New Exchange Online Feature Supports Sending Email from Proxy Addresses


A new Exchange Online feature allows users to send email using any of the SMTP proxy addresses assigned to their mailbox. An Outlook update will make the task easier, but for now it’s reasonably straightforward to insert a proxy address into the From field when composing a new message with OWA or Outlook and send a message.

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Q&A: How to Send Email Using Proxy Addresses with Exchange Online


Exchange Online supports the ability to send email using any SMTP proxy address assigned to a mailbox. Following the announcement of the feature, users had many questions including what clients can be used. Here are some common questions and answers about the feature, including some PowerShell to report the set of proxy addresses assigned to user mailboxes.

Hello, any idea if the ms graph will support it as well anyhow soon?

The fact we're still waiting for this basic feature years later (added to the roadmap over 2 years ago) really isn't good enough.


I've just migrated a company onto our system, they don't yet have their laptops and are using to get started and need to be able to send from their existing addresses which have been added as alias addresses.


That such basic yet critical functionality is missing really is just not on. Microsoft, please get on with it.


Roadmap Feature ID: 59437

@Tony Redmond 


I have tested this new functionality and it works when sending from a proxy address, but it seems like it doesn't work for a proxy address on a Shared Mailbox. 


I have a Shared Mailbox called SharedMailbox1, it has Primary SMTP address and proxy smtp address User1 has Delegate access and Send As permissions from SharedMailbox1.


User1 can Send As, but when trying to send email as I receive a message saying I don't have permissions.


Any idea or is this expected behavior? 




Did you find a solution? We have the same "problem".