A catch-all functionality that is enabled for a given mailbox will allow 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 somebody still sends an email to it, or to any misspelled email address under the same domain, you’ll receive the message in the catch-all mailbox. Using this feature implies that you won’t miss an email for any reason whatsoever, which could be essential if you are running some company, for instance. Since you may begin receiving unsolicited messages, you can use the catch-all functionality with anti-spam filtering software so as to get only authentic emails in your inbox. Just one single mailbox per domain can be a catch-all one and email forwarding cannot be enabled for a catch-all mailbox.