Mailflow with Microsoft 365 (formerly Office 365)

To recieve incoming and outgoing mail with the appliance, following things are required:

  • The MX Record for the Mail Domain(s) needs to point to the REDDOXX Appliance (or the company firewall that then routes mail to REDDOXX)
  • The Domain(s) have to be registered and configured in Exchange Online
  • Email Adresses and Domain (with Mailboxes and Licensing) have to be configured
  • The REDDOXX Appliance needs to have an external DNS configured
  • A valid ssl certificate in the appliance is configured and used for TLS

Set an external DNS in your Appliance Network Configuration
Add the Domain(s) in Appliance Admin Webinterface => Configuration => Local Domains

Configure Transport Rules in Appliance Admin Webinterface for each Domain to point to your corresponding Microsoft 365 mx record

The required DNS Name can be found in your Microsoft 365 domain view:

Add the Microsoft Adresses for to the Trusted Networks (Appliance Admin Webinterface -> Configuration -> E-Mail Transport -> Trusted Networks)

This will allow the appliance to relay mails for the configured networks.

  1. Login to your exchange admin center
  2. Create a new connector (mail flow => connectors) and adjust the settings accordingly (see following screenshots as example):

  3. Create a new transport rule (mail flow => rules)

    Click on "more options" so that all configuration options appear and use the following rules

    (the "use the following connector" - option can be selected with "redirect the message to => the following connector")