A catch-all email mailbox receives email messages sent to inactive email addresses under the exact same domain name. For example, an email sent to the mistyped suport@domain.com will be delivered to support@domain.com in case the catch-all feature has been activated for the latter. Thus, you can receive emails from friends or clients who may have sent a message to your email address with a typo or to an out-of-date one, which they may still have, but you have already deleted. Just one single mailbox per domain name 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 some point you may begin receiving spam email messages in the catch-all mailbox and the forwarding limitation means that the spam will not be re-sent to a 3rd-party mailbox.