A catch-all functionality that is enabled for a particular mailbox will allow you to receive emails that are sent to email addresses that do not actually exist. To state it differently, if you delete an email address and someone still sends an email message to it, or to any misspelled email address under the same domain name, you’ll receive the message in the catch-all mailbox. Using this functionality means that you will no longer miss an email for any reason whatsoever, which could be crucial if you are running a company, for instance. Since you may start receiving junk email messages, you can combine the catch-all feature with email filters so as to get only legitimate emails 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.