It seems strange that Outlook and Exchange used to make it difficult to work with more than one email address in an account. It turns out that there are many good reasons to use multiple addresses or even hide a personal address. Perhaps you share a customer contact mailbox in a CRM system with several users, are working on the merger of two different companies, or simply want to prevent users’ contact information from leaking to the outside world when they are working on a confidential product.
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Aliases in Exchange
Whatever the reason, it is increasingly common to give employees more than one address. But until recently, Exchange made it difficult to send messages with alternate identities.
Much of this was due to the design of Exchange’s mail transfer agent, the code that relays email to the chain of mail servers that make up the Internet. It was originally built to work with just one email address per user, with everything tied to that identity. If you tried to send an email using an alias, an alternate email address, it would be overwritten with the primary email address before being sent via SMTP.
If you were using Exchange within a company, that approach is fine: support emails appear to come from a support alias because they don’t leave the server or cluster. There is a nebulous reason to allow aliases to be received but not used for transmission, as users can then redirect email by replying from their correct address.
However, email now has to do a lot more than just connect the parts of a business – it’s very much how we do business. And aliases are part of those processes, especially as email tools like Microsoft 365’s booking service are becoming more common.
Inbound aliases have long been built into both on-premises Exchange and Exchange Online. You can give an individual user up to 400 different aliases without affecting how much you are charged. Aliases are not shared mailboxes or distribution lists: they are individual addresses that can be used to route email to specific mailboxes.
While you can use distribution lists to receive, route, and send email, they don’t give you the same level of control as individual user aliases and shared mailboxes. There were complex low-level techniques that allowed Exchange users to send email as aliases, but they had to work with custom email applications that used specific SMTP commands, not the familiar Outlook.
Manage Aliases in Exchange Online
Aliases for active users
It’s easy enough to add aliases using the Microsoft 365 admin center. If you are using alternate domains, make sure they are configured before adding an alias to a user.
In the Admin Center, choose Active Users under Users in the navigation pane. After this page opens, select a user and click on their name to open the user panel. Here you can choose Manage Username and Email to add an alias. You can type any username and choose any currently configured domain. Once configured, click Save Changes to set the alias.
Alternate domains must be set up with all correct DNS settings for Microsoft 365 accounts. That requires you to add them to your Microsoft 365 account using the setup tools in the admin center.
After adding the domain, associate it with your account by verifying it with a TXT record in the domain’s DNS records before configuring MX records to send email to the Microsoft 365 Exchange Online service . If you plan to send email through this domain, you must first configure the SPF, DKIM, and DMARC anti-spam features at your DNS host.
Change company name
After a company name change, you can set an address such as firstname.lastname@example.org as an alias for email@example.com, with the email sent to the old companyname address arriving in its normal new company name account. It’s a good idea to use aliases to redirect email sent to common nicknames to a single mailbox, so firstname.lastname@example.org can be an alias for the more formal email@example.com.
Similarly, you could give team accounts aliases so that all possible variants of a team name, such as ‘accountspayable’, ‘accounts’, ‘accounts.payable’ and all other versions, end up in the same email account. It’s worth checking your email logs to see if there are any common errors for important addresses that you can intercept and redirect with an alias.
Send email as an alias from Outlook
A recent update from Exchange Online finally added preview support for sending messages with aliases. Initially, you must use PowerShell to set the SendFromAliasEnabled parameter of the Set-OrganizationConfig cmdlet. When you set this up, you can enable full alias support for all mailboxes; there is currently no way to set this up for individual users or groups.
Once it’s enabled, you’re using a new version of Exchange’s SMTP service. As Microsoft points out, it is in preview for now as there are known issues that can cause problems in some cases. On-premises Exchange won’t get the new feature, which means that local users won’t be able to send aliases yet.
Not all Exchange email clients support the new feature. It is currently supported in Outlook mobile clients on iOS and Android, and Outlook on the web. Support for desktop Outlook is expected sometime in the second quarter of 2022, but is yet to come.
On the web, you should show the From field when composing messages, with a drop-down list of the available aliases. On mobile devices, you must manually enter an alias, but it will be saved for future use. When it’s released for desktop Outlook, you’ll be able to maintain a list of commonly used aliases, which should simplify choosing and choosing an alias.
Once you’ve set up support, users should find working with aliases easy enough. Where necessary, they can hide personal addresses or use nicknames or alternate email domains to ensure that email gets to them no matter how it is addressed.
Microsoft’s plan to merge the online Outlook with the desktop version should accelerate the delivery of such features. One Outlook codebase for all versions avoids situations where different Outlooks have different implementations of the same feature or don’t have everything.