firewall may be required. I won’t get too deep on how to make the SMTP server accessible from the Internet.

Once you have an SMTP Server that is reachable from the internet, you can create an “Connector” from the Exchange Online Admin Center.

Here are the steps:

1. From Exchange Online Admin, Access the Connectors feature via https://admin.exchange.microsoft.com/#/connectors

2. Click “Add a connector”

3. On the “New connector” page, choose “Connection from” > “Office 365” and “Connection to” > “Your ogranization’s email server“

4. Give the new Connector a name. For Example: “SharePoint On-Prem E-Mail Connector”

5. On the “Use of connector” page, you will use the “Only when email messages are sent to these domains” option. This will be the domain name that is set as the incoming email domain on the SharePoint Server.

6. On the “Routing” page, choose the type in the “IP Address” of your on-prem SMTP server that will accept and route e-mail to the SharePoint Server.

Note: This will be the IP address of the SMTP server that is handle e-mail for the on-prem SharePoint Server.

7. On the “Security restrictions” page you can enable or disable TLS. Since this e-mail will flow over the Internet, it’s strongly recommended to use TLS.
8. On the “Validation email” page, you will enter a valid e-mail address on the destination. For example, a Document Library email address”
9. If everything is configured correctly, the validation should succeed.

10. Complete the connector wizard to create the new connector.

Important Takeaways

  • Exchange Online is using an “address space” match when using this connector.  So, when Outlook users send email to SharePoint folder, the email is delivered by the connector without the need of an MX record.  This will work perfectly for email sent from your organization by Exchange Online. If you want SharePoint to receive email from public users over the internet, MX records will be needed.
  • Your SharePoint server only needs a location to the DROP folder. So, you don’t even need an SMTP Serer installed on the SharePoint server directly.

Conclusion

You are now able to continue using Exchange Online and your on-prem SharePoint servers and receive e-mail to Document libraries and Lists. I hope you found this Blog useful!

Additional Information:

Set up connectors to route mail between Microsoft 365 or Office 365 and your own email servers

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