A catch-all functionality that is activated for a certain email mailbox will permit you to receive email messages that are sent to addresses that do not actually exist. Otherwise stated, if you deactivate an email address and somebody still sends a message to it, or to any mistyped address under the very same domain, you’ll receive the email in the catch-all mailbox. Using this feature implies that you will no longer miss an email for any reason whatsoever, which could be crucial if you run some company, for instance. Since you may begin receiving spam, you can combine the catch-all functionality with email filters in order to get only real emails in your inbox. Only one mailbox per domain can be a catch-all one and email forwarding cannot be activated for a catch-all mailbox.