A catch-all feature that is enabled for a particular mailbox will allow you to receive emails that are sent to email addresses that do not actually exist. Otherwise put, if you remove an email address and someone still sends an email message to it, or to any miswritten address under the very same domain, you’ll receive the email in the catch-all mailbox. Using this functionality implies that you will no longer miss an email for any reason whatsoever, which could be essential if you run a business, for example. Since you may begin receiving unsolicited emails, you can combine the catch-all option with email filters so as to get only real email messages in your inbox. Just one single mailbox per domain can be a catch-all one and email forwarding cannot be set up for a catch-all mailbox.