A catch-all functionality that is activated for a certain e-mailbox will allow you to receive emails that are sent to addresses that do not really exist. Otherwise stated, if you deactivate an email address and somebody still sends a message to it, or to any mistyped email address under the very same domain name, you will receive 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 are running some business, for example. Since you may start receiving junk messages, you can combine the catch-all option with email filters so as to get only real email messages in your inbox. Only one single mailbox per domain can be a catch-all one and email forwarding cannot be enabled for a catch-all mailbox.