A catch-all mailbox receives messages sent to invalid email addresses under the very same domain name. For instance, an email sent to the mistyped suport@domain.com will be delivered to support@domain.com if the catch-all feature has been activated for the latter. Thus, you can receive emails from buddies or clients who may have sent a message to your email address with a typographical error or to an out-of-date one, which they may still have, but you have already disabled.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. This is so because of the fact that at a certain point you may start receiving spam email messages in the catch-all mailbox and the forwarding limitation means that the spam will not be received in a 3rd-party mailbox.