This is one of those Microsoft 365 features that makes you wonder why it took this long.
Microsoft has finally moved Send From Alias in Exchange Online to general availability. The feature lets you send an email using any SMTP alias assigned to your mailbox, and the recipient actually sees that alias as the sender.
Seems pretty obvious, right?
For years, Exchange aliases were basically a one-way street. You could have sales@company.com, info@company.com, and yourname@company.com all assigned to the same mailbox and receive mail at every one of them.
But sending from one of those aliases was another story.
Exchange really wanted everything going out the door to come from your primary SMTP address. If you needed to consistently send from another address, you usually ended up creating a shared mailbox, assigning permissions, or finding some other workaround for something that should have been simple.
Microsoft actually started previewing Send From Alias back in 2022, so this isn’t exactly new. What’s new is that Microsoft finally considers the feature ready for general availability after about 4 years of preview.
Once the feature is enabled for an Exchange Online organization, users can select one of the aliases already assigned to their mailbox and send from it. Exchange preserves that address instead of rewriting it to the primary address, and replies still come back to the same mailbox.
There are a bunch of situations where this is useful.
A small business owner might use sales@company.com along with their regular address. Someone may need to continue sending from an old domain after a company name change. A consultant might operate under several business names. An employee whose name changes may still need to occasionally use their previous address.
Until now, some of those situations ended up with another mailbox being created simply because Exchange wouldn’t let the existing mailbox send from an address it already owned.
That’s the part that always seemed ridiculous.
This doesn’t mean shared mailboxes suddenly aren’t necessary. If several people are working from support@company.com, need access to the same incoming messages, need a common Sent Items history, or require separate permissions and auditing, a shared mailbox is still the right tool.
But if one person simply needs to send from 2 or 3 addresses that all belong to them, creating another mailbox just to make that happen never made much sense.
There is one thing I’d check before turning this on.
Send From Alias is an organization-wide Exchange Online setting. Once enabled, users can send from aliases assigned to their mailboxes. Over the years, Microsoft 365 tenants tend to accumulate a lot of old proxy addresses. Previous domains, old naming conventions, migration leftovers, and addresses nobody even remembers assigning can still be sitting there.
When those addresses could only receive mail, that wasn’t necessarily a big deal.
When users can send from them, I’d want to know exactly what’s there.
So this isn’t some earth-shattering Microsoft 365 change. It’s just Exchange finally doing something it probably should have been able to do all along.
It only took about 4 years in preview to get there.
Better late than never I guess.
