A bit later than planned, but I was attending a training last week, but a long-awaited feature in Exchange is sending mail from another email address that is stamped on a user, a so called alias. In a typical environment, a mailbox has a primary SMTP address and this address is used to send an receive email. This can be something like firstname.lastname@example.org. Besides this primary SMTP address there can be more SMTP addresses that can be used to receive mail, for example Mr.Exchange@exchangelabs.nl or MasterOfDisaster@exchangelabs.nl. In Exchange on-premises and Exchange Online, these Aliasses are only used to receive email, not to send email. Up until now that is (for Exchange Online, no idea if they want to enable this for Exchange on-premises).
Microsoft has started to roll out the Send From Alias in Exchange Online starting in January 2022 (it was already announced back in April 2021) and it is available in Outlook on the Web and Outlook for iOS and Outlook for Android. Outlook for the PC will follow, according to Microsoft in Q2, 2022.
To enable the Send from Alias in Exchange Online, execute the following command in Exchange Online PowerShell:
[PS] C:\> Set-OrganizationConfig -SendFromAliasEnabled $True
It takes some time before effective, in my case it worked the next day.
All SMTP proxy addresses on a mailbox are available for this. When you logon as a user and go to settings | Mail | Compose and Reply you can check which aliases you want to use. + Addresses are also shown and so are the mail.onmicrosoft.com addresses. Don’t know who thought this was useful, in my opinion you don’t want to use these (internal) addresses at all:
Now when you write a new email in Outlook on the Web and select the From option, you can select the email address that you checked in the previous step.
The proxy addresses that are selected in the first step (the OWA settings) will automatically available in Outlook for Android and Outlook for iOS.
When you send an email using one of these aliases as a from address, it will automatically be visible in the recipient mailbox, in this example in Gmail:
I don’t expect much use of this feature until Outlook for the desktop will offer it, but it’s a nice add-on (finally).