A catch-all functionality that is activated for a specific mailbox will allow you to receive emails that are sent to addresses that do not really exist. Otherwise said, if you disable an email address and someone still sends an email to it, or to any misspelled address under the same domain name, you’ll get the message in the catch-all mailbox. Using this functionality implies that you will no longer miss an email for any reason whatsoever, which could be crucial in case you are running some company, for instance. Since you may begin receiving unsolicited bulk emails, you can use the catch-all option with anti-spam filtering software in order to receive only real email messages in your inbox. Only one single mailbox per domain can be a catch-all one and email forwarding cannot be activated for a catch-all mailbox.