Applies to: Exchange Server 2010 SP1

Topic Last Modified: 2012-07-23

Estimated time to complete: 5 minutes

After you've configured transport and other services on your Exchange 2010 hybrid server, you need to update your DNS configuration to deliver e-mail to it. After you redirect messages to be delivered to your hybrid server, the server becomes responsible for messages sent to your organization.

Learn more at: Understanding Transport Options

This topic is meant to be read as part of the Microsoft Exchange Server 2003 and Office 365 Hybrid Deployment checklist. Information or procedures in this topic may depend on prerequisites configured in topics earlier in the checklist. To view the checklist, see Checklist - Exchange 2003 and Office 365 Hybrid Deployment.

How do I do this?

Don't complete this step until you're ready to place the hybrid server in production.

Redirecting inbound messages to your hybrid server requires you take the following actions.

  1. Configure your firewall to accept inbound connections on TCP port 25, and direct them to the internal IP address of your hybrid server. For more information, see your firewall's documentation.

  2. If you change the external IP address that accepts inbound messages, update the MX record for your primary SMTP domain. The following table shows an example MX record that directs mail sent to to the hybrid server.

    Delivery domain DNS record type MX priority Hybrid server FQDN



Refer to your DNS host's Help for more information about how to add an MX record to your DNS zone.

How do I know this worked?

If you've completed these steps successfully, your hybrid server will start receiving messages sent to your primary SMTP domain. You can verify this by doing the following:

  1. Send a message to a recipient in your organization from a sender external to your organization.

  2. Open the message and inspect its SMTP headers.

  3. The delivery path of the message should show that the message was sent from an SMTP host on the Internet to the hybrid server and then handed off for appropriate routing within your organization.

Having problems? Ask for help in the Office 365 forums. To access the forums, you'll need to sign in using an account that's granted administrator access to your cloud-based service. Visit the forums at: Office 365 Forums