📨Mail Aliases: What & Why

Mail aliases are alternate email addresses that deliver to the same mailbox.

They let you:

• Filter & organize incoming mail
• Track where sign-ups/newsletters come from
• Protect your real address
• Quickly disable an address by removing the alias

Alias methods vary by provider—below are some common tricks and platform specifics.

Gmail Tricks

1. “Plus” Subaddressing ➕

Gmail ignores anything between your username and the @.

• Format: yourname+tag@gmail.com
• Example:

  realname@gmail.com
  realname+shopping@gmail.com → goes to realname@gmail.com
  realname+work@gmail.com → goes to realname@gmail.com

• Use Cases:

• Newsletter sign-ups: you+newsletter@gmail.com
• Automated filtering: label all you+shopping@… as “Shopping”

2. “Dot” Ignoring • • •

Gmail also ignores periods in the username part.

• Any of these are equivalent:

  your.name@gmail.com
  y.ourn.ame@gmail.com
  yourname@gmail.com

• Trick: Use different dot-patterns to test where spam or leaks originate.

Other Consumer-Level Aliasing

• Fastmail & ProtonMail: support full subaddressing (+tag) and custom domains.
• Catch-all Addresses: set up *@yourdomain.com to route everything to one mailbox (great for testing but beware of spam).

Enterprise Use Cases

Microsoft Exchange & Office 365

• Proxy Addresses (Aliases):

• You can assign up to 400 SMTP proxy addresses per mailbox (including the primary address).
• Supports multiple domains (e.g., user@primary.com, user@aliasdomain.com).
• How to Add an Alias (Exchange Admin Center):

1. Open Exchange admin center → Recipients → Mailboxes.
2. Select the user and click Email address.
3. Click + Add email address, choose SMTP, and enter the new alias.
4. Save changes.

• Office 365 (Microsoft 365) Portal:

1. Go to Users → Active users.
2. Select user → Manage username and email.
3. Under Aliases, click Add alias, enter it, then Save.

• Distribution Groups & Shared Mailboxes:

• Use when you need multiple people to receive mail to a single address (e.g., support@, sales@).
• Shared mailbox quotas and permissions managed separately from user mailboxes.

Other Enterprise Platforms

Best Practices & Tips ✅

1. Use consistent tags

• e.g., user+clientA@…, user+clientB@…

2. Automate filtering

• In Gmail/Workspace, create filters based on +tag → auto-label/archive.

3. Monitor alias usage

• If an alias starts receiving spam, you can disable it or add it to a blocklist.

4. Document aliases in your KB

• Keep a table of active aliases and their purpose, especially in larger orgs.

¹ Plus-addressing in Workspace can’t be disabled and works across all Google services.

Updated on: 17/12/2025