A catch-all functionality that is enabled for a specific e-mailbox will allow you to receive emails that are sent to addresses that do not actually exist. Otherwise said, if you disable an email address and somebody still sends a message to it, or to any miswritten address under the exact same domain name, you’ll get the email in the catch-all mailbox. Using this functionality means that you won’t miss an email for any reason whatsoever, which could be essential if you are running a company, for example. Since you may start receiving spam, you can use the catch-all functionality with anti-spam filtering software so as to receive only legitimate emails in your inbox. Just one mailbox per domain can be a catch-all one and email forwarding cannot be enabled for a catch-all mailbox.