A catch-all feature that is enabled for a given mailbox will allow you to receive emails that are sent to addresses that do not actually exist. Otherwise said, if you delete an email address and someone still sends an email to it, or to any miswritten address under the exact same domain, you will get the message 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 unsolicited messages, you can combine the catch-all option with anti-spam filters so as to receive only authentic messages in your inbox. Just one mailbox per domain name can be a catch-all one and email forwarding cannot be activated for a catch-all mailbox.