Mail Flow

Office 365

Applies to: Office 365

Topic Last Modified: 2015-11-06

You can configure custom email-flow scenarios using Inbound and Outbound connectors. Inbound connectors apply to mail flowing from the Internet, a specific partner, or a device to on-premises or cloud recipients in your organization. Conversely, outbound connectors apply to mail messages flowing from your organization to a device, service, or partner that you specify. You can create and edit connectors in the Exchange admin center.

Looking for information about domain management or Directory Based Edge Blocking (DBEB)? See Recipient, Domain, and Company Management. To learn more about all EOP features, see the Exchange Online Protection Service Description.

You can configure an Outbound EOP connector to redirect outbound mail to an on-premises server (smart host) that applies additional processing before delivering mail to its final destination. For more information, see Scenario: Outbound Smart Hosting.

As an Exchange Online customer, you can set up secure mail flow with a trusted partner by using Office 365 connectors. Office 365 supports secure communication through Transport Layer Security (TLS). You can create a connector to enforce encryption via TLS. You can also apply other security restrictions such as specifying domain names or IP address ranges from which your partner organization sends mail. TLS is a cryptographic protocol that provides security for communications over the Internet. Using connectors, you can configure both forced inbound and outbound TLS using self-signed or certification authority (CA)-validated certificates.

For more information, see Set up connectors for secure mail flow with a partner organization.

You can add a trusted partner’s IP address to a safe list to ensure that messages they send to you are not subject to spam filtering. To do this, you can use the connection filter’s IP Allow list. For more information, see Configure the Connection Filter Policy.

You can configure an Outbound EOP connector with a Transport rule in order to route mail to a specific site, based on conditions. For more information, see Scenario: Conditional Mail Routing.

Hybrid means that you host a portion of your mailboxes on premises, and a portion in the cloud (Exchange Online). You can move from a standalone to a hybrid deployment.

If you have a hybrid deployment, you can protect your cloud and on-premises mailboxes with EOP. Standalone licenses are required for on-premises mailboxes, when they are protected by EOP. For more information about mail routing in a hybrid deployment, see Transport Routing in Exchange 2013 Hybrid Deployments.

The Microsoft Exchange Server Deployment Assistant also provides detailed hybrid deployment provisioning and hybrid message transport guidance.

To view feature availability across Office 365 plans, standalone options, and on-premise solutions, see Exchange Online Protection Service Description.

Comments or questions about this topic? Send your feedback to Office 365 Service Description Feedback. Need help with Office 365? Visit the Microsoft support center. Want to chat with a customer service representative? Go to the Select a plan page and click Chat now in the red banner at the top.