A catch-all email mailbox is one that captures all the messages sent to inactive addresses. For example, if your email address is info@domain.com, but somebody miswrites it and sends an email to inof@domain.com, it will still be received in the catch-all mailbox that you have created. Just one mailbox per domain name can have this feature enabled and in this way you will never miss emails because the other party has an obsolete address or has made a spelling mistake. The negative aspect of using a catch-all mailbox is that you may begin receiving a lot of spam messages, but this issue can be resolved using anti-spam protection software. It is also important to know that a mailbox with an enabled catch-all feature cannot forward inbound messages to a third-party mailbox.