A catch-all mailbox receives messages sent to inactive email addresses under the same domain name. For example, an email sent to the mistyped email@example.com will go to firstname.lastname@example.org in case the catch-all feature has been enabled for the latter. Thus, you can receive messages from pals or clients who may have sent a message to your email address with a typographical error or to an old one, which they may still have, but you have already deactivated. Just one single mailbox per domain can be a catch-all one and email forwarding cannot be enabled for such a mailbox. This is so because of the fact that at a certain point you may begin receiving spam email messages in the catch-all mailbox and the forwarding limitation implies that the spam will not be delivered to a third-party mailbox.