A catch-all mailbox receives messages sent to inactive email addresses under the same domain. For example, an email message sent to the misspelled firstname.lastname@example.org will go to email@example.com if the catch-all feature has been activated for the latter. Thus, you can receive email messages from acquaintances or customers who may have sent a message to your email address with a spelling error or to an obsolete one, which they may still have, but you have already disabled. Just one mailbox per domain name can be a catch-all one and email forwarding cannot be activated for such a mailbox. The latter is due to the fact that at a certain point you may begin receiving spam emails in the catch-all mailbox and the forwarding limitation implies that the spam will not be redirected to a third-party mailbox.