Email relay via Office 365 / Exchange Online

Office 365

This is a quick tutorial to setup Email Relay using Office 365 or Exchange Online services.


  • Office 365 / Exchange Online Account
  • Static IP address at your site (from where emails will be sent)


  • Login to your Office 365 account using an account with admin right
  • Navigate to Admin > Exchange > Mail Flow > Connectors
  • Create a new connector, i.e:
    • Connector Type: On-premises
    • Connection Security: Opportunistic TLS
    • Domain Restrictions: None
    • Sender domains: *
    • Sender IP addresses: <your static IP address>
  • Save changes

SMTP server address will be the same as MX record for your Office 365 domain. It can be found in:
Admin > Office 365 > select your domain > Manage DNS 
No authentication is required (this is why you need to provide your IP address).



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