How to add a subdomain to the exchange server 2013?

I have Exchange Server 2013 which handles our corporate email. The default emails looks like this username@example.com.

I need to add a sub domain to the servers so one email can look something like this newUsername@subdomain.example.com

Finally I need to setup the new email newUsername@subdomain.example.com as a catch all email for the sub domain.

I found a good tutorial that explain how to add a catch all rule to an email.

How can I add the sub domain subdomain.example.com to my Exchange 2013 server without causing problems to my main domain?

Answer

Open EAC (Exchange Admin Center).

Select Mail Flow on the Left Panel Menu.

Select Accepted Domains from the Top Menu.

Click the + icon.

Enter a name in Name, enter the fqdn of the subdomain in Accepted Domain. ("subdomain.example.com").

Select Authoritative domain.

Select Save

Don't forget to add/update an MX record for the subdomain.

To confirm the setting use the powershell cmdlet Get-AcceptedDomain