📧 Exchange Online now supports sending emails from aliases — Generally Available!
Until now, aliases (proxy addresses) only received mail. Every outgoing message went out under the user’s primary SMTP address. With this release, users can:
- Send from any alias directly in Outlook (web, desktop, mobile)
- Reply automatically from the alias the original message was sent to
- Choose which aliases appear in their client
You can enable the feature tenant-wide using Exchange Online PowerShell:
Set-OrganizationConfig -SendFromAliasEnabled $True
Or go to Exchange Admin Center → Settings → Mail Flow → Sending from Aliases and turn it on.
If a domain should never be used for sending, set it to Receive-only with the SendingFromDomainDisabled parameter of Set-AcceptedDomain.
Before you roll it out, plan for these behavior changes:
- Mail flow rules, journaling, and hygiene rules that match on a specific address may not catch messages sent from an alias.
- Message Trace on a primary SMTP address will not return messages sent via an alias, so search with the alias itself.
- In hybrid setups, auto-replies may come from the user’s onmicrosoft.com routing address instead of the primary domain.
- Shared mailboxes are supported only in OWA, through “Open another mailbox.” Outlook desktop clients don’t support them.
- The feature works for Exchange Online mailboxes only. On-premises servers may rewrite aliases.
Microsoft is also considering per-alias display names, extra filtering and default controls, and calendar support. These are under investigation and not committed.
It’s a long-awaited capability, and the groundwork you do before enabling it will decide how smoothly it lands.
Official announcement and implementation details:
https://techcommunity.microsoft.com/blog/exchange/sending-from-email-aliases-–-general-availability/4562543
https://techcommunity.microsoft.com/blog/exchange/sending-from-email-aliases-–-general-availability/4562543