A catch-all functionality that is enabled for a certain e-mailbox will permit you to receive emails that are sent to addresses that do not actually exist. Otherwise put, if you disable an email address and someone still sends an email message to it, or to any misspelled address under the exact same domain name, you will receive the message in the catch-all mailbox. Using this feature means that you will no longer miss an email for any reason, which could be essential in case you run some business, for instance. Since you may start receiving unsolicited bulk email messages, you can use the catch-all option with anti-spam filtering software in order to get only legitimate messages 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.