> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mailchannels.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Set up Microsoft Exchange

> Configure a Send Connector in Exchange 2016 or 2019 to route outbound email through smtp.mailchannels.net using Basic Authentication over TLS.

Microsoft Exchange routes outbound email through Send Connectors. To relay through MailChannels, you create a new Send Connector that points to `smtp.mailchannels.net` as a smart host, authenticates using your MailChannels SMTP credentials over TLS, and applies to all external recipient domains. This guide covers Exchange 2016 and 2019, which share a nearly identical configuration workflow through the Exchange Admin Center (EAC).

<Note>
  These instructions apply to Exchange 2016 and Exchange 2019. If you are running Exchange 2010, the configuration is done through the Exchange Management Console rather than the EAC. See the [Exchange 2010 note](#exchange-2010) at the bottom of this page.
</Note>

## Prerequisites

* Administrator access to the Exchange Admin Center
* Your MailChannels SMTP username and password
* A working Exchange server configured for client access and able to route messages to the internet

***

## Configure the Send Connector

<Steps>
  <Step title="Open the Send Connectors list">
    Log in to the Exchange Admin Center (EAC).

    * **Exchange 2016:** Access the EAC at `https://localhost/ecp` from the Exchange server, or `https://<ServerFQDN>/ecp` from another machine.
    * **Exchange 2019:** Access the EAC from the Exchange Admin Center in your browser.

    Navigate to **Mail flow > Send connectors**, then click the **Add** (+) icon to open the New Send Connector wizard.
  </Step>

  <Step title="Name the connector and set the type">
    Enter a descriptive name for the connector — for example, **MailChannels-Relay** or **MC**.

    For **Type**, select **Internet**. This grants the connector the default permissions required to route messages through an external host outside your domain forest.

    Click **Next**.
  </Step>

  <Step title="Configure smart host routing">
    Select **Route mail through smart hosts**, then click **Add** (+).

    In the **Add smart host** dialog, select **Fully qualified domain name (FQDN)** and enter:

    ```
    smtp.mailchannels.net
    ```

    Click **Save**, then click **Next**.
  </Step>

  <Step title="Set authentication and TLS">
    On the smart host authentication page, select **Basic authentication** and check the box labeled **Offer basic authentication only after starting TLS**.

    Enter your MailChannels SMTP credentials in the **Username** and **Password** fields.

    Click **Next**.

    <Warning>
      You must select "Offer basic authentication only after starting TLS" to ensure credentials are never transmitted in plain text. MailChannels requires TLS for all authenticated connections.
    </Warning>
  </Step>

  <Step title="Set the address space">
    In the **Address space** section, click **Add** (+). In the **Add domain** dialog, enter the following:

    | Field                                  | Value |
    | -------------------------------------- | ----- |
    | **Type**                               | SMTP  |
    | **Fully Qualified Domain Name (FQDN)** | `*`   |
    | **Cost**                               | 1     |

    Using `*` as the FQDN means this connector applies to all external recipient domains. A cost of `1` makes this the preferred route.

    Click **Save**, then click **Next**.
  </Step>

  <Step title="Add the source server">
    In the **Source server** section, click **Add** (+). In the **Select a Server** dialog, select the Mailbox server that will route mail through MailChannels.

    Click **Add**, click **OK**, then click **Finish**.
  </Step>

  <Step title="Send a test message">
    Send a test email from an account on your Exchange server to an external address (for example, a Gmail or Outlook.com account) to confirm that the connector is working. Log in to your MailChannels Host Console and check **Activity > LogSearch** to verify that the message was received and processed.
  </Step>
</Steps>

***

## Alternate SMTP ports

MailChannels accepts connections on multiple ports. If outbound TCP port 25 is blocked by your network or ISP, configure your Send Connector smart host to use one of the following alternatives:

| Port | Use case                                 |
| ---- | ---------------------------------------- |
| 25   | Default SMTP                             |
| 587  | SMTP submission (commonly allowed)       |
| 465  | SMTPS (implicit TLS)                     |
| 2525 | Alternate if 25 and 587 are both blocked |

To change the port, edit the Send Connector's smart host entry and append the port number — for example, `smtp.mailchannels.net:587`.

***

## Exchange 2010

Exchange 2010 uses the **Exchange Management Console** rather than the web-based EAC. The setup follows the same general approach — create a new Send Connector with type **Internet**, set the smart host to `smtp.mailchannels.net`, and enable **Basic Authentication over TLS** with your MailChannels credentials — but the steps are navigated through the console UI under **Organization Configuration > Hub Transport > New Send Connector**.

<Note>
  Exchange 2010 reached end of life in October 2020 and is no longer supported by Microsoft. Adding `X-AuthUser` headers in Exchange 2010 requires building a custom transport agent using an SDK that Microsoft has since retired. If you are running Exchange 2010 and need help configuring it to work with MailChannels Outbound Filtering, [contact MailChannels support](https://support.mailchannels.com/hc/en-us/requests/new) and include the Exchange version in your request.
</Note>