Configure custom mail flow by using connectors
Applies to: Exchange Online Protection, Exchange Online
Topic Last Modified: 2014-06-02
Exchange Online Protection (EOP) and Exchange Online are email services provided by Office 365. Within each of these services, you can configure connectors, which are a collection of instructions that help you customize the way your email flows. Throughout the connectors documentation, the terms “the service” can refer to either EOP, Exchange Online, or Office 365.
If your organization meets any of the following criteria, you definitely need to create Exchange connectors as a part of your email solution. If you don’t meet the following criteria, creating connectors is optional.
A connector is required if you use:
EOP only - You have your own email servers and you subscribe to Exchange Online Protection (EOP) only for its protection services. If you need help getting started with EOP and not just connectors, see Set up your EOP service.
Hybrid - You have a hybrid Exchange environment with some mailboxes in your own email servers and some in Exchange Online. If you need help setting up a hybrid environment, see Hybrid Configuration wizard. We recommend using the hybrid configuration wizard to set up these connectors instead of the procedures linked here that use the Exchange Admin Center (EAC).
TLS - You want transport layer security (TLS) always required on your email.
Ready to get started with connectors immediately? Go to Decide which connector to use.
To help you get started with connectors, you can review the explanations provided here about the different types of connectors that are available. Once you understand these basic concepts, it will be easier to decide which connectors you need and then follow our steps to create them.
You configure an inbound connector to allow the service (either EOP or Exchange Online) to accept email. You configure an outbound connector to allow the service to deliver email. The terms inbound and outbound refer to email direction from the point of view of the service. Customers who have used Forefront Online Protection for Exchange (FOPE) should notice that this terminology is different than that used in FOPE.
Inbound is for email being accepted by the service.
Outbound is for email being delivered by the service.
Regardless of the direction, there are two types of connectors that you can configure: On-premises and Partner, which refer to the location of the email sender or recipient.
Type: On-premises refers to your organization’s own email servers, which are typically located in your own data center.
Type: Partner refers to a company with which your organization is doing business, such as a bank. This can also include web-based security services or web-based email marketing services.
Here is a general description of the four resulting connector options:
An On-premises inbound connector applies to emails that are sent fromyour organization’s own email server such as Exchange 2013, and then come into the service. This is shown in the diagram below. EOP standalone customers and customers with a hybrid configuration need this connector in order for email to flow.
An On-premises outbound connector applies to emails that are sent by the service to your organization’s own email server. This is shown in the diagram below. EOP standalone customers and customers with a hybrid configuration need this connector in order for email to flow.
A Partner inbound connector applies to emails that are sent from your business partner to the service.
A Partner outbound connector applies to emails that are sent by the service to your business partner, such as a bank, or another email service provider.
The following diagram shows the relationship between email direction and connectors.