A catch-all feature that is enabled for a specific mailbox will permit you to receive emails that are sent to email addresses that do not actually exist. In other words, if you disable an email address and someone still sends an email message to it, or to any mistyped email address under the same domain, you will get the email in the catch-all mailbox. Using this functionality implies that you won’t miss an email for any reason whatsoever, which could be essential in case you are running a business, for instance. Since you may start receiving spam emails, you can combine the catch-all functionality with anti-spam filters so as to get only real email messages in your inbox. Just one single mailbox per domain name can be a catch-all one and email forwarding cannot be set up for a catch-all mailbox.