Changing the Email Routing for Microsoft 365

It is possible that the management of mailboxes for a domain of a company is split into multiple environments. If Microsoft 365 is one of these environments, emails from mailboxes in Microsoft 365 to mailboxes in the other environment will be rejected because Microsoft 365 cannot find those mailboxes in the domain.

To ensure that emails are also delivered to the other environment, a connector must be set up for forwarding to Hornetsecurity and the domain must be configured as an internal relay.

Figure 1: Rejected email from Microsoft 365

In addition, you can set up the traffic from Microsoft 365 mailboxes to be routed through the email service.