A catch-all functionality that is activated for a given mailbox will permit you to receive email messages that are sent to addresses that do not actually exist. Otherwise said, if you remove an email address and someone still sends an email 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 functionality implies that you will no longer miss an email for any reason, which could be crucial in case you run a business, for example. Since you may start receiving junk emails, you can combine the catch-all functionality with anti-spam filtering software so as to get only authentic email messages in your inbox. Just one mailbox per domain can be a catch-all one and email forwarding cannot be set up for a catch-all mailbox.