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How to set up an SMTP relay in Office 365
Article ID: 2600912 - View products that this article applies to.
This article discusses Microsoft Office 365, Microsoft Office 365 Preview, and Microsoft Office 365 pre-upgrade. The information about Office 365 Preview in this article is provided as is and is subject to change without notice. This includes any links.
Not sure what release of Office 365 you're using? Go to the following Microsoft website:
Am I using Office 365 after the service upgrade?
This article describes how to set up a Simple Mail Transfer Protocol (SMTP) relay in Microsoft Office 365. It describes how to set up Microsoft Exchange Online as an SMTP relay to send email messages to remote domains and to users in your Office 365 organization.
You may want to do this in scenarios in which you no longer have an on-premises messaging environment, such as Microsoft Exchange Server, and in which you have on-premises line-of-business (LOB) programs that have to send email messages to remote domains and to your migrated cloud mailboxes.
Important If you want on-premises LOB programs to send mail only to your migrated cloud mailboxes and not to remote domains (that is, domains for which you aren't authoritative in Exchange Online), you don't have to follow the steps in this article. Instead, see the following Microsoft Knowledge Base article:
(http://support.microsoft.com/kb/2799338/ )How to enable on-premises applications and devices to send mail to Office 365 users
SMTP relay settings for Office 365To set up an SMTP relay in Office 365, you must have the following:
Set up an SMTP relay in Office 365
Step 1: Obtain the SMTP server settingTo obtain the SMTP server setting, follow these steps:
Step 2: Create a user who has an Exchange Online mailboxTo do this, use one of the following methods:
Step 3: Set up the Internet Information Services (IIS) SMTP relay serverTo set up Internet Information Services (IIS) so that your LOB programs can use the SMTP relay, follow these steps.
Configure SMTP Email (IIS 7)
How to support multiple email addressesIf your LOB applications send mail from email addresses that differ from the Office 365 mailbox that's used for authentication, you have to either use a mail-enabled security group or add proxy addresses to support multiple email addresses.
Note If you don't perform one of the following procedures, the LOB applications will not send mail and will return the following error message:
5.7.1 Client does not have permissions to send as this sender
Method 1: Use a mail-enabled security groupIf the LOB applications send mail from email addresses that have mailboxes in Office 365, you can support multiple email addresses for relay by creating a mail-enabled distribution group and then granting it SendAs access. To do this, follow these steps:
Method 2: Add proxy addressesIf the LOB application doesn't have mailboxes in Office 365 that are associated with the email addresses that will be used for relay, the email addresses can be added as a secondary addresses to an existing mailbox. To set up proxy addresses, use one of the following procedures:
Use Postfix to set up an SMTP relay in Office 365Postfix is a third-party mail server that can be used to set up an SMTP relay for Exchange Server and Exchange Online. Currently, only specific versions of Postfix are supported to set up a relay with Exchange Online. You have to use Postfix 2.9 or a later version to set up an SMTP relay with Exchange Online.
For more information, go to the following Postfix website:
http://www.postfix.org/BASIC_CONFIGURATION_README.htmlThe third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.
Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information.
Still need help? Go to the Office 365 Community
Article ID: 2600912 - Last Review: March 8, 2013 - Revision: 13.0