A catch-all mailbox receives email messages sent to inactive email addresses under the very same domain name. For example, an email sent to the misspelled email@example.com will be delivered to firstname.lastname@example.org in case the catch-all feature has been activated for the latter. Thus, you can get email messages from buddies or customers who may have sent a message to your email address with a spelling mistake or to an old one, which they may still have, but you have already deleted. 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 messages in the catch-all mailbox and the forwarding limitation means that the spam will not be re-sent to a 3rd-party mailbox.