A catch-all functionality that is activated for a certain mailbox will permit you to receive emails that are sent to addresses that do not really exist. To state it differently, if you delete an email address and someone still sends a message to it, or to any misspelled address under the same domain, you will get the email in the catch-all mailbox. Using this feature means that you will no longer miss an email for any reason whatsoever, which could be vital in case you run some company, for instance. Since you may start receiving unsolicited bulk messages, you can combine the catch-all option with anti-spam filters in order to get only authentic messages in your inbox. Only one single mailbox per domain name can be a catch-all one and email forwarding cannot be enabled for a catch-all mailbox.