SMTP Server and O365 – On Premises Solution - TechNet Articles - United States (English) - TechNet Wiki

Once you de-commission your own mail server and moved to cloud based server (Office 365), few of the server/service required SMTP relay server to achieve the task, which is your network printer to send scan documents, fax server to send fax etc. In order to do that, you need to deploy SMTP relay server in your on-premises. This can be a virtual server.

SMTP relay server installation details:

In service, SMTP service should be Automatic at the startup

Go to Access Select Authentication, and do the settings as mentioned in the picture above.

Then on the Security Tab, Provide the security as required.

In the Domains create one domain, right-click to get the properties.

That's it on the SMTP server side..!!!

Now for the internal devises to send email to O365, configure all the devices or software, with the SMTP IP address and the username which you configured.

The device will now send email to SMTP relay server and then it gets forwarded to the O365 email server, configured in the SMTP relay Outbound server name.

That's all…Enjoy!!!