A catch-all email mailbox receives email messages sent to non-existent email addresses under the very same domain. For example, an email sent to the mistyped firstname.lastname@example.org will go to email@example.com in case the catch-all feature has been enabled for the latter. In this way, you can receive email messages from pals or customers who may have sent a message to your email address with a typo or to an obsolete one, which they may still have, but you have already disabled. Just one mailbox per domain can be a catch-all one and email forwarding cannot be set up for such a mailbox. This is due to the fact that at some point you may start receiving spam messages in the catch-all mailbox and the forwarding limitation means that the spam will not be delivered to a 3rd-party mailbox.