Historically, Exchange has used a user’s primary SMTP address as the From address when sending messages. Other SMTP addresses assigned to a user (e.g., proxy addresses, also known as aliases) were mainly intended for receiving messages. Even when an email client tries to use an alias for the From address, that value is overwritten with the user’s primary SMTP address when the message is sent.
Today, business operations are much more challenging and complex, and activities such as mergers and acquisitions, rebranding, and other such changes have created the need for multiple identities and SMTP domains to be managed by an organization. To address these challenges, we started a journey toward making aliases first-class addresses in Exchange Online. We are excited to announce that we’ve reached the first milestone of this journey.
In the past, those wanting to send from aliases had a few options. They could use the SMTP AUTH client submission protocol, which didn’t rewrite the From addresses. Shared mailboxes could be used, but that meant another identity and another Inbox, as well.
To eliminate the need for these suboptimal solutions, we have introduced new capabilities in Exchange Online that enable Outlook clients to use and preserve aliases and to display the original alias used to send the message. This is accomplished by no longer replacing aliases during the sending or delivery of messages in Exchange Online.
The new capabilities are now available in Public Preview for Outlook on the Web and Outlook for iOS and Android. You can access the Preview using the SendFromAliasEnabled parameter of the Set-OrganizationConfig cmdlet. The setting enables the new functionality for all Exchange Online mailboxes in the organization. Note: it might take up to 60 minutes for this change to take effect in your tenant.
This feature is in Preview because we have made fundamental changes throughout the email pipeline. There are known compatibility issues with some features that assume the user’s primary SMTP address will always be used. These known issues are listed below. We will work to the update the known issues list in this post periodically.
This is the first iteration of our support for aliases. We do have plans for additional functionality, but we want to hear from customers about what they want.
Support for sending from aliases has been added to Outlook on the web and Outlook for iOS and Android. Mobile clients allow users to enter aliases in the From field and those will be saved for future use. Support for Outlook for Windows is currently planned for Monthly Channel customers by Q2 of this calendar year. Desktop clients will display a list of enabled aliases in the From field, and messages sent from an alias will have that address preserved.
Aliases will also be preserved when messages are addressed to them. If a user replies to a message that was sent to their alias, their reply will come from the alias by default.
Outlook on the web
The From drop-down now contains a list of available aliases:
This list of aliases can be customized by the user in Settings from the full list of aliases (proxy addresses) that are associated with their mailbox.
Outlook for iOS and Android
Aliases can be entered into the From field. Previously used aliases will be saved and available via a dropdown list:
Outlook for Windows
Support for aliases is on the way for Outlook for Windows. The From field will also support a customized list of aliases.
It’s possible to customize the list by clicking on Manage List…, which is the same as changing them on the Settings page in Outlook on the web.
Outlook for Mac support for this feature is planned (we will provide more information as it becomes available).
This being a preview, we are aware of several known issues:
To provide feedback on the Preview (such as requests for additional features or functionality) we have set up an email to send those to: aliases-feedback[AT]Microsoft[DOT]com. We will monitor these to determine what functionality to invest resources into. Please note that we will not be individually replying to this feedback.
Outlook client feedback / features can also be filed (and voted on) on our new Feedback Portal. Please use the in-app support for Outlook Mobile issues, and regular support tickets can be opened for other versions of Outlook clients.
Let us know below what you think!
Exchange Online team
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