To set up a domain alias:
Domain aliases can comprise letters, digits and hyphens. Each part of the domain alias between dots should not be longer than 63 symbols.
Example: You have an e-mail address mail@yourdomain.com. You have set up an alias for your domain name, for example, alias.com. If you want to receive mail to your mailbox mail@yourdomain.com when it is sent to mail@alias.com, select the Mail check box.