How to Manage Custom Domain Mailboxes and Aliases in Microsoft 365
Question details
The user wants to understand how Microsoft 365 Business Standard handles custom domain mailboxes, alias configurations, and tenant user limits.
- Product
- Microsoft 365 Business Standard
- Device & OS
- not provided
- Scenario
- Setting up a business email environment, including individual user mailboxes and secondary email addresses (aliases) for a custom domain.
- Observed behavior
- The system allows management of up to 300 mailboxes via the admin center, supports multiple aliases per mailbox for receiving mail, and uses the primary SMTP address for outgoing messages.
Ensure you are logged in with Global Administrator or Exchange Administrator permissions in your Microsoft 365 tenant to configure mailboxes and domain aliases.
Create Mailboxes and Manage Aliases via the Admin Center
Use the Microsoft 365 admin center to set up individual user mailboxes and assign secondary email addresses (aliases) to them.
Microsoft 365 Business Standard supports up to 300 users in a single tenant. You can manage these individually managed Exchange Online mailboxes centrally.
Log in to the Microsoft 365 admin center using your administrator credentials and navigate to the main dashboard.
Go to Users > Active users in the left-hand navigation menu. Select an existing user to modify, or click 'Add a user' to create a new mailbox.
In the user's account properties pane, click on 'Manage email aliases'. Enter the desired secondary email addresses. All aliases will route incoming mail to this primary inbox.
Click 'Save changes' to apply the new aliases. Note that outgoing messages will still default to the mailbox's primary SMTP address.
Verify Exchange Online Protection Settings
Confirm that your tenant is utilizing the built-in Exchange Online Protection (EOP) for spam and malware filtering.
Switch to WPS Office for a Lightweight Business Alternative
While you manage your business email infrastructure through Exchange, you can optimize your software budget by deploying WPS Office for your team. It provides a complete, lightweight, and free office suite that is fully compatible with major document formats.
- 1. Download the Installer: Visit the official WPS Office website and download the free version suited for your operating system.
- 2. Install the Software: Run the setup file and follow the standard installation prompts to deploy the suite on your device.
- 3. Open Your Documents: Launch WPS Office to instantly view and edit your existing .docx, .xlsx, and .pptx files without formatting loss.
Frequently Asked Questions
How many mailboxes can I create in Microsoft 365 Business Standard?
Microsoft 365 Business Standard supports a maximum of 300 users in a single tenant. This allows you to create and manage up to 300 individual Exchange Online mailboxes.
Can I assign the same email alias to multiple users?
No, a specific email address or alias can only be assigned to one mailbox at a time. You cannot share a single alias across multiple individual mailboxes.
Which email address is used when sending an outgoing message?
Even if a mailbox has multiple aliases configured to receive incoming mail, outgoing messages will normally show the mailbox’s primary SMTP address as the sender.
Do I need a third-party spam filter with Microsoft 365 Business Standard?
Generally, no. Exchange Online Protection is included by default, offering a cloud-based service that helps protect your organization against spam and malware without requiring extra third-party tools.
